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Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: An accurate description of the atmospheric boundary layer (ABL) is a prerequisite for computational fluid dynamic (CFD) wind studies. This includes taking into account the thermal stability of the atmosphere, which can be stable, neutral or unstable, depending on the nature of the surface fluxes of momentum and heat. The diurnal variation between stable and unstable conditions in the Namib Desert interdune was measured and quantified using the wind velocity and temperature profiles that describe the thermally stratified atmosphere, as derived by Monin- Obukhov similarity theory. The implementation of this thermally stratified atmosphere into CFD has been examined in this study by using Reynoldsaveraged Navier-Stokes (RANS) turbulence models. The maintenance of the temperature, velocity and turbulence profiles along an extensive computational domain length was required, while simultaneously allowing for full variation in pressure and density through the ideal gas law. This included the implementation of zero heat transfer from the surface, through the boundary layer, under neutral conditions so that the adiabatic lapse rate could be sustained. Buoyancy effects were included by adding weight to the fluid, leading to the emergence of the hydrostatic pressure field and the resultant density changes expected in the real atmosphere. The CFD model was validated against measured data, from literature, for the flow over a cosine hill in a wind tunnel. The standard k-ε and SST k-ω turbulence models, modified for gravity effects, represented the data most accurately. The flow over an idealised transverse dune immersed in the thermally stratified ABL was also investigated. It was found that the flow recovery was enhanced and re-attachment occurred earlier in unstable conditions, while flow recovery and re-attachment took longer in stable conditions. It was also found that flow acceleration over the crest of the dune was greater under unstable conditions. The effect of the dune on the flow higher up in the atmosphere was also felt at much higher distances for unstable conditions, through enhanced vertical velocities. Under stable conditions, vertical velocities were reduced, and the influence on the flow higher up in the atmosphere was much less than for unstable or neutral conditions. This showed that the assumption of neutral conditions could lead to an incomplete picture of the flow conditions that influence any particular case of interest. / AFRIKAANSE OPSOMMING: 'n Akkurate beskrywing van die atmosferiese grenslaag (ABL) is 'n voorvereiste vir wind studies met berekenings-vloeimeganika (CFD). Dit sluit in die inagneming van die termiese stabiliteit van die atmosfeer, wat stabiel, neutraal of onstabiel kan wees, afhangende van die aard van die oppervlak vloed van momentum en warmte. Die daaglikse variasie tussen stabiele en onstabiele toestande in die Namib Woestyn interduin is gemeet en gekwantifiseer deur gebruik te maak van die wind snelheid en temperatuur profiele wat die termies gestratifiseerde atmosfeer, soos afgelei deur Monin-Obukhov teorie, beskryf. Die implementering van hierdie termies gestratifiseerde atmosfeer in CFD is in hierdie studie aangespreek deur gebruik te maak van RANS turbulensie modelle. Die handhawing van die temperatuur, snelheid en turbulensie profiele in die lengte van 'n uitgebreide berekenings domein is nodig, en terselfdertyd moet toegelaat word vir volledige variasie in die druk en digtheid, deur die ideale gaswet. Dit sluit in die implementering van zero hitte-oordrag vanaf die grond onder neutrale toestande sodat die adiabatiese vervaltempo volgehou kan word. Drykrag effekte is ingesluit deur die toevoeging van gewig na die vloeistof, wat lei tot die ontwikkeling van die hidrostatiese druk veld, en die gevolglike digtheid veranderinge, wat in die werklike atmosfeer verwag word. Die CFD-model is gevalideer teen gemete data, vanaf die literatuur, vir die vloei oor 'n kosinus heuwel in 'n windtonnel. Die standaard k-ε en SST k-ω turbulensie modelle, met veranderinge vir swaartekrag effekte, het die data mees akkuraat voorgestel. Die vloei oor 'n geïdealiseerde transversale duin gedompel in die termies gestratifiseerde ABL is ook ondersoek. Daar is bevind dat die vloei herstel is versterk en terug-aanhegging het vroeër plaasgevind in onstabiele toestande, terwyl vloei herstel en terug-aanhegging langer gevat het in stabiele toestande. Daar is ook bevind dat vloei versnelling oor die kruin van die duin groter was onder onstabiele toestande. Die effek van die duin op die vloei hoër op in die atmosfeer is ook op hoër afstande onder onstabiele toestande gevoel, deur middel van verhoogte vertikale snelhede. Onder stabiele toestande, is vertikale snelhede verminder, en die invloed op die vloei hoër op in die atmosfeer was veel minder as vir onstabiel of neutrale toestande. Dit het getoon dat die aanname van neutrale toestande kan lei tot 'n onvolledige beeld van die vloei toestande wat 'n invloed op 'n bepaalde geval kan hê.

L'idée de base est de permettre à deux microorganismes de partager le même environnement tout en les maintenant séparées à l'aide d'une membrane perméable les retenant sélectivement. La principale contrainte résulte du transfert des composées d'intérêts limité par l'écoulement dans et autour des fibres ainsi que dans module et par le colmatage. Le double bioréacteur a membrane étudié dans cette thèse, de par son fonctionnement, alterne les cycles de filtration et rétrofiltration (ou rétrolavage), limitant ainsi en partie le colmatage. Ce travail de thèse s'est donc attaché à approfondir la connaissance des mécanismes de limitation au transfert mis en jeu lors de la filtration de fluide biologique complexes et évolutifs en fonction des conditions opératoires et des caractéristiques géométriques du module de filtration à fibres creuses. Dans cet objectif, sur la base des choix de configuration de module membranaire proposés dans cette étude, et afin de tendre vers une optimisation rationnelle de l'utilisation de ce dispositif, l'étude s'appuya sur l'utilisation d'outils de mécanique des fluides numériques, complétée par une approche expérimentale menée dans des conditions modèles. Les simulations réalisées par cette approche ont ainsi mis en évidence de grandes variations des vitesses de filtration le long de la fibre et ceci en lien direct avec une augmentation de la perte de charge à l'extérieur des fibres due au confinement induisant une baisse des performances de filtration. De manière similaire, un modèle numérique de formation de dépôt nous a permis d'évaluer l'effet du confinement de fibres. Il entraine une augmentation de pression dans la partie fluide externe induisant une forte variation de pertes de charges entrainant une répartition du dépôt le long de la fibre beaucoup plus inhomogène. Le retour du numérique à l'expérimental réalisé s'est attaché à décrire l'influence des conditions de mise oeuvre sur les performances de filtration du pilote. L'analyse méthodique de l'influence du sens de filtration et de la compacité dans le cas de fluides modèles (suspension de différents microorganismes / solutions de protéines modèles) et dans le cas de fluides biologiques évolutifs (milieux de fermentation + micro organismes) fut réalisée. L'ensemble de ces résultats nous permettent de donner des recommandations aux futurs utilisateurs du double bioréacteur à membranes. / This work presents a specific bioreactor previously designed to study microbial interactions. In this process, the microbial species in two tanks are physically separated by a microfiltration membrane. In order to give to the microorganisms a molecular environment in each compartment similar to the one that would be obtained if the microbial cells were cultivated in the same reactor, two criteria have to be considered: (i) the flow rates between compartments have to be sufficient with respect to the microbial kinetics and (ii) all the molecular compounds of the medium that have an effect on the microorganism behaviour must pass through the membrane. The main constrain is due to transfer of component limited by the fluid flow in and around the fiber of the filtration module. This thesis has therefore committed to deepening the understanding of the mechanisms limiting the transfer involved during the filtration of biological fluid complex according to operating conditions and geometric characteristics of the hollow fiber module of filtration. For this purpose, based on the choice of membrane module configuration proposed in this study, and to strive for a rational optimization of the use of this device, the study relied on the use of CFD tools, supplemented by an experimental approach conducted under models conditions. The numerical simulations of fluid flow have shown a modification of the axial filtration velocity profile with packing density. Similarly, a numerical model of cake deposit was developed and show difference of cake growth along the fiber with packing density. Two experimental hollow fiber modules with two packing densities were tested with clean water and biological fluid, and showed good agreement with the numerical data. These results underline the variations of filtration velocity along the fiber that will allow some predictions on fouling deposit to be done.

O formato do perfil de velocidades do vento varia de acordo com as características locais da superfície terrestre e de rugosidade do terreno, parâmetros que definem o perfil da Camada-Limite Atmosférica (CLA). As características do escoamento do ar atmosférico sobre e ao redor de acidentes geográficos, tais como morros e colinas, são de grande interesse para aplicações relacionadas à Engenharia de Turbinas e Parques Eólicos. No topo de morros, ocorre a aceleração do vento, fenômeno que pode representar um fator decisivo para a instalação de aerogeradores. Este trabalho dedica-se ao estudo do comportamento da CLA como função da inclinação e rugosidade superficial da elevação, fazendo uso da Dinâmica de Fluidos Computacional (CFD) para construir perfis de velocidade do vento e de intensidade de turbulência. O problema de fechamento das Equações Médias de Reynolds (RANS) é contornado com o uso do modelo de turbulência k-ω SST; os resultados numéricos obtidos são comparados com dados experimentais medidos em túnel de vento sobre modelos em escala dos morros. São testados oito modelos de morros com declives que variam de 25° a 64° para dois tipos de categorias de terreno, em 2D e 3D, e são aplicados dois códigos analíticos para representar o perfil de velocidades de entrada. Resultados numéricos para os perfis de velocidade apresentam diferença inferior a 4% em relação aos respectivos dados obtidos experimentalmente. Os perfis de intensidade de turbulência apresentam diferença máxima na casa dos 7% em comparação aos dados experimentais, o que é explicado pelo fato de que não é possível inserir o perfil de entrada de intensidade de turbulência nas simulações numéricas. Em alternativa, foi usado um valor constante resultado da média dos valores dos perfis usados no túnel de vento. Os modelos de morro em 3D apresentam maior concordância nos resultados de velocidade que os modelos em 2D e que ademais quanto maior é a inclinação do morro maior é a concordância com as medições experimentais. / The shape of the wind velocity profile changes according to local features of terrain shape and roughness, which are parameters responsible for defining the Atmospheric Boundary Layer (ABL) profile. Air flow characteristics over and around landforms, such as hills, are of considerable importance for applications related to Wind Farm and Turbine Engineering. The air flow is accelerated on top of hills, which can represent a decisive factor for Wind Turbine placement choices. The present work focuses on the study of ABL behavior as a function of slope and surface roughness of hill-shaped landforms, using the Computational Fluid Dynamics (CFD) to build wind velocity and turbulent intensity profiles. Reynolds-Averaged Navier-Stokes (RANS) equations are closed using the SST k-ω turbulence model; numerical results are compared to experimental data measured in wind tunnel over scale models of the hills under consideration. Eight hill models with slopes varying from 25° to 64° were tested for two types of terrain categories in 2D and 3D, and two analytical codes are used to represent the inlet velocity profiles. Numerical results for the velocity profiles show differences under 4% when compared to their respective experimental data. Turbulent intensity profiles show maximum differences around 7% when compared to experimental data, this can be explained by not being possible to insert inlet turbulent intensity profiles in the simulations. Alternatively, constant values based on the averages of the turbulent intensity at the wind tunnel inlet were used. The 3D models present greater concordance in the speed results than the 2D models and that in addition the greater the slope of the hill, the greater the agreement with the experimental measurements.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2017-03-16T12:44:59Z No. of bitstreams: 1 Daniel Augusto Kestering_.pdf: 4709572 bytes, checksum: bd1166e3946f589fd86f700a714928c2 (MD5) / Made available in DSpace on 2017-03-16T12:44:59Z (GMT). No. of bitstreams: 1 Daniel Augusto Kestering_.pdf: 4709572 bytes, checksum: bd1166e3946f589fd86f700a714928c2 (MD5) Previous issue date: 2016-10-31 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares / A investigação dos modelos de arrasto gás-sólido é fundamental para se obter bons resultados de fluidização utilizando dinâmica dos fluidos computacional. A tecnologia de fluidização é muito utilizada para conversão térmica de combustíveis sólidos e tem como principal vantagem a boa mistura entre gás e sólido. O presente trabalho utiliza dois softwares para simulação de leitos fluidizados, MFIX e Ansys Fluent, para comparar os modelos de arrasto de Syamlal e O`Brien (1987) e Di Felice (1994). A abordagem utilizada para modelagem do problema é o modelo de dois fluidos (Two Fluid Model, TFM), juntamente com a teoria cinética para escoamento laminar (Kinetic Theory for Granular Flow, KTGF). Um método para ajuste do modelo de DF (DI FELICE, 1994), baseado no trabalho de Esmaili e Mahinpey (2011), é sugerido, assim como o modelo de SO (SYAMLAL; O`BRIEN,1987) é ajustado utilizando dados em condição de mínima fluidização. Foram conduzidos experimentos para obtenção de velocidade e fração de vazios em condição de mínima fluidização a fim de ajustar ambos os modelos. As partículas utilizadas nos experimentos foram esferas de vidro de 1,21 mm, 0,8 mm e areia de fundição de 0,29 mm. O método proposto representa de forma adequada os dados obtidos em mínima fluidização das três partículas. Com os modelos de arrasto ajustados, simulações numéricas em regime de fluidização foram conduzidas em domínio bidimensional e tridimensional. Os resultados obtidos nestas simulações apresentam boa concordância com resultados experimentais em queda de pressão do leito e borbulhamento. Concomitantemente, um código para obtenção de modelo de arrasto utilizando o algoritmo EMMS/Bubbling foi desenvolvido e simulações numéricas bidimensionais foram conduzidas, para teste e validação. Os resultados do código mostram que o modelo segue a mesma tendência de Shi, Wang e Li (2011), que desenvolveram o modelo EMMS/Bubbling. / The investigation of gas-solid drag models is a key to obtain good results of fluidization by using computational fluid dynamic tools. The fluidization technology is used for solid fuel thermal conversion and its main advantage is the high gas-solid mixture. The present effort uses two software for fluidized beds simulation, MFIX and Ansys Fluent, in order to compare the drag models of Syamlal and O`Brien (1987) and Di Felice (1994). Two Fluid Model is the approach used to model together with Kinetic Theory for Granular flow. A method to adjust DF drag model (DI FELICE, 1994), based on Esmaili and Mahinpey (2011), is suggested, as well as SO drag model (SYAMLAL; O’BRIEN, 1987) is adjusted using data obtained from minimum fluidization condition. Experiments were realized to obtain velocity and void fraction at minimum fluidization condition in order to adjust both models. Glass beads with diameter of 1,21 mm and 0,8 mm and sand with diameter of 0,29 mm were used on experiments. The purposed method fits the data obtained on minimum fluidization condition of the three particles, in accordance with experimental data. With the models adjusted, numerical simulation were conducted using drag models for two- and three-dimensional domain. The results of this simulations agrees with experimental data of pressure drop and bubble formation. Simultaneously, a code to obtain a drag model using EMM/Bubbling algorithm was developed and numerical simulation were conducted. Results of EMMS show that the model have the same tendency of results of Shi, Wand and Li (2011), who developed EMMS/Bubbling model.

The use of steady-state aerodynamic optimization methods in the computational fluid dynamic (CFD) community is fairly well established. In particular, the use of adjoint methods has proven to be very beneficial because their cost is independent of the number of design variables. The application of numerical optimization to airframe-generated noise, however, has not received as much attention, but with the significant quieting of modern engines, airframe noise now competes with engine noise. Optimal control techniques for unsteady flows are needed in order to be able to reduce airframe-generated noise. In this thesis, a general framework is formulated to calculate the gradient of a cost function in a nonlinear unsteady flow environment via the discrete adjoint method. The unsteady optimization algorithm developed in this work utilizes a Newton-Krylov approach since the gradient-based optimizer uses the quasi-Newton method BFGS, Newton's method is applied to the nonlinear flow problem, GMRES is used to solve the resulting linear problem inexactly, and last but not least the linear adjoint problem is solved using Bi-CGSTAB. The flow is governed by the unsteady two-dimensional compressible Navier-Stokes equations in conjunction with a one-equation turbulence model, which are discretized using structured grids and a finite difference approach. The effectiveness of the unsteady optimization algorithm is demonstrated by applying it to several problems of interest including shocktubes, pulses in converging-diverging nozzles, rotating cylinders, transonic buffeting, and an unsteady trailing-edge flow. In order to address radiated far-field noise, an acoustic wave propagation program based on the Ffowcs Williams and Hawkings (FW-H) formulation is implemented and validated. The general framework is then used to derive the adjoint equations for a novel hybrid URANS/FW-H optimization algorithm in order to be able to optimize the shape of airfoils based on their calculated far-field pressure fluctuations. Validation and application results for this novel hybrid URANS/FW-H optimization algorithm show that it is possible to optimize the shape of an airfoil in an unsteady flow environment to minimize its radiated far-field noise while maintaining good aerodynamic performance.

The use of steady-state aerodynamic optimization methods in the computational fluid dynamic (CFD) community is fairly well established. In particular, the use of adjoint methods has proven to be very beneficial because their cost is independent of the number of design variables. The application of numerical optimization to airframe-generated noise, however, has not received as much attention, but with the significant quieting of modern engines, airframe noise now competes with engine noise. Optimal control techniques for unsteady flows are needed in order to be able to reduce airframe-generated noise. In this thesis, a general framework is formulated to calculate the gradient of a cost function in a nonlinear unsteady flow environment via the discrete adjoint method. The unsteady optimization algorithm developed in this work utilizes a Newton-Krylov approach since the gradient-based optimizer uses the quasi-Newton method BFGS, Newton's method is applied to the nonlinear flow problem, GMRES is used to solve the resulting linear problem inexactly, and last but not least the linear adjoint problem is solved using Bi-CGSTAB. The flow is governed by the unsteady two-dimensional compressible Navier-Stokes equations in conjunction with a one-equation turbulence model, which are discretized using structured grids and a finite difference approach. The effectiveness of the unsteady optimization algorithm is demonstrated by applying it to several problems of interest including shocktubes, pulses in converging-diverging nozzles, rotating cylinders, transonic buffeting, and an unsteady trailing-edge flow. In order to address radiated far-field noise, an acoustic wave propagation program based on the Ffowcs Williams and Hawkings (FW-H) formulation is implemented and validated. The general framework is then used to derive the adjoint equations for a novel hybrid URANS/FW-H optimization algorithm in order to be able to optimize the shape of airfoils based on their calculated far-field pressure fluctuations. Validation and application results for this novel hybrid URANS/FW-H optimization algorithm show that it is possible to optimize the shape of an airfoil in an unsteady flow environment to minimize its radiated far-field noise while maintaining good aerodynamic performance.

O formato do perfil de velocidades do vento varia de acordo com as características locais da superfície terrestre e de rugosidade do terreno, parâmetros que definem o perfil da Camada-Limite Atmosférica (CLA). As características do escoamento do ar atmosférico sobre e ao redor de acidentes geográficos, tais como morros e colinas, são de grande interesse para aplicações relacionadas à Engenharia de Turbinas e Parques Eólicos. No topo de morros, ocorre a aceleração do vento, fenômeno que pode representar um fator decisivo para a instalação de aerogeradores. Este trabalho dedica-se ao estudo do comportamento da CLA como função da inclinação e rugosidade superficial da elevação, fazendo uso da Dinâmica de Fluidos Computacional (CFD) para construir perfis de velocidade do vento e de intensidade de turbulência. O problema de fechamento das Equações Médias de Reynolds (RANS) é contornado com o uso do modelo de turbulência k-ω SST; os resultados numéricos obtidos são comparados com dados experimentais medidos em túnel de vento sobre modelos em escala dos morros. São testados oito modelos de morros com declives que variam de 25° a 64° para dois tipos de categorias de terreno, em 2D e 3D, e são aplicados dois códigos analíticos para representar o perfil de velocidades de entrada. Resultados numéricos para os perfis de velocidade apresentam diferença inferior a 4% em relação aos respectivos dados obtidos experimentalmente. Os perfis de intensidade de turbulência apresentam diferença máxima na casa dos 7% em comparação aos dados experimentais, o que é explicado pelo fato de que não é possível inserir o perfil de entrada de intensidade de turbulência nas simulações numéricas. Em alternativa, foi usado um valor constante resultado da média dos valores dos perfis usados no túnel de vento. Os modelos de morro em 3D apresentam maior concordância nos resultados de velocidade que os modelos em 2D e que ademais quanto maior é a inclinação do morro maior é a concordância com as medições experimentais. / The shape of the wind velocity profile changes according to local features of terrain shape and roughness, which are parameters responsible for defining the Atmospheric Boundary Layer (ABL) profile. Air flow characteristics over and around landforms, such as hills, are of considerable importance for applications related to Wind Farm and Turbine Engineering. The air flow is accelerated on top of hills, which can represent a decisive factor for Wind Turbine placement choices. The present work focuses on the study of ABL behavior as a function of slope and surface roughness of hill-shaped landforms, using the Computational Fluid Dynamics (CFD) to build wind velocity and turbulent intensity profiles. Reynolds-Averaged Navier-Stokes (RANS) equations are closed using the SST k-ω turbulence model; numerical results are compared to experimental data measured in wind tunnel over scale models of the hills under consideration. Eight hill models with slopes varying from 25° to 64° were tested for two types of terrain categories in 2D and 3D, and two analytical codes are used to represent the inlet velocity profiles. Numerical results for the velocity profiles show differences under 4% when compared to their respective experimental data. Turbulent intensity profiles show maximum differences around 7% when compared to experimental data, this can be explained by not being possible to insert inlet turbulent intensity profiles in the simulations. Alternatively, constant values based on the averages of the turbulent intensity at the wind tunnel inlet were used. The 3D models present greater concordance in the speed results than the 2D models and that in addition the greater the slope of the hill, the greater the agreement with the experimental measurements.

O formato do perfil de velocidades do vento varia de acordo com as características locais da superfície terrestre e de rugosidade do terreno, parâmetros que definem o perfil da Camada-Limite Atmosférica (CLA). As características do escoamento do ar atmosférico sobre e ao redor de acidentes geográficos, tais como morros e colinas, são de grande interesse para aplicações relacionadas à Engenharia de Turbinas e Parques Eólicos. No topo de morros, ocorre a aceleração do vento, fenômeno que pode representar um fator decisivo para a instalação de aerogeradores. Este trabalho dedica-se ao estudo do comportamento da CLA como função da inclinação e rugosidade superficial da elevação, fazendo uso da Dinâmica de Fluidos Computacional (CFD) para construir perfis de velocidade do vento e de intensidade de turbulência. O problema de fechamento das Equações Médias de Reynolds (RANS) é contornado com o uso do modelo de turbulência k-ω SST; os resultados numéricos obtidos são comparados com dados experimentais medidos em túnel de vento sobre modelos em escala dos morros. São testados oito modelos de morros com declives que variam de 25° a 64° para dois tipos de categorias de terreno, em 2D e 3D, e são aplicados dois códigos analíticos para representar o perfil de velocidades de entrada. Resultados numéricos para os perfis de velocidade apresentam diferença inferior a 4% em relação aos respectivos dados obtidos experimentalmente. Os perfis de intensidade de turbulência apresentam diferença máxima na casa dos 7% em comparação aos dados experimentais, o que é explicado pelo fato de que não é possível inserir o perfil de entrada de intensidade de turbulência nas simulações numéricas. Em alternativa, foi usado um valor constante resultado da média dos valores dos perfis usados no túnel de vento. Os modelos de morro em 3D apresentam maior concordância nos resultados de velocidade que os modelos em 2D e que ademais quanto maior é a inclinação do morro maior é a concordância com as medições experimentais. / The shape of the wind velocity profile changes according to local features of terrain shape and roughness, which are parameters responsible for defining the Atmospheric Boundary Layer (ABL) profile. Air flow characteristics over and around landforms, such as hills, are of considerable importance for applications related to Wind Farm and Turbine Engineering. The air flow is accelerated on top of hills, which can represent a decisive factor for Wind Turbine placement choices. The present work focuses on the study of ABL behavior as a function of slope and surface roughness of hill-shaped landforms, using the Computational Fluid Dynamics (CFD) to build wind velocity and turbulent intensity profiles. Reynolds-Averaged Navier-Stokes (RANS) equations are closed using the SST k-ω turbulence model; numerical results are compared to experimental data measured in wind tunnel over scale models of the hills under consideration. Eight hill models with slopes varying from 25° to 64° were tested for two types of terrain categories in 2D and 3D, and two analytical codes are used to represent the inlet velocity profiles. Numerical results for the velocity profiles show differences under 4% when compared to their respective experimental data. Turbulent intensity profiles show maximum differences around 7% when compared to experimental data, this can be explained by not being possible to insert inlet turbulent intensity profiles in the simulations. Alternatively, constant values based on the averages of the turbulent intensity at the wind tunnel inlet were used. The 3D models present greater concordance in the speed results than the 2D models and that in addition the greater the slope of the hill, the greater the agreement with the experimental measurements.

Orientador: Jose Roberto Nunhez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-06T09:02:08Z (GMT). No. of bitstreams: 1 Fernandes_LuisAntonioGalhego_M.pdf: 1106385 bytes, checksum: 6b2e2fa17d2a53c5051005b064878165 (MD5) Previous issue date: 2005 / Resumo: Com aplicações nos mais variados ramos industriais, tais como o alimentício, o químico, o farmacêutico, o de bebidas e o de toucador, entre outros, a operação unitária de agitação ou mistura de fluidos desempenha importante papel nos processos industriais. Os misturadores estáticos constituem uma alternativa aos vasos agitados tradicionais, sendo aplicados em processos contínuos. Os atuais fabricantes nacionais de misturadores estáticos têm apresentado dificuldade em definir o tipo adequado de misturador para as aplicações de um modo geral, como selecionar um misturador que, apesar de promover a mistura apresenta um alto consumo de energia para a aplicação. A constante preocupação em se reduzir o consumo de energia exige um cuidado especial com relação à escolha do misturador adequado ao processo. Dois misturadores denominados ALETAS e EDA foram selecionados de um trabalho anterior que desenvolveu e otimizou misturadores estáticos, utilizando a ferramenta fluido-dinâmica computacional (CFD), sendo que um destes se opera em regime laminar (ALETAS) e o outro em regime turbulento (EDA). O presente estudo buscou complementar o desenvolvimento destes novos tipos de misturadores estáticos, sob a forma de ensaios experimentais, em regimes laminar e turbulento. Como resultado dos ensaios experimentais pôde-se concluir que o misturador tipo ALETAS é adequado para se operar em regime laminar e o EDA pode ser utilizado em ambos regimes, laminar e turbulento, com alguns cuidados especiais para o caso de regime laminar. Os mesmos foram comparados com misturadores bastante estudados na literatura (Kenics e Sulzer SMX) apresentando desempenho similar a estes dois misturadores comerciais / Abstract: Mixing is a unit operation with applicability in many industrial fields, such as food, chemical, petrochemical, beverages and pharmaceutical, just to say some fields. The static mixers appear with an alternative to the traditional agitated vessels. They could be used such in batch mixing operation as in continuous processes, but mainly in continuous processes. The Brazilian suppliers had some problems in choosing the adequate equipment, and it is not rare that they choose an equipment that really does the proper mixture, but with a very high consumption of energy. The recently concern about saving energy demands a special care about the choosing of the best static mixer for the particular task.It was selected two models (ALETAS and EDA) from another work that developed static mixers using computational fluid-dynamic (CFD) method, the ALETAS mixer for laminar mixing and EDA for turbulent mixing. This work searches to complete this study, by experimental tests in laminar and turbulent mixing conditions.The results show that ALETAS static mixer can be used in laminar mixing, as the EDA static mixer but the EDA can be used in laminar mixing with some particular cares. The EDA can also be used in the turbulent mixing. Both models of static mixers were also compared with the Kenics and Sulzer SMX commercial static mixers using the data available in the literature with very similar results / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química