Master of Science / Department of Mechanical and Nuclear Engineering / Steven Eckels / Both cavitating and flashing flows are important phenomena in fluid flow. Cavitating flow, a common consideration in valves, orifices, and metering devices, is also a concern in loss of coolant accidents for liquid water in power plants when saturation pressures are below atmospheric pressure. Flashing flow is a common consideration for devices such as relief and expansion valves and fluid injectors as well as for loss of coolant accidents in which the coolant’s saturation pressure is above atmospheric. Of the two phenomena, flashing flow has received greater interest due to its applicability to safety concerns, though cavitating flow is perhaps of greater interest in terms of energy efficiency. It is possible for cavitating and flashing flow to actually become sonic. That is, the local velocity of a fluid can exceed the local speed of sound due to the unique properties of two-phase mixtures. When a flow becomes sonic, it is possible for the flow to accelerate and impose additional energy losses that would not otherwise occur. Models of this aspect of two-phase flow are not well developed, typically only being presented for the case of constant area ducts. In this paper two models for cavitating sonic flow are developed and described by applying the integral forms of the mass, momentum, and energy equations to a control volume of variable cross-sectional area. These models, based on the homogeneous equilibrium model (HEM) and separated flow model, are then applied to experimental data taken by the author with R-134a as the fluid of interest. Experimental data were taken with four instrumented converging-diverging nozzles of various geometries using a custom testing rig that allowed for precise control and measurement of flow parameters such as mass flow, temperature, and pressure. The resultant data from the models are then examined, focusing on the resultant velocities, Mach numbers, quality, and shear stresses.

L'objectif de cette étude est d'examiner les écoulements diphasiques liquide/gaz dans les canaux des plaques bipolaires des piles à combustible afin de comprendre et de trouver des solutions au problème d'engorgement. L'influence de la section du canal et du matériau utilisé sur les pertes de charge (PDC) et sur la structure de l'écoulement d'eau liquide est plus particulièrement étudiée dans une expérience hors pile. Les mesures des PDC ont permis de mettre en évidence des séquences de bouchages et de débouchages, la fréquence de ces dernières augmentant avec le débit. Par ailleurs il est montré que le rapport des PDC diphasiques moyennées par les PDC en air sec décroit avec le débit et ceci indépendamment de la dimension du canal et qu'il est d'autant plus faible que le revêtement est hydrophile. Enfin différents régimes d'écoulements diphasiques (stratifié et de gouttes) ont pu être mis en évidence dans les différentes zones du canal et un modèle pour chacun d'eux a été établi, confirmant les résultats expérimentaux / This work focuses on the gas-liquid flows in the cathode plate, with the objective to observe their patterns, to understand their behavior, to estimate the pressure drops (PD) and eventually, to reduce clogging and its possible consequences in term of oxygen starvation downstream. A special emphasis is put on the effect of the channel section (typically between 0.5 and 1 mm²) and on the surface properties of the flow field plate materials. The experiments are performed ex-situ. The PD is measured locally along the channel as well as globally between the inlet and outlet, which put forward the existence of clogging/unclogging sequences. The characteristic frequency of these sequences increases with the air flow rate. The results show that the ratio of PD in two-phase flow to PD in dry flow decreases with the air flow rate while it does not seem to depend on the channel size (within the tested range). Moreover this ratio is lower with hydrophilic coating. Finally two main flow patterns (slug and annular flow) have been observed depending on the distance from the inlet and they have been simulated

[pt] Escoamentos intermitentes bifásicos são caracterizados pela sucessão de golfadas de líquido separadas por bolhas de diferentes tamanhos, escoando com frequência variável. A previsão deste tipo de escoamento é muito importante, uma vez que o mesmo pode ser encontrado em diversas aplicações industriais. No presente trabalho, é realizado um estudo do regime intermitente em tubulações verticais, utilizando o Modelo de Dois Fluidos uni-dimensional, juntamente como o método de Volumes Finitos. O Modelo de Dois Fluidos uni-dimensional requer a inclusão de diversas relações de fechamento para as fases líquida e gasosa. Estas relações devem representar realisticamente o fenômeno físico de interesse, e as equações resultantes devem ser bem postas. No presente trabalho, duas relações de fechamento foram consideradas: salto de pressão devido à curvatura da interface e parâmetro de distribuição de fluxo de quantidade de movimento. A presença do salto de pressão não se mostrou significativa, enquanto que o parâmetro relacionado a distribuição da fase líquida ampliou a região em que o sistema de equações é bem posto. Para os casos analisados, o parâmetro de distribuição da fase líquida apresentou influência nas características do escoamento. As principais grandezas do regime estatisticamente permanente, como comprimento e velocidade de translação da golfada e da bolha, foram comparadas com dados experimentais disponíveis na literatura, apresentando boa concordância. / [en] Intermittent two phase flows are characterized by a succession of liquid slugs separated by bubbles of different sizes, with varying frequency. The prediction of this type of flow is very important, since it can be found in several industrial applications. In the present work, studies of intermittent flows in vertical pipes are performed, employing the Two Fluid Model along with the Finite Volume method. The one-dimensional Two Fluid Model requires the inclusion of several closure relations for both gas and liquid phases. These relations should realistically represent the physical phenomenon of interest, and the resulting equations should be well posed. In this work, two closure relations were considered: pressure jump due to the interface curvature and momentum flux distribution parameter. The inclusion of the pressure jump did not present a significant influence, whereas the momentum flux parameter of the liquid phase increased the region in which the system of equations is well posed. For the cases analyzed, the momentum flux parameter of the liquid phase affected the flow characteristics. The main statistical slug quantities, such as length and translational speed of the bubble and slug, were compared with experimental data available in the literature, showing good agreement.

Neste trabalho estudou-se a modelagem termodinâmica do equilíbrio de fases de sistemas aquosos bifásicos formados por um polímero neutro, especificamente o poli(etileno glicol), e um sal. O modelo implementado é baseado na equação de Pitzer para soluções de eletrólitos, dele diferindo ao considerar a influência das propriedades do polímero no cálculo da constante dielétrica e da densidade do meio, presentes no cálculo do termo relativo às interações de longo alcance da energia de Gibbs excedente. Além disso, procurou-se também considerar a dependência dos parâmetros relativos ao polímero com respeito ao tamanho de sua cadeia. Dados experimentais obtidos da literatura foram utilizados para a obtenção dos parâmetros ajustáveis do modelo, em cuja implementação foi utilizada a linguagem FORTRAN. A alteração nas propriedades do meio modificou o estado de equilíbrio calculado, fato que pôde ser observado por meio da análise de fatores como o desvio entre a composição calculada pelos modelos e os valores experimentais em cada fase e a inclinação da linha de amarração. Em alguns sistemas o desempenho do modelo modificado foi superior nesses parâmetros, mas em termos gerais a modificação no cálculo da constante dielétrica e da densidade não resultou em melhora no cálculo do equilíbrio de fases, por vezes piorando-o, de modo que investigações específicas sobre o termo de longo alcance foram conduzidas para verificar a razão deste comportamento. A inclusão de parâmetros ternários aumentou a capacidade de correlação de ambos os modelos. No que diz respeito à possibilidade de correlação dos parâmetros de interação como função do tamanho da cadeia polimérica, que poderia levar a um modelo preditivo, observou-se que somente para tamanhos grandes de cadeia foi possível estabelecer uma dependência direta e inequívoca. / The thermodynamic modeling of phase equilibrium in aqueous two phase systems containing the neutral polymer poly(ethylene glycol) and a salt was studied in this work. The implemented model is based on the Pitzer equation for electrolytes solutions, modified in order to account for the influence of polymer properties in both the medium dielectric constant and the medium density, values which are present in long range term of the excess Gibbs energy. The dependence of the adjustable parameters on the polymer molecule size was also investigated. Experimental data from literature were used to obtain the adjustable parameters of the model, in whose implementation the FORTRAN computer language was used. The changes introduced into the long range term resulted in a shift of the calculated equilibrium compositions, which could be observed by analyzing the deviation between calculated and experimental compositions and tie-line slopes. For some systems the performance of the modified model was superior, but in most cases the changes introduced did not result in a significant improvement in phase equilibrium calculations, and even worsened them. Specific investigations on the long range term were carried out to verify the reason for such behavior. The insertion of ternary parameters increased the correlation capacity of both models. Concerning the hypothesis that the interaction parameters can be directly related to the polymer chain size, which might eventually lead to a predictive model, it was noticed that a direct dependency holds only for larger chain sizes.

O ambiente Antártico é caracterizado por condições ambientais restritivas de clima, hábitat e biogeografia. Neste sentido, o objetivo deste estudo foi avaliar a diversidade de leveduras em amostras marinhas e terrestres do ambiente Antártico, além da prospecção de lipases que atuem em processos que requerem baixas e moderadas temperaturas. De acordo com os resultados obtidos, 97 leveduras foram recuperadas por semeadura em meio de cultura PDA e YMA a partir de diferentes amostras coletadas na OPERANTAR XXVIII (verão 2010), das quais foram identificados 12 gêneros e 21 espécies. Destas, 45 apresentaram atividade de lipase e duas foram selecionadas para o ensaio de otimização da produção enzimática: C. laurentii L59 e L. scotti L117. A extração de lipase de L. scottii L117 foi avaliada por Sistema de Duas fases Aquosas e o sistema micelar utilizando TX-114 foi o mais eficiente para purificação parcial desta enzima. Por fim, a avaliação da diversidade das 405 leveduras isoladas de macroalgas e liquens (coletadas na OPERANTAR XXXII no verão de 2013) revelou a ocorrência de 24 taxons de leveduras a partir das amostras de macroalgas e 18 taxons a partir das amostras de liquens, sendo apenas cinco espécies comuns a estes dois substratos. / The Antarctic continent is characterized by restrictive environmental conditions of climate, habitats and biogeography. In this sense, the objective of this study was to evaluate the diversity of yeasts in marine and terrestrial samples of the Antarctic environments, as well as the propspecting of lipases that can act in proceses that require low and moderate temperatures. According to the results, 97 yeasts were recovered from different samples collected in OPERANTAR XXVIII (summer 2010), representing 21 different species. Among them, 45 showed lipase activity and two were selected for the optimization of enzyme production: C. laurentii L59 and L. scotti L117. Extraction of L. scottii L117 lipase was assessed by Aqueous Two-Phase System and the micellar system TX-114 was the most efficient for partial enzyme purification. Finally, the diversity evaluation of 405 isolates from seaweeds and lichens (collected in XXXII OPERANTAR, summer of 2013) revealed the occurrence of 24 taxa from macroalgae samples and 18 taxa from lichens samples, being only five substrates common to these two substrata.

A presente dissertação de mestrado envolve o estudo da perda da pressão e dos padrões para escoamentos água/ar em um canal retangular segundo inclinações a partir do plano horizontal de -90° a 90°. Também foi avaliado o efeito nestes parâmetros de rotacionar a seção de testes em torno de seu eixo axial segundo ângulos de 45° e 60°, determinados a partir da condição de suas faces superior e inferior posicionadas horizontalmente. O texto se inicia com a apresentação de um amplo estudo da literatura sobre métodos de previsão de padrões de escoamento e perda de pressão durante escoamentos bifásicos no interior de dutos. Em seguida é descrito o aparato experimental projetado e construído para este estudo. Tal descrição inclui o detalhamento da seção de testes, que consiste em um canal retangular de seção transversal com dimensões de 6,0 x 6,5 mm². Resultados foram levantados para vazões mássicas entre 90 e 760 kg/m²s, correspondendo a velocidades superficiais entre 0,03 a 19,42 m/s e 0,1 a 0,76 m/s, para, respectivamente as fases gás e líquido. Mapas de escoamento foram desenvolvidos com base em imagens capturadas por câmera de alta velocidade, e também com base na técnica de agrupamento de dados k-means. Os escoamentos foram classificados segundo os padrões bolhas, intermitente e anular. As características hidrodinâmicas e as transições entre estes padrões foram significativamente alteradas pela inclinação do canal. Constatou-se também significativa influência da rotação em torno do eixo do canal, favorecendo efeitos de estratificação no escoamento. As transições obtidas experimentalmente foram comparadas com os métodos de previsão disponíveis na literatura. Os métodos de Taitel e Dukler (1976), para escoamento horizontal, e Taitel et al. (1980) para escoamento vertical ascendente, apresentaram as melhores previsões dos dados experimentais. Com o objetivo de estimar a parcela gravitacional da perda de pressão, levantou-se resultados para a fração de vazio superficial avaliada com base na velocidade média de bolhas alongadas e no tratamento de imagens no caso do escoamento em bolhas. Resultados de perda de pressão por atrito foram comparados com vinte métodos de previsão da literatura. As correlações de Mishima e Hibiki (1996) e Zhang et al. (2010) proporcionaram as melhores previsões para escoamento horizontal. Para escoamentos inclinados, comparou-se 25 métodos da literatura para a determinação da perda de pressão por atrito com os resultados de perda de pressão experimentais, com a perda de pressão gravitacional estimada considerando 20 métodos para a fração de vazio superficial. Desta análise constatou-se que a combinação dos métodos de Mishima e Hibiki (1996) e Zhang et al. (2010) para a previsão da parcela de perda de pressão devido ao atrito e o método de Spedding e Chen (1984) para previsão da fração de vazio superficial, utilizado para a determinação da parcela gravitacional, proporcionam previsões satisfatórias dos dados experimentais. / The present dissertation concerns a study on pressure drop and flow patterns for air/water flows inside a rectangular channel positioned according to inclination angles, relative to the horizontal plane, from -90° to 90°. The effects on flow patterns and pressure drop of rotating the test section relative to its longitudinal axis according to angles of 45° and 60° are also evaluated. Initially, a broad review of the literature concerning experimental studies and predictive methods for flow pattern and pressure drop inside channels is presented. Then, the experimental facility developed for this study is described. In this description, the test section, consisting of a rectangular channel with cross-sectional area of 6.0 x 6.5 mm² is detailed. Experimental data were obtained for mass velocities from 90 to 760 kg/m²s, corresponding to gas and liquid superficial velocities from 0.03 to 19.4 m/s and from 0.1 to 0.76 m/s, respectively. Flow patterns maps were developed based on the following approaches: analyses of two-phase flow images from a high speed video camera; and using the k-means clustering algorithm based on pressure drop and optical signals. The bubbly, intermittent and annular flow patterns were characterized. From the analyses of the data, it was found that the flow pattern transitions are significantly affected by the flow inclination and channel rotation. Two-phase flow stratification effects are enhanced by rotating the channels. Among the flow pattern predictive method evaluated in the present study, Taitel and Dukler (1976), for horizontal channels, and Taitel et al. (1980), for upward flow, provided the best predictions of the data obtained in the present study. In order of estimating the gravitational parcel of the pressure drop, superficial void fraction results were obtained based on the mean velocity of elongated bubbles, for intermittent flow, and on the image processing of bubbles, for bubbly flow. Experimental results for frictional pressure drop were compared against 20 predictive methods available in the literature. The methods of Mishima e Hibiki (1996) and Zhang et al. (2010) performed the best for horizontal flows. The frictional pressure drop predictions were also evaluated for inclined flows by comparing the measured total pressure drop against the corresponding calculated values based on the combination of 25 frictional pressure drop predictive methods and the gravitational parcel of pressure drop estimated according to 20 predictive methods for superficial void fraction. From this analysis, it was found that the combination of Mishima e Hibiki (1996) and Zhang et al. (2010) methods for frictional pressure drop with the method of Spedding e Chen (1984), for void fraction, used to determine the gravitational parcel, provide satisfactory predictions of the experimental data.

Plusieurs régimes d’écoulement diphasiques adiabatiques eau/air horizontaux (écoulements dispersés àbulles et intermittents) et leur développement axial ont été étudiés dans l'expérience METERO,constituée d’une conduite circulaire horizontale de 100 mm de diamètre interne. Différentes techniques d’instrumentation ont été améliorées et utilisées pour mesurer les grandeurs caractéristiques de l’écoulement afin d’apporter une description locale et l'évolution axiale des écoulements. Les mécanismes physiques responsables des régimes d’écoulement et de leurs transitions, notamment la compétition entre forces turbulente et de flottabilité ont été explicités. Les différences entre les régimes à bulles et intermittent ont été mises en évidence et les processus physiques à l’origine de ces différences ont été expliqués. Deux nouvelles cartes de régime d’écoulement adimensionnelles ont été proposées: la première apporte une amélioration à la représentation de Taitel & Dukler (1976) et propose un nouveau critère de transition. La deuxième, novatrice, quantifie les effets des forces de turbulence et de flottabilité en fonction du taux de vide. / Several horizontal water-air two-phase adiabatic flows (dispersed bubbly flows and intermittent flows)and their axial evolutions have been studied in the METERO experiment which is consisted of ahorizontal circular test section with an internal diameter of 100 mm. Different measurement techniqueshave been improved and utilized to measure the flow characteristics in order to bring a localdescription and axial evolution of the flows. The responsible physical mechanisms of the flow regimesand their transitions, particularly the competition between turbulent force and buoyancy force havebeen explained. The differences between dispersed bubbly flows and intermittent flows have beenhighlighted and the physical process at the origin of these differences has been explained. Two newdimensionless flow regime maps have been proposed: the first one brings an improvement to therepresentation of Taitel & Dukler (1976) and proposes new transition criteria. The second novel maptakes into account the effects of turbulent and buoyancy forces and the void fraction.

<div>Nucleate boiling is an efficient heat transfer mechanism that enables the dissipation of high heat fluxes at low temperature differences. Heat transfer phenomena during nucleate boiling are closely linked to the two-phase flow morphology that evolves in time and based on the operating conditions. In particular, the critical heat flux, which is the upper limit for the nucleate boiling regime, can be triggered by hydrodynamic mechanisms resulting from interactions between the liquid and vapor phases. The aim of this thesis is to characterize the two-phase flow morphology evolution during nucleate boiling at high heat fluxes in two configurations: pool boiling, and confined and submerged two-phase jet impingement. The characterization is performed via non-invasive, high-speed optical based diagnostic tools. </div><div>Experimental characterization of liquid-vapor interfaces during boiling is often challenging because the rapidly evolving vapor structures are sensitive to invasive probes and multiple interfaces can occlude one another along a line of sight. In this thesis, a liquid-vapor interface reconstruction technique based on high-speed stereo imaging is developed. Images are filtered for feature enhancement and template matching is used for determining the correspondence of local features of the liquid-vapor interfaces between the two camera views. A sampling grid is overlaid on the reference image and windows centered at each sampled pixel are compared with windows centered along the epipolar line in the target image to obtain a correlation signal. To enhance the signatures of true matches, the correlation signals for each sampled pixel are averaged over a short time ensemble correlation. The three-dimensional coordinates of each matched pixel are determined via triangulation, which yields a set of points in the physical world representing the liquid-vapor interface. The developed liquid-vapor interface reconstruction technique is a high-speed, flexible and non-invasive alternative to the various existing methods for phase-distribution mapping. This technique also has the potential to be combined with other optical-based diagnostic tools, such as tomographic particle image velocimetry, to further understand the phase interactions.<br></div><div>The liquid-vapor interface reconstruction technique is used to characterize liquid-vapor interfaces above the heated surface during nucleate pool boiling, where the textured interface resulting from the boiling phenomena and flow interactions near the heated surface is particularly suited for reconstruction. Application of the reconstruction technique to pool boiling at high heat fluxes produces a unique quantitative characterization of the liquid-vapor interface morphology near heated surface. Analysis of temporal signals extracted from reconstructions indicate a clear transition in the nature of the vapor flow dynamics from a plume-like vapor flow to a release mode dominated by vapor burst events. Further investigation of the vapor burst events allows identification of a characteristic morphology of the vapor structures that form above the surface that is associated to the square shape of the heat source. Vapor flow morphology characterization during pool boiling at high heat fluxes can be used to inform vapor removal strategies that delay the occurrence of the critical heat flux during pool boiling.</div><div>As compared to pool boiling, nucleate boiling can be sustained up to significantly higher heat fluxes during two-phase jet impingement. The increases in critical heat flux are explained via hydrodynamic mechanisms that have been debated in the literature. The connection between two-phase flow morphology and the extension of nucleate boiling regime is investigated for a single subcooled jet of water that impinges on a circular heat source via high-speed visualization from two synchronized top and side views of the confinement gap. When boiling occurs under subcooled exit flow conditions and at moderate heat fluxes, the regular formation and collapse of vapor structures that bridge the heated surface and the orifice plate is observed, which causes significant oscillations in the pressure drop across. Under saturated exit flow conditions, the vapor agglomerates in the confinement gap into a bowl-like vapor structure that recurrently shrinks, due to vapor break-off at the edge of the orifice plate, and replenishes due to vapor generation. The optical visualizations from the top of the confinement gap provide a unique perspective and indicate that the liquid jet flows downwards through the vapor structure, impinges on the heated surface, and then flows underneath the vapor structure, as a fluid wall jet the keeps the heated surface wetted such that discrete bubbles continue to nucleate. At high heat fluxes, intense vapor generation causes the fluid wall jet to transition from a bubbly to a churn-like regime, and some liquid droplets are sheared off into the vapor structure. The origin of critical heat flux appears to result from a significant portion of the liquid in the wall jet being deflected off the surface, and the remaining liquid film on the surface drying out before reaching the edge of the heater.</div><div>The flow morphology characterizations presented in this dissertation further the understanding of flow and heat transfer phenomena during nucleate boiling. In the pool boiling configuration, the vapor release process was quantitatively described; during two-phase jet impingement, a possible mechanism for critical heat flux was identified. Opportunities for future work include the utilization of image processing techniques to extract quantitative measurements from two-phase jet impingement visualizations. Also, the developed liquid-vapor interface reconstruction technique can be applied to a boiling situation with a simpler liquid-vapor interface geometry, such as film boiling, to generate benchmark data for validation and development of numerical models.</div><div><br></div>

Escoamentos gás-líquido assim como escoamento líquido-líquido-gás em duto de geometria anular estão presentes em muitas aplicações industriais, por exemplo, em poços de petróleo direcionais. No entanto, até mesmo características globais de escoamento gás-líquido nessa geometria, como os padrões de escoamento ou gradiente de pressão, não são ainda totalmente compreendidas. E ainda, informações são escassas quando se refere a escoamento trifásico nessa geometria, cuja aplicação está relacionada ao fenômeno de inversão de fase, que é de extrema importância não apenas para ao setor petrolífero, como para a indústria alimentícia. O presente estudo experimental tem como objetivo avaliar o escoamento líquido-gás, apresentar dados inéditos de escoamento gás-líquido para três viscosidades de óleo, além de avaliar o fenômeno de inversão de fase em escoamento ascendente vertical em duto anular de grande diâmetro. Um aparato experimental inclinável com 10,5 m de comprimento foi projetado e construído para este trabalho. As dimensões radiais do duto anular estão em escala real, conforme se verifica em poços de petróleo e gás. A investigação em escoamento gás-líquido foi conduzida utilizando água, óleo e ar comprimido como fluidos de trabalho em escoamento ascendente vertical em duas geometrias: (i) um tubo com diâmetro de 95 mm e (ii) um duto de configuração anular e concêntrico, com diâmetro hidráulico de valor igual ao diâmetro do tubo. A avaliação do fenômeno de inversão de fase em escoamento trifásico foi conduzida em condições equivalentes em três geometrias: (i) tubo vertical menor com diâmetro de 50 mm, (ii) tubo com diâmetro de 95 mm e (iii) um duto anular concêntrico. Padrões de escoamento, queda de pressão e fração volumétrica de fase foram obtidos para ambos os escoamentos gás-líquido e líquido-líquido-gás. Os dados coletados nesse trabalho são de grande importância para o desenvolvimento de novas correlações de fechamento, que são essenciais para o projeto otimizado de poços de petróleo. Dados inéditos de escoamento bifásico óleo-gás são apresentados, bem como um estudo pioneiro em inversão de fase em escoamento trifásico com velocidade superficial de gás e viscosidade do óleo elevadas. / Two-phase flows as well as three-phase flow in annular geometry are present in many industrial applications, for example in oil directional wells. However, even global characteristics of gas-liquid flow in this geometry, such as flow patterns and pressure gradient are not fully understood. Moreover, information is scarce when it refers to three-phase flow in this geometry, which application is related to the phase inversion phenomenon, which is of extreme importance and not only for the oil industry. This experimental study aims to evaluate the liquid-gas flow, present new data from gas-liquid flow for three oil viscosities and evaluate the phase inversion phenomenon in vertical upward flow in large diameter annular duct. An experimental apparatus with 10.5 m length was designed and built for this work. The radial dimensions of the annular duct are similar to full scale, as observed in oil and gas wells. The investigation into gas-liquid flow was conducted using water, oil and compressed air as working fluids in an ascending vertical flow in two geometries: (i) a tube with 95 mm diameter and (ii) a concentric annular duct with hydraulic diameter equivalent to the tube internal diameter. The evaluation of the phase inversion phenomenon in three-phase flow was conducted under equivalent conditions for three geometries: (i) smaller vertical tube with 50 mm of internal diameter, (ii) tube with 95 mm of internal diameter and (iii) concentric annular duct with hydraulic diameter of 95 mm. Flow patterns, pressure drop and volumetric phase fraction were obtained for both gas-liquid and gas-liquid-liquid flows. The data collected in this study are of great importance for the development of new closing correlations, which are essential for the optimized design of oil wells. New two-phase flow data for three oil viscosities, not found in the literature, are presented as well as a pioneer study in three-phase-flow phase inversion with high oil viscosity and high superficial gas velocity.

Processos biotecnológicos dependem significativamente das técnicas de separação e purificação utilizadas, para manter boa relação custo-benefício na produção em escala industrial de produtos biotecnológicos com fins comerciais, industriais e terapêuticos. A aplicação do sistema micelar de duas fases aquosas (SMDFA) é proposta como alternativa para purificação de biomoléculas/biopartículas, pois permite sua separação e análise, muitas vezes sem que essas percam sua atividade ou propriedades desejadas. Com essa técnica é possível realizar uma partição seletiva que possibilita altos rendimentos. Esse trabalho destinou-se a estudar o emprego dessa metodologia na extração e purificação de Adenovírus em sistema micelar de duas fases aquosas formado por Triton X-114/Suspensão viral. Os ensaios foram realizados em sistemas de 5 g seguindo um planejamento fatorial completo (23) com 4 pontos centrais. Os fatores estudados foram temperatura de extração, pH da suspensão viral e concentração do tensoativo. Sistemas contendo massas de 3g, 10g e 40g foram avaliados. Foi avaliado o efeito do processo de extração com SMDFA sobre a integridade e infectividade de Adenovírus. Alguns dos parâmetros avaliados no processo foram a recuperação da potência viral (RPv) e a recuperação da potência viral específica (RPv&#248;). Esses dois parâmetros avaliam a inativação do Adenovirus pelo processo de extração e ambos apresentaram melhoras quando comparados com a própria suspensão viral para alguns dos sistemas estudados (i.e RPv:341 % e RPv&#248; 1466 %). Esses resultados indicam que o SMDFA foi capaz de particionar seletivamente as partículas virais infecciosas. De acordo com os resultados do planejamento é possível aumentar ainda mais esses resultados controlando as variáveis concentração de tensoativo, pH da suspensão viral e temperatura de extração. / Biotechnological processes depend significantly on separation and purification techniques used to maintain cost-effective industrial-scale production of biotechnological products for commercial, industrial and therapeutic uses. The application of the aqueous two-phase micelar system (ATPMS) is proposed as an alternative for purification, since it allows the separation and analysis of biomolecules /bioparticles, often without loses of activity or their properties. This allows to perform a selective partition that enables high yields. This work aims to study the use of this methodology in the extraction and purification of adenovirus in micelle aqueous two-phase formed by TritonX-114/Viral suspension. All assays were performed in 5 g systems following a full factorial design (23) with four central points. The studied factors were extraction temperature, pH of the viral suspension and concentration of the surfactant. Systems containing masses of 3g, 10g and 40g were evaluated. Extraction procedure effects over integrity and infectivity of adenovirus were also evaluated. Some of the parameters evaluated in the viral recovery process were viral potency (RPv) and recovery of viral specific potency (RPv&#248;). These two parameters measure the inactivation of Adenovirus by the extraction process and both showed improvement when compared with the viral suspension for some of the systems studied (i.e RPv: 341% and RPv&#248; 1466%). These results show that ATPMS selectively partition the infectious viral particles. According to the results of the experimental design is possible to increase, even further, these results controlling the surfactant concentration, viral suspension pH and temperature of extraction.