Дисертації з теми "Contact water heater"

Дипломний проект першого (бакалаврського) рівня вищої освіти на тему: «Котельня на базі контактних водонагрівачів для теплопостачання житлового масиву в м. Миргороді»: пояснювальна записка на 66 с., 13 рис., 5 табл., 8 бібліографічних найменувань; креслення – 3 арк. ф. А1. Мета проекту – розробити котельню для теплопостачання житлового масиву у місті Миргороді та підібрати котлоагрегати. У дипломному проекті було розраховано максимальні, середні та річні витрат теплоти на опалення, вентиляцію і гаряче водопостачання споживачів житлових та громадських будівель, відповідно до завдання. За результатами цих розрахунків у якості теплогенеруючих пристроїв були підібрані котли загальною номінальною потужністю 3,4 МВт Також була розроблена теплова схема із закритою системою теплопостачання, на основі якої було проведено аеродинамічний та гідравлічний розрахунки, визначено діаметри основних трубопроводів котельні та швидкості теплоносіїв в них. Залежно від потрібного тиску та об'ємної подачі було підібрано допоміжне обладнання, зокрема тягодуттєві пристрої та насоси. За температурним режимом, масовими витратами гріючої і нагріваної води та тепловій потужності нагрівача, було підібрано пластинчастий теплообмінник для системи ГВП. Було надано рекомендації з охорони праці при монтажі обладнання котельні та технічні рішення та організаційні заходи з виробничої санітарії. На кресленнях наведені компоновка обладнення котельні, теплова схема котельні та контактний водонагрівач.
Degree project of the first (Bachelor) level of higher education on the topic: «Boiler room on the basis of contact water heaters for heat supply of the residential area in Mirgorod»: explanatory note for 66 pages, 13 figures, 5 tables, 8 bibliographic names; drawings - 3 s. f. A1 The purpose of the Вegree is to develop a boiler house for heat supply of a residential area in the city of Mirgorod and to pick up boiler units. In the diploma project, maximum, average and annual heat consumption for heating, ventilation and hot water supply of residential and public buildings consumers was calculated in accordance with the task. As a result of these calculations, boilers with a total rated power of 3.4 MW were selected as heat-generating devices. Also, a thermal circuit with a closed system of heat supply was developed, on the basis of which aerodynamic and hydraulic calculations were carried out, the diameters of the main pipelines of the boiler house and the speed of the heat carrier in them were determined. Depending on the pressure and volume required, auxiliary equipment, such as payload units and pumps, was selected. Under the temperature regime, the massive consumption of heating and hot water and the heat capacity of the heater, a plate heat exchanger for the system of high-pressure cookers was selected. The recommendations were given on the safety of work during the installation of boiler equipment and technical solutions and organizational measures for industrial sanitation. The drawings show the arrangement of the boiler equipment, the heating circuit of the boiler house and the contact water heater.
Дипломный проект первого (бакалаврского) уровня высшего образования на тему: «Котельная на базе контактных водонагревателей для теплоснабжения жилого массива в г. Миргороде»: объяснительная записка на 66 с., 13 рис., 5 табл., 8 библиографических наименований, чертежи - 3 л. ф. А1. Цель проекта - разработать котельную для теплоснабжения жилого массива в городе Миргороде и подобрать котлоагрегаты. В дипломном проекте было рассчитано максимальные, средние и годовые расхода теплоты на отопление, вентиляцию и горячее водоснабжение потребителей жилых и общественных зданий, в соответствии с заданием. По результатам этих расчетов в качестве теплогенерирующих устройств были подобраны котлы общей номинальной мощностью 3,4 МВт Также была разработана тепловая схема с закрытой системой теплоснабжения, на основе которой был проведен аэродинамический и гидравлический расчеты, определены диаметры основных трубопроводов котельной и скорости теплоносителей в них. В зависимости от нужного давления и объемной подачи было подобрано вспомогательное оборудование, в частности тягодуттеви устройства и насосы. По температурному режиму, массовыми расходами греющей и нагревов воды и тепловой мощности нагревателя, было подобрано пластинчатый теплообменник для ГВС. Были предоставлены рекомендации по охране труда при монтаже оборудования котельной и технические решения и организационные мероприятия по производственной санитарии. На чертежах приведены компоновка оборудования котельной, тепловая схема котельной и контактный водонагреватель.

A model was developed for predicting the performance of direct contact membrane distillation (DCMD) to evaluate the feasibility of using sensible heat to drive DCMD treatment of oilfield produced water. Algorithms for performance prediction of instantaneous and counter-current DCMD flow were developed. These algorithms used equation-based models of heat transfer, mass transfer, concentration polarization, and counter-current flow to predict performance of DCMD systems. The performance prediction model was validated against experimental data from the literature, and limitations to the accuracy of predictions were identified. The model was applied to evaluate performance sensitivity to nine operational parameters. The model was applied to evaluate the feasibility of sensible heat driven DCMD treatment of produced water using DCMD alone and using a reverse osmosis-DCMD hybrid system. The largest water recoveries that were energetically favorable (lower energy demand than reverse osmosis) for sensible heat driven DCMD produced water treatment were 0.5% and 0.75% for 1% and 3.5% NaCl feeds, respectively. As feed NaCl concentration increased, higher recoveries were energetically favorable over RO. A bulk NaCl concentration of 6% was evaluated to simulate the feasibility of further treatment of reverse osmosis retentate using sensible heat driven DCMD. Compared to treatment alternatives of multiple-stage flash distillation (MSF) and multiple-effect distillation (MED), recoveries up to 2.5% were favorable and up to 4.0% were competitive. Due to model limitations, the performance of optimal conditions for sensible heat driven DCMD produced water treatment could not be predicted, so the recoveries presented in this work are likely lower than the expected recoveries for optimal field conditions. Water recovery of produced water using sensible heat driven DCMD is limited thermodynamically to low recoveries, but any treatment using sensible heat that is energetically favorable reflects the utilization of two waste streams (produced water and waste heat) to produce high quality water. Using sensible heat to drive produced water treatment could be useful for providing small quantities of usable water, but would only result in a very small reduction of the volume of produced water needing to be disposed.

Direct contact condensation of steam injected into water is a special mode of condensation where condensation occurs on the interface between steam and water. This type of condensation forms an essential part of various industrial applications and correct prediction and modelling of the condensation behaviour is crucial to obtain an optimised design of such devices. While present prediction models for direct contact condensation are valid for a limited range of flow conditions only, the work presented in this thesis provides improved models for direct contact condensation. The models are developed in the form of diagrams and include: a condensation regime diagram, for predicting the condensation behaviour, a steam plume length diagram, for predicting the penetration distance of steam into water, and a heat transfer coefficient diagram. These models are derived using a wide range of data and therefore provide more accurate predictions compared with alternative models available in literature. In contrast to present models, the derived models presented in this work are constructed using an additional physical parameter to describe the process. The diagrams are validated against independent experiments and demonstrate close agreement. Furthermore, the predictions from the condensation regime diagram and steam plume length diagram are self-consistent. The models developed in this study are capable of predicting condensation behaviour for a wide range of initial conditions and can be used in conjunction with computational fluid dynamics techniques for direct contact condensation.

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on October 5, 2009). Thesis advisor: Dr. Alan G. Whittington. Includes bibliographical references.

The coupled transport of water and heat, involving freezing and thawing, in the road structure and its immediate environment is important to consider for optimal design and maintenance of roads and when assessing solute transport, of e.g. de-icing salt, from roads. The objective of this study was to develop mechanistic models, and measurement techniques, suitable to describe and understand water flow and heat flux in road structures exposed to a cold climate.

Freezing and thawing was accounted for by implementing new routines in two numerical models (HYDRUS1D/2D). The sensitivity of the model output to changes in parameter values and operational hydrological data was investigated by uncertainty and sensitivity analyses. The effect of rainfall event characteristics and asphalt fractures on the subsurface flow pattern was investigated by scenario modelling. The performance of water content reflectometers (WCR), measuring water content, was evaluated using measurements in two road structure materials. A numerical model was used to simulate WCR sensor response. The freezing/thawing routines were stable and provided results in agreement with laboratory measurements. Frost depth, thawing period, and freezing-induced water redistribution in a model road was greatly affected by groundwater level and type of subgrade. The simulated subsurface flow patterns corresponded well with published field observations. A new method was successful in enabling the application of time domain reflectometer (TDR) calibration equations to WCR output. The observed distortion in sampling volume for one of the road materials could be explained by the WCR sensor numerical model. Soil physical, hydrological, and hydraulic modules proved successful in simulating the coupled transport of water and heat in and on the road structure. It was demonstrated in this thesis that numerical models can improve the interpretation and explanation of measurements. The HYDRUS model was an accurate and pedagogical tool, clearly useful in road design and management.

The boreal forests represent 8 % of all forested areas on the earth and have a significant role in the control of greenhouse gases and an impact on global climate change. The main objective of this thesis is to increase the understanding of how evaporation and heat-flux processes in the boreal forest zone are affecting the regional and global climate.

A meteorological mesoscale model with an advanced land-surface parameterization has been utilized to study aggregation of fluxes of water vapour and heat. The model has been compared against four other methods for flux estimation in a southern boreal landscape. The results show that the mesoscale model is successfully reproducing 24-hour averages of fractionally weighted mast measurements of sensible and latent heat flux.

The model was also evaluated against in-situ observations of surface fluxes and other meteorological variables. The results reveal that a correct initialization of soil moisture is crucial to simulate a realistic partitioning of the sensible and latent heat fluxes. Significant differences in surface fluxes and friction velocities between two apparently similar forest sites indicate the need for careful assessment of areal representativity when comparing mesoscale model results with in-situ observations.

A parameterization for the absorption of solar radiation of high-latitude sparse forests was implemented and tested in the model that significantly improved the simulation of high wintertime midday sensible heat fluxes. A scheme for heat storage in vegetation was also implemented which improved the results, but the scheme needs further evaluation for high latitude forests.

Two commonly used strategies for the description of land-surface heterogeneity, the effective parameter approach and the mosaic approach, were tested in the mesoscale model against airborne observations of sensible and latent heat fluxes. The results show that the mosaic approach produces better results especially when small lakes are present in model grid-squares.

Norra halvklotets barrskogsbälte representerar 8 % av all skogsbeklädd mark på jorden och har stor betydelse för kontrollen av växthusgaser och påverkan på globala klimatförändringar. Syftet med denna avhandling är att öka förståelsen av hur avdunstning och värmeflöden i den boreala skogszonen påverkar klimatet regionalt och globalt.

En meteorologisk mesoskalemodell med en avancerad landyteparameterisering har använts för att studera aggregering av avdunstning och värmeflöden. Modellen jämfördes med fyra andra metoder för uppskattning av värmeflöden i den boreala skogszonens södra delar. Resultaten visade att mesoskalemodellen reproducerar 24-timmarsmedelvärden av sensibelt och latent värmeflöde från areellt viktade mastmätningar med bra resultat.

Modellen utvärderades även mot markbaserade mätningar av sensibelt och latent värme och andra meteorologiska variabler. Resultaten visar att en korrekt initialisering av markvatteninnehållet är avgörande för att simulera en realistisk uppdelning av de sensibla och latenta värmeflödena. Markanta skillnader i markyteflöden och friktionshastigheter mellan två liknande skogsmätstationer påvisar nödvändigheten av en noggrann bedömning av den areella representativiteten när man jämför resultat från mesoskalemodellen med markbaserade mätningar.

En parameterisering för absorption av solstrålning i glesa skogsbestånd på höga breddgrader infördes och testades i modellen vilket markant förbättrade simuleringen av de höga sensibla värmeflöden som observerats vid middagstid på vintern. Ett uttryck för att beskriva värmelagring i vegetationen infördes också vilket förbättrade resultaten, men uttrycket behöver vidare utvärdering för skogsbestånd på höga breddgrader.

Två ofta använda strategier för att beskriva markytans heterogenitet, effektiva parametermetoden och mosaikmetoden, testades i mesoskalemodellen mot flygburna observationer av sensibla och latenta värmeflöden. Resultaten visar att mosaikmetoden ger bättre resultat särskilt när mindre sjöar förekommer i modellrutorna.

En réponse à un stress nutritif, les espèces du genre Bacillus sont susceptibles de former desspores métaboliquement dormantes résistantes à d’autres formes de stress. Ces spores peuventse retrouver à forte concentration dans beaucoup d’aliments secs, ce qui peut provoquer desintoxications alimentaires ou dégrader les aliments lorsqu’ils sont réhydratés. Comme leurdestruction est très difficile, la plupart des méthodes couramment utilisées pour décontaminerles aliments secs sont peu efficaces. L’objectif de ce travail est de comprendre l’influence del’hydratation de la spore sur l’inactivation des spores sèches de B. subtilis. Une étudefondamentale a été menée en soumettant les spores placées dans les capsules d’AnalyseEnthalpique Différentielle à différent traitements thermiques et en associant simultanémentles thermogrammes obtenus à la viabilité des spores traitées. Les résultats montrent lapersistance d’une teneur en eau relativement élevée dans le protoplaste des spores équilibréesà faible aw (0,13). De plus, une relation forte a été mise en évidence entre la teneur en eau duprotoplaste de la spore et sa sensibilité thermique. La spectroscopie IR à transformée deFourier a montré que cette sensibilité est fortement reliée à la dénaturation/agrégation desprotéines et à la libération de l’acide dipicolinique. Ces résultats ont finalement permis dedévelopper un procédé d’inactivation thermique sous pression (entre 2 et 7 bar) des sporessèches. Le maintien d’une pression d’azote dans le réacteur chauffé permet d’empêcherl’évaporation de l’eau du protoplaste des spores et donc de favoriser leur inactivation. A termeet après développement, ce procédé peut être un moyen original de décontaminationd’aliments secs
In response to starvation, species from the genre Bacillus are able to form metabolicallydormant spores which are very resistant to multiple forms of stress. They are found in quitehigh concentrations in some dried foods which, upon rehydration, may lead to food deterioration or food-borne diseases. Moreover, their destruction is rather difficult and mostof the techniques commonly used to treat dry foods result in a very low spore inactivation.The aim of this work is to better understand the role spore hydration in the inactivation ofdried Bacillus subtilis spores. A fundamental study was conducted using DifferentialScanning Calorimetry pans as reactors to perform a heat treatment in dried spores andsimultaneously relate the thermograms to spore viability. Results show the persistence of arelatively high water concentration in the core of extremely dry spores. Besides, a strongrelation between this core water concentration and spore thermal sensitivity wasdemonstrated. This destruction was found to be highly related to proteindenaturation/aggregation and dipicolinic acid release through Fourier Transform InfraredSpectroscopy analysis. From this fundamental study, a procedure for the inactivation of driedspores using low pressures (2-7 bar) and high temperature was developed. The systemconsisted of a heated reactor in which gaseous nitrogen was compressed to prevent theevaporation of water from the spores and so favor spore inactivation (> 5 log10). This methodof inactivation could be an interesting new way to optimize the decontamination of driedfoods

Current methods for measuring energy flow rate in a pipe use a variety of invasive sensors, including temperature sensors, turbine flow meters, and vortex shedding devices. These systems are costly to buy and install. A new approach that uses non-invasive sensors that are easy to install and less expensive has been developed. A thermal interrogation method using heat flux and temperature measurements is used. A transient thermal model, lumped capacitance method LCM, before and during activation of an external heater provides estimates of the fluid heat transfer coefficient h and fluid temperature. The major components of the system are a thin-foil thermocouple, a heat flux sensor (PHFS), and a heater. To minimize the thermal contact resistance R" between the thermocouple thickness and the pipe surface, two thermocouples, welded and parallel, were tested together in the same set-up. Values of heat transfer coefficient h, thermal contact resistance R", time constant �[BULLET], and the water temperature �[BULLET][BULLET], were determined by using a parameter estimation code which depends on the minimum root mean square RMS error between the analytical and experimental sensor temperature values. The time for processing data to get the parameter estimation values is from three to four minutes. The experiments were done over a range of flow rates (1.5 gallon/minute to 14.5 gallon/minute). A correlation between the heat transfer coefficient h and the flow rate Q was done for both the parallel and the welded thermocouples. Overall, the parallel thermocouple is better than the welded thermocouple. The parallel thermocouple gives small average thermal contact resistance average R"=0.00001 (m2.�[BULLET][BULLET]/W), and consistence values of water temperature and heat transfer coefficient h, with good repeatability and sensitivity. Consequently, a non-invasive energy flow rate meter or (BTU) meter can be used to estimate the flow rate and the fluid temperature in real life.
MS

Theme of diploma thesis is the heat transfer medium in heating systems. The thesis is departed to three parts. In the first part, there is a theoretical solution of heat transfer mediums. In the second part, there is a calculation solution of the project. Project solves heating of the apartment building. There are two variants of heating source and water treatment. Those variants are compared. The last part is experimental part. Theme of the experiment is quality of heating water in heating systems.

Le mouvement d’humidité dans le réseau poreux de certains matériaux est très souvent à l’origine de phénomènes préjudiciables pour la durabilité des constructions du génie civil. C’est en particulier le cas pour le séchage du bois, générateur de fissures et de délaminations aux interfaces de collage, et pour le béton en situation d’incendie où le mouvement d’humidité peut induire des désordres irréversibles (écaillage). Le recours à des modèles prédictifs de ruine des structures nécessite donc la simulation du mouvement d’humidité au sein des matériaux. Ces modèles de transfert de masse et de chaleur sont sophistiqués et nécessitent d’être confrontés à des mesures afin d’être validés. Peu de techniques expérimentales existent pour mesurer les mouvements ou gradients d’humidité dans les réseaux poreux, en particulier en régime transitoire (séchage, incendie). Les techniques existantes sont de plus généralement coûteuses et imposent des conditions sévères de sécurité pour les chercheurs. L’objectif de la thèse est donc de mettre au point un dispositif de mesure de gradients d’humidité basé sur l’imagerie Térahertz. Il s’agit d’une technique de mesure relativement peu onéreuse et permettant de réaliser des mesures en régime transitoire. Un banc expérimental existant sera donc adapté à la mesure du champ d’humidité sur éprouvettes de bois en conditions thermo-hydriques variables, et sur éprouvettes de béton en situation de chauffage. Les résultats constitueront une base de données utile à la compréhension des phénomènes de dégradation des matériaux et seront directement utilisables comme outil de validation de modèles de calcul
The movement of moisture in the porous network of certain materials is very often at the origin of phenomena prejudicial to the durability of the constructions of the civil engineering. This is particularly the case for the drying of wood, which creates cracks and delaminations at bonding interfaces, and for concrete in situations of fire where the movement of moisture can induce irreversible disorders (chipping). The use of predictive models of structural ruin therefore requires the simulation of the moisture movement within the materials. These mass and heat transfer models are sophisticated and need to be confronted with measurements in order to be validated. Few experimental techniques exist to measure moisture movements or gradients in porous networks, especially in transient conditions (drying, fire). Existing techniques are often expensive and impose severe conditions of safety for the researchers. The objective of the thesis is therefore to develop a device for measuring gradients of moisture based on Terahertz imagery. This is a comparatively inexpensive measuring technique and makes it possible to carry out transient measurements. An existing experimental bench will therefore be adapted to the measurement of the moisture field on wood specimens under variable water-moisture conditions and on concrete specimens in a heating situation. The results will constitute a database useful for understanding the phenomena of degradation of materials and will be directly usable as a validation tool for calculation models

A Confluência Brasil-Malvinas (CBM) é formada pelo encontro da Corrente do Brasil (CB) com a Corrente das Malvinas (CM) no Atlântico Sul e, por constituir o encontro de correntes de contorno oeste (CCO), é demarcada por um intenso gradiente horizontal de temperatura. A inclinação das isopicnais na porção mais quente de regiões de encontro de duas CCO favorece a formação de águas modais ao final do inverno. O estudo de águas modais subtropicais ainda é incipiente no Atlântico Sul, quando comparado com os diversos trabalhos versando sobre o fenômeno em outras regiões do mundo. A realização do primeiro cruzeiro oceanográfico especificamente planejado para o estudo de águas modais na região da CBM e de retroflexão da CB permitiu verificar a anisotropia desse extenso corpo d\'água, cuja espessura e profundidades máxima e mínima variam mormente com a latitude em que o fenômeno ocorre. Os dados fornecidos pelos perfiladores Argo lançados durante o cruzeiro, e ainda em operação na região da CBM, corroboraram tal observação e revelaram o limite norte da região de formação da água modal subtropical do sudoeste do Atlântico Sul (AMSTAS) em torno da latitude de 34°S. A comparação dos resultados obtidos in situ com os dados do modelo oceânico HYCOM, numa simulação de 4 anos, permitiu observar a mesma anisotropia e limite norte da área de formação. Embora relativamente curta, a série temporal viabilizou a primeira estimativa de volume da AMSTAS e uma avaliação preliminar dos processos envolvidos na dissipação da AMSTAS recém formada. O emprego de dados de satélites altímetros para o cálculo do calor armazenado (CA) na região de estudo permitiu verificar que a instabilidade apresentada na série temporal de dados do modelo HYCOM se deve sobretudo à dinâmica de mesoescala na região mais próxima do encontro das duas CCO. A análise do CA na região onde foi realizado o cruzeiro oceanográfico do estudo, permitiu identificar mais claramente a existência de diferentes padrões de calor armazenado coincidentes com áreas típicas de formação, os quais não ocorreram em áreas que continham AMSTAS apenas afundada.
The Brazil-Malvinas confluence zone (BMCZ) is an energetic region of the South Atlantic Ocean where the Brazilian Current (BC) and the Malvinas Current (MC) meet. As a convergence area of Western Boundary Currents (WBC), it is marked by intense horizontal temperature gradients. The inclination of isopycnals in the warm side of WBC convergence zone enables the formation of mode water at the end of winter. The study of subtropical mode waters in the South Atlantic is still incipient compared to similar investigations conducted in other regions of the world. The first oceanographic cruise specifically dedicated to the study of mode waters in the BMCZ and the BC retroflection helped verify the anisotropy of such extensive water masses, whose maximum and minimum thickness and depth vary mainly with the latitude where these phenomenon occur. Data derived from Argo profilers released during the cruise and currently still operating in the BMCZ, support this observation and indicate the northern limit of the formation region of the Southwestern Atlantic subtropical mode water (SASTMW) near latitude 34°S. Comparison of in situ results with those obtained from a 4-years simulation with the HYCOM ocean model, indicates similar anisotropy and northern limit of the formation area. Despite its relatively small length, this time series enabled the first estimation of the SASTMW volume, and a preliminary validation of the processes involved in the dissipation of newly formed SASTMW. The use of satellite altimetry data for the computation of heat content in the study area helped conclude that the instability observed in the time series of the HYCOM model output is due to mesoscale dynamics near the convergence zone of the BC and the MC. Analysis of heat content in the region where the oceanographic cruise was conducted helped identify the existence of different patterns in heat content, that coincide with typical formation areas but not with areas where SASTMW is already submerged.

This diploma thesis deals with the issue of the determination of the frost susceptibility of soils in the subgrades of road structures. The theoretical part compares the ways of testing the frost susceptibility in the Czech Republic and other selected countries of the European Union. Furthermore, it also deals with the development of the frost susceptibility index in the Czech Republic. The empirical part focuses on the laboratory testing of the frost susceptibility of the given sample of soil by the direct frost heave method. Moreover, it also deals with the simulation of penetration of frost by the subgrade and the possibility of shortening the length of the freezing during the direct testing the frost susceptibility.

Роботу присвячено експериментальним дослідженням, що направлені на підвищення ефективності роботи контактних тепломасообмінних апаратів шляхом збільшення міжфазної поверхні тепломасообміну при розпилені рідини відцентровими форсунками, впровадження яких приводить до суттєвої економії матеріальних та енергетичних ресурсів. Виконано комплексні експериментальні дослідження характеристик факелу розпилу рідини (густини зрошення, кута розкриття факела форсунки, середнього об’ємно-поверхневого діаметра крапель рідини). Встановлено вплив вхідних параметрів на відповідні характеристики та визначено площу поверхні крапель розпиленої рідини. Експериментально встановлено значення граничної температури нагріву води та її залежність від початкового паровмісту, при якій вода нагрівається до граничної температури в залежності від початкового паровмісту й витрати сухого повітря. Визначено параметричні границі ефективного використання відцентрової механічної форсунки без випаровування крапель нагрітої рідини. Експериментально досліджено інтенсивність тепло- і масоовіддачі в контактному апараті газокрапельного типу з відцентровою форсункою в умовах утилізації теплоти відхідних газів енергетичних агрегатів. Вперше отримано емпіричні залежності для розрахунку середніх коефіцієнтів тепловіддачі та масовіддачі, які відносяться до дійсної поверхні крапель розпиленої води. Встановлено особливості процесів переносу в газокрапельній системі та отримано узагальнювальні залежності для процесів тепло- і масовіддачі. На основі експериментальних досліджень характеристик розпилу та процесів тепломасообміну при конденсації пари з парогазової суміші на краплях розпиленої рідини розроблено методику розрахунку крапельного контактного утилізаційного апарату.
Dissertation is devoted to experimental research, aimed at improving the efficiency of contact heat and mass transfer units by increasing the interfacial surface of heat and mass transfer during the liquid spraying by centrifugal nozzles, implementation of which results in significant savings of material and energy resources. Comprehensive experimental study of the characteristics of the liquid spraying torch (irrigation density, expansion angle of nozzle torch, the average volume-surface diameter of liquid droplets) was done. The influence of input parameters to the relevant properties was shown and surface area of the sprayed liquid droplets was defined. The limit temperature of water heating and its dependence on initial vapor content in which water is heated to the limit temperature depending on the initial vapor content and dry air output were experimentally set. The parametric borders of effective use of centrifugal mechanical nozzle without evaporation of heated liquid drops were defined. Intensity of heat and mass transfer in the contact gas-droplet unit with centrifugal nozzle in terms of heat utilization of energy units’ exhaust gases was experimentally researched. The empirical dependences for calculating the average heat transfer and mass transfer coefficients relating to the actual surface of the sprayed liquid droplets are obtained for the first time. The peculiarities of transfer processes in the gas-droplet system were determined and generalized dependence for heat and mass transfer were received. Based on experimental studies of spraying characteristics and heat and mass transfer processes at vapor condensation from vapor-gas mixture on the sprayed liquid droplets, the method of calculating the droplet contact utilization unit was developed.
Диссертация посвящена исследованиям, направленным на повышение эффективности работы контактных аппаратов путем увеличения межфазной поверхности теплообмена путем распыления жидкости, внедрение которых приводит к существенной экономии материальных и энергетических ресурсов. Работа содержит результаты экспериментальных исследований характеристик распыла и процессов тепломассоотдачи при конденсации пара из парогазовой смеси на каплях распыленной жидкости. Исследовано влияние температуры и давления воды на тонкость распыла (величину среднего объемно-поверхностного диаметра капель) для центробежной форсунки в параметрических условиях ее работы и применительно к условиям работы контактного утилизатора теплоты отходящих газов. На основании проведенных опытов получены новые зависимости величины среднего объемно-поверхностного диаметра капель для параметров распыливания жидкости с помощью центробежной форсунки в новом диапазоне изменения избыточного давления и температуры воды перед форсункой. В результате теоретического анализа движения капель жидкости в факеле распыления центробежной форсунки и использования экспериментальных данных по средним объемно-поверхностным диаметрам капель предложена методика определения действительной межфазной поверхности процессов тепломассообмена в контактных газожидкостных аппаратах капельного типа. Экспериментально определена зависимость граничной температуры нагрева воды в контактном аппарате газокапельного типа с центробежной форсункой применительно к условиям утилизации теплоты отходящих газов энергетических агрегатов. Исследования проведены в диапазоне избыточных давлений воды перед форсункой (0,2–0,6) МПа и объемной доли водяных паров парогазовой смеси на входе в аппарат от 0,02 до 0,45. Показано использование полученной зависимости для рас чета предельных значений параметров парогазового потока, ограничивающих область эффективной работы контактного аппарата с конденсацией пара и отсутствием режима испарения капель нагретой жидкости. Экспериментально определена интенсивность тепло- и массоотдачи в контактном аппарате газокапельного типа с центробежной форсункой в условиях утилизации теплоты отходящих газов энергетических агрегатов. Исследование проведены в диапазоне избыточного давления воды перед форсункой (0,2 - 0,6) МПа и объемной долей водяного пара парогазовой смеси на входе в аппарат от 0,08 до 0,35. По результатам экспериментальных исследований определены коэффициенты тепло- и массоотдачи, которые были отнесены к реальной поверхности капель. Полученные в работе результаты экспериментальных исследований коэффициентов тепло- и массоотдачи сравнивались с известными литературными данными для одиночной капли. Установлено, что интенсивность теплоотдачи для капель жидкости с парогазовым потоком выше, чем для одиночной капли, а для массоотдачи, ниже. Установлены особенности процессов переноса в газокапельной системе и получены обобщающие зависимости для процессов тепло- и массообмена для факела капель конуса распыла. В результате указанного комплекса работ предложена методика теплового расчета контактного газокапельного утилизатора теплоты низкотемпературных отходящих газов при распылении жидкости механической центробежной форсункой, которая учитывает реальные условия протекания процессов переноса в рассматриваемой двухфазной системе. Приведенная процедура теплового расчета утилизационной установки позволяет при заданных параметрах отходящих газов и воды на входе получить тип и количество распылителей для генерирования капель воды, выполнить компоновку в штатном коробе для отвода газов, рассчитать параметры теплоносителей на выходе с установки и определить ее теплопроизводительность.

Роботу присвячено експериментальним дослідженням, що направлені на підвищення ефективності роботи контактних тепломасообмінних апаратів шляхом збільшення міжфазної поверхні тепломасообміну при розпилені рідини відцентровими форсунками, впровадження яких приводить до суттєвої економії матеріальних та енергетичних ресурсів. Виконано комплексні експериментальні дослідження характеристик факелу розпилу рідини (густини зрошення, кута розкриття факела форсунки, середнього об’ємно-поверхневого діаметра крапель рідини). Встановлено вплив вхідних параметрів на відповідні характеристики та визначено площу поверхні крапель розпиленої рідини. Експериментально встановлено значення граничної температури нагріву води та її залежність від початкового паровмісту, при якій вода нагрівається до граничної температури в залежності від початкового паровмісту й витрати сухого повітря. Визначено параметричні границі ефективного використання відцентрової механічної форсунки без випаровування крапель нагрітої рідини. Експериментально досліджено інтенсивність тепло- і масоовіддачі в контактному апараті газокрапельного типу з відцентровою форсункою в умовах утилізації теплоти відхідних газів енергетичних агрегатів. Вперше отримано емпіричні залежності для розрахунку середніх коефіцієнтів тепловіддачі та масовіддачі, які відносяться до дійсної поверхні крапель розпиленої води. Встановлено особливості процесів переносу в газокрапельній системі та отримано узагальнювальні залежності для процесів тепло- і масовіддачі. На основі експериментальних досліджень характеристик розпилу та процесів тепломасообміну при конденсації пари з парогазової суміші на краплях розпиленої рідини розроблено методику розрахунку крапельного контактного утилізаційного апарату.

Ce travail de these porte sur des etudes experimentales relatives aux transferts monodimensionnels d'humidite sous differents gradients thermiques dans des materiaux poreux qui sont: le beton autoclave non expanse, la vermiculite, deux roches extraites de carrieres (rouffach et rorschach) servant a la restauration de monuments historiques. Un dispositif experimental est utilise pour le suivi continu des evolutions de teneurs en eau (methode gammametrique) et de temperatures (sondes thermiques) durant des essais de condensation et de sechage. L'objectif principal de ce travail est la determination des coefficients de transfert pour chaque materiau, determination basee sur la theorie classique du transfert de masse et de chaleur de de vries. Les coefficients de transfert sont calcules par un procede de regression entre les variables mesurees: flux de masse, gradient de temperature et gradient de teneur en eau, on donne leurs evolutions avec la teneur en eau et pour differentes temperatures. D'autres experiences sont aussi realisees donnant les conductivites thermiques et les isothermes d'adsorption permettant, ainsi, d'acquerir des informations sur le comportement des materiaux vis a vis du transfert de chaleur et de vapeur d'eau

The diploma thesis is elaboration of project documentation of the object Housing for seniors in Brno - Dolní Heršpice. The site is located un the area with the planned development of the city. The object is detached, three-story with a partial basement. The building is divided into five parts. The building is based on concrete foundation pads and strips. The structural construction is a combined column and wall system in technological design as monolithic concrete. The building is designed as a low energy building, with contact insulation (ETICS). The whole building is designed with forced air exchange. An extensive and intensive walkable flat roof is designed. The aim is to create small, barrier-free, community housing with affordable services and support, with a possible life expectancy. Services for the elderly with reduced self-sufficiency and with mild health and mental dysfunctions are considered. The building is equipped with space for accommodation with a capacity of 48 beds, space for eating with a separate kitchen, space for leisure and physical activities, space for basic health and social care and space for administrative and technical facilities. The construction is divided into several buildings, the subject of the thesis is primarily the solution SO.01 - Housing for seniors

A thesis submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 1990
This work was carried out in response to the need for a simple engineering method for the thermal analysis of direct-contact air-water heat exchangers. A simple method of performance analysis is developed which is directly analogous and consistent with the fundamental approach used in conventional heat exchanger analysis and one in which the algebraic form of the overall equation and the grouping of each of the parameters are apparent. The range of conditions considered are air and water temperatures of between 0 and 50 DC and barometric pressures ranging from 80 to 120 kPa. The air conditions considered range from completely dry to completely satucated with water vapour. Both air cooling and water cooling processes are considered. [Abbreviated abstract. Open document to view full version]

Large-scale circulation in the northern North Atlantic plays a crucial role in the global climate by influencing ocean storage of atmospheric heat and carbon. Temperature and salinity changes in this region can have important consequences on ocean circulation due to density stratification at sites of deep water formation. Such influences can involve feedback mechanisms related to the Atlantic Meridional Overturning Circulation, which has been shown to influence the hydrography of the northern North Atlantic on decadal timescales. Current expectations are that through increasing sea-ice melting, river discharge, an intensifying hydrological cycle and glacial melt anomalies, future climate change could disrupt North Atlantic circulation patterns with cascading effects on carbon cycling and global climate. These interactions were investigated through circulation changes associated with salinity and freshwater variability, as well as variability in temperature and heat content. Recent changes in phytoplankton concentration and biological productivity in the Labrador Sea were also examined as part of this study. Spatial and temporal patterns of salinity in the North Atlantic were examined with the help of objective analysis and reanalysis salinity products using Argo observations of the recent decade (2005 to 2015). An overall freshening trend was evident, but with clear regional differences, particularly between the western subpolar gyre and the central North Atlantic. In general, the western subpolar region exhibited high interannual variability in surface salinity compared to the central North Atlantic. The western subpolar region also revealed a seasonal pattern of salinity fluctuation related to sea ice retreat and accretion, but with some years (i.e., 2008, 2012 and 2015) showing unusually large and negative salinity anomalies which were not present in the central or eastern North Atlantic. To understand the dominant factors influencing salinity and freshwater in the northern North Atlantic, budgets for liquid freshwater content over the northern North Atlantic were derived using a state-of-the-art ocean state estimate (ECCOv4). Here the subpolar North Atlantic (between $\sim$45\oN and the Greenland Scotland ridge) is distinguished from the Nordic Seas (north of the Greenland Scotland ridge). In a separate investigation ECCOv4 was used to describe global ocean heat budgets at varying spatial and temporal resolutions. This analysis showed that anomalies in temperature tendency are driven by atmospheric forcing at short time scales, while advection is the principle term at long time scales. ECCOv4 budget analysis was then used to investigate mechanisms behind interannual freshwater content variability in the northern North Atlantic over the time period 1992-2015. From the mid-1990s to the mid-2000s warming and salinification occurred in the subpolar North Atlantic. Consistent with the upper layer analysis with Argo-observations, ECCOv4 confirmed an overall freshening since about 2005. This freshening occurs simultaneously with an overall cooling in the subpolar North Atlantic. Advective convergence has been identified as the dominant driver of liquid freshwater content and ocean heat content variability in the subpolar North Atlantic, with liquid freshwater and heat content being anti-correlated. Consistent with the global heat analysis in ECCOv4, our results revealed that forcing is only important for establishing anomalies over shorter time scales (i.e., seasonal to interannual), but advective convergence becomes more important at longer (i.e., decadal) scales. Advection is the dominant term due to changes across the southern boundary on the decadal time scale, while exchanges with the Arctic Ocean have minor impact. Changes in freshwater and heat content in the subpolar North Atlantic due to advection occur through anomalies in the circulation itself, and not by the advection of anomalies in either liquid freshwater or heat content. In contrast to the subpolar North Atlantic, in the Nordic Seas interannual changes in liquid freshwater content are predominantly driven by forcing due to sea ice melting, which is in turn strongly correlated with Arctic sea ice export through Fram Strait. The overall concurrent warming and salinification followed by cooling and freshening in the subpolar North Atlantic suggests a relationship with changes in northward heat and salt transport through the Atlantic Meridional Overturning Circulation. This is consistent with decadal variability in deep convection in the Labrador Sea. It is evident that another consequence of changes in the Labrador Sea deep convection is the potential effects on nutrient availability and thus biological productivity. The Labrador Sea has become more productive in recent years, with mean chlorophyll-a concentrations closely correlated with silicate concentrations in the upper waters, which in turn are strongly correlated with wintertime convection depth. Thus annual production in the Labrador Sea appears to be influenced by the extent of deep winter mixing, thereby linking the Atlantic Meridional Overturning Circulation and deep convection to nutrient availability and ocean productivity in the subpolar North Atlantic.

Achieving and maintaining sustainability in irrigated agriculture production in the era of rapidly increasing stress on our natural resources require, among other essential actions, optimum control and management of the applied water. Thus, a significant upgrade of the currently available soil water monitoring technologies is needed. The primary goal of this work was to reduce the uncertainties of spatially variable soil water in the field. Two approaches are suggested: 1) The Bayesian decision model that implicitly accounts for spatial variability at minimal cost based on limited field data, and 2) The Actively Heated Fiber Optic (AHFO) method that explicitly accounts for spatial variability with high sampling density at relatively low cost per measurement point. The Bayesian decision model uses an algorithm to integrate information embodied in independent estimates of soil water depletion to derive a posterior estimation of soil water status that has the potential to reduce the risk of costly errors in irrigation scheduling decisions. The sources of information are obtained from an ET based water balance model, soil water measurements, and expert opinion. The algorithm was tested in a numerical example based on a field experiment where soil water depletion measurements were made at 43 sites in an agricultural field under center pivot irrigation. The results showed that the estimates of the average soil water depletion in the field obtained from the posterior distributions of soil water depletion proved to outperform simple averaging of n soil water depletion measurements, up to n = 35 measurements. For n< 3, the model also provided a 39% average reduction in risk of error derived from non-representative measurements. The AHFO method observes the heating and cooling of a buried fiber optic (FO) cable through the course of a pulse application of energy as monitored by a distributed temperature sensing (DTS) system to reveal soil water content simultaneously at sub-meter scale along the FO cable that can potentially exceeds kilometers in length. A new and simple interpretation of heat data that takes advantage of the characteristics of FO temperature measurements is presented. The results demonstrate the feasibility of AHFO method application to obtain <0.05 m³m⁻³ error distributed measurements of soil water content under laboratory controlled conditions. The AHFO method was then tested under field conditions using 750 m of FO cables buried at 30, 60, and 90 cm depths in agricultural field. The calibration curve relating soil water content to the thermal response of the soil to a heat pulse was developed in the lab. It was successively applied to the 30 and 60 cm depths cables, while the 90 cm depth cable illustrated the challenges of soil heterogeneity for this technique. The method was used to map with high spatial (1m) and temporal (1hr) resolution the spatial variability of soil water content and fluxes induced by the non-uniformity of water application at the surface.
Graduation date: 2012

碩士
靜宜大學
食品營養研究所
99
The resistant starch is defined by Food and Agriculture Organization of the United Nations as “The small intestine of healthy people can not be absorbing and degradation products which can enhance the probiotics, decreasing the functional colonic disease and reducing calorie ingestion and then control the body weight”. The purpose of this study were to investigate the effect of osmotic pressure treatment (OPT) and simultaneous heat-moisture phosphorylation treatment (HMPT) on the physicochemical properties, resistant starch content and estimated glycemic index of high amylase starches. Two local starches, including mung bean and water caltrop, and high amylase corn starch (Hylon VII) were treated by both treatment methods for 15-60 min, respectively, in this experiment. The results indicated that the content of resistant starch increased with the increase of processing time in all three tested samples. The treatment of OPT and HMPT promoted the gelatinization temperature (To, Tp, Tc) but decreased the gelatinization enthalpy and pasting viscosity of tested starches. The results also observed that the swelling power and solubility decreased as the treatment time increased on three tested starches. The hardness of mung bean and water caltrop starch gel decreased as those starches were treated by OPT but increased in HMPT mung bean gel. According to X-ray diffraction, the relative crystallinity of starch increased as the starches were treated by OPT and HMPT. The crystal type of Hylon VII corn starch was changed from B-type to Ca-type after OPT treatment. The changes of particle size were observed that the particle size of three tested starches decreased with the increase of HMPT processing time. Moreover, the surface of mung bean starch particle appeared concavity when mung bean starch was processed by OPT. The estimated glycemic index of all processed starches by OPT and HMPT decreased as compared with rice starch

碩士
國立中興大學
園藝學系所
101
Taiwan is an oriental fruit fly quarantine area. Therefore, vapor heat quarantine treatment is necessary before the export of papaya fruits. Besides, papaya fruits are also susceptible to disease caused commercial loss during storage, transporting and marketing. Previouse research, hot water treatment is able to control the pathogen infection in papaya fruit. Therefore, this study is to evaluate to effect of combinafion of hot water and vapor heat treatment on fruit disease control and the influence on color change of fruits’ peel. Furthermore, this study also investigated the changes of the antioxidant content and antioxidant enzymatic activity of papaya fruits under 25℃ for 24 hours after the hot water treatment and the time after the vapor heat treatment. For the winter fruits, 57℃ hot water treatment for 90 seconds caused heat injury. On the contrary, the summer fruits had no sign of heat injury either in 55℃ or 57℃ hot water treatment for 90 seconds. Undergoing a vapor heat treatment immediately after a hot water treatment had led the declination chlorophyll fluorescence value and inhibited the color change of the fruits’ peel. This phenomenon also followed the decreasing of chlorophyll fluorescence, increasing in hydrogen peroxide (H2O2) content and no significant changed in the activity of antioxidant enzyme. However, placing at 25℃ for 24 hours after hot water treatment then vapor heat treatment significantly improved the color change of fruits’ peel which might due to the recovery of chlorophyll fluorescent value and H2O2 content and increasing in antioxidant enzyme like superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD). Meanwhile, when the fruit placed at 25℃ for 24 hours after hot water treatment then vapor heat treatment found only CAT and APX had significantly increased. All of the treatments in this study had no significant influence on the electrolyte leakage, malondialdehyde (MDA), antioxidant capacity (FRAP), ascorbic acid (AsA), and total phenolic compounds (TPC).

Dissertação de Mestrado em Engenharia Electrotécnica
Hoje em dia, com o desenvolver da técnica de gestão de processos agrícolas, torna-se imperativo a utilização de aparelhos de medição mais precisos e baratos de forma a rentabilizar o processo agrícola. Tradicionalmente, a instrumentação associada a esse tipo de aparelhos revela alguns pontos fracos a serem desenvolvidos, tais como a necessidade de fios ou então o desfasamento temporal entre leitura e verificação dos dados. Além disso, as mais recentes técnicas de controlo baseadas na resposta fisiológica das plantas requerem a monitorização de parâmetros extraídos das próprias plantas, parâmetros como o teor de água no solo junto às raízes, concentração de nitratos e de poluentes, bem como o fluxo de água/nutrientes nas raízes. Estas são algumas das grandezas que podem ser obtidas e processadas numa sonda Multi-Funcional com comunicações sem fios. Sensores baseados no método do pulso de calor demonstram eficácia em medir simultânea e automaticamente e em várias situações o teor de água no solo, as propriedades térmicas e a condutividade elétrica do solo. A capacidade de análise dos dados recolhidos in loco por tal conjunto de instrumentos é de grande importância, uma vez que tradicionalmente os dados são colectados e posteriormente processados e, com isso, perde-se tempo de actuação. O presente equipamento pretende dar uma resposta a essa questão na medida em que tanto a leitura como o processamento de dados serão efectuados no próprio dispositivo e posteriormente transmitidos. Na presente dissertação, é demonstrado o desenvolvimento do software por trás de tal dispositivo e são sugeridos e testados alguns métodos de análise de dados tradicionalmente utilizados, como os algoritmos de Levenberg-Marquardt, Trust Region, o método do valor máximo mas também um novo método.
Nowadays with the developing of the management of agricultural processes, becomes imperative the development of cheaper and preciser measurement devices, so to become profitable and economically viable. Traditionally the instrumentation used has some weak spots that must be developed, like the need of wires or the challenge to collect and process de data sequentially. Beyond that, the newest control techniques based on the physiological response of plant require the monitoring of the extracted parameters of plants. Parameters like water content near the roots, pollutant and nitrates concentration, water/nutrients flux in roots. These are some of the characteristics that must be collected and processed in a multi-functional probe enriched with wireless communications. Sensors based in the heat pulse method show efficiency in the simultaneous and automatic measurement of the water content, thermal properties and electrical conductivity in soils. The ability to locally analyze the collected data by such device is of great importance, since, traditionally the data is collected and processed later. In this situation the response time is delayed. The present solution intents to overcome this by means of collecting and processing the data in the same device. In this dissertation it is shown the development of the software underneath such device. It is also compared and tested some methods of data analysis like the Levenberg-Marquardt, Trsut-Region algorithm, peak point algorithm and also a new method.