Due to the ever increasing concerns about pollutants and contaminants found in water, new treatment technologies have been developed. Ozonation is one of such technologies. It has been widely applied in the treatment of pollutants in water and wastewater treatment processes. Ozone has many applications such as oxidation of organic components, mineral matter, inactivation of viruses, cysts, bacteria, removal of trace pollutants like pesticides and solvents, and removal of tastes and odours. Ozone is the strongest conventional oxidant that can result in complete mineralisation of the organic pollutants to carbon dioxide and water. Because ozone is unstable, it is generally produced onsite in gas mixtures and is immediately introduced to water using gas/liquid type reactors (e.g. bubble columns). The ozone reactions are hence of the type gas liquid reactions, which are complex to model since they involve both chemical reactions, which occur in the liquid phase, and mass transfer from the gas to the liquid phase. This study focuses on two aspects: mass transfer and chemical reactions in multicomponent systems. The mass transfer parameters were determined by experiments under different conditions and the chemical reactions were studied using single component and multicomponent systems. Two models obtained from the literature were adapted to the systems used in this study. Mass transfer parameters in the semi-batch reactor were determined using oxygen and ozone at different flow rates in the presence and absence of t-butanol. t-Butanol is used as a radical scavenger in ozonation studies and it has been found to affect the gas-liquid mass transfer rates. An experimental study was carried out to investigate the effects of t-butanol concentrations on the physical properties of aqueous solutions, including surface tension and viscosity. It was found that t-butanol reduced both properties by 4% for surface tension and by a surprising 30% for viscosity. These reductions in the solution physical properties were correlated to enhancement in the mass transfer coefficient, kL. The mass transfer coefficient increased by about 60% for oxygen and by almost 50% for ozone. The hydrodynamic behaviour of the system used in this work was characterised by a homogeneous bubbling regime. It was also found that the gas holdup was significantly enhanced by the addition of t-butanol. Moreover, the addition of t-butanol was found to significantly reduce the size of gas bubbles, leading to enhancement in the volumetric mass transfer coefficient, kLa. The multicomponent ozonation was studied with two systems, slow reactions when alcohols were used and fast reactions when endocrine disrupting compounds were used. ii These experiments were simulated by mathematical models. The alcohols were selected depending on their volatilization at different initial concentrations and different gas flow rates. The degradation of n-propanol as a single compound was studied at the lowest flow rate of 200 mL/min. It was found that the degradation of n-propanol reached almost 60% within 4 hours. The degradation of the mixture was enhanced with an increase in the number of components in the mixture. It was found that the degradation of the mixture as three compounds reached almost 80% within four hours while the mixture as two compounds reached almost 70%. The effect of pH was studied and it was found that an increase in pH showed slight increase in the reaction. Fast reactions were also investigated by reacting endocrine disrupting chemicals with ozone. The ozone reactions with the endocrine disrupters were studied at different gas flow rates, initial concentrations, ozone concentrations and pH. The degradation of 17β-estradiol (E2) as a single compound was the fastest, reaching about 90% removal in almost 5 minutes. However estrone (E1) degradation was the lowest reaching about 70% removal at the same time. The degradation of mixtures of the endocrine disruptors was found to proceed to lower percentages than individual components under the same conditions. During the multicomponent ozonation of the endocrine disruptors, it was found that 17β-estradiol (E2) converted to estrone (E1) at the beginning of the reaction. A MATLAB code was developed to predict the ozone water reactions for single component and multicomponent systems. Two models were used to simulate the experimental results for single component and multicomponent systems. In the case of single component system, good simulation of both reactions (slow and fast) by model 1 was obtained. However, model 2 gave good agreement with experimental results only in the case of fast reactions. In addition, model 1 was applied for multicomponent reactions (both cases of slow and fast reaction). In the multicomponent reactions by model 1, good agreement with the experimental results was also obtained for both cases of slow and fast reactions.

The issue of descaling is an important part of the forging and heat treatment of steel and semi products of steel production. Rising of new information and study of this process can increase efficiency and improve the surface quality after descaling. This thesis is focused on the mechanisms of the high pressure hydraulic descaling qualification and study of the chemical compounds of which the scales grown. To achieve all goals of this work and to get a comprehensive view of descaling process, few experimental measurements and numerical analyses were performed. All experimental measurements were focused on obtaining data about fundamental parameters and effects of the hydraulic descaling. The data obtained from measurements were applied to numerical analyses, which aimed to discover a deeper relation and to confirm the experimental results. This thesis can be divided into two main parts. The first part is devoted to parameters of the water jet study. The main studied characteristics of the high pressure hydraulic water jet were heat transfer coefficient and impact pressure at different modes such as standard or pulsating water jet. Experimentally measured data of these parameters were applied in numerical analyses. The numerical analyses were focused on studying the impact of the water jet parameters on the stresses in the oxide scale layers. A further water jet analysis was focused on the influence of the individual parts of the hydraulic system (such as water chamber or stabilizer) on its characteristics. In this part different types of the water chambers in combination with different types of stabilizers on the impact pressure values were investigated. These measurements were supported by fluid flow analysis through the hydraulic system. The second part of this work was focused on getting mechanical properties of the oxide scales from specimens prepared from standard structural steel and specimens from silicon steel. In this thesis, the influence of various parameters and characteristics was studied on these two types of steel. Mechanical properties of oxide scale structures were carried out by the Small Punch Test method. To obtain the fundamental mechanical properties such as Young´s modulus, yield strength and ultimate strength, material parameters based on the measured data were optimized. The whole work was carried out in order to get valuable and comprehensive results about high pressure hydraulic descaling process and influencing factors as well as about oxide scales themselves.

A pesquisa realizada tratou do estudo da transferência de calor e do fluxo crítico durante a ebulição convectiva no interior de canais de diâmetro reduzidos a partir de dados levantados em bancadas experimentais construídas para esta finalidade. Extensa pesquisa bibliográfica foi efetuada e os principais métodos disponíveis para previsão de coeficiente de transferência de calor, fluxo crítico e mapas de escoamento foram levantados. Os resultados obtidos foram parametricamente analisados e comparados com os métodos da literatura. Pela primeira vez para microcanais, resultados experimentais foram levantados por um mesmo autor em laboratórios distintos buscando verificar a tendência e comportamentos. Tal comparação tem sua importância destacada em face das elevadas discrepâncias observadas na literatura quando resultados de autores distintos, obtidos em condições similares, são comparados. Os resultados levantados foram utilizados na elaboração de modelos que consideram os padrões de escoamento observados em microcanais. A incorporação dos padrões permitiu o desenvolvimento de modelos mecanísticos para coeficiente de transferência de calor, fluxo crítico e critérios para a caracterização da transição entre macro e microcanais baseados na formação do padrão de escoamento estratificado e na simetria do filme líquido no escoamento anular. / This research comprises an experimental and theoretical study on flow boiling heat transfer and critical heat flux inside small diameter tubes based on data obtained in experimental facilities specially designed for this purpose. A broad literature review was carried out and the main methods to predict the heat transfer coefficient, critical heat flux and flow patterns were pointed out. The experimental results were parametrically analyzed and compared against the predictive methods from literature. For the first time, microchannels experimental results obtained by an unique researcher in distinct laboratories were compared and a reasonable agreement was observed. The importance of such a comparison is high-lighted for flow boiling inside microchannels due to the high discrepancies ob-served when results from independent laboratories obtained under similar experimental conditions are compared. Moreover, the experimental results obtained in the present study were used to develop correlations and models for the heat transfer coefficient and heat flux that takes into account the flow patterns observed in microchannels. The heat transfer coefficient and critical heat flux models were developed based on mechanistic approach. In addition, criteria to characterize macro to microchannel transition were proposed based in the occurrence of the stratified flow pattern and the liquid film symmetry under annular flow conditions.

A têmpera dos aços envolve a austenitização de uma peça seguida por um resfriamento rápido para promover a formação de microestrutura martensítica. É necessário avaliar os meios de têmpera para manter o processo de têmpera sob controle. Os parâmetros mais importantes no processo de resfriamento são o coeficiente de transferência de calor e/ou o fluxo de calor entre o meio de têmpera e a peça a ser resfriada. Um dos métodos de se avaliar os meios de têmpera (meios de resfriamento) e saber o que está acontecendo dentro da peça durante o resfriamento do ponto de vista térmico é o problema inverso de condução de calor. O problema inverso de condução de calor consiste na determinação de parâmetros como fluxo de calor, taxa de resfriamento e temperatura em qualquer posição através da peça, assim como o coeficiente de transferência de calor. Esses parâmetros são obtidos a partir de medições de temperatura em um ou mais pontos dentro da peça. O escopo deste trabalho foi desenvolver um software baseado no problema inverso condução de calor para avaliar meios de resfriamento para têmpera. A validação deste código foi feita usando água, óleo de soja, óleo mineral e solução aquosa de NaNO3. / Steels quenching involves part austenitization followed by a fast cooling to promote martensitic microstructure formation. It is necessary to evaluate quenchants in order to keep the quenching process under control. The most important cooling process parameters are the heat transfer coefficient and/or the heat flux between the quenchant and the part to be cooled. One of the methods to evaluate quenchants (cooling media) and to know what is happening inside the part during the cooling in the thermal point of view is the inverse heat conduction problem. The inverse heat conduction problem consists in the determination of parameters like heat flux, cooling rate and temperature in any position across the part, as well as the heat transfer coefficient. These parameters are obtained from temperature measurements in one or more points inside the part. The scope of this work was to develop a software based in the inverse heat conduction problem in order to evaluate quenchants for quenching. The validation of this code was made using water, soybean oil, mineral oil and NaNO3 aqueous solution.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-05-25T14:45:18Z No. of bitstreams: 1 Bruno de Sá Beckerle.pdf: 3991624 bytes, checksum: 500b993c0f3a1c3a8c3abae05ed51c5e (MD5) / Made available in DSpace on 2015-05-25T14:45:18Z (GMT). No. of bitstreams: 1 Bruno de Sá Beckerle.pdf: 3991624 bytes, checksum: 500b993c0f3a1c3a8c3abae05ed51c5e (MD5) Previous issue date: 2015-01-05 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho apresenta um estudo experimental da transferência de calor e queda de pressão na ebulição do isobutano, R-600a, em um tubo composto por 7 mini canais paralelos, cujo diâmetro hidráulico é de 1,47 mm. Os testes em ebulição foram realizados com uma temperatura de saturação de 22 ºC e pressão de saturação de 302 kPa, com velocidade mássica entre 50 e 200 kg/(m²s) e fluxos de calor na seção de testes entre 7 e 40 kW/m². Com os testes realizados verificou-se que o coeficiente de transferência de calor aumenta conforme o incremento do fluxo de calor e velocidade mássica, sendo que esta última tem maior influência para baixos títulos de vapor. O coeficiente de transferência de calor atingiu valores máximos próximos a 3.200 W/(m²K) para a condição de maior vazão e fluxo de calor. A queda de pressão aumentou com o incremento da velocidade mássica e título de vapor em todos os testes, enquanto que o fluxo de calor apresentou influência na queda de pressão apenas nas maiores velocidades mássicas. A perda de pressão por atrito representou até 93,7% da perda total. Também foram analisados os padrões de escoamento, sendo observados os padrões de bolhas isoladas, bolhas alongadas, intermitente e anular, sendo que o padrão de bolhas isoladas foi observado para baixos fluxos e títulos de vapor, e o padrão anular mostrou-se presente para títulos superiores a 0,13. / This work presents an experimental study of heat transfer and drop pressure in flow boiling of the isobutane, R-600a, in a 7 mini channel of 1,47 mm hydraulic diameter. The tests were performed a boiling with a saturation temperature of 22 °C and saturation pressure of 302 kPa, with a mass velocity between 50 and 200 kg/(m²s) and heat fluxes in the test section between 7 and 40 kW/m². In the tests, it was found that the heat transfer coefficient increases with increasing heat flux and mass velocity has more influence at low quality. The heat transfer coefficient achieved values around 3.200 W/(m²K) for the condition of greater flow and heat flux. The drop pressure was increase by increasing the mass velocity and quality in all tests, while the heat flow have any influence on the drop pressure to the greater mass velocity. The friction drop pressure represented to 93.7% of the total loss. As well analyzed the flow patterns, and observing the patterns of isolated bubbles, plugs/slugs, intermittent and annular, and that the pattern of isolated bubbles were observed for low quality and heat flux and the annular pattern was present for quality from 0.13.

No presente trabalho são relatados os resultados obtidos por meio de ensaios de caracterização para os diferentes tipos de óleos vegetais (algodão, canola, girassol, milho e soja), no estado novo e puro, tais como viscosidade, número de acidez, índice de iodo, índice de saponificação, cromatografia gasosa, curvas de resfriamento e coeficiente de transferência de calor. Esses mesmos ensaios foram realizados também com as amostras de óleo de soja com diferentes concentrações de aditivos antioxidantes. As diferentes formulações feitas com óleo de soja foram submetidas a um processo de envelhecimento acelerado (durante 72 horas), suas propriedades foram comparadas com as de dois óleos minerais utilizados para têmpera. O mesmo foi feito para os óleos vegetais, estes porém foram envelhecidos durante 48 horas. Pode-se então, comparar qual amostra sofreu menor oxidação durante um mesmo tempo de envelhecimento e, desta maneira, avaliar qual aditivo antioxidante obteve melhor desempenho, retardando o processo de oxidação no óleo de soja. Esses estudos também permitiram verificar qual, dentre os óleos vegetais, possui as melhores propriedades para ser utilizado no tratamento térmico de têmpera. Amostras do aço AISI 4140 foram temperadas nos diferentes óleos estudados, obteve-se a curva de dureza e as micrografias óticas para cada amostra temperada. / In this work, the results obtained from the characterization of different vegetable oils (cotton, canola, sunflower, corn and soybean) are reported. The oils were evaluated at \"new condition\" and \"pure\" by viscosity, acid and iodine number, saponification, gas chromatography, cooling curves and heat transfer coefficient. These same analyses were also performed on samples of soybean oil containing various concentrations of antioxidant. The various formulations prepared with soybean oil were accelerated aged for 72 hours and their properties were compared with two mineral oils used for quenching. Likewise, the vegetable oils were aged for 48 hours long. Therefore, it was possible to identify which sample exhibited the lower oxidation process at the same aging time and, thus, evaluate the antioxidant additive that promoted the improved oxidation performance for soybean oil. Also, these studies allowed verifying which of the vegetable oils had the best properties to be used as quenchants. Samples of AISI 4140 steel were quenched in different oils and the hardness curve and optical microscopy for each sample were obtained.

An experimental investigation has been carried out to study the heat transfer in a two-phase two-component mixture flowing upward inside a 1" double pipe heat exchanger. The heat transfer coefficient was measured using either air to lift the liquid (air-lift system) or a mechanical pump. The heat transfer coefficient results have been extensively studied and compared with other workers' results. An attempt was made to correlate the present heat transfer data in dimensionless correlations. Possible factors affecting the two-phase heat transfer coefficient have been studied with special attention being given to the fluid properties, particularly the liquid viscosity. Experiments were also carried out to investigate the effect of solid particles added to a liquid flow on the measured heat transfer coefficient. The present investigation was carried out using air as the gas-phase ranging from 2x 10-5 up to 80 x 10-5 m3/s. Liquids used were water and glycerol solutions with viscosity ranging from 0.75 up to 5.0 C. P. and flowrates between 4x 10-5 and 25 x 10-5 m3/s. Void fraction and pressure drop were also measured during the heat transfer process. Flow pattern in gas-liquid mixture was investigated in a perspex tube of identical dimensions to the heat exchanger tube.

Det finns stora vinningar att göra inom både transport- och industrisektorn genom att effektivisera materialanvändningen i produkter. Denna vinning återfinns i både materialkostnader och energieffektivisering. Scandymet AB är ett företag som tillverkar värmeväxlare och elektriska doppvärmare för ytbehandlingsindustrin. Denna rapport syftar till att utvärdera hur väl ett kalkylark som används som underlag för dimensionering av värmeväxlare hos företaget stämmer överens med verkligheten. En testrigg har därför konstruerats för att undersöka kalkylarkets validitet gällande temperaturer under 46 grader Celsius. I rapporten redovisas resultaten av tester på fyra olika värmeväxlare och resultaten har jämförts med företagets kalkylark. Undersökningarna visar att två av dessa värmeväxlare är överdimensionerade och två värmeväxlare stämde väl överens med kalkylarket. I samtliga tester används vatten som media, men då Scandymet AB värmeväxlares huvudsakliga användningsområde är korrosiva vätskor dras slutsatsen att fler undersökningar med andra fluider skulle behövas för att ytterligare fördjupa kunskapen inom värmeväxlarnas korrekta dimensionering. / There are huge gains in both the transport and industry sectors by making material use more efficient in products. This gain is found in both material costs and energy efficiency. Scandymet AB is a company that manufactures heat exchanger and electric immersion heaters for the surface treatment industry. This report aims to evaluate how well a spreadsheet used as basis for the dimensioning of heat exchangers at the company is consistent with reality. A test rig has therefore been designed and constructed to investigate the validity of the spreadsheet. The report presents the results of tests on four different heat exchangers and the results have been compared with the company’s spreadsheet. In all tests water has been used as the media to be heated, but since Scandymet AB’s heat exchanger’s main application is corrosive liquids, therefore I consider that a deeper investigation with additional fluids would be necessary to further deepen the knowledge in the area.

L’opération de transfert de matière gaz/liquide est une étape essentielle en génie desprocédés. Elle conditionne directement les performances des contacteurs gaz/liquide en représentantbien souvent l’étape limitant l’efficacité du procédé. L'objectif de cette étude est de proposer denouvelles investigations afin d'étudier l'effet de la présence dans l'eau pure, de certains composésgénéralement rencontrés dans les procédés biologiques, sur les coefficients de diffusion de l'oxygèneet de quantifier leurs conséquences sur les coefficients de transfert de matière côté liquide. Lescoefficients de diffusion de l'oxygène DO2 ont été mesurés dans diverses phases liquides contenant dusel (NaCl), du sucre (glucose) ou des tensio-actifs (laurylsulfate de sodium). Comparé à l'eau pure,des réductions de coefficient de diffusion DO2 ont été observées, la variation de DO2 avec laconcentration C de composé a été modélisée, elle dépend de la nature du composé ajouté. Ensuite,des expériences réalisées sur un train de bulles et sur les mêmes phases liquides ont permis ladétermination des coefficients de transfert de matière côté liquide kL. Quelle que soit la solutionaqueuse étudiée, une diminution des valeurs de kL est observée avec l'augmentation de C. Cesrésultats mettent en évidence que, même si les propriétés de l'eau pure (densité, viscosité, tensionsuperficielle) ne sont pas significativement modifiées par l'ajout de sels (NaCl), les coefficients detransfert de matière côté liquide kL peuvent être modifiés. Pour les solutions aqueuses de glucose, laréduction de kL avec DO2 est bien corrélée, et principalement due à la variation de viscosité avec laconcentration. Pour les solutions de tensio-actif, les nombres de Reynolds restent presque constantspour toutes les concentrations. Le seul responsable de la réduction du coefficient de transfert dematière côté liquide kL est donc le coefficient de diffusion de l’oxygène qui diminue avec laconcentration. La présente étude a clairement confirmé la nécessité de compléter et/ou rendre comptedes données liées aux coefficients de diffusion de l’oxygène DO2 et aux coefficients de transfert dematière côté liquide kL dans des milieux complexes (solution électrolytique, solution organique ettensioactif). Ces informations sont nécessaires pour décrire et modéliser correctement lesphénomènes de transfert de matière gaz/liquide / The gas/liquid mass transfer is an essential step in process engineering. It directly affects theperformance of gas/liquid reactor in being often limiting process efficiency. The objective of this studyis to propose new investigations in order to study (i) the effect on oxygen diffusion coefficients underthe presence in clean water of some compounds usually found in biological process and (ii) quantifytheir consequences on liquid-side mass transfer coefficients. The oxygen diffusioncoefficients DO2 were measured in various synthetic liquid phases containing either salt (NaCl), sugar(glucose) or surfactant (sodium laurylsulphate). When compared to clean water, reductionsof DO2 were observed; the variation of DO2 with the compound concentration C was modeled andfound dependent on the nature of the compound added. Then, to determine the liquid side masstransfer coefficient kL, experiments on a train of bubbles rising in a quiescent liquid phase were carriedout by the same synthetic liquid phases. For all cases, whatever the aqueous solutions, a decreaseof kL with increasing C was clearly observed. These results firstly showed that, even if the properties ofclean water (density, viscosity, surface tension) were not significantly changed by the addition of salts(NaCl), the liquid-side mass transfer coefficients could be modified. For the aqueous solutions ofglucose, the reduction of kL with DO2 was well correlated, and mainly due to the change in viscositywith concentration. For surfactants, the hydrodynamic conditions (i.e. bubble Reynolds number) beingalmost kept constant for all concentrations, only the change in DO2 was thus responsible for thedecrease of kL. The present study clearly confirmed the need to complete and/or account for thedatabase related to oxygen diffusion coefficients and liquid side mass transfer coefficient in complexmedia (electrolytic solution, organic solution and surfactant). This condition is imperatively required todescribe and to model appropriately the gas-liquid mass transfer phenomena

Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2016-10-10T12:43:24Z No. of bitstreams: 1 TeseGYR.pdf: 8156092 bytes, checksum: 727d9cd338ae7ed90fe24238b42228bd (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2016-10-11T20:34:55Z (GMT) No. of bitstreams: 1 TeseGYR.pdf: 8156092 bytes, checksum: 727d9cd338ae7ed90fe24238b42228bd (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2016-10-11T20:35:04Z (GMT) No. of bitstreams: 1 TeseGYR.pdf: 8156092 bytes, checksum: 727d9cd338ae7ed90fe24238b42228bd (MD5) / Made available in DSpace on 2016-10-11T20:42:33Z (GMT). No. of bitstreams: 1 TeseGYR.pdf: 8156092 bytes, checksum: 727d9cd338ae7ed90fe24238b42228bd (MD5) Previous issue date: 2015-03-25 / Outra / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Pneumatic bioreactors are devices free of moving parts which have the purpose of converting raw materials in bio-products of commercial interest by the action of enzymes or cells. They are promising in the biochemical industry, ensuring good oxygen transfer and consuming less energy. Global performance parameters such as global gas hold up and the volumetric oxygen transfer coefficient are important criteria in the design and selection among different geometries of the mentioned devices. In the present work it was carried out modeling and simulation of pneumatic bioreactors based on Computational Fluid Dynamics (CFD) in order to estimate the global gas hold up and the volumetric oxygen transfer coefficient in three different geometries of pneumatic bioreactors: bubble column, concentric tube airlift and split tube airlift. The simulated results of each performance parameter were verified by comparison with the experimental values reported by Thomasi et al. (2010) and Mendes and Badino (2015) for the fluids distilled water, glycerol solution 10 cP and xanthan gum solution 0.2% w/v (weight/volume) in a wide range of specific air flow rate (0 to 5 min- 1). Application suite ANSYS® 14.5 was used for numerical simulations in CFD. Important parameters such as the bubble diameter played a great influence on results of the volumetric oxygen transfer coefficient. It can be observed by the experimental and simulated results that the concentric tube airlift bioreactor was the best alternative to the global gas hold up and the volumetric oxygen transfer coefficient (reaching 14% and 0.06 s-1 for distilled water, respectively). It was found that the results obtained via the CFD agreed with the majority trend of experimental data, capturing the most important hydrodynamic phenomena and mass transfer characteristics, showing that the modeling of different systems with different fluids fulfilled the main objective of obtaining reliable models design and performance of other geometries of pneumatic bioreactors. / Os biorreatores pneumáticos são equipamentos industriais isentos de partes móveis que têm a finalidade de converter matérias-primas em bioprodutos de interesse comercial pela ação de enzimas ou células. São promissores na indústria bioquímica, pois garantem boa transferência de oxigênio consumindo menos energia. Parâmetros globais de desempenho, como a retenção gasosa global e o coeficiente volumétrico de transferência de oxigênio são critérios importantes no projeto e seleção entre geometrias diferentes dos equipamentos mencionados. No presente trabalho foi realizada a modelagem e a simulação de biorreatores pneumáticos baseada na Fluidodinâmica Computacional (CFD - Computational Fluid Dynamics) de forma a estimar a retenção gasosa global e o coeficiente volumétrico de transferência de oxigênio em três geometrias distintas: coluna de bolhas, airlift de cilindros concêntricos e airlift split. Os resultados simulados de cada parâmetro de desempenho foram verificados comparando-se com os valores experimentais reportados nos trabalhos de Thomasi et al. (2010) e Mendes e Badino (2015) para os fluidos água destilada, solução de glicerol 10 cP e solução de goma xantana 0,2% m/v (massa/volume) e vazão de alimentação específica de ar numa ampla faixa (0 a 5 min-1). Foi empregada a suíte de aplicativos ANSYS® 14.5 para as simulações numéricas em CFD. Parâmetros importantes, como o diâmetro de bolha, exerceram grande influência nos resultados referentes ao coeficiente volumétrico de transferência de oxigênio. Destaca-se, pelos resultados experimentais e simulados, que o biorreator pneumático do tipo airlift de cilindros concêntricos apresentou-se como a melhor alternativa para a retenção gasosa global e para o coeficiente volumétrico de transferência de oxigênio (atingindo 14% e 0,06 s-1 para a água destilada, respectivamente). Verificou-se que os resultados obtidos via CFD concordaram com a tendência majoritária dos dados experimentais, capturando os fenômenos mais relevantes das características hidrodinâmicas e da transferência de massa, mostrando que a modelagem dos diferentes sistemas com diferentes fluidos atendeu ao principal objetivo de obter modelos confiáveis para o projeto e comparação de desempenho de outras geometrias de biorreatores pneumáticos. / CNPq: 478472/2011-0 / CNPq: 140466/2011-8