Дисертації: "Pumping mode"

1

Stranna, Andrea. "Testing of RPT in pumping mode of operation." Thesis, Norges Teknisk-Naturvitenskaplige Universitet, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20656.

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In this project two pump mode tests has been carried out on a model RPT in the Waterpower Laboratory at NTNU. The measurement set up and execution of the tests were the same, except for the method of dissipating energy in the system. In the first test one of the feed pumps in the basement was used as energy dissipator. In the second test a throttle valve was used as energy dissipator.The objective has been to see how the Waterpower Laboratory is suited for such a test. It was also important to test the two different dissipation methods and evaluate which should be preferred when performing a pump mode test.During the tests it was observed that the guide vane angle kept changing. When the results were processed it became evident that the variations in guide vane angle during the tests had a big influence on the measured pump curves. Variations in guide vane angle has not previously been observed during turbine mode testing. It is presumed that the variation in guide vane angles is due to play in the guide vane system and the design of the guide vanes. The guide vanes are Francis vanes, and not RPT vanes. It is assumed that it is the sharp trailing edge of the guide vanes that causes turbulence over the vanes in pump mode, thus making the guide vanes move about within the play of the guide vane system. It is suggested that the guide vane system is replaced with an RPT guide vane system for further testing in pump mode.The two dissipation methods tested were both effective. The throttle valve works best for achieving 0 flow, while the feed pump is easier to regulate. None of the methods showed signs of high noise or vibrations, and both may be used for future tests.

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2

Ješe, Uroš. "Numerical study of pump-turbine instabilities : pumping mode off-design conditions." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI090/document.

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Actuellement, la flexibilité et le stockage de l'énergie sont parmi les principaux défis de l'industrie de l'énergie. Les stations de transfert d'énergie par pompage (STEP), en utilisant des turbines-pompes réversibles, comptent parmi les solutions les plus rentables pour répondre à ces besoins. Pour assurer un réglage rapide du réseau électrique, les turbines-pompes sont sujettes à de rapides changements entre modes pompage et turbinage. Elles sont souvent exposées à un fonctionnement prolongé dans des conditions hors nominal. Pour assurer la stabilité du réseau, la zone d'exploitation continue de turbines-pompes réversibles doit être libre de toute instabilité hydraulique. Deux sources principales d'instabilités en mode pompage peuvent limiter la plage de fonctionnement continu. Il s'agit de la présence de cavitation et de décollement tournant, tous deux survenant à charge partielle. La cavitation peut conduire à des vibrations, des pertes de performance et parfois même à l'érosion de la turbine-pompe. En outre, en raison de décollements tournants (apparition et décomposition périodique de zones de recirculation dans les régions du distributeur), la machine peut être exposée à un changement incontrôlable entre les points de fonctionnement, avec une modification de charge et une baisse significative des performances. Les deux phénomènes sont très complexes, tri-dimensionnels et délicats à étudier. Surtout le phénomène de décollement tournant dans les turbines-pompes est peu abordé dans la littérature. Le premier objectif de l'étude du doctorat présenté a été d'utiliser un code numérique, testé au laboratoire, et de développer une méthodologie de calcul pour permettre la prévision des phénomènes à charge partielle. L'étude a été faite sur une géométrie à échelle réduite d'une turbine-pompe de haute chute. Des calculs numériques ont été effectués en utilisant le code FINE/Turbo avec le modèle de cavitation barotrope qui a été développé au laboratoire. L'analyse des écoulements cavitants a été faite pour des débits et de niveaux de cavitation différents. Les principales analyses portent sur des valeurs naissantes de cavitation, des courbes de chute et sur le prédiction des formes de cavitation pour différents débits et valeurs de NPSH. Une attention particulière a été portée sur l'interaction entre les formes de cavitation à l'entrée de la roue et la baisse de performance (zone de feston), causée par le décollement tournant qui apparaît dans la région du distributeur. Les résultats numériques ont montré un bon accord avec les données expérimentales disponibles. La deuxième partie de la thèse a concerné la prédiction et l'analyse de décollements tournants. Des simulations ont été utilisées pour prédire les régions d'exploitation stables et instables de la machine. La méthodologie mentionnée pourrait fournir des résultats globaux précis pour différents points de fonctionnement avec un faible coût de calcul. Afin d'obtenir des informations détaillées sur les écoulements instables, des simulations instationnaires plus précises ont été réalisées. L'analyse locale des écoulements a permis la description des mécanismes gouvernant le phénomène de décollement tournant. Les analyses permettent l'étude du nombre, de l'intensité et des fréquences de rotation des cellules tournants. En outre, les calculs instationnaires donnent une très bonne prédiction de la performance de la turbine-pompe. L'approche proposée est fiable, robuste et précise. La méthodologie de calcul proposée peut être utilisée sur plusieurs géométries de turbine-pompe (ou pompe centrifuge), pour une large gamme de débits et de géométries de directrices. Les simulations proposées peuvent être utilisées à l'échelle industrielle pour étudier les effets de géométrie, d'angles d'ouverture de directrices ou de l'influence du jeu entre la roue et le distributeur afin de réduire ou même éliminer les effets négatifs des décollements tournants
Flexibility and energy storage seem to be the main challenges of the energy industry at the present time. Pumped Storage Power Plants (PSP), using reversible pump-turbines, are among the most cost-efficient solutions to answer these needs. To provide a rapid adjustment to the electrical grid, pump-turbines are subjects of quick switching between pumping and generating modes and to extended operation under off-design conditions. To maintain the stability of the grid, the continuous operating area of reversible pump-turbines must be free of hydraulic instabilities. Two main sources of pumping mode instabilities are the presence of the cavitation and the rotating stall, both occurring at the part load. Presence of cavitation can lead into vibrations, loss of performance and sometimes erosion. Moreover, due to rotating stall that can be observed as periodic occurrence and decay of recirculation zones in the distributor regions, the machine can be exposed to uncontrollable shift between the operating points with the significant discharge modification and the drop of the efficiency. Both phenomena are very complex, three-dimensional and demanding for the investigation. Especially rotating stall in the pump-turbines is poorly addressed in the literature. First objective of the presented PhD study has been to develop the cost-efficient numerical methodology in order to enable the accurate prediction and analysis of the off-design part load phenomena. The investigations have been made on the reduce-scaled high head pump-turbine design (nq = 27rpm) provided by Alstom Hydro. Steady and unsteady numerical calculations have been performed using code FINE/Turbo with barotropic cavitation model implemented and developed before in the laboratory. Some of the numerical results have been compared to the experimental data. Cavitating flow analysis has been made for various flow rates and wide range of cavitation levels. Flow investigation has been focused on the cavitation influence on the flow behavior and on the performance of the machine. Main analyses include incipient cavitation values, head drop curves and cavitation forms prediction for wide ranges of flow rates and NPSH values. Special attention has been put on the interaction between cavitation forms and the performance drop (hump zone) caused by the rotating stall. Cavitation results showed good agreement with the provided experimental data. Second part of the thesis has been focused on the prediction and analysis of the rotating stall flow patterns. Computationally fast steady simulations has been presented and used to predict stable and unstable operating regions. The analyses have been done on 4 different guide vanes openings and 2 guide vanes geometries. In order to get detailed information about the unsteady flow patterns related to the rotating stall, more exact unsteady simulations have been performed. Local flow study has been done to describe in details the governing mechanisms of the rotating stall. The analyses enable the investigations of the rotating stall frequencies, number of stalled cells and the intensity of the rotating stall. Moreover, the unsteady calculations give very good prediction of the pump-turbine performance for both, stable and unstable operating regions. Numerical results give very good qualitative and quantitative agreement with the available experimental data. The approach appears to be very reliable, robust and precise. Even though the numerical results (rotating stall frequencies, number of cells...) on the actual geometry should be confirmed experimentally, author believes that the methodology could be used on any other pump-turbine (or centrifugal pump) geometry. Moreover, the simulations can be used industrially to study the effects of the guide vanes geometries, guide vanes opening angles and influence of the gap between the impeller and the distributor in order to reduce or even eliminate the negative effects of the rotating stall

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3

Eibna, Halim Md Zubaer. "Passively mode-locked picosecond Nd:KGW laser with low quantum defect diode pumping." Astro Ltd, 2016. http://hdl.handle.net/1993/31913.

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Solid-state lasers are capable of providing versatile output characteristics with greater flexibility compared to other popular laser systems. Lasing action has been achieved in many hundreds of solid-state media, but Nd-ion doped gain media are widely used to reach high power levels with short pulses. In this work, commercially available Nd:KGW crystal served as a gain medium to achieve pulsed operation at 1067 nm. This laser crystal offers large stimulated emission crosssection and gain bandwidth which facilitates generation of high peak power pulses in the picosecond regime. The KGW crystal is monoclinic and biaxial in structure, and anisotropic in its optical and thermal properties. Due to poor thermal conductivity, this crystal can be operated within a limited power range before crystal fracture takes place. To reduce the amount of heat deposited in the gain media, we introduced a new pumping wavelength of 910 nm which reduces the quantum defect by more than 45%. Continuous-wave laser operation was optimized to operate in mode-locked regime. In order to achieve short light pulses from the continuous-wave laser, one of the end mirrors was replaced by a semiconductor saturable absorber mirror (SESAM) to generate 2.4 ps pulses at a repetition rate of 83.8 MHz. An average output power of 87 mW was obtained at lasing wavelength of 1067 nm and the beam was nearly diffraction limited with M^2 < 1.18. The peak power of the generated pulses was 427 W and energy of each pulse was >1 nJ. Pumping the crystal at longer wavelength (910 nm) reduced the thermal lensing of the crystal by half when compared to conventional pumping at shorter wavelength (808 nm). To the best of our knowledge, this is the first time passive mode-locking of a Nd:KGW laser was explored using the pump wavelength at 910 nm.
February 2017

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4

Langford, N. J. "Pumping and mode-locking techniques for near-infrared dye and colour centre lasers." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47146.

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5

Ito, Takeshi. "Mode of action study of inhibitors of energy converting NADH-quinone oxidoreductases." Kyoto University, 2018. http://hdl.handle.net/2433/232338.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第21137号
農博第2263号
新制||農||1057(附属図書館)
学位論文||H30||N5111(農学部図書室)
京都大学大学院農学研究科応用生命科学専攻
(主査)教授三芳秀人, 教授宮川恒, 教授加納健司
学位規則第4条第1項該当

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6

Yip, Ka Wa. "Optical pumping of multiple atoms in the single photon subspace of two-mode cavity QED." Miami University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=miami1438288697.

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7

Adur, Rohan. "Magnetic Coupling and Relaxation at Interfaces Measured by Ferromagnetic Resonance Spectroscopy and Force Microscopy." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406120604.

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8

MALDONADO, EDISON P. "Estudo dos mecanismos de geracao de pulsos ultracurtos em lasers de neodimio com bombeamento continuo longitudinal." reponame:Repositório Institucional do IPEN, 1995. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10465.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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9

ROSSI, WAGNER de. "Construcao e operacao de lasers de neodimio: estudo do comportamento temporal." reponame:Repositório Institucional do IPEN, 1995. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10435.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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10

Рєзва, Ксенія Сергіївна. "Удосконалення проточних частин високонапірних оборотних гідромашин на основі чисельного моделювання їх гідродинамічних характеристик". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/40009.

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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.05.17 – гідравлічні машини і гідропневмоагрегати. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2019 р. Дисертацію присвячено вирішенню науково-практичної задачі удосконалення проточних частин високонапірних оборотних гідромашин за рахунок розробки методів розрахунку та аналізу їх гідродинамічних характеристик. На підставі розгляду тенденцій розвитку гідроенергетики України, з урахуванням ролі високонапірних оборотних гідромашин в об'єднаній енергетичній системі, відмічено актуальність проектування нових проточних частин. Визначено переваги та недоліки існуючих методів дослідження гідродинамічних процесів у проточних частинах оборотних гідромашин. Наведені результати розрахунку гідродинамічних характеристик елементів проточної частини на основі методу осереднених безрозмірних параметрів для оборотних гідромашин ОРО200-В-100 та ОРО500-В-100. Застосована математична модель робочого процесу гідромашини на основі блочно-ієрархічного підходу для проведення дослідження балансу енергії. Визначено вплив геометричних параметрів елементів проточної частини на показники роботи. Проведено чисельне дослідження просторової течії рідини в проточній частині високонапірних оборотних гідромашин за допомогою CFD, що дозволило визначити та візуалізувати картину течії. Складено баланси енергії гідромашин ОРО200-В-100 та ОРО500-В-100. Відмічено, що розподіл втрат по елементам проточної частини нерівномірний: для ОРО200-В-100 найбільшу частину втрат складають втрати в робочому колесі (близько 56 %), для ОРО500-В-100 – втрати у підводі (близько 62 %). Описано основні положення визначення оптимального режиму роботи оборотної гідромашини. Запропоновано та досліджено модифікований підвід для тихохідної оборотної гідромашини ОРО500-В-100, щоб підвищити її енергетичні показники: краще узгоджені елементи ПЧ та гідравлічний ККД збільшився на 2 %.
Thesis for granting the Degree of Candidate of Technical sciences in speciality 05.05.17 – Hydraulic machines and hydropneumatic units. – National Technical University "Kharkiv Polytechnic Institute", 2019. The tеhesis is devoted to the solution of the scientific and practical problem of improvement of the water passages of the high-pressure reversible hydraulic due to calculation and analysis their hydrodynamic characteristics. Based on the review of the trends in the development of hydropower engineering in Ukraine and given the role of high-pressure reversible hydraulic machines in the United Power System, it was noted that the designing a new flow parts is topical task. Advantages and disadvantages of the existing methods for research hydrodynamic processes in water passages of reversible hydraulic machines were identified after their analysis. The results of the calculation of the hydrodynamic characteristics of the elements of the water passages based on the method of averaged dimensionless parameters using the example of reversible hydraulic machines OPO200-B-100 and OPO500-B-100 were demonstrated. The mathematical model of the hydraulic machine working process based on a block-hierarchical approach was used to study the energy balance in the turbine and pump modes of hydraulic machines. The influence of the geometrical parameters of the elements of the water passage on the performance was determined: how the angle of flow in the spiral casing (cп ), the height of the wicket gate (b0 D) and the shape of the wicket gate profile influence the value of the coefficient resistance in the wicket gate. A numerical study of the three-dimensional flow of fluid in the water passage of high-pressure reversible hydraulic machines was carried out using the CFD software. This program allows determining the character of the flow and presenting the fields of distribution of velocity components, pressure and streamlines. The balances of energy were compiled: for the OPO200-B-100 in the turbine and pump operation modes, for the OPO500-B-100 in the turbine operation mode. It is noted that the distribution of losses on the elements of the water passage is not uniform: for the OPO200-B-100, the greatest part of the total losses are losses in the runner (about 56%), for OPO500-B-100 - losses in the inlet (about 62%). The main points for determining the optimal operating mode of the reversible hydraulic machine are described. The modified inlet for low-speed high-pressure hydraulic machine OPO500-B-100 was proposed and investigated to increase energy performance of hydraulic machine. The spiral casing was expanded, the number of stay vane blades and wicket gate blades were reduced to 16. As a result of the calculations of the modified inlet, the obtained results showed that the second variant made it possible to better align the elements of the water passage and the hydraulic efficiency increased by 2 %.

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11

Рєзва, Ксенія Сергіївна. "Удосконалення проточних частин високонапірних оборотних гідромашин на основі чисельного моделювання їх гідродинамічних характеристик". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/40011.

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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.05.17 – гідравлічні машини і гідропневмоагрегати. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2019 р. Дисертацію присвячено вирішенню науково-практичної задачі удосконалення проточних частин високонапірних оборотних гідромашин за рахунок розробки методів розрахунку та аналізу їх гідродинамічних характеристик. На підставі розгляду тенденцій розвитку гідроенергетики України, з урахуванням ролі високонапірних оборотних гідромашин в об'єднаній енергетичній системі, відмічено актуальність проектування нових проточних частин. Визначено переваги та недоліки існуючих методів дослідження гідродинамічних процесів у проточних частинах оборотних гідромашин. Наведені результати розрахунку гідродинамічних характеристик елементів проточної частини на основі методу осереднених безрозмірних параметрів для оборотних гідромашин ОРО200-В-100 та ОРО500-В-100. Застосована математична модель робочого процесу гідромашини на основі блочно-ієрархічного підходу для проведення дослідження балансу енергії. Визначено вплив геометричних параметрів елементів проточної частини на показники роботи. Проведено чисельне дослідження просторової течії рідини в проточній частині високонапірних оборотних гідромашин за допомогою CFD, що дозволило визначити та візуалізувати картину течії. Складено баланси енергії гідромашин ОРО200-В-100 та ОРО500-В-100. Відмічено, що розподіл втрат по елементам проточної частини нерівномірний: для ОРО200-В-100 найбільшу частину втрат складають втрати в робочому колесі (близько 56 %), для ОРО500-В-100 – втрати у підводі (близько 62 %). Описано основні положення визначення оптимального режиму роботи оборотної гідромашини. Запропоновано та досліджено модифікований підвід для тихохідної оборотної гідромашини ОРО500-В-100, щоб підвищити її енергетичні показники: краще узгоджені елементи ПЧ та гідравлічний ККД збільшився на 2 %.
Thesis for granting the Degree of Candidate of Technical sciences in speciality 05.05.17 – Hydraulic machines and hydropneumatic units. – National Technical University "Kharkiv Polytechnic Institute", 2019. The tеhesis is devoted to the solution of the scientific and practical problem of improvement of the water passages of the high-pressure reversible hydraulic due to calculation and analysis their hydrodynamic characteristics. Based on the review of the trends in the development of hydropower engineering in Ukraine and given the role of high-pressure reversible hydraulic machines in the United Power System, it was noted that the designing a new flow parts is topical task. Advantages and disadvantages of the existing methods for research hydrodynamic processes in water passages of reversible hydraulic machines were identified after their analysis. The results of the calculation of the hydrodynamic characteristics of the elements of the water passages based on the method of averaged dimensionless parameters using the example of reversible hydraulic machines OPO200-B-100 and OPO500-B-100 were demonstrated. The mathematical model of the hydraulic machine working process based on a block-hierarchical approach was used to study the energy balance in the turbine and pump modes of hydraulic machines. The influence of the geometrical parameters of the elements of the water passage on the performance was determined: how the angle of flow in the spiral casing (cп ), the height of the wicket gate (b0 D) and the shape of the wicket gate profile influence the value of the coefficient resistance in the wicket gate. A numerical study of the three-dimensional flow of fluid in the water passage of high-pressure reversible hydraulic machines was carried out using the CFD software. This program allows determining the character of the flow and presenting the fields of distribution of velocity components, pressure and streamlines. The balances of energy were compiled: for the OPO200-B-100 in the turbine and pump operation modes, for the OPO500-B-100 in the turbine operation mode. It is noted that the distribution of losses on the elements of the water passage is not uniform: for the OPO200-B-100, the greatest part of the total losses are losses in the runner (about 56%), for OPO500-B-100 - losses in the inlet (about 62%). The main points for determining the optimal operating mode of the reversible hydraulic machine are described. The modified inlet for low-speed high-pressure hydraulic machine OPO500-B-100 was proposed and investigated to increase energy performance of hydraulic machine. The spiral casing was expanded, the number of stay vane blades and wicket gate blades were reduced to 16. As a result of the calculations of the modified inlet, the obtained results showed that the second variant made it possible to better align the elements of the water passage and the hydraulic efficiency increased by 2 %.

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12

Assam, Ukpong D. "Storage model for multibladed water pumping windmills with piston pumps." Thesis, University of Ottawa (Canada), 1986. http://hdl.handle.net/10393/4730.

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13

Hansen, Brigham Wheeler. "Smart Technologies for Oil Production with Rod Pumping." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6936.

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This work enables accelerated fluid recovery in oil and gas reservoirs by automatically controlling fluid height and bottomhole pressure in wells. Several literature studies show significant increase in recovered oil by determining a target bottomhole pressure but rarely consider how to control to that value. This work enables those benefits by maintaining bottomhole pressure or fluid height. Moving Horizon Estimation (MHE) determines uncertain well parameters using only common surface measurements. A Model Predictive Controller (MPC) adjusts the stroking speed of a sucker rod pump to maintain fluid height. Pump boundary conditions are simulated with Mathematical Programs with Complementarity Constraints (MPCCs) and a nonlinear programming solver finds a solution in near real-time. A combined rod string, well, and reservoir model simulate dynamic well conditions, and are formulated for simultaneous optimization by large-scale solvers. MPC increases cumulative oil production vs. conventional pump off control by maintaining an optimal fluid level height.

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14

Wong, Yuen-wah, and 黃婉華. "Performance prediction model for a solar water pump." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31223722.

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15

Wong, Yuen-wah. "Performance prediction model for a solar water pump /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21607424.

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16

Stanko, Milan Edvard Wolf. "Topics in Production Systems Modeling: Separation, Pumping and Model Based Optimization." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26826.

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This thesis addresses three distinct topics within oilfield production technology: 1) Inline oil-water separation for subsea applications, 2) Model based constrained optimization for production networks of high water cut wells boosted by ESPs (Downhole Electric Submersible Pumps), and 3) Hydraulic analysis of a novel configured hexagonal positive displacement pump. While each of the three topics in the thesis is investigated and discussed in a stand-alone manner, they all share a common industry objective; increasing the yield and prolonging the viable production period of hydrocarbon producing fields. More specifically, they reside within two important classes of production technology challenges; (a) boosting the deliverability and the flow of wells with high water content, and (b) separating and removing of water from hydrocarbon streams as close as possible to the source in a production gathering system. Numerical modeling is the main methodology employed in the three topics, where modeling results are substantiated by field scale or laboratory generated data. The inline oil-water separation technology addressed in this thesis is based on a controlled and distributed tapping from the lower side of a water rich stream flowing in an inclined pipe spool. The long term objective is to develop a capability for seabed separation near the subsea wells in mature offshore fields with high water production and declining reservoir pressure. The intention is to reduce the backpressure on the wells and increase or maintain their production level. The production gain is achieved by harnessing and hydraulically manipulating the energy of the inlet mixture stream to reduce the backpressure exerted by the outlet streams. Important and unique features of the concept are; the separation and phase splitting do not consume external energy, there are no major moving parts, and there is inherent performance tolerance to deviations from the design set-points. The thesis expands an earlier IPT/NTNU concept verification research project (Sponsored by the Research Council program DEMO 2000) which involved experimenting with a low pressure full scale separator test facility. This thesis progresses the relevant previous knowledge and information from a concept validation level to establishing and validating a more detailed design strategy and a more focused performance design for the separator. The thesis brings the investigated separation approach to a mature level where the fluid mechanics design aspects are largely clear and understood and are ready as an input for the mechanical design of a separator prototype. The separation was analyzed from the multiphase hydraulic design point of view using numerical experimentation as the primary tool. The research methodology comprised of conducting the following tasks: (a) developing a procedure to assess the potential production gain of installing the inline separator in a subsea production system and to identify the design requirements for obtaining a specified separator performance, (b) introducing and demonstrating concepts to quantify the drainage performance of a single and multiple taping points, (c) Validating the usefulness of 3D CFD (Computational Fluid Dynamics) methods to represent the fluid dynamics details of an oil-in-water dispersion and separation, (d) Employing the same 3D CFD model to reproduce the laboratory experimental results. The other two topics in the thesis constitute a response to emerging field scale problems where the industry have called for an immediate and sound modeling based diagnostic and modeling based investigative design. The second topic addresses an optimization strategy for large oil production systems consisting of clusters of high water cut, low GOR oil wells producing by ESP. The production streams of the wells converge through a multi branched surface gathering system into a system of main flow conduits leading to a single processing plant. The objective is to perform a model based numerical optimization to maximize oil production and reduce lift costs by modifying ESP rotor rotation frequency while complying with multiple operational constraints. While industry is currently in possession of tools to perform such tasks the outcome is inconsistent and yields poor optimization result when modeling large system with many wells, complex network and large number of constraints. An investigative task to clarify the source of the difficulties was deemed necessary. The optimization technique is described in the thesis and employed to quantifying the achievable production gains. It also identifies the computational hurdles encountered in computing the global production optimum. The thesis reports and discusses modeling and optimization using three cases: two are scaled-down synthetic cases to establish the fundamentals of the computational process, and one case on a field-scale production system is used to capture the impact of system complexity. The observed outcome and the conclusions of the investigation provide bases for a robust and consistent production optimization program of a large field. The details of this industrial scale project are beyond the scope of this thesis The third topic deals with modeling and critical analysis of a novel design of a positive displacement pump for drilling mud circulation. The concept has been commercialized and launched to the offshore market in recent years (commercially called “Hex pump”). The obvious attractiveness of the pump is its compactness and its small footprint when mounted on congested offshore platforms. However, the pumping performance of the pilot installation was very poor exhibiting excessive pulsation, vibration, mechanical failures and noise. These have driven expensive and critical drilling operations offshore to a halt. It has been recognized at this stage that the unique and innovative design features of the pump together with the criticality of it good and safe performance warned a thorough model based concept analysis and verification. The thesis describes the hydraulic performance modeling and its use to identify the concept inherent pulsation generating source. The conducted modeling and its interpretation are of novel nature and the results revealed a fundamental conceptual flaw. The research outcome had a prompt and an immediate impact on the industry decision of deploying this novel pump type.

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17

Solomon, Brad K. "Methods for Identifying Acoustic Emissions From the Front Face of a Small Piezoelectric Blower." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3542.

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This thesis focuses on identifying acoustic noise generating components in piezoelectric blowers through transverse velocity measurements and the development of a numerical fluid model. Piezoelectric ceramics have proven useful for many industries and areas of research involving: high precision actuators, noise control, ultrasonic devices, and many other areas. As of late, a unique adaptation of piezoelectric ceramics is surfacing in the area of pumping and cooling. Air pumps that use these ceramics replace the traditional electric motor, resulting in lower power consumption, less moving parts, constant pressure gradients, lower overall weight, and a low profile. The current drawback of this application is the acoustic radiation produced by the blowers. Since these blowers are new to market, little research or development has been done to characterize the noise emissions. This thesis studies the acoustic emissions from the front face of a Murata piezoelectric blower. Jet noise and structural vibrations are two acoustic sources of interest that are studied in this research. A Direct Numerical Simulation (DNS) of the fluid flow through a Murata blower is developed to better identify noise generating mechanisms. The model solutions predict trends in sound pressure levels (SPL) of the jet noise and volumetric flow rates. Both the SPL and flow rate are shown to be functions of critical geometrical dimensions within the flow path of a Murata blower. Important dimensional components are identified as well as non-influential ones. Design guidelines are given to reduce noise emission from the front side of a blower and increase the volumetric flow rate. The results of this research have a direct impact on the piezoelectric blower industry and future blower designs.

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18

Merlini, Maurizio. "Implementation and validation of a design model for photovoltaic water pumping system (PVPS)." Thesis, KTH, Skolan för kemivetenskap (CHE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145860.

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Desertification is one of the main problems plaguing the Chinese countryside. The main cause is the heavy overgrazing of pastures and in this context the irrigation can be a solution to the problem. As regard the existent irrigations systems, pumps are driven manually or by diesel engines. Actually the use of electric motors would be a better solution for the irrigation development, but the lack of the access to electric network for the isolated rural areas represents a great obstacle. Therefore the use of PV stand-alone systems to produce the electricity for the motor-pumps (PVPS- Photovoltaic Pumping Systems) represents a both economic and technical good solution. However the weak point for PVPS diffusion is lack of tools to design these systems and predict their performances. This thesis work wants to provide a sizing software and the technical guidelines to select the suitable components for a PVPS. The developed sizing method has been validated applying it to two real cases where PVPS were already existing. Then, the obtained results have been compared with the characteristics of the real PVPS. The reliability of the design procedure has been verified, observing the similarity between the calculated outputs and the respective real values. Finally simulations have been done using the designed PVPS. The scope of those simulations has been to add some technical recommendations useful for the PVPS designer. The influence of the total head variations on the pumping performance and also the effect of the motor-pump subsystem choice on the final power size of PV array have been investigated.

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19

Shen, Dawei. "Deterministic Modeling of a Rotary Lip Seal with Microasperities on the Shaft Surface." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/8728.

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The rotary lip seal is the most widely used dynamic seal. It is used extensively in the automotive and appliance industries. Experimentally, it is well known that the microasperities on the shaft surface can significantly affect the performance of a lip seal, even though the shaft roughness, after run-in, is much smaller than the lip roughness. In the present study, several deterministic numerical models are developed to investigate the effect of shaft surface finish on rotary lip seal behavior, through an understanding of the basic physics of lip seal operation. This project is performed in a step by step manner with gradually increasing complexity. Four models are included in this study: hydrodynamic analysis, elastohydrodynamic analysis for full film lubrication, mixed-EHL model for mixed lubrication with asperity contact, and transient dynamic mixed-EHL model for startup and shutdown processes. Those analyses allow the examination of some important seal characteristics, such as the load support sharing between hydrodynamic and contact pressure, contact and cavitation area ratio, reverse pumping rate, liftoff speed for tracing the liftoff process and average film thickness. The development of fluid, contact and cavitation areas as a result of the changing operation condition is also examined. The results of the present deterministic modeling indicate that shaft surface roughness can produce significant desirable effects on lip seal behavior. An appropriate shaft surface profile could improve the sealing ability and prevent seal failure.

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20

Akin, Ryan E. "Minimally invasive assessment of lymphatic pumping pressure using near infrared imaging." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47536.

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Although the major functions of the lymphatic system are fairly well defined, its vasculature has yet to be well characterized in comparison to its blood vasculature counterpart. Recent advances in optical imaging techniques have allowed for more detailed and quantitative evaluations of lymph flow dynamics and mechanism. A rat tail is often used for investigations of lymph flow because of the simple geometry, superficial nature, and disease progression models of its collecting lymphatic vessels. In this study, a pressure cuff system was fabricated and coupled with an existing functional near infrared (NIR) imaging system to measure the overall pumping pressure of the lymphatic vessels of a rat tail. In addition to adapting the system for use on rodents, previous systems used for measuring lymphatic pumping pressure in humans were improved upon in several ways. The system defined here utilizes closed-loop feedback control of pressure application at smaller, more precise intervals. Using this device, a significant difference in lymphatic vessel pumping pressure was detected between a control case and a treatment case in which a vasoactive substance with a nitric oxide donor (GTNO ointment) was applied to the tail. Although it is known that nitric oxide plays a crucial physiologic role in propagation of flow through lymphatic vessels, this study has quantified its significant pharmacological reduction of pumping pressure for the first time.

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21

Kleynhans, S. H. "Physcial hydraulic model investigation of critical submergence for raised pump intakes." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20304.

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Thesis (MScEng)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: Various design guidelines have been published over the past four decades to calculate the minimum submergence required at pump intakes to prevent vortex formation. These design guidelines also require the suction bell to be located not higher than 0.5 times the suction bell diameter (D) above the floor. Sand trap canals are an integral part of large river abstraction works, with the pump intakes located at the end of the sand trap canals. The canals need to be flushed by opening a gate, typically 1.5 m high, that is located downstream of the pump intake. This requires the suction bell be raised to not interfere with the flushing operation, which leads to the question – what impact does the raising of the suction bell have on the minimum required submergence? A physical hydraulic model constructed at 1:10 scale was used to determine the submergence required to prevent types 2, 5 and 6 vortices for prototype suction bell inlet velocities ranging from 0.9 m/s to 2.4 m/s, and for suction bells located at 0.5D, 1.0D and 1.5D above the floor. The tests were undertaken for four suction bell configurations with a conventional flat bottom suction bell, fitted with a long radius bend, being the preferred suction bell configuration in terms of the lowest required submergence levels. The experimental test results of the preferred suction bell configuration were compared against the published design guidelines to determine which published formula best represents the experimental test results for raised pump intakes. It became evident from the experimental test results that the required submergence increased markedly when the suction bell was raised higher than a certain level above the floor. It was concluded that this “discontinuity” in the required submergence occurred for all the suction bell configuration types when the ratio between the prototype bell inlet velocity and the approach canal velocity was approximately 6.0 or higher. It is recommended that, for pump intakes with a similar geometry to that tested with the physical hydraulic model, critical submergence is calculated using the equation published by Knauss (1987), i.e. S = D(0.5 + 2.0Fr), if the prototype bell inlet velocity/approach canal velocity ratio is less than 6.0, and that the equation published by the Hydraulic Institute (1998), i.e. S = D(1 + 2.3Fr), can be used where the ratio, as determined with Knauss’ (1987) equation, exceeds 6.0. It is also recommended that prototype bell inlet velocities be limited to 1.5 m/s.
AFRIKAANSE OPSOMMING: Oor die afgelope vier dekades is verskeie ontwerpriglyne vir die berekening van minimum watervlakke, om werwelvorming by pompinlate te voorkom, gepubliseer. Hierdie ontwerpriglyne vereis dat die klokmond van die pompinlaat nie hoër as 0.5 keer die deursnee van die klokmond (D) bokant die kanaalvloer geleë moet wees nie. Sandvang kanale vorm ‘n integrale deel van groot riveronttrekkingswerke, met pompinlate wat aan die einde van hierdie kanale geleë is. Die kanale word aan die stroomaf kant van die pompinlaat voorsien met sluise sodat die kanale gespoel kan word. Hierdie sluise is tipies 1.5 m hoog. Dit is derhalwe nodig om die hoogte onder die klokmond dieselfde te maak as die hoogte van die sluis sodat die klokmond die spoelwerking nie beïnvloed nie. Die vraag is egter – wat is die impak op die minimum vereiste watervlakke indien die klokmond op ‘n hoër vlak installeer word? ‘n Fisiese hidrouliese model met ‘n 1:10 skaal is gebruik om die minimum watervlakke te bepaal waar tipes 2, 5 en 6 werwels aangetref word vir prototipe inlaatsnelhede van 0.9 m/s tot 2.4 m/s en klokmond hoogtes van 0.5D, 1.0D en 1.5D bokant die kanaalvloer. Vier klokmond konfigurasies is getoets. Die minimum vereiste watervlakke was die laagste vir die tradisionele plat klokmond met ‘n lang radius buigstuk en was dus die voorkeur klokmond. Die eksperimenttoetsresultate vir die voorkeur klokmond is met die gepubliseerde ontwerpriglyne vergelyk om te bepaal watter van die ontwerpsriglyne van toepassing sal wees vir verhoogde klokmond installasies. Uit die eksperimenttoetsresultate is dit duidelik dat die vereiste watervlakke skielik verhoog sodra die klokmond installasie ‘n seker hoogte bokant die kanaal vloer oorskry. Daar is bevind dat hierdie verskynsel by al vier klokmond konfigurasies voorkom sodra die verhouding tussen die prototipe klokmond inlaatsnelheid teenoor die snelheid in die kanaal hoër as 6.0 is. Daar word aanbeveel dat die minimum vereiste watervlak vir pompinlate met dieselfde geometrie as die fisiese model, met Knauss (1987) se vergelyking bereken word, naamlik S = D(0.5 + 2.0Fr), waar die snelheidsverhouding tussen die klokmond en kanaal 6.0 nie oorskry nie, en dat die vergelyking gepubliseer deur die Hydraulic Institute (1998), S = D(1 + 2.3Fr), gebruik word waar die snelheidsverhouding 6.0, so bereken met Knauss (1987) ser vergelyking, wel oorskry. Die prototipe klokmond inlaatsnelheid moet ook beperk word tot 1.5 m/s.

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22

Huston, Davis. "CLOGGING OF FINE SEDIMENT WITHIN GRAVEL SUBSTRATES: MACRO-ANALYSIS AND MOMENTUM-IMPULSE MODEL." UKnowledge, 2014. http://uknowledge.uky.edu/ce_etds/24.

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An understanding of the clogging of fine sediments within gravel substrates is advanced through the use of dimensional analysis and macro-analysis of clogging experiments in hydraulic flumes. Dimensional analysis is used to suggest that the dimensionless clogging depth can be collapsed using the original and adjusted bed-to-grain ratios, substrate porosity, roughness Reynolds number, and Peclet number. Macro-analysis followed by statistical analysis of 146 experimental test results of fine sediment deposition in gravel substrates suggests that the dimensionless clogging depth can be collapsed using the substrate porosity and roughness Reynolds number reflecting the processes of gravity settling and turbulence induced fluid pumping between substrate particles. In addition, a clear cutoff of fine sediment unimpeded static percolation and sediment clogging is found using the adjusted bed-to-grain ratio. Thereafter, a physics-based approach is used to predict the clogging depth of fine sediment in gravel and in turn approve upon the preliminary findings in the empirical analysis. A momentum-impulse model that accounts for the critical impulse of a particle bridge is balanced with a fluid pulse resulting from turbulent pumping. The momentum-impulse model reduces the number of unknown parameters in the clogging problem and increases the model predictability as quantified using k-fold validation and model comparison with the empirical approach. A nomograph derived from applying the momentum-impulse model is provided herein, which will be useful for stream restoration practitioners interested in estimating embeddedness. Also, prediction of the clogging profile is shown using the clogging depth predicted with the momentum-impulse model.

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23

Giron, Efrain. "Development of a SWMM-GIS Flood Model for New Orleans Drainage Pumping Station No 4 Basin." ScholarWorks@UNO, 2005. http://scholarworks.uno.edu/td/261.

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An urban flood damage model for the drainage area serve by Pump Station No. 4 (Prentiss, New Orleans, Louisiana) has been completed. This study presents the research effort needed to develop a stormwater management model (SWMM) integrated with GIS that includes a Damage Model to estimate the losses produced by storm events on flood prone areas. The latest LIDAR data are used for the topography. The drainage area for this study covers approximately 3218 acres, with elevations ranging from -9 ft to 6 ft above sea level. The runoff produced is pumped into Lake Pontchartrain via London Outfall Canal. The study area includes a pump station with a capacity of 106 m3/s and a complex drainage system including a 10 ft siphon that drains the runoff on the western side. The hydrology and hydraulic routing for the watershed was estimated using the U.S. EPA Storm Water Management Model (SWMM) and the input of the model was created using a geodatabase composed of nodes, conduits and subcatchment areas developed in ArcGIS 8.2. The GIS was designed to take advantage of the importing node and graphic capabilities of the SWMM. Since all features used by SWMM were georeferenced, node flood elevation data were transferred back for display in geographic space. This approach allows for a more accurate volume computation of flooded areas by using Boolean operations on a Triangular Irregular Network (TIN) surface of node elevations and a TIN surface of LIDAR elevation data. Flood volumes were obtained for the study area by simulating a series of rain events. These flood volumes were then incorporated into a Damage model to estimate damage rating curves for the study area. The 1:100 year damage was estimated to be 17.2 million of dollars (2005 US dollars). The average annual flood damage was estimated to be 5.5 million of dollars (2005 US dollars). The developed Annual Flood Maps can be used to set rational flood insurance rates or to plan improvements to the drainage system. This information can be used by FEMA and by the private insurance industry of the State

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24

Do, Nguyen Ba. "Modeling of Frictional Contact Conditions in Structures." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7123.

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This thesis explores two aspects of modeling the behavior of joint friction in structures. The first aspect deals with the accurate and efficient simulation of a simple system that incorporates the LuGre friction law. Energy transfer and dissipation in a structural joint model is the second topic of this thesis. It is hypothesized that friction could serve to pump energy from one frequency to higher frequencies where it might be dissipated more quickly. Motivation for this study stems from the need to have accurate models of high-precision space structures. Because friction at connecting joints plays a major role in the damping capacity of the structure, a good understanding of this mechanism is necessary to predict the vibratory response and enhance the energy dissipation of the structure. Simulation results of a dynamic system with LuGre friction show that the system is relatively well-conditioned when the slip velocity is small, and ill-conditioned for large slip velocities. Furthermore, the most efficient numerical method to simulate this system is determined to be an implicit integration scheme. To study the energy transfer and dissipation, two models of a jointed structure with friction are considered. Results from the steady-state forced responses of the two structural systems indicate that friction converted low frequency, single harmonic excitation to multi-harmonic response through internal resonances. However, differences in energy dissipation results between the models show that the response of a frictional system is highly sensitive to system parameters and friction laws. Conclusions and suggestions for future research are also discussed.

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25

Retana, Angel Gabriel. "Salinity Transport in a Finite-Volume Sigma-Layer Three-Dimensional Model." ScholarWorks@UNO, 2008. http://scholarworks.uno.edu/td/880.

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The objective of this study was to develop a 3-D model for The Pontchartrain Estuary that was capable of long-term mass conservative simulation of salinities. This was accomplished in a multi-stage approach involving: a physical model of salinity exchange through a pass; a 3-D FVCOM model of the physical experiment; the development and testing of an FVCOM model for an idealized Pontchartrain Basin; and for the entire estuary. The data from the physical model tests were used to validate the performance of the FVCOM model with density-driven flows. These results showed that hydrostatic FVCOM captured the primary internal wave movement. The idealized basin simulations were used to evaluate several issues related to salinity transport, namely the relative importance of baroclinic forcing, tidal forcing and hydrology. The idealized domain also permitted the testing of sigma-gradients, spatial distribution of friction coefficients, wind stress and various boundary treatments. The results showed that the density-driven exchange of saltwater at the open boundary required a baroclinic boundary condition for salinity as well as a lateral filter at the boundary on each sigma layer. A new radiative baroclinic open boundary condition was developed for FVCOM. When tides and hydrology were included, the FVCOM model was shown to reproduce the seasonal salinity that has been observed for long-term periods. It was also found that the simulation of tides and salinity in FVCOM is very sensitive to the spatial distribution of the friction coefficient; relatively low friction was required in the open water regions and high friction was needed in the passes and waterways to reproduce the tides and salinity distribution. A variable friction coefficient option was coded on FVCOM. The findings from the idealized model were utilized to setup two models for the actual estuary. Both models extend from Lake Maurepas, one to the Chandeleurs Islands and the other to Mobile Bay. The baroclinic open boundary and variable friction were implemented in these models. They were calibrated for tides and salinity. The 2008 Bonnet Carré Spillway Opening was applied to the first model. A tidal pumping effect in Lake Pontchartrain was observed and captured by the model.

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26

Knight, Jacob. "Use of an Integrated Hydrologic Model to Assess the Effects of Pumping on Streamflow in the Lower Rio Grande." Thesis, The University of Arizona, 2015. http://hdl.handle.net/10150/556878.

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Irrigation practices in the Rincon Valley and Mesilla Basin of the Lower Rio Grande have evolved over the last century into a complex setting of transboundary conjunctive use. Three major water users have surface and groundwater appropriation rights regulated by compact, treaty, and operating rules and agreements. The analysis of complex relationships between supply/demand components and the effects of surface-water and groundwater use requires an integrated hydrologic model to track all of the use and movement of water. Models previously developed for the region relied on a priori estimates of net irrigation flux or externally-calculated landscape water budgets. This study instead utilizes a MODFLOW model with the Farm Process (MF-FMP), which directly couples the surface-water and groundwater regimes through simulation of landscape processes. This allows the assessment of stream-aquifer interactions in the context of fulfilling irrigation demands with variable supplies of surface water allotments and supplemental groundwater pumping. MF-FMP also simulates direct uptake of groundwater by crops, an important utility for modeling a region with significant acreage dedicated to pecan orchards, a phreatophytic crop. The abilities and limitations of this new model are explored through scenario simulations meant to estimate streamflow depletions caused by historic pumping levels.

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27

Roberge, Jennifer Anne. "Use of Computational Fluid Dynamics (CFD) to Model Flow at Pump Intakes." Digital WPI, 1999. https://digitalcommons.wpi.edu/etd-theses/1046.

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"This thesis presents a series of physical experiments and numerical simulations intended to determine whether the use of commercially available computational fluid dynamics (CFD) software may provide a viable alternative to the use of physical models for predicting the occurrence of vortices and swirl in pump intakes. The physical experiments were set up at Alden Research Laboratories, Inc. (ARL) of Holden, Massachusetts, using a simple pump intake model donated by ARL for use in this study. Swirl and velocity measurements and dye injections were used to characterize the flow in the physical model. Three flow conditions were chosen for the physical experiments because they demonstrated swirl and vortices developing at the pump intake. Once the physical experiments were performed, FIDAP, a general-purpose finite-element CFD package, was used to simulate the circulation patterns in the vicinity of a pump intake. The model configuration and scale were selected to simulate experimental conditions in the physical pump intake model. Some similarities were also identified in the locations of the models predicted vortex characteristics and the vortex characteristics that were observed in the experimental facility. However, the characteristics of swirl within the pump intake differed from experimental observations. Therefore, additional simulations were conducted to analyze the sensitivity of simulations to model assumptions. These additional simulations showed that the assumptions related to these model parameters have minor affects on the general nature of the predicted vortices, but do affect the predicted vortex strength. This thesis represents a first step in addressing the discrepancies between numerical and experimental results. Additional investigations are recommended to clarify the applicability of CFD to address pump intake problems."

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28

Hoppe, Mark Mathew. "Validation of computational fluid dynamics model of a simple pump sump with vertical intake." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86337.

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Thesis (MScEng)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: The designs of pump intake structures are generally verified by means of a hydraulic model study to ensure the structure will operate without large air or swirl entraining vortices. This is an expensive and time consuming process. The popularity of Computational Fluid Dynamics (CFD) is ever increasing in the engineering world and the use thereof in the modelling of flows in pump intake structures is just one of the many areas of focus. The use of a validated CFD model in the design phase of pump intakes would be beneficial, and ideally would reduce the frequency of requiring hydraulic model studies. This study investigates the applicability of using a 3 dimensional CFD model as a design tool by validation with a physical model. A physical model of a simple pump intake was available and with a few modifications the flow conditions were significantly improved. The quantitative validation of the CFD model was carried out by means of comparing corresponding point velocity magnitudes. An Acoustic Doppler Velocimeter (ADV) was used in the physical model. The data obtained were successfully filtered to remove noise and other disturbances. The qualitative validation was done by means of photographs and observations. The photographs made use of illuminated tracer particles to identify flow patterns. The CFD model compares well qualitatively, but the velocity magnitudes are not yet sufficiently reliable. It is recommended that the CFD model can be used for qualitative studies, but future research should focus on the accuracy of the CFD model. Using higher resolution velocity measurements in the physical model by means of other types of instruments, a better comparison can be made, as well as enabling validation of the ADV readings.
AFRIKAANSE OPSOMMING: Die ontwerpe van die pomp inname strukture word gewoonlik bevestig deur middel van 'n hidrouliese model studie om lug-intrekking te minimeer. Dit is 'n duur en tydrowende proses . Die gebruik van Computational Fluid Dynamics ( CFD ), ‘n tipe numeriese modelle neem toe in die ingenieurswese wêreld. Die gebruik daarvan in die modellering van vloei in pomp inname strukture is net een van die vele areas van toepassing . Die gebruik van 'n betroubare CFD model in die ontwerp fase van pomp innames sal voordelig wees , en ideaal sou die noodaaklikheid van fisiese hidrouliese model studies verminder. Hierdie studie ondersoek die toepaslikheid van die gebruik van 'n 3 -dimensionele model CFD model as 'n ontwerp instrument deur bevestiging met 'n fisiese model . 'n Eenvoudige pomp-inname model was beskikbaar en het met ‘n paar veranderinge die vloei toestande aansienlik verbeter . Die kwantitatiewe bevestiging van die CFD model is uitgevoer deur middel van vergelyking van korresponderende punt snelheid groottes. In die fisiese model is die snelhede met 'n Akoestiese Doppler Velocimeter (ADV) gemeet. Die data wat verkry is suksesvol gefiltreer om geraas en ander versteurings te verwyder . Die kwalitatiewe bevestiging is gedoen deur middel van foto's en waarnemings. In die foto's is gebruik gemaak van verligte spoor deeltjies om vloei patrone te identifiseer. Die CFD model vergelyk kwalitatief goed, maar die snelheid groottes is nog nie voldoende betroubaar nie. Dit word aanbeveel dat die CFD model gebruik kan word vir kwalitatiewe studies, maar toekomstige navorsing behoort te fokus op die verbeteringe van dieakkuraatheid van die CFD model. Met behulp van 'n hoër resolusie snelheid metings van die fisiese model, deur middel van ander tipe instrumente, kan 'n beter vergelyking gemaak word , sowel as die geldigheid van die ADV lesings in staat te stel.

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29

Харун, В. Р. "Обгрунтування раціональних параметрів виконавчих механізмів верстатів-качалок". Thesis, Івано-Франківський національний технічний університет нафти і газу, 2004. http://elar.nung.edu.ua/handle/123456789/4052.

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Анотація:

Дисертаційна робота присвячена раціональному вибору геометричних, кінематичних, масових та силових характеристик виконавчого механізму двоплечих верстатів-качалок. В роботі вирішуються задачі покращення роботи приводу свердловинної штангової глибинонасосної установки в умовах експлуатації свердловини при нестаціонарності навантаження, викликаного можливою зміною параметрів газорідинної суміші, що видобувається з свердловини. Розроблено математичну модель СШНУ, яка дозволяє проводити синтез геометричних параметрів виконавчого механізму, розраховувати його кінематичні параметри та проводити оцінку зміни навантаженості вузлів верстата-качалки. моделюючи наявність газу в циліндрі глибинного насосу та витікання в його прийомній та нагнітальній частинах. Вдосконалено методику розрахунку необхідної ваги противаг для кривошипного, балансирного та комбінованого типів зрівноважування. Розроблено та виготовлено експериментальну установку та інформаційно-вимірювальну систему, оснащену необхідними давачами та аналого-цифровим пристроєм, яка дозволяє проводити моделювання навантаження виконавчого механізму та записувати результати експериментів безпосередньо на ПЕОМ.
Диссертационная работа посвящена улучшению геометрических, кинематических, массовых и силовых характеристик исполнительного механизма двуплечих станков-качалок. Для этого в работе проведен анализ геометрических размеров и массы звеньев существующих типов двуплечих станков-качалок как аксиальной, так и дезаксиальных схем, определены преимущества схемы с положительным утлом дезаксиала и разработана методика выбора рациональных длин звеньев ее исполнительного механизма. При проведении эксперимента измеряются: действительная утповая скорость кривошипа; нагрузка, действующая на шатуне и в точке подвески нагружающего приспособления; движущий момент электродвигателя. Разработана методика обработки результатов измерений, которая определяет выбор необходимых функций интерполяции, регрессии и сглаживания данных.
The improvement of geometric, kinematic, mass and force characteristics of the actuating mechanism of double-arm pumping units has been observed in the thesis. In this connection geometric sizes and links mass of modern types of double-arm pumping units of both axial and disaxial patterns have been analyzed, the advantages of the patterns with the positive angle dexial has been defined, the method of the synthesis of its actuating mechanism has been worked out. The mathematical model of the pumping unit which allows to calculate both speeds, acceleration of all the links of a pumping units and reaction in kinematic pairs, resistance force moment, links mass moment, moments and inertia forces driven to the crank, has been worked out. The equalizations for the calculation of rod hanger center load, crank torque moment and the reactions in its kinematic pairs with due regard for the active motion law of the horsehead, for the change of rod hanger center load per operating cycle, for the mass change of a rod string and fluid, its density and level in a well, for the wellhead and well pressure, plunger diameter and discharge valve have been made. In the thesis the problems of improvement of the work of the borehole rod deep-well pumping units crank at the constant load exploitation which is resulted by the possible parameters' change of gas-fluid mixture which is extracted from a well, have been solved. The experimental unit with primary sensors and analog-digital equipment which allows to carry out the modeling of the actuating mechanism load of a pumping unit and record the results of the experiments directly on a computer, is worked out and made, viz line speed of the plunger stem, angular speed of a crank, rod hanger center load, connecting rod force and motor driving moment.

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30

Balzani, Laura. "Preliminary stages and studies for the development of a 3D aquifer physical model." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19033/.

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Groundwater issues are among the most important sustainability studies related to topics considered as critical point for the future of planet Earth(Gleeson et al., 2010) in the perspective of a sustainable world. Analyses are focused on two complementary aspects: quantity and quality.Thus, once physical behaviour is analysed, it is coupled with chemical characterisation studies, in order to obtain a better view of an investigated site.The work begins with a brief overview of the literature which summarizes the challenges of teaching hydrogeology by theoretical lessons coupled with practical activities. The focus is on laboratory experiments implemented on physical models. In fact, to fully understand the process of groundwater flow and solute transport, and to demonstrate the basics fundamental concepts behind, it is important to visualize them in a lab-scale. This thesis is undertaken in the context of the installation of a 3D physical model at the University of Liège as a support to teaching and research works: dimension, set up, construction and support devices used for system optimal functioning are presented. The global aim of the work is to prepare everything needed to set up the sand tank. This is a fundamental step in order to be able to pre-dimension real experiments, to give ideas about the magnitude order of the expected results and to check the reliability of mathematical results and/or low-dimensionality models. Part of the document is centred on the characterization of porous aquifer materials to implement in the physical model, in particular through sand column one-dimensional lab experiments performed on four distinguished types of quartz sands (differentiated by the particles size) in particular a Constant Head Permeability Test and a Salt Tracer Test(KCl).A numerical model of the 3D tank is also developed by the use of GMS-MODFLOW-MT3DS and few experiments are simulated(gradient variation, pumping test at different pumping rates and tracer test).

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31

Duong, Trong Vinh, and Trong Vinh Duong. "On the hydro-mechanical behavior of ancient railway flatforms in term of reinforcement by soil-mixing." Phd thesis, Université Paris-Est, 2013. http://pastel.archives-ouvertes.fr/pastel-00945680.

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Анотація:

The present work deals with the behavior of ancient railway sub-structure in France. A statistical study was firstly undertaken on problems occurred in the whole ancient French railway network. The analysis evidenced the particular importance of sub-grade quality for the performance of the sub-structure and the track geometry. Afterwards, an ancient railway line in the West of France was investigated. The analysis showed that the degradation speed of this line was correlated with different parameters such as the nature of sub-grades and the thickness of different layers. An increase trend of degradation speed with the increase in interlayer thickness was identified. The interlayer has a positive impact since it reduces the train-induced stress applied to the sub-grade. The hydro-mechanical behavior of interlayer soil under different conditions (water content, fines content, stress, number of cycles) was investigated. A set of triaxial tests and infiltration tests were performed for this purpose. By analyzing the shear strength properties, the permanent axial strain and the resilient modulus of interlayer soil, we found that the water content and the fines content must be considered together. Adding more fines into the interlayer presents a positive impact under unsaturated conditions thanks to the suction effect, but a negative impact under saturated conditions. The infiltration column tests with drying/wetting cycles showed that the hydraulic conductivity of interlayer soil is governed by fines fraction but did not change significantly with fines content. In order to study the mechanism of interlayer creation and mud pumping, a physical model of 550 mm inner diameter was developed. Soil samples representing the ancient French railway substructure with a ballast layer overlying an artificial silt layer (mixture of crushed sand and kaolin were tested. The effects of monotonic and cyclic loadings, water content and dry unit mass of sub-soil were investigated. It was found that the pore water pressure developed in the sub-soil and the sub-soil stiffness are the key factors for the migration of fine particles or the creation of interlayer/mud pumping. Water is the necessary condition, but it is the soil compressibility that governs the phenomenon to occur

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32

Emadi, Bagher. "Experimental studies and modelling of innovative peeling processes for tough-skinned vegetables." Queensland University of Technology, 2006. http://eprints.qut.edu.au/16212/.

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Анотація:

Tough-skinned vegetables such as pumpkin and melon currently are peeled either semi-automatically or automatically. The main limitation of both methods, especially for varieties with an uneven surface, is high peeling losses. Improvement of current mechanical peeling methods and development of new mechanical methods for tough-skinned vegetables which are close to the "ideal" peeling conditions using mechanical properties of the product were the main objectives of this research. This research has developed four innovative mechanical peeling methods on the basis of the mechanical properties of tough-skinned vegetables. For the first time, an abrasive-cutter brush has been introduced as the best peeling method of tough-skinned vegetables. This device simultaneously applies abrasive and cutting forces to remove the peel. The same peeling efficiency at concave and convex areas in addition to high productivity are the main advantages of the developed method. The developed peeling method is environmentally friendly, as it minimises water consumption and peeling wastes. The peeling process using this method has been simulated in a mathematical model and the significant influencing parameters have been determined. The parameters are related to either the product or peeler. Those parameters appeared as the coefficients of a linear regression model. The coefficients have been determined for Jap and Jarrahdale as two varieties of pumpkin. The mathematical model has been verified by experimental results. The successful implementation of this research has provided essential information for the design and manufacture of a commercial peeler for tough-skinned vegetables. It is anticipated that the abrasive-cutting method and the mathematical model will be put into practical use in the food processing industry, enabling peeling of tough-skinned vegetables to be optimised and potentially saving the food industry millions of dollars in tough-skinned vegetable peeling processes.

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33

Duong, Trong Vinh. "On the hydro-mechanical behavior of ancient railway flatforms in term of reinforcement by soil-mixing." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1106/document.

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Анотація:

Le présent travail porte sur le comportement des plates-formes ferroviaires anciennes en France. Tout d'abord, une étude statistique a été menée sur les problèmes survenus dans l'ensemble du réseau ferroviaire français. L'analyse montre l'importance particulière de la qualité du sol support pour la performance de la sous-structure et pour la tenue géométrique des voies. Ensuite, une ligne ferroviaire ancienne située à l'Ouest de la France a été étudiée spécifiquement. Les analyses montrent que la vitesse de dégradation de cette ligne est en corrélation avec les différents paramètres tels que la nature de sol support, l'épaisseur des couches de la sous-structure. Une tendance d'augmentation de la vitesse de dégradation avec la diminution de l'épaisseur de la couche intermédiaire est identifiée. Cette couche as un impact positif puisqu'elle réduit les contraintes appliquées au sol support. Le comportement hydromécanique du sol de la couche intermédiaire dans des conditions différentes (teneur en eau, teneur en particules fines, charge, nombre de cycles) a été étudié. Des essais triaxiaux et des essais de colonne d'infiltration ont été réalisés à cette fin. En analysant les propriétés de résistance au cisaillement, la déformation axiale permanente et le module réversible, on a constaté que les effets de la teneur en eau et de la teneur en fines doivent être pris en compte ensemble. Une augmentation de teneur en fines dans la couche intermédiaire présente un impact positif à l'état non saturé grâce à l'effet de la succion, mais un impact négatif à l'état saturé. Les essais de colonne d'infiltration avec des cycles de séchage/humidification ont montré que la conductivité hydraulique du sol est gouvernée par la fraction de fines et qu'elle ne change pas significativement avec la teneur en fines. Afin d'étudier les mécanismes de la création de la couche intermédiaire et de remontée boueuse, un modèle physique de 550 mm de diamètre intérieur a été développé. Des échantillons de sol qui représentent la sous-structure ferroviaire ancienne avec une couche de ballast posée sur une couche de limon artificielle (mélange de sable concassé et du kaolin) ont été testés. Les effets des charges monotones et cycliques, de la teneur en eau et de la masse volumique sèche du sol support ont été étudiés. Il a été constaté que la pression interstitielle développée dans le sol support et la rigidité du sol support sont des facteurs clés pour la migration des particules fines ou la création de la couche intermédiaire/la remontée boueuse. L'eau est la condition nécessaire, mais c'est la compressibilité du sol support qui gouverne le phénomène à se produire
The present work deals with the behavior of ancient railway sub-structure in France. A statistical study was firstly undertaken on problems occurred in the whole ancient French railway network. The analysis evidenced the particular importance of sub-grade quality for the performance of the sub-structure and the track geometry. Afterwards, an ancient railway line in the West of France was investigated. The analysis showed that the degradation speed of this line was correlated with different parameters such as the nature of sub-grades and the thickness of different layers. An increase trend of degradation speed with the increase in interlayer thickness was identified. The interlayer has a positive impact since it reduces the train-induced stress applied to the sub-grade. The hydro-mechanical behavior of interlayer soil under different conditions (water content, fines content, stress, number of cycles) was investigated. A set of triaxial tests and infiltration tests were performed for this purpose. By analyzing the shear strength properties, the permanent axial strain and the resilient modulus of interlayer soil, we found that the water content and the fines content must be considered together. Adding more fines into the interlayer presents a positive impact under unsaturated conditions thanks to the suction effect, but a negative impact under saturated conditions. The infiltration column tests with drying/wetting cycles showed that the hydraulic conductivity of interlayer soil is governed by fines fraction but did not change significantly with fines content. In order to study the mechanism of interlayer creation and mud pumping, a physical model of 550 mm inner diameter was developed. Soil samples representing the ancient French railway substructure with a ballast layer overlying an artificial silt layer (mixture of crushed sand and kaolin were tested. The effects of monotonic and cyclic loadings, water content and dry unit mass of sub-soil were investigated. It was found that the pore water pressure developed in the sub-soil and the sub-soil stiffness are the key factors for the migration of fine particles or the creation of interlayer/mud pumping. Water is the necessary condition, but it is the soil compressibility that governs the phenomenon to occur

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34

Balaji, A. "Analysis Of Solar Pumped Chemical Oxygen Iodine Laser." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/238.

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Анотація:

Chemical Oxygen Iodine Laser(COIL) is an electronic transition high energy chemical laser having a wavelength of 1.315 /mi. This is the first chemical laser to operate on an electronic rather than a rotational or vibrational transition. In principle the COIL can be operated either in pulsed or cw mode. Its interest lies in high chemical efficiency, high power and wavelength which is shortest among all the chemical lasers. COIL finds a wide range of applications as its output wavelength at 1.315/zm couples well with the surface of most metals. The applications include surface hardening and modification of metals, welding, drilling and cutting of metals, cutting of ceramics, micro machining, laser deposition of non metallic coatings on metallic surfaces, monitoring of atmospheric pollutants and solar hazardous waste detoxification. Moreover, its wavelength is suitable for fiber optic transmission. In COIL the laser output at 1.315 /an is achieved by stimulated emission on the f (2-PL/2) -* -f (2-p3/2) magnetic dipole transition in atomic iodine. The population inversion on this transition is obtained by resonant collisions! energy transfer from metastable excited Oj^A) molecules produced by a chemical reaction of KOH, H2O? and Cl2. The chemical reaction of H2O2 and Cl2 that produces oxygen molecules is highly exothermic, and because of spin conservation considerations, channels its energy directly into the metastable electronically excited singlet delta state of oxygen molecule. Since the O2(1A) has a 45 mins lifetime and hence an extremely low small signal gain coefficient, it cannot be lased directly. Lasing can be achieved, however, if this energy is transferred to an atom or molecule which has a reasonable transition moment between its excited and ground states. The iodine 52P^2 -> 52P3/2 magnetic dipole transition has an acceptable transition moment and is nearly resonant with the 02{lA) state in oxygen. Excited iodine atoms are obtained by mixing O2(l A) and l2 molecules resulting in their dissociation and subsequent excitation. Power levels in excess of 25 kW have been reported in COIL. Due to wide range of applications and mainly for its use as a laser weapon, efforts are being made to enhance the power to higher levels. The dissociation of I2 controls the gain of the coil and hence power. In the pure COIL scheme some of the I2 remains undissociated due to the recombination reactions. Hence if we add a mechanism to dissociate the residual I2 molecules, we can enhance the performance of the COIL. So we propose to add a solar pumping to conventional COIL, which by photo exciting the undissociated I2lead to increase in efficiency. The thesis contains six chapters in which chapter 1 contains a general introduction and the definition of the research problem. The basic theory and the chemical reactions are discussed in chapter 2, The proposed model is discussed and the rate equations are solved in chapter 3. The numerical scheme and the computer code along-with the validation of the code are presented in chapter 4. The numerical results for the species concentrations, population inversion density and the output power for the proposed solar pumped COIL are presented in chapter 5, Final conclusions and future scope of the proposed research are presented in the final chapter 6. (Pl refer the original document for formulas)

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35

Лагойда, А. І. "Антипомпажне керування газоперекачувальним агрегатом із застосуванням методів нечіткої логіки". Thesis, Івано-Франківський національний технічний університет нафти і газу, 2017. http://elar.nung.edu.ua/handle/123456789/4866.

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Анотація:

Дисертація присвячена питанню антипомпажного керування газоперекачувальним агрегатом. Проведено комплексний аналіз та узагальнення існуючих методів та засобів, призначених для синтезу систем автоматичного антипомпажного регулювання газоперекачувальних агрегатів, визначено основні напрямки їх розвитку й удосконалення. Розроблено основні принципи побудови і функціонування ПІ-фазі-регулятора та багатопараметричного ПІД-фазі-регулятора в складі системи автоматичного антипомпажного регулювання. Розроблено динамічну математичну модель явища помпажу в відцентровому нагнітачі газоперекачувального агрегату з врахуванням перепуску газу через антипомпажний клапан. Розроблено алгоритм моделювання процесу синтезування системи антипомпажного регулювання. Розроблено узагальнену статичну математичну модель відцентрового нагнітача газоперекачувального агрегату для сукупності газодинамічних характеристик. На основі функцій спектральних щільностей ступеня підвищення тиску газу та продуктивності нагнітача визначено функцію передачі відцентрового нагнітача газоперекачувального агрегату. Здійснено постановку задачі синтезу оптимальної за швидкодією підсистеми автоматичного антипомпажного регулювання. Сформульовано постановку задачі синтезу регулятора підсистеми автоматичного антипомпажного регулювання на основі використання оператора обернення. На основі функції передачі відцентрового нагнітача розроблено моделі багатопараметричних ПІДД2-, ПЩЦ2ДЗ'регуляторів і метод синтезу таких регуляторів. Розроблено структури ПДЦ2-, ПДПД-регуляторів, функція передачі яких обернена до функції передачі об’єкта керування. Здійснено синтез оптимального за швидкодією закону керування відцентровим нагнітачем газоперекачувального агрегату з газотурбінним приводом. Розроблено та синтезовано ПІДД2-, ПІ-фазі-регулятор та ПІД-регулятор з фазі-блоком автоматичного налаштування коефіцієнтів. Розроблено імітаційну модель відцентрового нагнітача газоперекачувального агрегату з урахуванням антипомпажного клапану. Проведено імітаційне моделювання з розробленими регуляторами та здійснено їх порівняльний аналіз.
Диссертация посвящена вопросу антипомпажного управления газоперекачивающим агрегатом. Проведен комплексный анализ и обобщение существующих методов и средств, предназначенных для синтеза систем автоматического антипомпажного регулирования газоперекачивающих агрегатов, определены основные направления их развития и совершенствования. Разработаны основные принципы построения и функционирования ПИ-фази-регулятора и многопараметрического ПИД-фази-регулятора в составе системы автоматического антипомпажного регулирования. Разработана динамическая математическая модель явления помпажа в центробежном нагнетателе газоперекачивающего агрегата с учетом перепуска газа через антипомпажный клапан. Разработан алгоритм моделирования процесса синтезирования системы антипомпажного регулирования. Разработана обобщенная статическая математическая модель центробежного нагнетателя газоперекачивающего агрегата для совокупности газодинамических характеристик. На основе функций спектральных плотностей степени повышения давления газа и производительности нагнетателя определены функции передачи центробежного нагнетателя газоперекачивающего агрегата. Осуществлена постановка задачи синтеза оптимальной по быстродействию подсистемы автоматического антипомпажного регулирования. Сформулирована постановка задачи синтеза регулятора подсистемы автоматического антипомпажного регулирования на основе использования оператора обращения. На основе функции передачи центробежного нагнетателя разработаны модели многопараметрических ПИДД2-, ПИДД2ДЗ-регуляторов и метод синтеза таких регуляторов. Разработаны структуры ПДД2-, ПДПД-регуляторов, функция передачи которых обратная к функции передачи объекта управления. Осуществлен синтез оптимального по быстродействию закона управления центробежным нагнетателем газоперекачивающего агрегата с газотурбинным приводом. Разработан и синтезирован ПИДД2-, ПИ-фази-регулятор и ПИД-регулятор с фази-блоком автоматической настройки коэффициентов. Разработана имитационная модель центробежного нагнетателя газоперекачивающего агрегата с учетом антипомпажного клапана. Проведено имитационное моделирование с разработанными регуляторами и осуществлен их сравнительный анализ.
The thesis is devoted to antisurge control of gas pumping units. A comprehensive analysis and synthesis of existing methods and tools, designed to synthesize subsystems of automatic antisurge regulation of gas compressor units, are conducted and the main directions for their development and improvement are defined. Basic principles of construction and operation of the Pl-fuzzy-regulator and multiparametric PID-fuzzy-regulator as a part of the subsystem of automatic antisurge control are developed. The dynamic mathematical model of the surge phenomenon in the centrifugal pumping unit supercharger with the account of the gas bypass through the antisurge valve is designed. The algorithm of the synthesis process modeling of the antisurge regulation subsystem is implemented. The generalized mathematical static model of the centrifugal pumping unit supercharger for a set of gas-dynamic characteristics is designed. On the basis of the spectral density functions of the gas compression ratio and supercharger performance, the transfer function of the centrifugal pumping unit supercharger is determined. The synthesis problem of the time optimal subsystem of automatic antisurge control is stated. The synthesis problem statement of the subsystem regulator of automatic antisurge control, based on the inversion operator usage, is formulated. Based on the transfer function of the centrifugal supercharger, the models of multiparametric PIDD2- and PIDD2D3-regulators, as well as the method for these regulators synthesis, are developed. The structures of the PDD2- and PDPD-regulators, the transfer function of which is inverse to the transfer function of the control object, are designed. The synthesis of the optimal time control law of the centrifugal pumping unit supercharger with the gas turbine drive is conducted. The PIDD2- and Pl-fUzzy-regulator, as well as the PID regulator with the fuzzy block of automatic adjustment of coefficients, are developed and synthesized. The simulation model of the centrifugal pumping unit supercharger with the account of the antisurge valve is designed. The simulation modeling of the developed regulators is conducted and their comparative analysis is carried out.

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36

Giraudon, Rémi. "Contribution to the manufacturing and the understanding of the thermal behaviour of capillary structures dedicated to Loop Heat Pipes." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI003/document.

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Анотація:

Les boucles diphasiques à pompage thermo-capillaire de type LHP (pour Loop Heat Pipe, en anglais), dont le fonctionnement s’apparente à celui d’un caloduc, permettent un transfert de chaleur particulièrement efficace et entièrement passif entre une source chaude et une source froide. Ce transfert s’effectue au moyen d’un fluide diphasique, mû grâce à la force motrice capillaire générée par un matériau poreux contenu dans l’évaporateur/réservoir de la LHP. Outre son rôle de barrière hydraulique entre les phases liquide et vapeur, ce matériau doit assurer une fonction de barrière thermique afin de favoriser l’évaporation du liquide. L’aptitude du matériau à remplir ses fonctions dépend étroitement de sa microstructure, elle-même liée à la méthode de fabrication. Dès lors, l’objectif de la thèse est d’associer la science des matériaux à celle de la thermique, pour améliorer les procédures de fabrication de structures capillaires existantes ou tester de nouvelles méthodes, et aboutir à des structures dont les caractéristiques sont en adéquation avec celles qui sont recherchées
The capillary pumped loops (CPL) or loop heat pipes (LHP), whom the operating principle is similar to classic heat pipes, enable an efficient heat transfer between a hot source and a cold source without additional energy sources. Indeed, a porous structure provides a capillary force that enables a two-phase fluid to circulate around the loop, transferring the heat from the evaporator to the condenser. The porous structure acts as a hydraulic barrier between the two phases and as a thermal barrier enabling the liquid evaporation. The ability of the capillary structure to fulfil its mission depends on its microstructure, and thus on the manufacturing process. Therefore, the objective of the present thesis is to join the thermal sciences with the material sciences in order to improve the existing manufacturing procedure or even to test new ones. It aims at obtaining capillary structures corresponding to heat transfer applications

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37

Pospíšil, Juraj. "Architektura chlazeného EGR systému pro benzínové motory." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-400446.

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Анотація:

Táto diplomová práca je zameraná na preukazovanie vplyvov rôznych architektúr spätnej recirkulácie spalín na preplňované benzínové motory. Simulácie boli vytvorené v termodynamickom simulačnom programme GT-Power. Práca začína porovnávaním vplyvov spätnej recirkulácie na ustálené stavy motora, najmä z hľadiska spotreby, ktoré sú následne implementované do tranzientných modelov, simulujúc emisné testovacie cykly. Na konci práce sa venujem vplyvom spätnej recirkulácie na funkciu oxidačno-redukčného katalyzátora a na funkciu turbodúchadla.

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38

Peglow, Natalie Marion Elisabeth [Verfasser]. "Systematik zur Bewertung von Varianten in der Angebotsphase von Common-Rail Pumpen der automobilen Zulieferindustrie auf Basis des Modells der PGE - Produktgenerationsentwicklung = Systematics for Evaluation of Variants in the Quotation Phase of Common-Rail Pumps of the Automotive Supplier Industry on the Basis on the Model of PGE - Product Generation Engineering / Natalie Marion Elisabeth Peglow." Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/1235072363/34.

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39

CHEN, SI-AN, and 陳璽安. "Semiconductor Saturable Absorber Mirror Mode-Locked Nd:YVO4 Laser With Direct In-Band Pumping at 914 nm." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/yf2dcp.

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40

Huang, Li-Ming, and 黃利民. "Evaluation of the Flood Pumping Station Management by Using the Failure Mode and Effects Analysis (FMEA) Technigue." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/y82wse.

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Анотація:

碩士
國立臺北科技大學
土木與防災研究所
97
There exist different management models in the current flood pumping station practice. The most common three types of management models include: (1) the local township office carries out the operation and the local contractor performs the maintenance, (2) the local township office carries out the operation but the county (or city) government is responsible for the commission of maintenance work and (3) the county (or city) government commissions contractors to perform both operation and maintenance. Furthermore, different pumping stations are equipped with variants of machine set. The specifications and capacities vary station to station. Therefore, the manpower arrangements and pumping frequencies is not possible fit to a standard planning. Without a unified and fair comparison basis, it would be extremely difficult to assess which management model can achieve the best performance in efficiency, cost reduction and manpower management. This thesis employs Failure Mode and Effects Analysis (FMEA) to establish an objective evaluation system, which is able to evaluate the working efficiency of flood pumping stations under different management models. This research investigates three flood pumping stations located in northern Taiwan. They are equipped with the same type of machine set, but operated in three different types of management models aforementioned. We collect the crucial causes that might lead to the pumping failure, i.e., failure mode, design the FMEA control table, and then develop a scoring system to evaluate the working efficiency of each station under different management models. The crucial causes include deterioration of material, operating procedure, equipment maintenance, equipment itself and so on. By means of the routine inspection records of each station through the most recent year as input data for the developed system, conclusions are drawn based on the analyses of these case studies. In this research we have successfully shown how to use Failure Mode and Effects Analysis (FMEA) to quantitatively evaluate the working efficiency of flood pumping stations under different management models. We also effectively differentiate working efficiency resulted from various management models through the established evaluation system. In addition, the use of FMEA control tables is helpful to discover how the failure mode occurred in different pumping stations, by which information the decision of corrective actions can be taken to prevent failure in advance.

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41

Tsai, Zong-Yu, and 蔡宗育. "Diode-pumped solid state laser operated at high-order transverse mode using an axicon focused pumping geometry." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/mt39r6.

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Анотація:

碩士
國立中山大學
光電工程學系研究所
107
Laser rod, for example Nd:YAG crystal are often used as laser amplifiers pumped by double-end-pump or side-pump approaches, which not only provide efficient amplification but also shape the output laser mode. In this thesis, we propose a new pumping scheme to excite high-order transverse laser mode using a 3.8-cm-long Nd:YAG rod placed between a planar pump mirror and a 15 cm-radius-of-curvature concave output coupler of 10% transmission for high order HG modes and in particular the LG modes carrying orbital angular momentum (OAM). To shape emitting laser beam into annularly shaped efficiently, we design a special laser rod holder that almost suspend the laser rod in free space. The laser rod is anti-refraction coated at 1064 nm all over the surfaces of the rod including two end surfaces and the cylindrical side wall. The pump beam is first shaped into an cylindrical form by a beam expander made of a pair of axicon lenses. It thus creates a favorable environment for high order vortex laser to extract gain. In experiment, we successfully generate high order Hermite Gaussian modes, Laguerre Gaussian modes, Ince Gaussian modes and other high-order transverse radiation pattern as a incoherent superposition of these modes. In particular, optical vortex of unit topological charge is demonstrated and confirmed by its spiral phase. However due to the failure in applying water cooling and poor thermal conduction of air when the laser rod is suspended in free space, the accumulated heat from non-radiative decay in the long laser crystal provides strong phase modulation and causes beam instability that eventually brings beam collapse. By adopting quasi-CW pump vortex and other high-order transverse radiation patterns lasts longer and the thermal issue is investigated. To extend the axicon focusing geometry, that delivers Bessel beams for the pump, we use the ring-shaped pumping for LG mode excitations. With a ring-shaped pumping in which its radius expands as propagating, modal overlaps can be calculated that reveals the possibility to excite a series of LG modes by properly placing the location of a disk-like laser crystal of 5 mm in thickness. Optical vortex carrying an unit topological charge corresponding to LG01 mode is demonstrated with a clear spiral phase structure in its wavefront.

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42

Dogan, Ahmet. "Variably saturated three-dimensional rainfall driven groundwater pumping model /." 1999. http://etd.fcla.edu/etd/uf/1999/amp7014/dogan.pdf.

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Анотація:

Thesis (Ph. D.)--University of Florida, 1999.
Printout. Vita. Includes bibliographical references (leaves 190-205). Also available on the World Wide Web; Adobe Acrobat Reader required to view and print PDF file.

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43

Chandran, M. "Turbomolecular Pumping A Markovian Chain Model And Some Experimental Investigations." Thesis, 1996. http://etd.iisc.ernet.in/handle/2005/1719.

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44

Lu, Ruey-Hsing, and 盧瑞興. "Three-Dimensional Finite Element Model for Land Displacements due to Pumping." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/93573091830042010193.

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Анотація:

博士
國立交通大學
土木工程研究所
83
The purpose of this thesis is to develop a general Galerkin finite element model for simulating the land displacements due to groundwater pumping. Three-dimensional equations of equilibrium (force balance) and flow in porous media were coupled to describe land displacements that occur as a result of the pressure decline in aquifers. A Galerkin finite element model based on these equations was developed. The saturated/ unsaturated behavior and the isotropic/cross-anisotropic properties of the permeability and elasticity were considered when the model was formulated. The change in the body force in saturated and unsaturated zones of aquifers was considered in the equilibrium equation. The proposed finite element model was verified by comparing its simulation results with those of known analytical solutions for simplified cases. The simulation of displacements due to pressure decline in unsaturated media was also preformed. Those results demonstrated that the choice of boundary ranges for an aquifer with infinite domain may significantly affect the estimated horizontal and vertical displacements. To obtain a good estimation of land displacements, the boundary ranges should be carefully chosen. Simulation results also indicated that the change in body force should be considered once an unconfined aquifer has been pumped. Otherwise, the horizontal displacement and vertical displacement in unconfined aquifers would be overestimated and underestimated, respectively. The behavior of land displacements due to pumping was shown to be affected by the change in the total stresses in aquifers and depend on the isotropic/cross-anisotropic properties of the aquifer elasticity and permeability.

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45

Li, Hsin-Hsien, and 李信賢. "A New Analytic Charge Pumping Current Model and Its Novel Applications." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/50342207603309537919.

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Анотація:

博士
國立交通大學
電子研究所
84
In this thesis, a new charge pumping current model is developed and the experimental charge pumping current can be simulated very well either in the suturation region or in the non- saturation region. The effective capture-cross -section models for electrons and holes are proposed and the possible physical mechanisms are discussed. Based on this model, several novel charge pumping techniques are developed. We have developed two novel methods to extract the effective channel length. Comparing to those using the I-V method, the proposed new method is simple, accurate and reliable. Besides, a novel charge-pumping method using DC source/drain biases and specified gate waveforms is proposed to extract the lateral distributions of interface-trap and effective oxide-trapped charge densities in this thesis and the analysis is the basis of hot-carrier lifetime prediction

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46

Yang, Jia-ming, and 楊家銘. "Simulation of pumping tests in a vertical leaky faulted aquifer using MODFOLW model." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/72252167676100108619.

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Анотація:

碩士
輔英科技大學
環境工程衛生系碩士班
93
Leaky fault provide an important flow path for fluids to move underground. It is often necessary to charucterize such faults in various eugineering projects. In this study, the drawdowns in the confined aquifer caused by pumping are simulated by the MODFLOW model. Three cases of aquifer drawdown results offer a clear comparison. That drawdown for leaky fault case is between that of the constant-head fault case and the Theis solution. Because of leakage from the fault, the contours of equal drawdown in the aquifer are deflected at the fault-aquifer intersection.

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47

Ho, Hsin-Wei, and 何信緯. "A Double-Porosity Model for Pumping in a Slant Fracture：The Distributed Parameter Approach." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/jcfsne.

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Анотація:

碩士
國立中央大學
應用地質研究所
105
Investigating the sandstone aquifer from field in Jianshi township indicates that the dip angles of fractured zones can be as large as 30-60 degrees. Such large dip angles may induce a regional flow in the fractured zone, of which the interference with the pumping test will create a non-radial flow field that is asymmetric with respect to the pumping well. The pressure response in the down-gradient and up-gradient of the pumping well is different and a capture zone effect exists in the neighborhood of the pumping well. In the past, a new double-porosity mathematical model for large dipping angle fracture has been developed, and the important theoretical and field pumping test data have been done and analyses. In this model the “lumped-parameter” approach is employed to account for the matrix flow by assuming the flow between the matrix and fractured zone is proportional to the pressure difference between these two flow domains. However, there is another approach, the ”distributed-parameter” approach, for modeling the matrix flow. It invokes the Darcy’s law for the matrix flow by assuming that the matrix flow is proportional to the hydraulic gradient between the matrix and fractured zone. While each approach has certain advantages and disadvantages, they complement each other and are commonly used. Therefore the purpose of this research are employing the distributed-parameter approach to develop a new double-porosity model for pumping test in a large-dip angle fracture zone. Compare the theoretical and data analysis results from the two models in order to investigate and differentiate the impact and consequences associated with two approaches. Finally, the flow field is used to delimit the boundary of capture zone. The solution that we developed is in Laplace-domain, it is found that the large-time drawdown data exhibit a straight line on semi-log paper, and its slop can be used to estimate transmissivity of the fractured zone Tf while its intersection with the time abscissa to determine the sum of the storage coefficient of the fractured zone Sf and of matrix Sm. The matrix conductivity Km, Sf and Sm can be determined by fitting the small- and intermediate- time data by the solution without difficulty. Both the distributed- and lumped-parameter models can be approximated by the same asymptotic solution at large times. The major difference in these two models; however, lies in that the transition from small times to large times of the lumped-parameter model is flatter than that of the distributed-parameter model. Both the distributed- and lumped-parameter models are useful for data analysis, depending on the characteristics of the transition from small times to intermediate times. In addition, we derive the analytic solution for the capture zone. Due to prove of solution, regional flow substituted the water supply from matrix and fracture to pumping well. When the regional flow or transmissivity of the fractured zone Tf increase, the capture zone will be bigger. In this project, we think the dip angle is needed to consider during the pumping test.

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48

Chen, Ching-Wen, and 陳敬文. "Development and Application of Optimization Model for the Optimal Operation of Pumping Well Group." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/28801604370142352480.

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Анотація:

博士
國立臺灣大學
土木工程學研究所
102
The study is to develop an optimization model for the pumping well group, which can be used to determine the maximum pumping rate under the limitation of groundwater level. The flow chart of this study can be divided into three procedures, which are (1) the development of groundwater simulation model for the study area; (2) the training of the artificial neural networks model and (3) the development of optimization model for the optimal operation of pumping well groups. The study first investigates the hydrological and geophysical characteristics of the study area. After the calibration of the groundwater simulation model is completed, three different artificial neural networks, feed forward neural network, radial basis neural network and linear layer neural network, are trained by random pumping rates generated by MODFLOW to determine which ANN is the most suitable to simulate the groundwater level of the observation station in the study area. The optimization model of the optimal operation for the pumping well group is developed. The objective function is to maximize the pumping rates of the well groups under the constraints of the maximum pumping rate of each well, the simulation of groundwater level at the observation well by ANN model, the limit of groundwater level during wet period and the on-off switch of each well group. Because the optimization problem developed by the study belongs to mixed integer nonlinear programming (MINLP), which contains large quantities of constraints, Lingo software is applied to obtain the optimal solution of the optimization problem. The methodology developed by this study is applied to Ming-Chu Basin. After training process and validation, the feed forward artificial neural network is the most suitable tool to represent the groundwater fluctuation of the observation well in the study area. The optimization model developed for Ming-Chu Basin is solved by Lingo software. The results show with increasing the division of well groups from 1 to 4 groups, the optimal pumping rates will be increased by nearly 80%. However, with increasing the recovery rate of groundwater level during wet period, the optimal pumping rate will be decreased accordingly. The optimal pumping rate is simulated by MODFLOW to validate the requirement of groundwater level during wet periods is fulfilled. The results show that the groundwater level of the optimal pumping rate simulated by MODFLOW is above or near the required groundwater level specified by the constraints. Therefore, the optimal pumping rate can be considered as the global optimal approximate solution of the optimization model.

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49

Hsueh, Hung-Yu, and 薛宏裕. "Model Study of Proposed Connecting Channels Between Existing and Proposed Yu-chan Pumping Stations." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/55244206907313368788.

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Анотація:

碩士
淡江大學
水資源及環境工程學系碩士班
96
This study conducted a model test for the proposed connecting channels between existing and planned Yu-chan pumping stations. Using the model, the flow at the fore bay and the wet well of the planned pumping station were also examined. Finally, the standard operation procedure for the combined existing and proposed pumping stations were secured. The results show that in order to fulfill the required discharge through the connecting channels the existing #4 to #6 entrances at the existing Yu-chan pumping station must be expanded and combined and the connecting channel size must at least be 5.00m 3.50m. The fore bay of the proposed pumping station is recommended a minor modification to reduce the vortices. Finally, the standard operation procedure for the combined existing and proposed pumping stations were provided.

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50

Lin, Sheng-Ting, and 林聖婷. "Development of the Distribution Model of Pumping and Recharge for Chou-Shui River Alluvial Fan." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/84424508571683785894.

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碩士
國立臺灣大學
土木工程學研究所
100
Chou-Shui River alluvial fan is the agricultural center and emerging industrial area of Taiwan. Surface water has been unable to meet the rising demand, and groundwater has become an important source of water supply. However, groundwater resources should be appropriately managed to avoid land subsidence and other adverse consequences caused by improper pumping. To achieve this goal, we need a well calibrated groundwater numerical model to assess the effectiveness of various management strategies. To establish the numerical model, we must complete the following two tasks: First, utilizing the data fusion technology for groundwater system identification; Second, integrating site survey for clarification of spatial distribution of hydrogeological parameters, recharging, and pumping. Thus, in this study, we present a two-stage procedure to establish a representative groundwater model. In the first stage, groundwater-hydrograph analysis is applied to evaluate the water balance of Chou-Shui River alluvial fan, and the total quantity of pumping and recharging is obtained. In the second stage, we used MODFLOW as the groundwater flow simulation model to correctly distribute the quantity of pumping and recharging into different space and time. The model establishment process includes aquifer stratification, hydrogeological parameters and boundary conditions setting, pmping and recharging distribution, and groundwater level observation fitting. The recharging is subdivided into three hydrologic components including rainfall infiltration, river leakage, and groundwater irrigation seepage. The subdivision is implemented according to riverbed materials, soil textures, and cropping systems. The pumping is subdivided into two components including public water supply pumping (involving pumping of both Water Corporation and Irrigation Association) and private pumping. The setting of each pumping is based on official pumping records and pumping well census results. The results show that, the groundwater resources of Chou-Shui River alluvial fan can be more properly distributed with the detailed settings of pumping and recharging. Furthermore, the quantity of pumping from first shallow unconfined aquifer might be overestimated before; the local pumping behavior in F3 and F4 are not clear, having to add the observation wells and more detailed pumping well census.

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Дисертації з теми "Pumping mode"

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