EE - Escola de Engenharia
URI permanente desta comunidadehttps://rihomolog.furg.br/handle/1/512
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8 resultados
Resultados da Pesquisa
- ItemApplication of the computational modeling in the resin transfer molding (RTM) process: a case study of a marine propeller(2012) Porto, Joseane da Silva; Letzow, Max; Santos, Elizaldo Domingues dos; Souza, Jeferson Avila; Isoldi, Liércio André; Amico, Sandro CamposThis work presents one example of how the computational modeling can help in the Resin Transfer Molding (RTM) process when it is applied to the production of parts with complex geometry, such as the marine propellers. This manufacture process of composite material parts consists in the injection of a polymeric resin into a closed mold where a fibrous reinforcement is previously placed. The numerical simulation of the RTM process can be considered as the resin flow through a porous media. This computational model was developed in the FLUENT package, which is based on the Finite Volume Method (FVM), and was applied to study a propeller for naval propulsion. As the propeller has a complex format, the use of computational approach as a preliminar step in the manufacturing process is very important for the correct definition of the inlet and outlet nozzles. So, it is possible to design an efficient mold, avoinding extras costs related with the mold redesign, the resin waste and the increase of injection time. The results showed that an inadequate positioning of the mold outlet nozzles causes an increase about 10% and 2% in the production time and in the resin amount, respectively, for obtaining the marine propeller by RTM process.
- ItemNumerical analysis of a regular wave over a vertical pile with a square section(2010) Teixeira, Paulo Roberto de Freitas; Gomes, Mateus das Neves; Santos, Elizaldo Domingues dos; Isoldi, Liércio André; Rocha, Luiz Alberto OliveiraThe study of the action of waves on piles is very important for the design of structures in coastal and oceanic areas. Currently, there is strong interest in analyzing the action of waves on piles with non-circular sections, such as rectangular or square ones. According to Vengatesan et al. (2000), the main reason for this interest is the low cost of the connections of the members in the structures with these sections. The objective of this paper is to analyze the action of a regular wave on a vertical pile with a square section employing two differents numerical methodologies for prediction of the wave fluid dynamic. To achieve this goal were used the FLUINCO and FLUENT® softwares. FLUINCO (Teixeira, 2001) employs a partitioned two-step semi-implicit Taylor-Galerkin method in the Navier-Stokes equations. The free surface is governed by its kinematic boundary condition and an arbitrary Lagrangian-Eulerian (ALE) formulation is used to enable movements of the free surface. The FLUENT® code (2006), version 6.3.26, implements a finite volume technique to solve the equation of continuity and the Navier-Stokes equations. The free surface is described by using the VOF method (Volume Of Fluid). The wave period of the studied problem is 4s and its height is 0.05 m. The pile is seated on the bottom and located in the center of a channel. The dimensions of the pile section are 1m × 1m and the channel is 30m long, 10m wide and 1m deep. This paper shows the results obtained by the models in terms of the velocity vectors, the deformation of the free surface and the drag force caused by the wave on the pile. The total horizontal force acting on the pile was analytically calculated using the Morison equation. It was observed very similar results to the numerical ones.
- ItemEstudo numérico de uma placa submersa vista como quebra-mar e conversor de energia das ondas(2012) Seibt, Flávio Medeiros; Couto, Eduardo Costa; Teixeira, Paulo Roberto de Freitas; Santos, Elizaldo Domingues dos; Isoldi, Liércio AndréA crescente pesquisa por fontes de energia limpa e renovável tem contribuído para dar relevância ao estudo da energia das ondas do mar. Este artigo apresenta um modelo computacional desenvolvido para analisar o dispositivo placa submersa utilizado como quebra-mar e como conversor de energia das ondas do mar em energia elétrica. A dupla função deste dispositivo o distingue dos demais conversores de energia das ondas. O modelo desenvolvido utiliza os códigos comerciais GAMBIT e FLUENT. Neste último, a metodologia usada para representar a interação ar-água nas simulações numéricas do dispositivo é a multifásica Volume de Fluido. O objetivo deste artigo é contribuir para um maior conhecimento deste dispositivo analisando a influência do comprimento da placa no seu desempenho nas duas funções. Para tanto, o modelo desenvolvido, depois de validado, é aplicado em cinco simulações que se distinguem apenas pelo comprimento da placa. Nestas simulações, o seu desempenho na função de quebra-mar é quantificado por meio do coeficiente de transmissão. Já, o seu desempenho como conversor de energia é avaliado por sua eficiência em captar a energia das ondas incidentes. Constata-se que para um comprimento de placa, adimensionalizado pelo comprimento da onda, inferior à 0.83, as funções quebra-mar e conversor de energia não são concorrentes.
- ItemExperimental and numerical analysis of an earth-air heat exchanger(2011) Vaz, Joaquim; Sattler, Miguel Aloysio; Santos, Elizaldo Domingues dos; Isoldi, Liércio AndréThe need to develop new technologies that allow the use of sustainable alternative sources of energy is increasingly evident. Thus, this work presents an experimental and numerical study of earth–air heat exchangers, which are used to reduce consumption of conventional energy for heating and cooling of built environments through the use of thermal energy contained in the soil. The experiment was conducted in southern Brazil in the city of Viamão, and its results were used to validate the computational modeling of heat exchangers. In the present work, the variation of air temperature inside the ducts, to an annual cycle, was investigated. The numerical solution of the conservation equations of the problem is performed with a commercial code (FLUENT) which is based on the Finite Volume Method (FVM). Turbulence is tackled with the Reynolds Stress Model (RSM). The transient temperature fields predicted numerically was compared with the experimental ones, the highest difference found was lower than 15%. The results showed the validity and effectiveness of the employed computational model, enabling its use for future researches and projects developments about earth–air heat exchangers.
- ItemTwo-dimensional computational modeling of the soil thermal behavior due to the incidence of solar radiation(2013) Brum, Ruth da Silva; Isoldi, Liércio André; Santos, Elizaldo Domingues dos; Vaz, Joaquim; Rocha, Luiz Alberto OliveiraNowadays, there is a focus on finding sustainable energy sources, as well as, alternatives to rationalize the use of electrical energy. In this sense, the employment of Earth-Air Heat Exchangers (EAHE) is one technique which allows the reduction of energy consumption for climatization of buildings environments. The present study shows the evaluation of a numerical method to estimate the ground thermal potential, allowing its applicability for future thermal design of EAHE. The soil domain is considered two-dimensional and a transient solution for the thermal behavior of the soil is obtained. Moreover, a soil surface temperature distribution equation based on experimental data is employed to define the domain boundary conditions. The simulations are performed with a numerical method based on the finite volume method, more precisely using the software FLUENT®. The results presented an excellent agreement with analytical solutions showing the validity and effectiveness of the computational model for prediction of the soil behavior. The numerical results were also confronted with experimental ones predicted into literature and show a good agreement, with a deviation lower than 14%. The main difference is attributed to the duct presence which is taken into account only for the experimental study.
- ItemA new computational modeling to predict the behavior of Earth-Air Heat Exchangers(2013) Brum, Ruth da Silva; Vaz, Joaquim; Rocha, Luiz Alberto Oliveira; Santos, Elizaldo Domingues dos; Isoldi, Liércio AndréThe use of renewable energy sources to improve the thermal conditions of built environments and hencedecreasing the consumption of conventional energy is an important aspect to design a sustainable build-ing. Within this context, it is possible to harness the solar energy that reaches the Earth’s surface andis stored by the soil as thermal energy. To do so, the Earth-Air Heat Exchanger (EAHE) device can beemployed, consisting of a buried duct through which the external ambient air is insufflated. The flowingair exchanges heat with surround soil, and leaves the device with a milder temperature compared to itsinput temperature. The main goal of this work was to present a new computational modeling to predictthe thermal behavior of EAHE. This new numerical model has the advantage of needing a lower com-putational effort, allowing the study about the influence of operational and constructive parameters, aswell as, the application of geometric optimization methods in EAHE. A case study was developed whereinfluence of the installation depth in the thermal potential of an EAHE was investigated. The results arein agreement with those found in literature; however they were obtained with a reduction in processingtime of almost 45%.
- ItemAnálise numérica de uma placa submersa como quebra mar e conversor de energia das ondas(2013) Seibt, Flávio Medeiros; Couto, Eduardo Costa; Teixeira, Paulo Roberto de Freitas; Santos, Elizaldo Domingues dos; Isoldi, Liércio AndréEste artigo apresenta um modelo computacional bidimensional desenvolvido para análise do quebra mar tipo placa submersa. O modelo desenvolvido utiliza os códigos comerciais GAMBIT e FLUENT. O escoamento da mistura água-ar nas simulações numéricas do dispositivo é realizada através do modelo multifásico Volume of Fluid. O objetivo deste artigo é contribuir para um maior conhecimento deste dispositivo mostrando seu bom desempenho nas funções de quebra mar e conversor de energia das ondas. É analisada a influência da posição vertical da placa no coeficiente de transmissão e na eficiência do dispositivo ao converter energia das ondas em energia elétrica. Para tanto, o modelo desenvolvido, depois do processo de validação, foi utilizado em seis simulações que diferem apenas na posição da placa. Nos casos estudados, o aumento da distância da placa ao fundo proporcionou aumento da eficiência e redução do coeficiente de transmissão.
- ItemModelagem Computacional de um Dispositivo do Tipo Coluna de Água Oscilante para a Costa de Rio Grande.(2009) Gomes, Mateus das Neves; Isoldi, Liércio André; Olinto, Cláudio Rodrigues; Rocha, Luiz Alberto Oliveira; Santos, Elizaldo Domingues dos; Souza, Jeferson AvilaEste trabalho apresenta a modelagem computacional de um conversor de energia das ondas do mar em energia elétrica do tipo Coluna de Água Oscilante (CAO) submetido ao clima de ondas da costa da cidade de Rio Grande. A simulação numérica foi realizada utilizando-se o pacote FLUENT® e empregando-se o modelo multifásico Volume of Fluid (VOF) na geração da onda e na interação da mesma com o conversor. O domínio computacional foi representado por um tanque de ondas acoplado ao dispositivo CAO, possibilitando analisar o seu comportamento quando sujeito a incidência de ondas regulares com características semelhantes ao clima de ondas na costa de Rio Grande. Os resultados obtidos demonstram a potencialidade da região em gerar energia elétrica a partir da energia das ondas do mar, através do conversor tipo CAO.