Дисертації з теми "CFD experimental"
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Hardie, Staffan. "Drag Estimations on Experimental Aircraft Using CFD." Thesis, Mälardalen University, Department of Mathematics and Physics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-334.
Повний текст джерелаThe drag approximations done in the initial design phase needed to be verified. A model of the aircraft has been analyzed with CFD and results examined to see how accurate the estimations were. A step by step analysis was made and then a simulation was run. The drag results of the CFD analysis did not meet the goal of the initial design study. Several reasons for this are discussed. The analysis shows that the aircraft design works well aerodynamically but also shows a few areas where the design can be improved.
Det approximerade värdet på luftmotståndet som gjordes I den preliminära designfasen behövde verifieras. En flygplansmodell har analyserats med CFD och resultaten har undersökts för att se hur exakta antagandena var. En analys gjordes steg för steg och slutligen har en simulering utförts. Det uppmätta luftmotståndet motsvarade inte målet i den preliminära designfasen. Flera olika anledningar till detta diskuteras. Analysen visar att denna flygplansdesign fungerar bra aerodynamiskt men identifierar också en del punkter på vilken den kan förbättras.
li, zhiliang. "EXPERIMENTAL AND CFD INVESTIGATIONS OF LIFTED TRIBRACHIAL FLAMES." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3048.
Повний текст джерелаPh.D.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering PhD
Wang, Zhiguo. "Experimental studies and CFD simulations of conical spouted bed hydrodynamics." Thesis, University of British Columbia, 2006. http://hdl.handle.net/2429/61.
Повний текст джерелаSupamusdisukul, Jirapat. "Experimental investigation of wing-fuselage integration geometries including CFD analyses." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8141.
Повний текст джерелаThesis research directed by: Dept. of Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Prasser, Horst-Michael, Tobias Sühnel, Christophe Vallée, and Thomas Höhne. "Experimental investigation and CFD simulation of slug flow in horizontal channels." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-28061.
Повний текст джерелаEbrahimi, Mohammadreza. "CFD-DEM modelling of two-phase pneumatic conveying with experimental validation." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9693.
Повний текст джерелаPrasser, Horst-Michael, Tobias Sühnel, Christophe Vallée, and Thomas Höhne. "Experimental investigation and CFD simulation of slug flow in horizontal channels." Forschungszentrum Dresden-Rossendorf, 2007. https://hzdr.qucosa.de/id/qucosa%3A21634.
Повний текст джерелаSemenzin, Clayton S. "Determination of Centrifugal Blood Pump Characteristics using CFD and Experimental Analysis." Thesis, Griffith University, 2021. http://hdl.handle.net/10072/401348.
Повний текст джерелаThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text
Naronikar, Aditya, and Anton Riström. "CFD and Experimental Study of Refuelling and Venting a Fuel System." Thesis, Linköpings universitet, Mekanisk värmeteori och strömningslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-159297.
Повний текст джерелаRiström, Anton, and Aditya Naronikar. "CFD and Experimental Study of Refuelling and Venting a Fuel System." Thesis, Luleå tekniska universitet, Rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-75410.
Повний текст джерелаCamara, Enrique. "Validation of Time Domain Flutter PredictionTool with Experimental Results." Thesis, KTH, Kraft- och värmeteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160541.
Повний текст джерелаThesis work done at Siemens Industrial Turbomachinery, Finspang, Sweden.
Songyu, Cao. "Experimental and CFD Study of Wind-Induced Response for Bridge Cables with Ice accretion." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32985.
Повний текст джерелаSeemann, Patrick. "Design of 120cc Single Cylinder Experimental Engine for Analysis of Intake Swirl and Multiple Ignition Sites." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_theses/219.
Повний текст джерелаVivekanandhan, Bagya. "Analysis on experimental and numerical modelling of floating structures using cfd codes." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Знайти повний текст джерелаXinzhe, Wang, and Li Xin. "Experimental and CFD Study of Flow Phenomenon in Flowrate-amplified Flotation Element." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200558.
Повний текст джерелаVieira, Neto José Luiz. "Estudo Experimental e de Simulação por CFD de Escoamentos em Seções Anulares." Universidade Federal de Uberlândia, 2011. https://repositorio.ufu.br/handle/123456789/15056.
Повний текст джерелаA crescente atividade de extração de petróleo e gás em águas cada vez mais profundas tem impulsionando diversos estudos para solucionar problemas encontrados na perfuração de poços. Durante a operação de perfuração, um fluido (lama de perfuração) é bombeado através da coluna até o fundo do poço, retornando à superfície carreando os cascalhos gerados pela broca, passando pelo espaço anular formado entre a coluna e a parede do poço. Neste tipo de escoamento pode ocorrer um tipo de instabilidade hidrodinâmica caracterizada pelo aparecimento de vórtices toroidais. Este tipo de instabilidade (Taylor-Couette), pode alterar profundamente a perda de carga do escoamento, a tensão cisalhante na parede do poço e a capacidade de carreamento de cascalho. Além disto, durante o processo de perfuração de um poço é necessário promover o revestimento e a cimentação do poço para fornecer a sua sustentação mecânica, bem como, para isolá-lo das diferentes formações rochosas atravessadas. Para esta etapa ser bem sucedida, a lama de perfuração deve ser completamente removida do anular, sendo que, esta remoção pode ser prejudicada em poços que apresentem excentricidade variando ao longo do tubo. Devido aos altos custos das operações de correção e a perda de tempo de perfuração, é fundamental prever este deslocamento da lama ao redor do anular. Os efeitos desta variação da excentricidade ainda não foram muito abordados na literatura e podem apresentar grande influência no deslocamento da lama no espaço anular. Como etapa inicial do trabalho, foram realizadas simulações numéricas para estudar o escoamento com surgimento de instabilidades do tipo Taylor-Couette em uma seção anular concêntrica, com intuito de compará-las com trabalhos da literatura. Depois foram desenvolvidas simulações numéricas em seções anulares periódicas, concêntrica e excêntrica (E = 0,5), a fim de obter perfis médios de velocidades axial e tangencial usando diferentes modelos de turbulência, visando uma comparação dos resultados simulados com os dados experimentais da literatura. Posteriormente, foi feito um estudo experimental e de simulação para avaliar o efeito da rotação do eixo interno sobre a queda de pressão no escoamento de fluidos não-Newtonianos (soluções aquosas de Goma Xantana e de Carboximetilcelulose a 0,2% em peso) numa seção anular concêntrica e outra com excentricidade fixa (E = 0,75). Finalmente, elaborou-se um planejamento fatorial de experimentos do tipo 3k com quatro variáveis, tais como, concentração de Goma Xantana (0,05%, 0,10% e 0,15%), excentricidade (0,0; 0,23 e 0,46), vazão volumétrica (5, 7 e 9 m3/h) e rotação do eixo interno (0, 100 e 200 rpm). Seguindo este planejamento foram levantados dados experimentais de queda de pressão, bem como, simulações numéricas (CFD) em seções periódicas para obtenção de resultados de velocidade axial, com intuito de avaliar efeito do movimento de rotação excêntrica variável sobre a dinâmica do escoamento de fluidos não-Newtonianos em espaços anulares.
Doutor em Engenharia Química
Ferreira, Tales Adriano. "Avaliação numérica e experimental de um veículo de competição de milhagem." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3150/tde-20072011-090936/.
Повний текст джерелаAmong the many competitions in which students are challenged to build up prototypes with specific purposes there, is one in which the goal is to design a car to carry one person and make it go as long as it can with one liter of fuel. One of the factors that contribute for fuel consumption is the aerodynamic resistance, so to predict its effects is essential for a good design. In this context, the present work had as goals the numerical and experimental evaluation of flow around a Supermileage vehicle and to calculate its drag and lift coefficients in these both ways. It was also studied the sensitivity of these forces to Reynolds number and, in the virtual case, to turbulence models. Thanks to simulation results it was verified that the front part of the model is responsible for great part of drag and negative lift. The drag coefficients fell with the increase of Reynolds number in both numerical and experimental tests. In a comparison of turbulence models comparison, k-E and k-w in their standard forms presented higher CD values than the other models. Experimental CD results showed the same tendency of numerical ones, and were closer to standard k-, although it was believed that a negative angle of attack due to experimental assembly issues has made for a higher experimental CD. Lift coefficients values fell with the increase of Reynolds number in virtual analysis and grew in experimental tests. In the simulations it was observed that the high velocity between the two front wheels, due to the short distance between the vehicle and the ground, is responsible for a large portion of the negative lift. Owing to assembly issues it was not possible to reproduce this ground effect on experimental tests. Flow visualization results presented good agreement between experimental and numerical testing.
Nasro-Allah, Youssef. "Experimental and numerical investigation of electrostatic effects in gas-solid fluidized beds." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0136.
Повний текст джерелаGas-solid fluidized beds are widely used in industrial processes for energy such as chemical looping combustion, catalytic polymerization, solar receiver, biomass gasification and petroleum refinery. In all these processes, electrostatic forces were usually neglected. In polyolefin industry, the phenomena of electrostatic charges presents a major issues including wall fouling. At a molecular scale, the contact between two particles generates a transfer of electrons/ions, inducing a charge on each particle. As a result, the surrounding gas carries an electric field, resulting in an additional force to the momentum equation known as Lorentz force. The phenomenon depend on many parameters, including materials properties and operating conditions. Several works in literature studied the effect of each parameter. However, there is a lack of research projects which combine both experimental study and theoretical modelling with numerical simulation. Thus, this study falls within the context. It is a part of the Attractivity Chair BIREM (BIological, REacting, Multiphase flows) attributed to Professor Rodney Fox, financially supported by the University of Toulouse, in the framework of the IDEX research program. The project is hosted by the research federation FERMaT. The study aims to combine both experimental study in a lab-scale pilot and the numerical modelling in order to represent the electrostatic force in CFD code through the Euler-Euler formalism. In this work, experiments were performed on different particles size distributions, different materials and different operating conditions. The experimental setup, designed and built during the PhD thesis, consisted of a 1 m height and 0.1 m inner diameter plexiglass column. The measuring technique used for charge is a Faraday cup connected to an electrometer. Results shows two categories of particles: dropped particles that falls immediately after opening the valve and wall particles that stick to the wall. Results show no effect of relative humidity on minimum fluidization velocity (Umf). The evolution of the net charge versus fluidization time showed an exponential trend that reached an equilibrium value for both categories. Wall particles were charged 250 to 450 times than dropped ones. The net charge was decreased by increasing relative humidity. Small particles showed a positive charge whereas all other PSDs were negatively charged. The equilibrium charge of dropped particles did not show significant changes when increasing gas velocity whereas the time needed to reach equilibrium was slightly increased. Wall particles equilibrium charge was significantly increased. On the other hand, the numerical work built an electrostatic model for the Lorentz force in an Eulerian approach. Simulations were carried out with a software called NEPTUNE_CFD. The walls were assumed to be grounded. The model was tested with several test cases. After that, a tribocharging model was developed to take into account the charge generation and transfer. The model was inspired from previous works and transposed into an Eulerian approach. The wall boundary conditions were developed in this study by using less restrictive hypothesis. An estimation of the characteristic times of both charge generation and diffusion was performed, showing that the timescale is very high (several days) and does not match with experimental findings (15 to 20 min). A corrective coefficient was proposed to match with experimental results. Moreover, numerical simulations on a fluidized bed with the same dimensions as the experimental pilot were carried out. In these simulations, the permanent regime was considered. The equilibrium charge was prescribed on the particles. Simulations aimed to compare the no-charge case and the charged case. The effect of the charge on the flow properties were highlighted. These results pointed out the crucial effect of the electrostatic on the gas-particle fluidized suspension
Vazquez, Numez Bernardo. "An experimental and numerical study of forced convection in ventilated chambers." Thesis, King's College London (University of London), 1997. https://kclpure.kcl.ac.uk/portal/en/theses/an-experimental-and-numerical-study-of-forced-convection-in-ventilated-chambers(5525a851-2a87-4a65-9669-d7098efd28ac).html.
Повний текст джерелаWang, Zhida. "Experimental and CFD Investigations of the Megane Multi-box Bridge Deck Aerodynamic Characteristics." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32209.
Повний текст джерелаSousa, Alves Joao. "Experimental and CFD Analysis of a Biplane Wells Turbine for Wave Energy Harnessing." Thesis, KTH, Mekanik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-124070.
Повний текст джерелаAbdulkadir, Mukhtar. "Experimental and computational fluid dynamics (CFD) studies of gas-liquid flow in bends." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12218/.
Повний текст джерелаSkirpan, Zachary. "Multiphase CFD benchmark of experimental critical heat flux data at PWR operating conditions." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127300.
Повний текст джерелаCataloged from the official PDF of thesis.
Includes bibliographical references (pages 85-89).
Critical Heat Flux (CHF) in flow boiling represents the fundamental upper limit for thermal hydraulic performance of PWR fuel. Currently, the nuclear industry relies on expensive, prototypical experiments using electrically heated, full-height rod assemblies to determine the limit of the boiling crisis. The development of next-generation Multiphase Computational Fluid Dynamics (M-CFD) approaches for the prediction of CHF seeks to represent the detailed physics of the boiling process up to its critical condition, rather than estimating it from ad-hoc thresholds. In this work we evaluate the advancement in M-CFD boiling attained by the Consortium for Advanced Simulation of Light water reactors (CASL). The CASL approach builds off an industry-lab-university collaboration with individual validation of interfacial momentum closures and wall boiling models.
The M-CFD simulations were implemented in the commercially available STAR-CCM+ software, and benchmarked against experimental observations of CHF collected at the University of Wisconsin by Duarte. In this work, 15 M-CFD simulations were completed. Boiling curves were generated for each test case. The modelled boiling characteristics were then compared to expected physical parameters to determine model accuracy. Structural spacers are the main driver of vapor accumulations leading to the breakdown of boiling heat transfer at CHF. Interestingly, M-CFD solutions indicate that the Departure from Nucleate Boiling (DNB) first occurs in areas not measured by the experimental thermal couples used to detect CHF, possibly resulting in a late experimental detection. Additionally, sensitivity studies are conducted for relevant model terms to understand their impact on CHF.
Leveraging the results from this sensitivity study, it is suggested that improved predictions could 1) increase the turbulent dispersion at the wall to account for turbulence under-prediction and 2) increase the minimum bubble size limiter to reflect physically observed coalesced bubble sizes after departure. For future work, higher spatial resolution measurements for detecting DNB are suggested for better experimental CHF predictions. A fully mechanistic approach for modeling the heat flux partitioning and subsequent wall boiling in M-CFD is also needed to more effectively simulate the proper heat transfer mechanisms and boiling physics before CHF. It is the hope that through this work and further M-CFD heat transfer investigations that similar methods may be validated for CHF detection and streamline the fuel design process in the nuclear industry.
by Zachary Skirpan.
S.M.
S.M. Massachusetts Institute of Technology, Department of Nuclear Science and Engineering
Santolini, Enrica <1989>. "Study of ventilation strategies, in agricultural buildings through CFD modeling and experimental analysis." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amsdottorato.unibo.it/8852/1/tesi_dottorato_ES.pdf.
Повний текст джерелаMarineau, Eric Christian. "Computational and Experimental Investigation of Supersonic Convection over a Laser Heated Target." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/27919.
Повний текст джерелаPh. D.
Silva, Marcela Kotsuka da. "Estudo numérico e experimental de uma coluna de bolhas operando em regime heterogêneo." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266911.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
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Resumo: Os principais problemas da simulação da fluidodinâmica em sistemas gás-líquido por CFD são as simplificações do comportamento dinâmico das bolhas. Na maioria dos processos industriais com escoamento gás-líquido em colunas de bolhas, as bolhas estão em velocidades altas e a coluna opera em regime heterogêneo. Existe ainda a influência da geometria do sistema e das propriedades físicas dos fluídos envolvidos no processo. Para que a técnica CFD seja aplicada adequadamente, visando aplicações industriais, é necessário considerar os fenômenos de quebra e coalescência. No entanto, existe uma carência de dados experimentais em tal regime de operação para testar a aplicabilidade dos modelos matemáticos empregados nas simulações. Neste trabalho é apresentado um estudo numérico e experimental de duas colunas de bolhas operando em regime heterogêneo. No primeiro caso, foram realizadas análises quanto a influência de diferentes modelos de arraste, além do emprego das forças interfaciais de sustentação e de dispersão turbulenta. Diferentes modelos de turbulência foram também verificados, tomando a fração volumétrica de gás em diferentes posições axiais e velocidade do gás provenientes da literatura. No segundo caso, realizou-se medidas por meio da técnica PIV de velocidades axiais médias da fase líquida e suas flutuações. Análises de intensidade turbulenta, tensores de Reynolds e energia sindética turbulenta foram realizadas, a fim de obter informações acerca da turbulência em três diferentes velocidades superficiais de gás. Para as análises numéricas foi aplicado um modelo matemático tridimensional, turbulento e transiente para a representação do escoamento nas duas colunas utilizadas. Este modelo trata ambas as fases, gás e líquido, a partir de uma abordagem Euleriana. Diferentes distribuições de tamanhos de bolhas foram empregados por meio do balanço populacional considerando os fenômenos de quebra e coalescência. Perfis radiais de fração volumétrica e velocidade de gás, além de perfis de velocidade média de líquido foram confrontados com dados experimentais publicados e medidos respectivamente. O modelo matemático previu um escoamento semelhante aos que foram encontrados nas colunas propostas
Abstract: The main problems encountered in the simulation of gas-liquid systems with the use of CFD are related to the simplifications of the bubble dynamic behavior. In most industrial procedures with gas-liquid flown in bubble columns, bubbles are at high speed and the column operates in the heterogeneous regime. There still is the influence of the system's geometry and fluids physical properties involved in the process. For correctly applying the CFD technique, aiming industrial applications, it is necessary to consider the breakup and coalescence phenomena. Nevertheless, there is a lack of experimental data available in this operational regimen to test the feasible application of the mathematical models used in simulations. In this work it is presented a numeric and experimental study of two bubble columns operating in the heterogeneous regime. In the first case, analyses of different drag models, besides the employ of the interfacial forces of lift and turbulent dispersion were performed. Different turbulence models were also verified, taking the gas holdup in different axial positions and gas velocity from literature. In the second case, measurements of mean axial liquid velocities and their fluctuations were performed with the PIV technique. Turbulence intensity, Reynolds stress tensors and turbulent kinetics energy analyses were performed in order to obtain information about the turbulence for three different gas superficial velocities. For the numerical analyses a tridimensional, turbulent and transient mathematical model to represent the flow in the two columns was applied. This model treats both phases, gas and liquid, with an Eulerian approach. Different bubbles size distributions were used by population balance considering the breakup and coalescence phenomena. Gas holdup, gas velocity and mean axial liquid velocity radial profiles were confronted to the published and acquired experimental data respectively. The mathematical model predicted a developed flow similar to those found in the proposed columns
Doutorado
Desenvolvimento de Processos Químicos
Doutor em Engenharia Química
Sagerman, Denton Gregory. "Hypersonic Experimental Aero-thermal Capability Study Through Multilevel Fidelity Computational Fluid Dynamics." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1499433256220438.
Повний текст джерелаAfolabi, Eyitayo Amos. "Experimental investigation and CFD simulation of multiphase flow in a three phase pipe separator." Thesis, University of Newcastle Upon Tyne, 2012. http://hdl.handle.net/10443/1756.
Повний текст джерелаOchieng, A., MS Onyango, and KH Kiriamiti. "CFD simulation and experimental measurement of nickel solids concentration distribution in a stirred tank." The Journal of The Southern African Institute of Mining and Metallurgy, 2010. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001926.
Повний текст джерелаChowdhury, Mohammed Gofran. "Experimental validation of CFD model predicting wind effects on inclined-roof mounted photovoltaic modules." Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-201033.
Повний текст джерелаDifferent models have been developed to identify and characterize photovoltaic system output with regards to irradiation and temperature. Experimental investigation suggests that when PV module is subjected to wind then the temperature differences on the module surfaces shows significant changes. The relation of wind flow field around the module in respect to the changing air gap and detailed roof structure was never studied in detail. In all of relevant studies, temperature of the PV surfaces was regarded as constant, whereas both the temperature and heat transfer rate on the module surfaces are variable with respect to positions on the module affected by wind flow conditions. Further changes in air flow occur when subjected to different air gap and different inclined roof structure. In this thesis the wind flow modelling was constructed with CFD. Experiments were performed on purpose built wind tunnel with the inclined roof setup of inclined building applied photo voltaic setup (BAPV) to validate the modelling. A satisfactory agreement was observed while comparing with simulation data and experimental results. Reynolds Averaged Navier Stokes with steady state solver was used to simulate a 3D geometric model of a BAPV module with the steady inlet condition. This study investigates wind flow field around and on near surfaces of the module. Wind flow velocity (1-5 [m/s]) and gap underneath the module (3.5,5.5 [cm]) was varied to study. Moreover, later in this thesis the impact of the different inclined roof structure was also studied with 3 different geometries. The result shows significant sensitivities of wind flow field due to small changes of inclined roof structure.
Liu, Ying. "Computational and experimental investigation of turbulent mixing in multiscale reactors for CFD model validation." [Ames, Iowa : Iowa State University], 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3383368.
Повний текст джерелаRezende, Hugo Cesar. "Estudo teórico e experimental da estratificação térmica : monofásica em tubulações horizontais." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266765.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
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Resumo: O escoamento monofásico termicamente estratificado ocorre em tubulações horizontais onde duas camadas diferentes de um mesmo líquido escoam separadamente, sem que ocorra mistura significativa entre as camadas, devido às baixas velocidades e à diferença de densidade (e temperatura). As consequências desse fenômeno não foram consideradas no projeto da maioria das centrais nucleares atualmente em operação. Entretanto, em alguns componentes de centrais nucleares, as diferenças de temperatura podem atingir cerca de 200 °C em uma região bastante estreita nas proximidades da interface entre as camadas de água fria e quente. Nesta condição, as fortes tensões geradas pelas diferenças de dilatação podem comprometer a integridade estrutural e a vida útil de tubulações relacionadas aos sistemas de segurança dessas centrais nucleares. Com o objetivo de estudar o fenômeno da estratificação foi projetada e construída a Instalação de Testes de Estratificação Térmica (ITET), tendo sido realizada uma série de experimentos simulando o bocal de injeção do gerador de vapor de uma central nuclear tipo PWR. Foram estudadas a evolução e as configurações de escoamento em regime de estratificação térmica, assim como a influência do número de Froude nos gradientes de temperatura, na posição da interface entre as camadas de água fria e de água quente e no aparecimento de oscilações desta interface. Os experimentos foram realizados com número de Froude variando de 0,02 a 0,4...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital
Abstract: One phase thermally stratified flows occur when two different layers of the same liquid at different temperatures flow separately in horizontal pipes without appreciable mixing due to the low velocities and difference in density (and temperature). The phenomenon was not considered in the design stage of most of the operating nuclear power plants. However, temperature differences of about 200 °C have been found in a narrow band around the hot and cold water interface in components under stratified flows. Loadings due to this phenomenon affected the integrity of safety related piping systems. The Thermal Stratification Test Facility (ITET), built to allow the experimental simulation of the thermal stratification, is presented so as the results of some experiments simulating one phase thermally stratified flows in geometry and flow condition similar to a nuclear reactor steam generator nozzle. They have the objective of studying the flow configurations and understanding the evolution of the of thermal stratification process. The driving parameter considered to characterize flow under stratified regime due to difference in specific masses is the Froude number. Different Froude numbers, from 0.02 to 0.4, were obtained in different testes by setting injection cold water flow rates and hot water initial temperatures as planned in the test matrix. Results are presented showing the influence of Froude number on the hot and cold water interface position, temperature gradients and striping phenomenon...Note: The complete abstract is available with the full electronic document
Doutorado
Sistemas de Processos Quimicos e Informatica
Doutor em Engenharia Química
Priyadarshi, Harsh. "Experimental and Numerical Study of Calcium Treatment of Steel." Thesis, Ecole centrale de Nantes, 2019. http://www.theses.fr/2019ECDN0017/document.
Повний текст джерелаIn order to diminish the harmful effects of aluminate inclusions and improve the castability of molten steel, calcium treatment is widely used in Aluminum killed steels. However, calcium treatment gives irregular results. Even with many efforts done to understand the behavior of calcium in liquid steel, it is not yet accurately predicted. Therefore, the mechanism by which the calcium dissolves into the liquid steel and transforms the solid inclusions must be understood to optimize the process conditions such as injection speed, injection depth, injection wire diameter, stirring time, etc. In order to understand the mechanism by which the calcium dissolves into the liquid steel, laboratory scale experiments have been performed in a small induction furnace of 2.5 kg metal capacity. The calcium injections are performed at the temperature below and above the boiling point of calcium. Then, the corresponding yields (calcium recovery) are compared. Rise of calcium droplet or bubble in liquid steel is a three-phase problem (calcium droplet or calcium bubble/liquid steel/air at the top). Therefore, an in-house scientific computational platform (ICI-tech) based on finite element methods is adapted to allow the modeling of such three-phase flows, which is validated using the classical benchmark issued from the literature. The dissolution model has been implemented in our software, and their validation has been performed. Thereafter, the rise of Calcium droplets and bubbles are studied in the liquid steel, and their respective average mass transfer coefficient in the liquid steel is reported. In order to study the calcium liquid/gas phase change, the nucleation model has been implemented in the code (ICI-tech). A typical test is performed where the growth of a bubble (water vapor) in uniformly superheated water and growth of a calcium bubble in uniformly superheated Ca liquid is computed
Atkins, D. W. "The CFD assisted design and experimental testing of a wing-sail with high lift devices." Thesis, University of Salford, 1996. http://usir.salford.ac.uk/14811/.
Повний текст джерелаBenzon, Shaun. "The Turgo impulse turbine : a CFD based approach to the design improvement with experimental validation." Thesis, Lancaster University, 2016. http://eprints.lancs.ac.uk/82918/.
Повний текст джерелаThe CFD model verification has shown that although the absolute performance of the Turgo system can be modelled numerically to within a good degree of accuracy, it requires combining injector and runner models as well as estimating additional losses in the pipework which can prove time consuming. However for design comparison and optimisations the CFD models have been shown to be far more accurate suggesting that this is where these numerical models are most useful.
Jalili, Vahid. "Application of CFD in designing a drug delivery mixing chamber : an experimental and computational study." Thesis, University of Greenwich, 2004. http://gala.gre.ac.uk/6196/.
Повний текст джерелаMaciel, Liliane Fernandes. "Brise-chaminé-solar: avaliação experimental e por simulação CFD/EnergyPlus de um dispositivo de ventilação." Universidade Federal de Viçosa, 2016. http://www.locus.ufv.br/handle/123456789/8454.
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Eletrobrás
Dentre os múltiplos critérios a serem considerados na concepção do projeto de escolas, destaca-se o conforto ambiental por apresentar relação direta na eficácia do processo educativo. Esta pesquisa trata do desenvolvimento de um elemento arquitetônico e da avaliação de seu potencial de utilização em salas de aula. O objetivo deste trabalho consiste em conceber e avaliar o desempenho de um brise- chaminé-solar. Investigou-se o potencial de utilização de proteções solares sob a forma de chaminés solares para promover a ventilação natural. Soluções projetuais foram avaliadas parametricamente por meio de dois pacotes comerciais de simulação computacional, cujas potencialidades e fragilidades foram discutidas. Os resultados deste estudo constatam que os programas de simulação predial e de CFD (Dinâmica de Fluidos Computacional) apresentaram discrepâncias relevantes, de modo que se torna arriscada a tomada decisões projetuais com base em resultados de simulação não validados. Em seguida, discutiu-se de forma mais aprofundada a simulação CFD, incluindo os métodos de modelagem, medição in loco, e os desafios pertinentes à validação dos resultados obtidos com ferramentas de simulação CFD. Os dados reais indicaram que os resultados da simulação CFD foram válidos. Ressalta-se a importância da realização de testes para calibração. Por fim, avaliou-se o desempenho térmico e luminoso de uma sala de aula com brise-chaminé-solar. Identificou-se que o dispositivo foi capaz de reduzir a temperatura operativa da sala de aula, alterando os percentuais de horas em conforto térmico. Com relação à renovação de ar, o brise-chaminé-solar alcançou as taxas recomendadas para a qualidade do ar interior. O brise-chaminé-solar apresentou, ainda, capacidade de reduzir os níveis de desconforto por excesso de iluminação em salas de aula, especialmente sob condições de céu encoberto.
Among the multiple criteria to be considered during the design of scholar buildings, the environmental comfort can be highlighted because of its straight relation with the efficacy of the learning process. This research considers the development of an architectural element and evaluates its potential to be used in classrooms. This study aims to design and evaluate the performance of a shading- solar-chimney. It was investigated the potential use of shading devices under the shape of a solar chimney to promoting natural ventilation. Design solutions were parametrically evaluated using two commercial simulation software, for whose the strengths and weakness were discussed. The results showed that building simulation and CFD (Computational Fluid Dynamics) presented relevant discrepancies, in a way that the design decision based on non-validated simulation results might be risky. In addition, the CFD simulation was discussed in a deeper way, including the modeling methods, in loco measurements, challenges about the validation of the results achieved by CFD simulation tools. The measured data indicated that the CFD results are valid. It is emphasized the importance of the calibration tests. Finally, the thermal and lighting performance of a classroom with the shading-solar-chimney was evaluated. It was identified that the shading-solar-chimney was able to reduce the classroom operative temperature and it changed the percentage of hours in thermal comfort. About the air changes, the shading-solar-chimney achieved the recommended rates to interior air quality. The shading-solar-chimney was, also, able to reduce the levels of discomfort by glare in classrooms, especially under overcast sky.
Amiraftabi, Maryamsadat. "Experimental and CFD–PBM investigation of an agitated bioreactor using a dual helical ribbon impeller." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2021. https://ro.ecu.edu.au/theses/2424.
Повний текст джерелаPavani, Marília Gusman Thomazi. "Estudo experimental e simulação da fluidodinâmica de amido de milho em leito fluidizado pulsado." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/74/74133/tde-26092016-163234/.
Повний текст джерелаFluidization is a unit operation in the chemical, pharmaceutical and food industries. During the fluidization, the solid particles is suspended by a stream air flow. The minimum fluidization velocity indicates the lowest gas velocity in which the particles begin agitation while the terminal velocity is characterized by elutriation, or drag the particles along with gas. Therefore, a fluidized bed must be operated at a gas velocity which is between the minimum fluidization velocity and the terminal velocity. However, cohesive solid particles, characterized by Geldart Group C, are difficult to be fluidized due to the formation of cracks and channeling and areeasily elutriated from chamber. In this work, the fluidization of cornstarch particles occurred by anair flow at 27 °C. Cornstarch showed a mean diameter and solid density equal to 30.3 µm and 1446.7 kg/m3 and could be characterized as a cohesive particulate solid. The effective fluidization velocity and the terminal velocity were equal to (0.66 and 0.68) m/s respectively. The fluidization quality was improved by the use of pulsation air flow. The minimum fluidization velocity was reduced, increasing the fluidization velocity operational range. The air pulsation frequency were studied at (0, 5, 10 and 15) Hz. In a first step, the experimental tests obtained the fluidynamics profiles of pressure drop versus air velocity. Subsequently, the experimental profiles were used to validate the Euler-Euler model in simulations by COMSOL software. The main results emphasized that the numerical models described the fluid dynamic profiles with good approximation. The numerical approach established an equivalent diameter of 100 µm, which was greater than the mass median diameter. This result showed that the fluidization occurred in the form of aggregates of particles, which is a characteristic of cohesive systems. The use of air pulsation also resulted in the rupture of channeling and allowed the fluidization at lower air velocities.
Subramaniam, Vignaesh. "Topology Optimization of Conjugated Heat Transfer Devices : Experimental and Numerical investigation." Thesis, Ecole nationale supérieure Mines-Télécom Lille Douai, 2018. http://www.theses.fr/2018MTLD0013/document.
Повний текст джерелаDesigning thermal devices that are more compact with less mass, less frictional losses and increased thermal efficiency is a key requirement for enhanced performances at a lower cost. The present PhD thesis investigates the potential and validity of topology optimization numerical method as a viable CFD tool to generate optimal thermal designs as compared to conventional approaches like shape and parametric optimization. The first part of the thesis presents an experimental investigation of topology optimized tree-like structures made of two materials. The topolgy optimization mathematical problem is formulated and implemented in OpenFOAM®. It is applied to the topolgy optimization problem of volume-to-point heat removal. Experimental thermal measurements are carried out, on the optimal structures, using infrared thermography in order to quantify their heat transfer performances and thus validate the performances of the optimal structures determined by the developed topology optimization code. The second part of the thesis presents an innovative bi-objective optimization technique for topology optimization of Conjugate Heat Transfer (CHT) systems under laminar flow regimes. For that purpose, an inequality constrained bi-objective topology optimization problem is developed mathematically and implemented inside the Finite Volume based OpenFOAM® solver. The objective function is formulated by linear combination of two objective functions for pressure drop reduction and heat transfer enhancement which is numerically a very challenging task due to a competition between the two objectives (minimization of pressure drop and maximization of recoverable thermal power). Non-intuitive Pareto-optimal designs were obtained, analyzed, discussed and justified with the help of various global and local numerical analysis methods. Additionally, a recent Lattice Boltzmann topology optimization problem form the literature was solved using the developed OpenFOAM® solver. The objective, in addition to the comparison of the optimal solutions, is also to initiate a case of reference for future studies in this field of research and innovation so as to be able to fully compare the optimal solutions obtained by different and different methods. solvers. Finally, the various experimental and numerical findings highlighted and illustrated in this PhD thesis, demonstrate the importance of the methodology and immense potential behind topology optimization method for designing efficient industrial thermal systems
Bastos, Jaci Carlo Schramm Camara. "Analise experimental e numerica de um jato de dispersão gas-solido." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267143.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Apresenta-se nesta pesquisa uma análise experimental e numérica do comportamento da fase dispersa em um jato circular bifásico confinado e uma comparação com jato circular bifásico livre. Nas análises experimentais, uma câmara pentagonal em acrílico foi utilizada como sistema de confinamento para a obtenção de perfis axiais e radiais de velocidade média, flutuação de velocidade (RMS) e intensidade de turbulência. Estes dados foram analisados a fim de desenvolver uma análise completa da região desenvolvida do jato. Três diferentes jatos foram utilizados para a alimentação da fase gás no topo da câmara, mas apenas o jato central foi carregado com partículas entre 60 e 90µm de diâmetro. Os outros dois foram utilizados para proporcionar uma maior interação entre as fases no interior da câmara. A técnica óptica Phase Doppler Anemometry (PDA), foi empregada na medição da velocidade instantânea da fase sólida e do diâmetro das partículas nas diferentes posições axiais a partir do bico do jato. Nove casos de estudo distintos são investigados individualmente e, em seguida, comparados entre si. Estes casos fornecem informações importantes sobre o comportamento e o efeito do confinamento dos jatos sobre o transporte macrocóspico e turbulento das partículas entre o centro e as regiões de contorno do jato. As análises numéricas tratam da modelagem matemática tridimensional, turbulenta e transiente do escoamento no jato bifásico confinado. O modelo trata as fases gás e sólida a partir de uma abordagem Euleriana. O fechamento das equações de transporte foi realizado utilizando o modelo de turbulência de duas equações k-e para a fase gás e modelos de turbulência de zero-equação para a fase sólida, e ainda em alguns casos esta última apenas sofreu efeitos turbulentos advindos da fase contínua. A acurácia das previsões do modelo em um jato de partículas confinadas com as características médias no tempo, assim como os coeficientes da correlação de turbulência foram avaliados. Perfis radiais de velocidade média e fração volumétrica das partículas foram capturados em quarenta e dois níveis, subdivididos em nove casos e comparados aos dados experimentais adquiridos. O diâmetro médio das partículas utilizado nas simulações foi de 75µm e as velocidades iniciais utilizadas variam entre 3 e 11m/s no jato central. O modelo matemático previu um escoamento desenvolvido semelhante ao que foi encontrado experimentalmente.
Abstract: It is presented in this research an experimental and numerical analisys of the dispersed phase behavior in a circular confined two-phase jet and a comparison with circular free two-phase jet. In the experimental analysis, a pentagonal plexiglass chamber was used as confined system for the axial and radial profiles investigation of mean velocity, fluctuation velocity known as RMS velocity and turbulence intensity. These data were analyzed in order to develop a complete analysis in the developed region of the jet. Three different nozzles were used to feed the gas phase at the top of the chamber, but just the central nozzle was loaded with particles between 60 and 90µm of diameter. The other two were used to increase the interaction between the phases in the chamber. An optical technique known as Phase Doppler Anemometry was used to measure the instantaneous velocity of the solid phase and particle diameter in different axial positions of the jet nozzle. Nine different cases of study are investigated individually and then compared among each other. These cases provide important information about the jets behavior and the confinement effect on the macrocospic and turbulent transport of particles between the jet center and the jet contour regions. The numerical analysis deals with three-dimensional, turbulent and transient mathematical modeling of a confined two-phase jet flow. The model treats the gas and the solid phases from an Eulerian approach. The closure of the transport equations have been accomplished by using the k-e turbulence model for the gas phase and the zero-equation turbulence model for the solid phase, and in some cases the latter suffered turbulent effects occuring only from the continuos phase. The accuracy of the model predictions in a particle-laden confined jet with the characteristics as well as turbulence correlation coefficients have been evaluated. Radial mean velocity profiles for the solid phase were computed on forty two axial levels, subdivided in nine cases and compared to the obtained experimental data. The mean particle diameter used in the simulations was 75µm and the initial velocities used vary between 3 and 11m/s. The mathematical model predicted a flow development similar to that found experimentally.
Doutorado
Desenvolvimento de Processos Químicos
Mestre em Engenharia Química
Renjie, Ke. "Experimental and CFD investigations of the fluid flow inside a hydrocyclone separator with an air core." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1449145729.
Повний текст джерелаMorgan, Ashley T. "Comparison of CFD Simulation and Experimental Data for Heating and Cooling Low N Packed Beds of Spherical Particles." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/1312.
Повний текст джерелаLiu, Hong. "Optimization for Fuel Cells/Fuel Cell Stacks Using Combined Methods---CFD Modeling Analysis, and Experiments." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/297027.
Повний текст джерелаShrestha, Kendra. "Partially Premixed Combustion (PPC) for low loadconditions in marine engines using computationaland experimental techniques." Thesis, KTH, Mekanik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-202624.
Повний текст джерелаKent, Jason A. "Numerical and Experimental Analysis of a TurboPiston Pump." ScholarWorks@UNO, 2010. http://scholarworks.uno.edu/td/1189.
Повний текст джерелаSánchez, Morales Valentin. "Experimental and CFD analysis of the flow in the wake of a vertical axis wind turbine." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/454742.
Повний текст джерелаEsta tesis se divide en dos bloques donde se analiza el flujo de una VAWT. El primer bloque se centra en el estudio experimental y numérico de una VAWT con ocho palas basada en el fenómeno de resistencia. En la primera parte, la velocidad del viento se fija en 10 m/s para medir la curva de potencia de la turbina y los resultados se comparan con los de otras turbinas Savonius en diferentes túneles de viento. También se ha analizado la reducción del número de palas y se ha comprobado que el rendimiento aumenta. En la segunda parte, la velocidad del viento se establece en 4,5 m/s para realizar experimentos de visualización de humo. La técnica de visualización del humo ha permitido validar cualitativamente las simulaciones 2D porque los patrones de flujo visualizados son similares a los simulados numéricamente. Las simulaciones numéricas han demostrado que el rendimiento es mayor con cuatro palas. En el segundo bloque, se propone y analiza un nuevo modelo para predecir la estela de las VAWTs. El modelo se basa en el disco actuador y en los métodos de Doble tubo de flujo múltiple. El modelo, denominado MAB (Multiple Actuator Block), se basa en la definición, dentro del dominio computacional, de múltiples bloques paralelepipédicos distribuidos a lo largo de la trayectoria de las palas. Los sumideros volumétricos de momento se imponen en estos bloques para modelar el efecto de las palas sobre el flujo. Las simulaciones con el modelo MAB se han comparado con una simulación de volumen finito completo usando la técnica de malla deslizante. Esta simulación requiere aproximadamente diez veces más tiempo de CPU que las simulaciones usando el modelo MAB. Se ha encontrado que las características a gran escala de la estela lejana pueden ser reproducidas utilizando el modelo MAB.
This thesis is divided in two blocks where the flow around a VAWT is analysed. The first block is focused on the experimental and numerical study of a VAWT with eight blades based in drag phenomenon. The experiments are carried out in two parts. In the first part, the wind velocity is set to 10 m/s to measure the power curve of the turbine and the results are compared with those of Savonius turbines in different wind tunnels. The reduction of the number of blades of the turbine has been also analysed and it has been found that the performance increases. In the second part, the wind velocity is set to 4.5 m/s to perform smoke visualization experiments. The smoke visualization technique has allowed the qualitative validation of the 2D simulations because the flow patterns visualized are similar to those numerically simulated. The numerical simulations have demonstrated that the four blades turbine generates higher torque than the turbine with eight blades. In the second block, a new model to predict the wake of VAWTs is proposed and analysed. The model is based on the actuator disk and the Double Multiple Stream Tube methods. The model, denoted as Multiple Actuator Block (MAB), is based on the definition, inside the computational domain, of multiple parallelepipedic blocks distributed along the path of the blades. Volumetric momentum sinks are imposed in these blocks to model the effect of the blades on the flow. The simulations with the MAB model have been compared with a complete finite volume simulation using the sliding mesh technique. This simulation requires about ten times more CPU time than the simulations using the MAB model. It has been found that the large scale features of the far wake can be reproduced using the MAB model.
Lance, Blake. "Experimental Validation Data for CFD of Steady and Transient Mixed Convection on a Vertical Flat Plate." DigitalCommons@USU, 2015. http://digitalcommons.usu.edu/etd/4546.
Повний текст джерелаKuoppala, Oskar. "Cavitation analysis on test rig. : An experimental and CFD study executed in collaboration with Epiroc AB." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-188337.
Повний текст джерелаKucukal, Erdem. "EXPERIMENTAL AND CFD INVESTIGATIONS OF THE FLUID FLOW INSIDE A HYDROCYCLONE SEPARATOR WITHOUT AN AIR CORE." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1424174590.
Повний текст джерела