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Search Results: 1 - 10 of 188114 matches for " Severino Rodrigues de Farias Neto "
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Theoretical Evaluation of Two-Phase Flow in a Horizontal Duct with Leaks  [PDF]
Morgana de Vasconcellos Araújo, Severino Rodrigues de Farias Neto, Antonio Gilson Barbosa de Lima
Advances in Chemical Engineering and Science (ACES) , 2013, DOI: 10.4236/aces.2013.34A1002
Abstract: The transport of oil and its derivates are done, mostly, by pipeline. The time to detect leaks has to be short for pre-venting big disasters in the nature and decreasing losses for industries. The techniques available for leak detection vary from visual inspection to the use of computational techniques such as mathematical modeling. This paper aims to study the fluid dynamics of two-phase flow (water-oil) in the pipe with leakage. The equations of the mass and momentum conservation are numerically solved by using the ANSYSCFX commercial code with the aid of a structured mesh of a horizontal pipe with three holes of leaks. The Eulerian-Eulerian model was adopted considering the oil as continuous phase and water as dispersed phase, and constant fluid properties. With profiles of pressure and volume fraction along the time in the pipe, the influence of leakage on the single-phase (oil) and two-phase (water-oil) was evaluated.
Unsteady Fluidynamic Behavior of Gas Bubbles Flowing in Curved Pipes: A Numerical Study  [PDF]
Jose Luis Gomes Marinho, Ramdayal Swarnakar, Severino Rodrigues de Farias Neto, Antonio Gilson Barbosa de Lima
Advances in Chemical Engineering and Science (ACES) , 2012, DOI: 10.4236/aces.2012.22033
Abstract: Petroleum is considered as one of the factors for the development of a nation as well as a cause of economic and political conflicts around the world because of the diversity of products obtained with their derivatives such as fuel for automotives and aviation, and manufacturing plastic parts, among others. The crude petroleum (usually oil, water and gas) found in an underground reservoir is transported to the surface by pipes, and has drawn the attention of researchers because of the problems generated in the pipeline with particular attention to the loss of pressure, friction and bubbles. For a fluid flow in plug regime, where many of the bubbles formed coalesce and produce bigger ones of sizes almost equal to the pipe diameter (Taylor bubble), severe instability in the flow is caused. In this context, the objective of this research has been to study the Taylor bubble flow in curved ducts using the software CFX. Results of the transient effects of the air concentration on the bubble air volumetric fraction, of the viscosity on bubble format, and pipe angle of 90? on bubble symmetry are presented and interpreted.
Thermo-Hydrodynamics of Core-Annular Flow of Water, Heavy Oil and Air Using CFX  [PDF]
Antonio José Ferreira Gadelha, Severino Rodrigues de Farias Neto, Ramdayal Swarnakar, Antonio Gilson Barbosa de Lima
Advances in Chemical Engineering and Science (ACES) , 2013, DOI: 10.4236/aces.2013.34A1006
Abstract: The transport of heavy and ultra-viscous oil employing the core-flow technique has been increasing recently, because it provides a greater reduction of the pressure drop during the flow. In this context, the effect of temperature and the presence of gas on the thermo-hydrodynamics of a three-phase water-heavy oil-air flow in a horizontal pipe under the influence of gravity and drag forces, using the commercial software ANSYS CFX?, have been evaluated. The standard κ ? ε turbulence model, the mixture model for heavy oil-water system and the particle model for heavy oil-gas and water-gas systems, were adopted. Results of velocity, volume fraction, pressure and temperature fields of the phases present along the pipe are presented and discussed. It has been found that the presence of the air phase and the variation in the temperature affect the behavior of annular flow and pressure drop.
Numerical Analysis of Heavy Oil-Water Flow and Leak Detection in Vertical Pipeline  [PDF]
Jo?o Victor Nunes de Sousa, Cristiane Holanda Sodré, Antonio Gilson Barbosa de Lima, Severino Rodrigues de Farias Neto
Advances in Chemical Engineering and Science (ACES) , 2013, DOI: 10.4236/aces.2013.31002

Pipeline is a conventional, efficient and economic way for oil transportations. The use of a good system for detecting and locating leaks in pipeline contribute significantly to operational safety and cost saving in petroleum industry. This paper aims to study the heavy oil-water flow in vertical ducts including leakage. A transient numerical analysis, using the ANSYS-CFX? 11.0 commercial software is performed. The mathematical modeling considers the effect of drag and gravitational forces between the phases and turbulent flow. Mass flow rate of the phases in the leaking orifice, the pressure drop as a function of the time and the velocity distributions are presented and discussed. We can conclude that volumetric fraction of phases and fluid mixture velocity affect pressure drop and mass flow rate at the leak hole.

Non-Isothermal Separation Process of Two-Phase Mixture Water/Ultra-Viscous Heavy Oil by Hydrocyclone  [PDF]
Josedite Saraiva de Souza, Fabiana Pimentel Macêdo Farias, Ramdayal Swarnakar, Severino Rodrigues de Farias Neto, Antonio Gilson Barbos de Lima
Advances in Chemical Engineering and Science (ACES) , 2011, DOI: 10.4236/aces.2011.14038
Abstract: Environmental agencies do not allow effluents, from the petroleum productions, which contain oil concentrations that exceed the amounts permitted by the regulations. In recent time heavy oil operating petroleum industries are generating oil/water mixture by products, which are difficult to separate. Industrially, hydrocyclone is generally used to separate oil from an oil/water mixture. This is due to its high performance of separation, low cost of installation and maintenance. In the present work, therefore, the thermal fluid dynamics of water/ultra-viscous heavy oil separation process in a hydrocyclone has been studied. A steady state mathematical model which simulates the performance of a non-isothermal separation process is presented. The Eulerian-Eulerian approach for the interface of the phases involved (water/ultra-viscous heavy-oil) is used and the two-phase flow is considered as incompressible, viscous and turbulent. For carrying out numerical solutions of the governing equations the CFX11® commercial code was used. Results of the behavior of the two-fluid flow inside the hydrocyclone and separation efficiency are presented and analyzed. The role of the average temperature of the fluid, oil droplet diameter and the fluid mixture inlet velocity on the separation efficiency of the hydrocyclone are verified.
Numerical Study of Oil/Water Separation by Ceramic Membranes in the Presence of Turbulent Flow  [PDF]
Josedite Saraiva de Souza, Tássia Mota Vieira, Enivaldo Santos Barbosa, Acto de Lima Cunha, Antonio Gilson Barbosa de Lima, Severino Rodrigues de Farias Neto
Advances in Chemical Engineering and Science (ACES) , 2012, DOI: 10.4236/aces.2012.22030
Abstract: Disposal of produced water during petroleum extraction causes serious environmental damage, hence the need to complete the water treatment before being disposed to environment within the criteria set established by environmental agencies in the countries. Ceramics membranes have been highlighted as a good device for separating oil/water. These act as a barrier to oil in the aqueous stream, because their essential properties for filtration, such as chemical inertness, biological stability and resistance to high temperatures. The limitation of the separation process is the decay of permeate flux during operation, due to concentration polarization and fouling. In this sense, this paper aims to evaluate numerically the feasibility of the process of separating oil/water by means of ceramic membranes in the presence of a turbulent flow induced by a tangential inlet. The results of the velocity, pressure and volumetric fraction distributions for the simulations different by varying the mass flow rate inlet and different geometric characteristics of the membrane are presented and analyzed.
A computational fluid dynamics study of hydrogen bubbles in an electrochemical reactor
Cavalcanti, Renata da Silva;Farias Neto, Severino Rodrigues de;Vilar, Eudésio Oliveira;
Brazilian Archives of Biology and Technology , 2005, DOI: 10.1590/S1516-89132005000400027
Abstract: most electrochemical reactors present reactions with the growth and departure of gas bubbles which influence on the reactor hydrodynamics and this study is usually complex, representing a vast field for research. the present paper had as objective to study a bi-phase (gas-liquid) system aiming to foresee the influence of departure of hydrogen bubbles generated on effective electrode surface situated on cathodic semi-cell. nevertheless, it was idealized that the gas was injected into the semi cell, through the effective electrode surface with this hypothesis, it was possible to study, and numerically analyze, the hydrodynamic behavior of the hydrogen bubbles in the interior of the study domain, applying concepts of computational fluid dynamics by using the computational applicative cfx-4 for the application of the musig ("multiple-size-group") model, taking into consideration the phenomena of coalescence and the distribution of the diameter of the bubbles.
Análise econ mica da explora o de leite no cariri paraibano = Economic analysis of the milk production in the cariri region of the Paraíba State
José Fábio Paulino de Moura,Edgard Cavalcanti Pimenta Filho,Severino Gonzaga Neto,Saulo Vilarim de Farias Leite
Acta Scientiarum : Animal Sciences , 2010,
Abstract: Este estudo objetivou avaliar os custos de produ o, receitas e rentabilidade da atividade leiteira de seis sistemas de produ o de leite bovino no Cariri paraibano. Foi objetivo, também, identificar os componentes que exerceram maior influência sobre os custos finais da atividade por meio dos resultados econ micos e indicadores técnicos de desempenho econ mico. Para a realiza o das análises econ micas, os produtores foram divididos em dois grupos, em fun o do vínculo com a Cooperativa, sendo sócios e n osócios. A receita bruta da atividade foi suficiente para cobrir os custos operacionais efetivos e totais nas propriedades 1, 2, 3 e 5. Os itens que comp em o custo operacional efetivo de produ o do leite foram responsáveis por porcentuais superiores a 60% em todas as propriedades analisadas. O valor superior recebido pelo grupo de produtores sócios da Cooperativa, para o litro de leite comercializado, tem possibilitado investimentos tecnológicos na atividade e, consequentemente, aumento da produtividade nessas propriedades. This study aimed to evaluate the costs of production, revenue andprofitability of six milk production systems in Paraíba State, Brazil and to identify major variables related to the final cost of milk through the economic results and indicators of economic performance. In order to carry out the economic analysis, farmers were groupedinto two clusters, depending on the link to a cooperative, i.e., members and non-members. The gross revenue was sufficient to cover total and operating costs in the farms 1, 2, 3 and 5. The items that make up the operational cost of milk production accounted forpercentages above 60% in all these farms. The higher value received by the cluster of producers comprised by members of the cooperative for a gallon of milk has allowed investments in technology leading to productivity increase in these farms.
Rela??o materno-filial da ra?a Morada Nova recebendo dietas com três níveis de energia, ao final da gesta??o
Mariz, Tobyas Maia de Albuquerque;Pimenta Filho, Edgard Cavalcanti;Medeiros, Ariosvaldo Nunes de;Gonzaga Neto, Severino;Leite, Saulo Vilarim de Farias;Torre?o, Jacira Neves da Costa;
Revista Brasileira de Zootecnia , 2007, DOI: 10.1590/S1516-35982007000800024
Abstract: the present work was carried out with the objective to evaluate the effects of different energy levels offered in the final third of gestation on the ewe-lambs behavior of animals from the morada nova breed. the experiment was divided into three treatments - three groups of eight ewes, fed isoprotein diets containing different energy levels (2.0, 2.4, and 2.8 mcal me/kg dm), with eight replicates each. there was effect of the treatment on the maternal behavior evaluated variables (vocalization, act of smell and lick the lambs and the position of the ewe - stand up or lying), in the ewes, but no difference was observed for the filial behavior (position of animal, time from the birth to the first time that the animal was up, time from the birth to the first sucking and total time sucking) of the lambs. the mobilization of reserves or the direct carrying of nutrients of the diet for normal fetal growth, in the groups fed with diets containing 2.0 and 2.4 mcal me/kg dm, minimized the possible effects on the filial behavior of lambs. the mobilization of reserves or direct carry of nutrients of the diet for normal fetal growth, in the groups fed with diets containing 2.0 and 2.4 mcal me/kg dm, minimized the possible effect on the filial behavior of lambs. despite the interference in their relationship with the kids, ewes morada nova attained to keep the conditions of the lambs unchanged in all treatments.
Avalia??o radiográfica da adenóide em crian?as: métodos de mensura??o e parametros da normalidade
Araújo Neto, Severino Aires de;Queiroz, Suélio Marinho de;Baracat, Emílio Carlos Elias;Pereira, Inês Minniti Rodrigues;
Radiologia Brasileira , 2004, DOI: 10.1590/S0100-39842004000600012
Abstract: radiograph of the nasopharynx is still the most commonly used imaging method to investigate the adenoidal tissue. due to the variety and complexity of proposed methods to measure the adenoid size, some radiologists prefer subjective evaluation, which can, however, be imprecise and inaccurate. we review and describe several methods to determine the adenoid size, taking into account the practicity, accuracy and precision with the aim of pointing out the best methods to be applied in daily routine practice.
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