Дисертації з теми "Pressurized Condition"
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Dumnernchanvanit, Ittinop. "Characterization and mitigation of crud at pressurized water reactor conditions." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/115003.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 448-467).
The nuclear industry is no exception when it comes to those affected by fouling deposit problems. Fouling deposits on fuel rods in nuclear reactors, known as crud, can cause a variety of undesirable effects including axial power shifts, accelerated corrosion, increased primary circuit radiation dose, and possible fuel failure. This study revisits the crud problem once again using a newly constructed Internally Heated Testloop For PWRs (IHTFP) and new analytical techniques, and attempt to find a way to prevent or mitigate crud, or at least better understand it. This is the first time that fuelrod coatings are examined as a way of countering crud growth. These coatings are chosen based on their surface chemical properties and robustness at PWR conditions. For the goal of gaining a better understanding of crud, this study is the first to apply fractal analysis to characterize crud. To achieve both of these goals, the IHTFP was built to obtain crud grown under the PWR thermal-hydraulic and chemical conditions. The crud-resistant coatings experiments show significantly reduced crud surface coverage, indicating reduced crud adhesion, for TiC and ZrN coatings. The results roughly agree with London-van der Waals theoretical force predictions, suggesting that London-VDW forces are responsible for the adhesion of crud to fuel cladding. This knowledge can be useful in designing better crud-resistant materials. The fractal analysis can provide a simple, effective way to characterize the macro-scale behavior of crud with its micro-scale properties. The fractal analysis experimental study found R2 values to be very close to one when applying the box-counting method to crud, which is one piece of evidence to support the usage of fractal analysis on crud. Moreover, a strong logarithmic relationship trend between fractal dimension and porosity was found. This relationship applies to both the IHTFP's and Westinghouse loop's crud, even though the two experimental setups used different crud precursors and heat flux. This could indicate that crud's fractal dimension is dependent only on porosity. This relationship could simplify crud modeling and lead to better predictions of crud's behaviors. Better predictions can lower margins, leading to more efficient reactors.
by Ittinop Dumnernchanvanit.
Ph. D.
Guo, Weiqing. "Miscibility and phase separation of polymer blends under normal and pressurised conditions." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47460.
Повний текст джерелаSchmidt, Sebastian. "Entwicklung und Validierung eines Verfahrens zur Zustandsüberwachung des Reaktordruckbehälters während auslegungsüberschreitender Unfälle in Druckwasserreaktoren." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-235206.
Повний текст джерелаHawkes, Joshua Mahlon. "The Simulation and Study of Conditions Leading to Axial Offset Anomaly in Pressurized Water Reactors." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/7612.
Повний текст джерелаSalnikova, Tatiana. "Two-phase CFD analyses in fuel assembly sub-channels of Pressurized Water Reactors under swirl conditions." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-27307.
Повний текст джерелаEinphasige CFD Analysen stellen für typische thermohydraulische Fragestellungen aus dem Kernkraftwerksbereich bereits jetzt ein wichtiges Werkzeug für die Brennelement (BE)¬Auslegung dar. Die zweiphasige CFD-Modellierung befindet sich dagegen in der Entwicklungsphase. Die in dieser Dissertation präsentierten Arbeiten zeigen Fortschritte für die detaillierte zweiphasige Modellierung drallbehafteter Strömungen im Unterkanal eines BEs des Druckwasserreaktors (DWR) einschließlich der realistischen Beschreibung des kritischen Wärmestroms (CHF) sowie die Bestimmung zweiphasiger Indikatoren, welche das Auftreten von CHF-Phänomen beschreiben. Verschiedene drallerzeugende Komponenten im BE wurden mit dem 3-D CFD-Code STAR-CD modelliert. Es wurden neue Erkenntnisse zur lokalen Blasenverteilung in Unterkanälen unter Drallbedingungen gewonnen, die für CHF relevant sind (“bubble pockets”). Durch eine Modifikation des Wärmeübergangsmodells (heat partitioning model) wird der starke Anstieg der Stabtemperatur infolge CHF realistischer beschrieben. Die durchgeführten Validierungen zeigen eine gute Übereinstimmung mit verfügbaren Experimenten unter DWR-Bedingungen für die radialen Blasenverteilungen und für die Bestimmung von CHF. Die vorliegenden Ergebnisse dieser Dissertation verdeutlichen den Nutzen und die Möglichkeiten von zweiphasigen CFD-Anwendungen für die Entwicklung und die thermohydraulische Optimierung von DWR-Abstandshaltern bezüglich des Wärmeübergangs und der Verbesserung des CHF-Verhaltens
Модели однофазовой среды в вычислительной гидродинамике (англ. CFD) являются уже сейчас важным инструментом для решения типичных термогидравлических задач в ядерной энергетике, например, при конструировании тепловыделяющих сборок (ТВС). Двухфазовое моделирование, в сравнении с однофазовым, находится на сегодняшний момент в стадии развития. Данная диссертация связана с совершенствованием двухфазовой модели в направлении улучшения детализации вихревого течения внутри ячейки ТВС в условиях работы двухконтурного ядерного реактора (тип PWR). Также в работе показана возможность более реалистичного описания феномена кризиса теплоотдачи и определения двухфазовых индикаторов, характеризующих критический тепловой поток (англ. CHF). Комплекс расчетов выполнен для различных интенсификаторов теплоотдачи, размещенных на дистанционирующих решетках TBC. Расчеты производились с помощью программного обеспечения STAR-CD, позволяющего моделировать трехмерные гидродинамические системы. Полученные новые данные о локальном распределении пузырьков в ячейках с вихревым течением дали важную информацию для идентификации критического теплового потока. Усовершенствование модели теплоотдачи на поверхности тепловыделяющего элемента (ТВЭЛ) позволило более реалистично описать резкое повышение температуры на поверхности ТВЭЛа при достижении критических условий. Полученные результаты численного моделирования для радиальных распределений пузырьков при нормальных условиях работы PWR и также для определения критического теплового потока показали хорошее совпадение с известными экспериментальными данными. Представленные в диссертации результаты показывают возможности применения двухфазовых CFD-расчётов для разработки и термогидравлической оптимизации дистанционирующих решеток с целью улучшения теплообмена и характеристик критического теплового потока в двухконтурном ядерном реакторе типа PWR
Vereen, Keon. "An experimental investigation on the dynamics of bubbles utilizing refrigerant R134a under pressurized flow boiling conditions." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4717.
Повний текст джерелаID: 030646273; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.A.E.)--University of Central Florida, 2011.; Includes bibliographical references (p. 107-115).
M.S.A.E.
Masters
Mechanical and Aerospace Engineering
Engineering and Computer Science
Aerospace Engineering; Thermofluid Aerodynamics Systems Track
Salnikova, Tatiana. "Two-phase CFD analyses in fuel assembly sub-channels of Pressurized Water Reactors under swirl conditions." Doctoral thesis, Salnikova, T.: Two-phase CFD analyses in fuel assembly sub-channels of Pressurized Water Reaktors under swirl conditions. Fortschr.-Ber. VDI Reihe 7 Nr. 497. Düsseldorf: VDI-Verlag 2010. ISBN 978-3-18-349707-2, ISSN 0178-9538, 2008. https://tud.qucosa.de/id/qucosa%3A25245.
Повний текст джерелаEinphasige CFD Analysen stellen für typische thermohydraulische Fragestellungen aus dem Kernkraftwerksbereich bereits jetzt ein wichtiges Werkzeug für die Brennelement (BE)¬Auslegung dar. Die zweiphasige CFD-Modellierung befindet sich dagegen in der Entwicklungsphase. Die in dieser Dissertation präsentierten Arbeiten zeigen Fortschritte für die detaillierte zweiphasige Modellierung drallbehafteter Strömungen im Unterkanal eines BEs des Druckwasserreaktors (DWR) einschließlich der realistischen Beschreibung des kritischen Wärmestroms (CHF) sowie die Bestimmung zweiphasiger Indikatoren, welche das Auftreten von CHF-Phänomen beschreiben. Verschiedene drallerzeugende Komponenten im BE wurden mit dem 3-D CFD-Code STAR-CD modelliert. Es wurden neue Erkenntnisse zur lokalen Blasenverteilung in Unterkanälen unter Drallbedingungen gewonnen, die für CHF relevant sind (“bubble pockets”). Durch eine Modifikation des Wärmeübergangsmodells (heat partitioning model) wird der starke Anstieg der Stabtemperatur infolge CHF realistischer beschrieben. Die durchgeführten Validierungen zeigen eine gute Übereinstimmung mit verfügbaren Experimenten unter DWR-Bedingungen für die radialen Blasenverteilungen und für die Bestimmung von CHF. Die vorliegenden Ergebnisse dieser Dissertation verdeutlichen den Nutzen und die Möglichkeiten von zweiphasigen CFD-Anwendungen für die Entwicklung und die thermohydraulische Optimierung von DWR-Abstandshaltern bezüglich des Wärmeübergangs und der Verbesserung des CHF-Verhaltens.
Модели однофазовой среды в вычислительной гидродинамике (англ. CFD) являются уже сейчас важным инструментом для решения типичных термогидравлических задач в ядерной энергетике, например, при конструировании тепловыделяющих сборок (ТВС). Двухфазовое моделирование, в сравнении с однофазовым, находится на сегодняшний момент в стадии развития. Данная диссертация связана с совершенствованием двухфазовой модели в направлении улучшения детализации вихревого течения внутри ячейки ТВС в условиях работы двухконтурного ядерного реактора (тип PWR). Также в работе показана возможность более реалистичного описания феномена кризиса теплоотдачи и определения двухфазовых индикаторов, характеризующих критический тепловой поток (англ. CHF). Комплекс расчетов выполнен для различных интенсификаторов теплоотдачи, размещенных на дистанционирующих решетках TBC. Расчеты производились с помощью программного обеспечения STAR-CD, позволяющего моделировать трехмерные гидродинамические системы. Полученные новые данные о локальном распределении пузырьков в ячейках с вихревым течением дали важную информацию для идентификации критического теплового потока. Усовершенствование модели теплоотдачи на поверхности тепловыделяющего элемента (ТВЭЛ) позволило более реалистично описать резкое повышение температуры на поверхности ТВЭЛа при достижении критических условий. Полученные результаты численного моделирования для радиальных распределений пузырьков при нормальных условиях работы PWR и также для определения критического теплового потока показали хорошее совпадение с известными экспериментальными данными. Представленные в диссертации результаты показывают возможности применения двухфазовых CFD-расчётов для разработки и термогидравлической оптимизации дистанционирующих решеток с целью улучшения теплообмена и характеристик критического теплового потока в двухконтурном ядерном реакторе типа PWR.
Rebak, Raúl Basilio. "Environmentally induced cracking in alloy 600 and SA 302 steel in pressurized water reactor steam generator conditions /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487846885777343.
Повний текст джерелаByakika, Stephen Nyende. "Modelling of Pressurised Water Supply Networks that May Exhibit Transient Low Pressure - Open Channel Flow Conditions." Thesis, Vaal University of Technology, 2011. http://hdl.handle.net/10352/421.
Повний текст джерелаGrowing demand for water due to increasing populations, industrialisation and water consuming lifestyles puts stress on existing water supply systems. To cater for the rising demand, water distribution networks are expanded beyond their design capacities and this creates transient “low-pressure-open-channel flow” (LPOCF) conditions. Current water supply models use “demand driven approach” (DDA) methodology which is not able to simulate transient LPOCF conditions, that poses an impediment to management/analysis of pressure-deficient networks. With a case study of the water supply network of Kampala City, LPOCF conditions were studied in this research. A “pressure/head driven approach” (PDA/HDA) was used in order to determine what demand is enabled by particular nodal pressures. Conversion of free surface to pressurised flow was analysed and modelled, with a view to clearly understanding occurrence of this phenomenon. The research demonstrated that if adequate pressures and flows are to be maintained, effectiveness of the water distribution network should be given as much attention as water production capacity. The research also indicated that when network pressures are low, the head-driven approach to water distribution modelling gives more accurate results than the traditional demand-driven methodology. Coexistence of free-surface and pressurised flow in networks prone to LPOCF conditions was confirmed and modelled. Results obtained highlighted the advantages of developing fully dynamic and transient models in the solution of transient LPOCF conditions in water distribution networks. Models developed allow application of PDA/HDA and DDA methodologies in systems that may exhibit LPOCF conditions thus enabling identification, understanding and analysis of the status of all sections of the network. These culminated in the development of a DSS to guide operational decisions that can be made to optimise network performance.
Wang, Mi. "Electrochemical Behaviour of Stainless Steel under Radiation and Exposed to Representative Chemistry in Pressurised Water Reactor Conditions." Palaiseau, Ecole polytechnique, 2013. http://pastel.archives-ouvertes.fr/docs/00/91/55/75/PDF/Mi_WANG_thesis.pdf.
Повний текст джерелаThe dissertation focuses on the behaviour of stainless steel under irradiation and exposed to primary PWR conditions. The electrochemical potential of austenitic 316L stainless steel and the environmental parameters (hydrogen pressure, temperature, etc. ,) have been measured continuously at high temperature (HT) and high pressure (HP) under irradiation, using a unique experimental HTHP working cell. Two sources of irradiation, proton and electron beams, have been employed in the study. A high similarity of electrochemical behaviour under both types of irradiations has been observed: (i) an oxidative potential response under irradiation (few tens of millivolts); (ii) an increase in the hydrogen pressure reduces the oxidative potential response; (iii) a synergetic effect of thermal ageing and fluence leading to a decrease of the oxidative response under irradiation. The observations of the oxide film showed that without irradiation, metallic nickel in the inner and outer oxide films has been observed under a high hydrogen pressure. Under irradiation, um scale cavities (pits) have been observed in the strongly electron irradiated oxide film formed on 316L stainless steel. These defects are induced by the effect of irradiation of the passive film and water radiolysis. It is also shown that water radiolysis influences the PWR water chemistry by making it become a stronger oxidant at the oxide/solution interface. As a result, the release of metallic cations is increased and a-Fe2O3 hematite has been observed on the irradiated outer oxide film where cavities were formed
Zhang, Kanglong [Verfasser], R. [Akademischer Betreuer] Stieglitz, and C. [Akademischer Betreuer] Queral. "Multi-Scale Thermal-hydraulic Developments for the Detailed Analysis of the Flow Conditions within the Reactor Pressure Vessel of Pressurized Water Reactors / Kanglong Zhang ; R. Stieglitz, C. Queral." Karlsruhe : KIT-Bibliothek, 2020. http://d-nb.info/1205807659/34.
Повний текст джерелаColonelli, Talita Amábile da Silva. "Síntese contínua e não catalítica de ésteres etílicos de ácidos graxos a partir do óleo da polpa de macaúba (Acrocomia aculeata)." Universidade Estadual do Oeste do Parana, 2014. http://tede.unioeste.br:8080/tede/handle/tede/1798.
Повний текст джерелаCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
This paper proposes biodiesel production by non-catalytic process using ethanol in pressurized conditions in continuous mode of Macaúba oil (Acrocomia aculeata), evaluating the effect of process variables (temperature, pressure, mass ratio oil: alcohol and addition of cosolvent) on the conversion of the reaction in terms of fatty acid esters to determine the best experimental conditions. As well as envisioned, a study of changes in driving the reaction in pressurized conditions, seeking to decrease the reaction conditions of temperature and pressure. The results show this study that regarding obtaining better rates of mass transfer, the use of fillings of glass spheres presented performed better. Through planning Plackett Burman 12, it was found that the variables that showed greater significance in the process were the weight ratio (alcohol: oil) and the addition of cosolvent, besides that, it was observed that the results for the decomposition were satisfactory (<5.0%). With this we was performed a kinetic study, based on these two variables, where it was found that the use of a larger amount of alcohol in the process did not prove to be beneficial, already the addition of cosolvent played a positive role enabling reduction in the time and reaction temperature, since the condition of 275 º C was achieved a yield of 89.62%.
O presente trabalho propõe a produção de biodiesel pelo processo não catalítico utilizando etanol em condições pressurizadas em modo contínuo do óleo de Macaúba (Acrocomia aculeata), avaliando o efeito das variáveis de processo (temperatura, pressão, razão mássica óleo:álcool e adição de cossolvente) sobre a conversão da reação em termos de ésteres de ácidos graxos visando determinar as melhores condições experimentais. Vislumbrou-se também um estudo de modificações na condução da reação em condições pressurizadas, buscando diminuir as condições reacionais de temperatura e pressão. Os resultados obtidos demonstram que, no estudo referente a obtenção de melhores taxas de transferência de massa, a utilização de recheios de esferas de vidro apresentaram melhor desempenho. Através do planejamento Plackett Burman 12, verificou-se que as variáveis que apresentaram maior significância no processo foram a razão mássica (álcool:óleo) e a adição de cossolvente, além de que, observou-se que os resultados referentes a taxa de decomposição apresentaram-se satisfatórios (<5,0%). Com isso realizou-se um estudo cinético baseado nestas duas variáveis, onde verificou-se que a utilização de uma maior quantidade de álcool no processo não apresentou-se benéfico, já a adição de cossolvente desempenhou um papel positivo ao possibilitar a diminuição do tempo e temperatura de reação, uma vez que na condição de 275ºC houve um rendimento de 89,62%.
Chang, Chih-Kai, and 張智凱. "Velocity and discharge at the bridge deck under pressurized flow condition." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/85418336194393200307.
Повний текст джерела國立成功大學
水利及海洋工程學系
87
Bridge become partially or totally submerged during large floods are subjectto pressure-flow scour. Under this flow condition, the velocity and bed scour at the bridge deck are much larger than that under non-pressure situations. In order to understanding the contraction scour at the bridge deck under pressurized flow condition, the first course is to analyze velocity and discharge flowing through the bridge deck. The experiments were conducted to study the flow field, discharge, and water level at the bridge deck under the pressurized flow condition. A model bridge deck was tested under a variety of controlled pressurized flow conditions, and the experimental data were all recorded. The experimental data were substituted into energy equation and continuity equation to calculate energy loss, energy loss coefficient. An equation to evaluated flow discharge related the energy loss was derived. The deviation from actual discharge and calculated discharge were within 10%. The velocity data were compared with the log-law velocity distribution to predict the fore influence region (FIR) and behind influence region (BIR). The result showed that when the upstream Fround No. was smaller than 0.1 and the contraction ratio was smaller than 0.267, the maximum FIR would be within one quarter width of the bridge deck and the BIR would be within 4.7 width of the bridge deck.
Wu, Wen-Jui, and 吳文瑞. "Stress Analysis and Design Optimization of Angled Circular Pressurized Tube Under a Non-Isothermal Condition." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/89817395045366612585.
Повний текст джерела大葉大學
機械工程研究所碩士在職專班
97
Pressure tubes are used in various industries to transport high temperature steam, gas, liquid, and other fluids. Some components are usually required in pressurized tubing systems to relieve the high stress due to thermal expansion. Among them, U-tube is a kind which plays an important role. It is mainly serves as reinforcement and connection usage. In this study, the structural behavior of a non-isothermal U-tube under its simulated operating condition is investigated based on finite element analysis in conjunction with heat transfer and fluid mechanics theories. The investigation includes the structural stress analysis, temperature distribution analysis, the modal analysis, as well as the design optimization. A program based on the use of ANSYS is then provided for the users to select the optimal thickness of a U-tube under a safe operating condition.
Derardja, Bilal. "Innovative Approaches for Mapping the Pressurized Irrigation Systems Performances Under Unsteady Flow Conditions." Doctoral thesis, 2022. http://hdl.handle.net/11589/237798.
Повний текст джерела黃家烈. "A Study on the Thermal-Hydraulic Phenomena of a Pressurized Water Reactor under LOCA Conditions." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/57050019237929228272.
Повний текст джерела中原大學
機械工程學系
85
Ever since the occurrence of the Three Mile Island Accident in 1979, it became increasingly important for an in-depth understanding of the thermal-hydraulic (T-H) phenomena associated with the uncovering of the fuel rods during an accident. In the meantime, evaluation of the core behavior resulting from the loss-of-coolant accidents (LOCAs) has long become one the key issues needed to be addressed for the design basis accidents (DBAs) related to the design of a nuclear power plant. In the Final Safety Analysis Report (FSAR) of the Third Nuclear Power Station owned by the Taiwan Power Company (TPC), it was indicated that after the initiation of a DBA LOCA, the peak cladding temperature (PCT) of the fuel rods reached 2199.9℉, which is almost the same as the upper temperature limit of 2200℉ set by the nuclear regulatory authority. In addition, it is commonly believed that, after more than ten years of operation of a nuclear plant, such as the Third Nuclear Power Station of TPC, the percentage of tube blockage for the steam-generator (S-G) assembly or the actual flow rates associated with the emergency core cooling systems (ECCSs) may be quite different from what have been used for the FSAR analyses. Thus it is necessary to perform the LOCA analyses based on the current realistic conditions of the plant. This study used RELAP5YA T-H code, developed by the Yankee Atomic Company, for the LOCA analyses of the Third Nuclear Power Station of TPC. Even though this code lacks the capability for the modeling of the omission of the water inventory in the region below the reactor core during the reactor vessel blow-down, this deficiency was made-up by raising the temperature of the injecting water for the ECCS flow. For the LOCA analyses done for this study, the percentage of blockage of the S-G tubes was raised from a typical value of 1% to 5%. Also, a number of sensitivity studies were carried out using various values of the discharge coefficients for the breaks. The results obtained in this study indicated that the PCT of the fuel rods for all cases studied was 1548.5℉, which is much below the upper temperature limit of 2200℉ set by the nuclear regulatory authority.
Benfell, Katharine Elaine. "Assessment of char morphology in high pressure pyrolysis and combustion." Thesis, 2001. http://hdl.handle.net/1959.13/1312422.
Повний текст джерелаDrives to reduce carbon dioxide emissions and improve efficiency make pressurised gasification an attractive option in future coal utilisation technologies. Process conditions in pressurised gasification differ from conventional entrained flow combustion in pressure, atmosphere, peak temperature and heating rate, yet there is sparse literature concerning coal behaviour under pressurised conditions. Previous work suggests that bituminous coals can show enhanced plasticity at high pressures and this phenomenon may not be predicted by standard tests of coking properties. Previous modelling of char reactivity and burnout in combustion and gasification has failed to take account of the petrographic variability of coals. Current work to improve the predictive capacity of these models requires evaluation of the effects of different macerals and of char preparation pressure on char behaviour. Prior studies of whole coals subjected to high pressure and high temperature conditions have shown that daughter char morphology is influenced by particle heating rate, the size distribution of the feed coal, furnace pressure, feed rate, coal rank and the parent coal petrography. Chars were produced by pyrolysis at 1100 or 1300 °C and 1, 5, 8, 10 and 15 atm furnace pressure, and by combustion at 1100 °C and 1 atm furnace pressure, from a suite of East Australian bituminous coals. The characteristics of the chars and their parent feed coals were quantified using semi-automated image analysis, as well as petrographic, particle size and chemical analyses. Relationships between the morphology of the chars and properties of the parent coal and furnace pressure were established. Daughter char morphology and volatile yield was found to be related to the petrographic composition of the parent feed coals, their full reflectance profiles and the char preparation pressure. Chars derived from vitrinite-rich lithotypes and those prepared under high pressure conditions show larger mean diameters, porosities, sphericities and proportions of porous char types. Volatile yield is related to the vitrinite content of the lithotype. A parameter derived from full coal reflectograms proves to be effective for prediction of char morphology and trends in volatile yield. The Carbon Burnout Kinetic model is improved in its predictive value by including parent coal vitrinite content as an input parameter and could be further improved by utilising the full coal reflectogram parameter.
Schmidt, Sebastian. "Entwicklung und Validierung eines Verfahrens zur Zustandsüberwachung des Reaktordruckbehälters während auslegungsüberschreitender Unfälle in Druckwasserreaktoren." Doctoral thesis, 2017. https://tud.qucosa.de/id/qucosa%3A30954.
Повний текст джерелаChi-HanLiu and 劉其翰. "Comparison of Combustion Models and Analyses of Operating Conditions for the Pressurized, Pulverized-Coal, Entrained-Bed Gasifier." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/18348869513112653023.
Повний текст джерела國立成功大學
航空太空工程學系碩博士班
100
In the present study, a numerical model has been developed for a pressurized, pulverized-coal, entrained-bed gasifier by the commercial CFD software, ANSYS-FLUENT. The accuracy for the predicted composition of the outlet syngas is investigated for different combustion models. The influence of the operating conditions on the composition of the outlet syngas is also examined. Three different combustion models including non-premixed equilibrium, non-premixed flamelet, and finite-rate/eddy dissipation model, are investigated. The results obtained from the present computations show that the predicted syngas composition by the non-premixed flamelet model is in the best agreement with the experimental data. The non-premixed equilibrium model, however, leads to a composition of the outlet syngas more due to combustion. The concentrations of CO, H2, and CO2 are over-estimated by the finite-rate/eddy-dissipation model. The present study also indicates that the reaction parameters of water-gas shift reaction significantly affect the outlet syngas composition. The effects of the oxygen/carbon ratio and the operating pressure on the gasification performance are studied in the present parametric study. The results show that a lower oxygen/carbon ratio leads to higher fractions of gasification species such as CO and H2, and a lower fraction of combustion species such as CO2. A lower operating pressure results in a lower char conversion rate, and the gasification zone is not conspicuous. With a higher operating pressure, the char conversion rate increases. The mole fractions of CO and H2 at outlet increase, while that of CO2 decreases.
Salnikova, Tatiana [Verfasser]. "Two-phase CFD analyses in fuel assembly sub-channels of pressurized water reactors under swirl conditions = Zweiphasige CFD-Analysen in Unterkanälen von Brennelementen von Druckwasserreaktoren unter Drallbedingungen / von Salnikova Tatiana." 2008. http://d-nb.info/1008707880/34.
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