L'étude des arcs électriques dans les liquides débute au XXème siècle suite à la création des premiers disjoncteurs à bain d'huile et à l'utilisation de différents procédés de soudure/découpe en pleine eau de coques de navire. Ces études ont été délaissées pendant environ 60 ans jusqu'à ce que de nouvelles applications voient le jour comme la fabrication de nanostructures (pour le génie électrique, la médecine, etc), la fracturation électrique ou encore diverses applications environnementales (dépollution, stérilisation, gazéification, ondes de chocs). Ces diverses applications se font avec des temps et des énergies mises en jeu pour la décharge très variables. Malgré ces différences, il y a toujours l'apparition d'une phase gazeuse globalement sphérique due au passage du courant. Cependant, cette phase est très peu étudiée dans la littérature notamment pour des décharges de l'ordre du kilojoule pour des durées de 10ms environ. L'objectif de la thèse est donc d'améliorer la compréhension de la formation et de la dynamique de la bulle de gaz alimentée par cet arc en jouant sur certains paramètres du système. Les travaux effectués s'articulent suivant deux axes : une étude expérimentale pour analyser le comportement de cette bulle par rapport à l'arc en modifiant notamment l'énergie injectée, la distance inter-électrode utilisée ou encore la nature du fluide employé ; et une étude numérique où un modèle diphasique 2D a été mis en œuvre sous Ansys Fluent pour simuler la création et le développement de cette phase gazeuse au sein d'une phase liquide. La complémentarité de ces deux études permet de témoigner de la présence de certains mécanismes comme ceux de la formation de bulles ou de cycles d'expansion et d'effondrement, gouvernés par des phénomènes de chauffage, d'évaporation ou électrothermiques. L'expérience mise en place se compose d'un réacteur hermétique en aluminium où l'arc électrique est amorcé par un fil fusible entre deux électrodes dans un liquide : eau ou huile. Des hublots permettent la visualisation par caméra rapide de l'espace inter électrode, et donc de l'arc et de la bulle de gaz qu'il engendre. Les caractéristiques courant et tension de l'arc électrique sont suivies dans le temps. Un capteur de pression dans le volume d'air situé au-dessus du liquide contrôle l'onde de pression générée par la décharge. Les résultats expérimentaux sont traités sous Matlab et permettent de conforter le modèle numérique mis en place. Le code utilise les équations de Navier-Stokes pour décrire les deux phases du fluide via la méthode Volume-Of-Fluids (VOF). A ces développements a aussi été intégré un modèle pour prendre en compte le transfert d'une phase de fluide vers une autre. Pour nos conditions de températures élevées, ce modèle a dû être adapté via le coefficient d'intensité de transfert de masse, qui est décrit en fonction de la température et de la proportion de phase dans une cellule. Les résultats de simulation issus de ce modèle permettent d'appuyer les observations expérimentales, et de poser les bases d'une étude sur la formation et le comportement de la phase gazeuse produite par le passage d'un arc électrique dans un liquide. / The study of electrical arcs in liquids begins in XXth century with the first oil circuit breaker and the use of welding/cutting processes on ship hulls in full water. These studies have been neglected for about 60 years, until the emergence of new applications such as the manufacture of nanostructures (for electrical engineering, medicine, etc.), electrical arc fracturing or different environmental applications (depollution, sterilization, gasification). In these applications different times and energies scales are involved for the discharge characteristics. Despite these differences, in all configurations a spherical gaseous medium dues to the current carrying path in the liquid exists. However, this gaseous phase is not much studied in the literature, particularly for an energy discharges of the order of kilojoule applied during 10ms. The goal of the thesis was to improve the understanding and to interpret the formation and the dynamic of the gas bubble created by this arc by varying the conditions. The work follows two ways: an experimental study to analyze the behavior of the bubble depending on the arc characteristics as the energy injected, the distance between the electrodes or the nature of the fluid; And a numerical study, where a 2D diphasic model has been implemented under Ansys Fluent to simulate the creation and the expansion of this gaseous phase in a liquid. The complementarity of these two approaches allows complementarities and interpretations. The experiment set up is composed by a closed aluminum reactor, where the electric arc is established in a liquid (water or oil) by a fusible wire between two electrodes. Windows allows to visualize by a speed camera the inter-electrode space, and so the arc and the gas bubble created. The current and voltage characteristics of the electric arc are recorded over time. A pressure sensor located in the volume of air above the liquid controls the pressure variations. The experimental results are treated through Matlab software and allow corroborating the numerical model developments. The code uses the Navier-Stokes equations to describe the two phases of the fluid via the Volume-Of-Fluids (VOF) method. Specifics developments have also been integrated to take into account the phase transfer at the gas/liquid interface adapting the mass transfer intensity coefficient. This coefficient is described as a function of the temperature and of the proportion of phase in a cell. The simulation results from the model support the experimental observations and build the foundations for a study on the behavior of the gaseous phase produced by the passage of an electric arc in a liquid.

Determinar o comportamento de materiais reforçados a partir do conhecimento das propriedades individuais de seus componentes é assunto de uma quantidade considerável de pesquisas experimentais e teóricas nas últimas décadas. Nesse trabalho, um modelo multifásico para determinação do comportamento macroscópico de estruturas de concreto armado no contexto da elastoplasticidade e considerando a interação entre o concreto e as armaduras é apresentado e incorporado em um código numérico em elementos finitos. Em uma escala macroscópica o meio multifásico é tomado como a superposição geométrica de meios contínuos em interação mútua, chamados de fase matriz e fase reforço. Cada fase possui cinemáticas distintas oferecendo, desta forma, um arcabouço adequado para levar em conta o deslizamento das barras de aço em relação à matriz de concreto. As equações de movimento são desenvolvidas com a aplicação do método dos trabalhos virtuais. A evolução elastoplástica é obtida a partir da avaliação de um critério próprio para cada constituinte e para interação, computando as tensões parciais correspondentes e obtendo um comportamento desacoplado por fase. A resistência do concreto em um estado de tensões multiaxial é estimada a partir do critério de falha de Ottosen e a fissuração do concreto é representada utilizando um modelo de fissuras distribuídas. Utilizando uma implementação tridimensional em elementos finitos, a ferramenta numérica desenvolvida é aplicada para analisar vigas e lajes sob carregamento prescrito e uma boa concordância entre os resultados numéricos e experimentais é obtida. Ao final é apresentado uma análise de ensaio de arrancamento onde o principal objetivo é a investigação dos parâmetros relevantes que controlam a lei de interação entre o concreto e as barras de aço. / Predicting the behavior of reinforced materials from the knowledge of the individual properties of its components has been a subject of several experimental and theoretical works in recent years. In this work, a multiphase model for assessing the macroscopic behavior of reinforced concrete structures in the context of elastoplasticity and accounting for the interaction between the reinforcing bars and the surrounding concrete is presented and implemented in a finite element numerical code. Considering a macroscopic scale, the multiphase model is regarded as superposition of several continua in mutual interaction, namely matrix phase and reinforcement phase. For each phase different kinematics are attributed providing a suitable framework to consider the slippage between the matrix and the reinforcement. The general equations of motion are derived by means of the virtual work method. The elastoplastic evolution is carried out considering each phase and the interaction separately, computing the corresponding partial stresses and projecting onto the yield domain of the multiphase medium. The strength of concrete under multiaxial states of stress is estimated from the so-called Ottosen failure criterion and the concrete cracking issue is accounted with a smeared crack model. Using a three-dimensional finite element implementation, the numerical tool developed is applied to analyze reinforced concrete beams and slabs under prescribed loading and a good agreement between numerical and experimental results is obtained. Finally, the investigation of the main parameters that govern the interaction law of concrete and reinforcing bars has been the central purpose of the pullout tests simulations.

Cette travail de thèse est lié au besoin de modélisation des écoulements diphasiques en générateurs de vapeur (entrée liquide et sortie vapeur). La démarche proposée consiste à faire le choix d'une modélisation hybride de l'écoulement, en scindant la phase gaz en deux champs, modélisés de manières différentes. Ainsi, les petites bulles sphériques sont modélisées avec une approche dispersée classique avec le modèle eulérien à deux fluides, et les bulles déformées sont simulées à l'aide d'une méthode de localisation d'interface.Le travail effectué porte sur la mise en place, la vérification et la validation du modèle dédié aux larges bulles déformées, ainsi que le couplage entre les deux approches pour le gaz gaz, permettant des premiers calculs de démonstration utilisant l'approche hybride complète. / The present study is related to the need of modeling the two-phase flows occuring in a steam generator (liquid at inlet and vapour at outlet). The choice is made to investigate a hybrid modeling of the flow, considering the gas phase as two separated fields, each one being modeled with different closure laws. In so doing, the small and spherical bubbles are modeled through a dispersed approach within the two-fluid model, and the distorted bubbles are simulated with an interface locating method.The main outcome is about the implementation, the verification and the validation of the model dedicated to the large and distorted bubbles, as well as the coupling of the two approaches for the gas, allowing the presentation of demonstration calculations using the so-called hybrid approach.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-10-05T16:36:00Z No. of bitstreams: 1 MARIA GORETHE DE SOUSA LIMA - TESE (PPGEP) 2008.pdf: 5258111 bytes, checksum: afc624a7c316b024f1b9064cef933c81 (MD5) / Made available in DSpace on 2018-10-05T16:36:00Z (GMT). No. of bitstreams: 1 MARIA GORETHE DE SOUSA LIMA - TESE (PPGEP) 2008.pdf: 5258111 bytes, checksum: afc624a7c316b024f1b9064cef933c81 (MD5) Previous issue date: 2008-05-29 / CNPq / O trabalho de tese em questão teve por objetivo geral realizar um estudo teórico/experimental para avaliar a fluidodinâmica de um reator anaeróbio de fluxo ascendente e manta de lodo (Upflow Anaerobic Sludge Blanket – UASB), tratando água residuária doméstica, visando contribuir para melhorar o desempenho dos dispositivos de separação de fases. Para o estudo experimental, foi realizado o monitoramento da estabilidade operacional e da eficiência de tratamento do reator por meio de análises físico – químicas de amostras do seu afluente e efluente e das pressões ao longo do reator. Os resultados obtidos experimentalmente constataram que o reator apresentava uma boa estabilidade operacional. A eficiência de remoção de matéria orgânica foi considerada baixa (42 %); enquanto que para os sólidos totais em suspensão a eficiência de remoção variou em torno 70 %. Os valores de pressão apresentaram uma relação linear decrescente à medida que a tomada de pressão se distanciava da zona de digestão. Para o estudo numérico, foram desenvolvidas malhas no espaço bi e tridimensional representativas do reator UASB modificando as disposições e inclinações do defletor de gases. Diferentes simulações foram realizadas usando o Ansys CFX 10.0 para diferentes fluxos. Os resultados numéricos constataram que a disposição e inclinação do defletor de gases além de exercer grande influência sobre a distribuição de velocidades no reator, também afetou consideravelmente o desempenho dos dispositivos de separação de fases (defletor de gases e separador trifásico). Com relação ao fluxo mássico, foi verificado que o mesmo apresentou uma relação diretamente proporcional com a eficiência de retenção de sólidos suspensos, para a faixa estudada no presente trabalho (10-4 a 0,11 kg/s). A análise comparativa dos resultados numéricos e experimentais da pressão e da concentração de lodo na saída do reator com inclinação do defletor voltada para cima apresentaram diferenças da ordem de 2 kPa e de 10 mg/L, respectivamente, sendo consideradas satisfatórias. / The thesis work in question had for general objective to accomplish a theoretical/experimental study to evaluate the fluid dynamic of an anaerobic reactor of ascending flow and sludge blanket (Upflow Anaerobic Sludge Blanket – UASB), treating domestic wastewater, seeking to contribute to improve the performance of the phases separation devices. For the experimental study, it was accomplished the monitorially of the operational stability and the efficiency of the reactor treatment through physical-chemical analyses from samples of its affluent and effluent, as well as, the pressure along the reactor. The results obtained experimentally proved that the reactor presented a good operational stability. The efficiency of removal organic matter was considered low (42%); while for the total solid in suspension the removal efficiency varied around 70%. The pressure values presented a decreasing linear relationship as the taken of pressure distanced itself of the digestion zone. For the numeric study, meshes were developed in the space bi and three-dimensional representative of the UASB reactor modifying the dispositions and inclinations of the reflector of gases. Different simulations were accomplished using the Ansys CFX 10.0 for different flows. The numeric results verified that the disposition and inclination of the gases diverter besides exercising great influence on the distribuition of speed in the reactor, they also affected considerably the acting of the devices of phases separation (gases diverter and three-phase separator). In relation to the mass flow, it was verified that the same one presented a relationship directly proportional with the efficiency of suspended solid retention, for the strip studied in the present work (10-4 to 0,11 kg/s). The comparative analysis of the numeric and experimental results of the pression and of the sludge concentration in the exit of the reator with inclination of the diverter returned upward they presented differences of the order of 2 kPa and of 10 mg/L, respectively, being considered satisfactory.

abstract: The Volume-of-Fluid method is a popular method for interface tracking in Multiphase applications within Computational Fluid Dynamics. To date there exists several algorithms for reconstruction of a geometric interface surface. Of these are the Finite Difference algorithm, Least Squares Volume-of-Fluid Interface Reconstruction Algorithm, LVIRA, and the Efficient Least Squares Volume-of-Fluid Interface Reconstruction Algorithm, ELVIRA. Along with these geometric interface reconstruction algorithms, there exist several volume-of-fluid transportation algorithms. This paper will discuss two operator-splitting advection algorithms and an unsplit advection algorithm. Using these three interface reconstruction algorithms, and three advection algorithms, a comparison will be drawn to see how different combinations of these algorithms perform with respect to accuracy as well as computational expense. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2015

abstract: Many physical phenomena and industrial applications involve multiphase fluid flows and hence it is of high importance to be able to simulate various aspects of these flows accurately. The Dynamic Contact Angles (DCA) and the contact lines at the wall boundaries are a couple of such important aspects. In the past few decades, many mathematical models were developed for predicting the contact angles of the inter-face with the wall boundary under various flow conditions. These models are used to incorporate the physics of DCA and contact line motion in numerical simulations using various interface capturing/tracking techniques. In the current thesis, a simple approach to incorporate the static and dynamic contact angle boundary conditions using the level set method is developed and implemented in multiphase CFD codes, LIT (Level set Interface Tracking) (Herrmann (2008)) and NGA (flow solver) (Desjardins et al (2008)). Various DCA models and associated boundary conditions are reviewed. In addition, numerical aspects such as the occurrence of a stress singularity at the contact lines and grid convergence of macroscopic interface shape are dealt with in the context of the level set approach. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2015

Among the different multiphase ac drive solutions, one of the most widely reported in the literature is the six-phase machine. The machines can be realised into two different configurations, symmetrical and asymmetrical. For the symmetrical configuration, the stator winding consists of two sets of three-phase windings that are spatially shifted by 60 degrees where spatial displacement between any two consecutive phases is the same and equal to 60 degrees. For the asymmetrical configuration, the two sets of three-phase windings are spatially shifted by 30 degrees. As a result, the spatial shift between consecutive phases becomes non-equidistant. In this thesis, modulation techniques for both symmetrical and asymmetrical six-phase machines are investigated. The machines are configured in open-end winding configuration where both ends of the stator winding are connected to separate isolated inverters in a topology known as dual-inverter supply. Compared to conventional single-sided supply topology where one end of the winding is connected to an inverter while the other side is star-connected, some additional benefits are offered by the dual-inverter supply topology. First, fault tolerance of the drive is improved, since the supply is realised with two independent inverters. In case one of the inverters is faulted, the other can continue to provide power to the machine. Second, the same phase voltages can be achieved with half the dc-link voltages on the two inverter inputs compared to the single-sided supply, which can be useful in applications such as electric and hybrid electric vehicles and medium sized ships, where the dc voltage levels are limited. Further, due to the nature of the topology, additional diodes and capacitors like in the Neutral Point Clamped (NPC) and Flying Capacitor (FC) VSIs are not required. The latter results in a further advantage - capacitor voltage balancing techniques are not required. Two pulse width modulation (PWM) techniques for control of the dual-inverter supplied six-phase drives are proposed in this thesis. The first is a reference sharing algorithm where the inverters are modulated using reference voltage that is shared equally and unequally between the two modulators. For both symmetrical and asymmetrical six-phase drives, a better performance, in term of total harmonic distortion (THD) of phase voltage is obtained when the reference is shared unequally between the two modulators. The second technique is carrier-based modulation where the modulation of the two inverters is determined by the disposition of the carrier signals. Three variations of carrier signals disposition are investigated namely; the phase disposition (PD-PWM), alternate phase opposition disposition (APOD-PWM) and phase-shifted PWM (PS-PWM). For the symmetrical six-phase drive, the best phase voltage and current THDs are obtained using APOD-PWM while for asymmetrical six-phase drive, the APOD-PWM produces the worst current THD despite having the best voltage THD among the three methods. All the developed modulation techniques are analysed using simulations and experiments undertaken using a laboratory prototypes. The waveforms and spectra of phase voltage and load current obtained from the simulation and experimental works are presented in this thesis together with the THD of both the voltage and current over entire linear modulation range.

Orientador: Tomaz Manabu Hashimoto / Banca: Marcelo dos Santos Pereira / Banca: Antonio Jorge Abdalla / Banca: Pedro Paulo de Campos / Banca: José Rubens de Camargo / Resumo: Este trabalho analisa a transformação da austenita retida induzida por deformação, em um aço AISI 4340 com estruturas multifásicas. O aço foi submetido a duas rotas de tratamentos isotérmicos selecionadas e foi analisado quanto à fração volumétrica das fases e características mecânicas através da valiação dos limites de escoamento. Os corpos de prova foram submetidos a três diferentes níveis de tensões de tração, acima do limite de escoamento, para que se produzissem deformações plásticas determinadas. A influência destas deformações, na microestrutura e nos novos limites de escoamento, foram avaliadas. Mostrando variações significativas nas frações volumétricas das fases, com diminuição das quantidades de austenita, indicando uma transformação, por efeito TRIP (Transformation Induced Plasticity), em martensita o que provocou um aumento nos valores dos limites de escoamento e envelhecimento por deformação. / Abstract: The Transformation induced plasticity of austenite on the multiphase microstructure in a AISI 4340 steel was studied. Two sequences of isothermal treatments were performed. The volume fractions of the phases were analyzed and evaluation of mechanical characteristics through the yield point measurements. The samples were submitted at three different levels of traction above of the yield strength, so that definitive plastic deformations were produced. The influence of these deformations in the microstructure and in the new yield strength was evaluated. Significant variations were showed in the phase volume fraction, with reduction of the amounts of austenite indicating a martensitic transformation, by effect TRIP (Transformation Induced Plasticity) which results increases in the values of the yield strength and deformation ageing. / Doutor

Determinar o comportamento de materiais reforçados a partir do conhecimento das propriedades individuais de seus componentes é assunto de uma quantidade considerável de pesquisas experimentais e teóricas nas últimas décadas. Nesse trabalho, um modelo multifásico para determinação do comportamento macroscópico de estruturas de concreto armado no contexto da elastoplasticidade e considerando a interação entre o concreto e as armaduras é apresentado e incorporado em um código numérico em elementos finitos. Em uma escala macroscópica o meio multifásico é tomado como a superposição geométrica de meios contínuos em interação mútua, chamados de fase matriz e fase reforço. Cada fase possui cinemáticas distintas oferecendo, desta forma, um arcabouço adequado para levar em conta o deslizamento das barras de aço em relação à matriz de concreto. As equações de movimento são desenvolvidas com a aplicação do método dos trabalhos virtuais. A evolução elastoplástica é obtida a partir da avaliação de um critério próprio para cada constituinte e para interação, computando as tensões parciais correspondentes e obtendo um comportamento desacoplado por fase. A resistência do concreto em um estado de tensões multiaxial é estimada a partir do critério de falha de Ottosen e a fissuração do concreto é representada utilizando um modelo de fissuras distribuídas. Utilizando uma implementação tridimensional em elementos finitos, a ferramenta numérica desenvolvida é aplicada para analisar vigas e lajes sob carregamento prescrito e uma boa concordância entre os resultados numéricos e experimentais é obtida. Ao final é apresentado uma análise de ensaio de arrancamento onde o principal objetivo é a investigação dos parâmetros relevantes que controlam a lei de interação entre o concreto e as barras de aço. / Predicting the behavior of reinforced materials from the knowledge of the individual properties of its components has been a subject of several experimental and theoretical works in recent years. In this work, a multiphase model for assessing the macroscopic behavior of reinforced concrete structures in the context of elastoplasticity and accounting for the interaction between the reinforcing bars and the surrounding concrete is presented and implemented in a finite element numerical code. Considering a macroscopic scale, the multiphase model is regarded as superposition of several continua in mutual interaction, namely matrix phase and reinforcement phase. For each phase different kinematics are attributed providing a suitable framework to consider the slippage between the matrix and the reinforcement. The general equations of motion are derived by means of the virtual work method. The elastoplastic evolution is carried out considering each phase and the interaction separately, computing the corresponding partial stresses and projecting onto the yield domain of the multiphase medium. The strength of concrete under multiaxial states of stress is estimated from the so-called Ottosen failure criterion and the concrete cracking issue is accounted with a smeared crack model. Using a three-dimensional finite element implementation, the numerical tool developed is applied to analyze reinforced concrete beams and slabs under prescribed loading and a good agreement between numerical and experimental results is obtained. Finally, the investigation of the main parameters that govern the interaction law of concrete and reinforcing bars has been the central purpose of the pullout tests simulations.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-09-26T17:18:12Z No. of bitstreams: 1 ENIVALDO SANTOS BARBOSA – TESE (PPGEP) 2011.pdf: 14587469 bytes, checksum: 427f6de191a79c41d2bb8c8b12fba569 (MD5) / Made available in DSpace on 2018-09-26T17:18:12Z (GMT). No. of bitstreams: 1 ENIVALDO SANTOS BARBOSA – TESE (PPGEP) 2011.pdf: 14587469 bytes, checksum: 427f6de191a79c41d2bb8c8b12fba569 (MD5) Previous issue date: 2011-08-26 / A indústria do petróleo tem se apoiado tradicionalmente na utilização de dispositivos separadores convencionais baseados no efeito da gravidade que, em geral, são volumosos e com tempo de residência elevado. Os hidrociclones vem sendo comumente usados na separação água/óleo pela indústria de petróleo, devido à elevada capacidade de processamento, baixo custo de manutenção e por exigirem pouco espaço para sua instalação. No entanto, tem-se observado a presença de areia e/ou gás durante a produção e transporte do petróleo. Daí surge a necessidade do desenvolvimento de tecnologias avançadas de separação areia/óleo/água/gás. Neste contexto,o presente trabalho, se propõe estudar o processo de separa¸c˜ao areia/água/gás de uma corrente de óleo utilizando um hidrociclone. As pesquisas foram desenvolvidas usando o pacote comercial ANSYS CFX 12. O modelo matemático usado considera escoamento tridimensional, turbulento, estacionário e é baseado na abordagem Euleriana-Euleriana, para os casos monofásico (água) e multifásico (água-óleo, areia- água - óleo, areia - água - óleo - gás). Foram avaliadas as influˆencias dos modelos de turbulência ( – , RNG – padrões e modificados, SST e RSM–SSG), dos aspectos geométricos e parâmetros físicos na previsão do comportamento do escoamento no hidrociclone. Resultados dos perfis de velocidade axial e tangencial, distribuições de velocidade, pressão e fração volumétrica das fases, eficiência de separação e queda de pressão são apresentados e analisados. Constatou-se o caráter tridimensional do escoamento e boa concordância dos resultados numéricos com dados experimentais da distribuição radial das componentes de velocidade tangencial e axial. O hidrociclone avaliado foi capaz de separar adequadamente a água, areia e gás da corrente de oleosa, com eficiência de remoção 33,07%, 92,52% e 3,81%, respectivamente, para uma vazão volumétrica da mistura tetrafásica de 8,5 m3/h, na entrada do hidrociclone. / The oil industry has traditionally been supported by the use of conventional separators devices based on the gravity effect which are generally bulky and provide high residence time. The hydrocyclone have been commonly used in oil-water separation by the oil industry due to high processing capacity, lower maintenance cost and minor physical space to installation. However has been observed the presence of sand and /or gas during oil production and transportation. For this reason, the need for developing of advanced technologies has strongly arisen, intending to separate sand/oil/water/gas. In this context, the present work aims to study the separation process of sand/water/gas from oil stream, using a hydrocyclone. The research were developed using the commercial package ANSYS CFX 12. The used threedimensional mathematical model considers turbulent and steady state flow and it is based on Eulerian-Eulerian approach for single-phase (water) and multiphase (wateroil, sand-water-oil, sand - water - oil - gas) cases. The influence of turbulence models ( – , RNG – standard and modified, SST and RSM–SSG), and geometric aspects of the physical parameters in predicting of flow behavior in the hydrocyclone were evaluated. Results of axial and tangential velocity profiles, tangential velocity, pressure and volumetric fraction distributions, separation efficiency and pressure drop are presented and analyzed. One can find the three-dimensional flow aspect and reasonable approximation of numerical results with experimental data of the radial distribution of tangential and axial velocity components. The evaluated hydrocyclone was able to separate adequately water, sand and gas from the oil flow with remotion efficiency of 33.07%, 92.52% and 3.81%, respectively, to a four-phase mixture and inlet volumetric flow rate of 8.5 m3/h in the hydrocyclone.