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URI permanente para esta coleçãohttps://rihomolog.furg.br/handle/1/515

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Autor: search.filters.author.Santos, Elizaldo Domingues dosAssunto: search.filters.subject.Geometric optimization

Resultados da Pesquisa

Agora exibindo 1 - 3 de 3
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    Constructal design applied to the light resin transfer molding (LRTM) manufacturing process
    (2013) Isoldi, Liércio André; Souza, Jeferson Avila; Santos, Elizaldo Domingues dos; Marchesini, Renato; Porto, Joseane da Silva; Letzow, Max; Rocha, Luiz Alberto de Oliveira; Amico, Sandro Campos
    The Light Resin Transfer Molding (LRTM) is a manufacturing process where a closed mold pre-loaded with a porous fibrous preform is filled by a liquid resin injected through an empty channel (without porous medium) which runs all around the perimeter of the mold, producing polymeric composite parts. Using the capability of FLUENT® package to simulate a multiphase flow (resin and air) in a geometry composed by porous media regions and empty regions, a computational model based on the Finite Volume Method (FVM) was applied to reproduce the resin flow behavior during the LRTM process. The aim of this work was to define the optimal geometry for the empty channel (border) by means the Constructal Design method. To do so, considering a border with a rectangular cross sectional area, the degree of freedom wb/tb (ratio between the width and thickness of the border) can vary while the border volume is kept constant. The results showed that employing the Constructal Design it is possible to decrease the filling time of the LRTM process in almost 20 %, being this an unpublished use for the Constructal Theory.
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    Numerical study of resin distribution in two different arrangements of vascular channels by means of constructal design
    (2013) Machado, Roselaine Neves; Isoldi, Liércio André; Santos, Elizaldo Domingues dos; Rocha, Luiz Alberto de Oliveira
    In the present work two different arrangements of vascular channels are studied numerically and their geometry is optimized by means of Constructal Design. The main purpose is to seek for the best geometry which minimizes the resin flow resistance inside the channels. The arrangement of vascular channels consists in two horizontal channels of diameter D2 connected with two vertical channels of diameter D1. The channels of resin flow are distributed in a solid domain with two different ratios of height and length (H/L = 0.67 and 1.5) in order to illustrate the process of regeneration of composite materials. For all of evaluated configurations the ratio between the areas occupied by the channels and by the solid domain are kept fixed (ϕ = 0.1). It is considered a two dimensional, laminar and steady state flow (ReD2 = 1.0). The conservation equations of mass and momentum are solved numerically by means of the finite volume method (FVM). The results showed that the optimal geometric configuration has a flow resistance several times lower than that found with the worst geometry. For example, for H/L = 0.67, the ratio (D1/D2)o = 0.76 conduct to a fluid dynamic performance nearly 32 times superior than that found for D1/D2 = 0.1. It is also noticed that the best shapes are achieved when the pressure and velocity fields has the most homogeneous distribution, i.e., according to the constructal principle of “optimal distribution of imperfections”.
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    Two-dimensional geometric optimization of an oscillating water column converter of real scale
    (2013) Gomes, Mateus das Neves; Santos, Elizaldo Domingues dos; Isoldi, Liércio André; Rocha, Luiz Alberto de Oliveira
    The present paper presents a two-dimensional numerical study about the geometric optimization of an ocean Wave Energy Converter (WEC) into electrical energy. The operational principle is based on the Oscillating Water Column (OWC). The main goal is to seek for the optimal geometry which maximizes the absorbed power take off (PTO) when it is subjected to a defined wave climate. To do so, Constructal Design is employed varying the degree of freedom (DOF) H1/L (ratio between the height and length of OWC chamber) and H3 (lip submergence), while the other DOF H2/l (ratio between height and length of chimney) is kept fixed. Moreover, the chamber and total areas of OWC device are also kept fixed, being the problem constraints. In this study was adopted a regular wave with real scale dimensions. For the numerical solution it is used the Computational Fluid Dynamic (CFD) commercial code FLUENT®, based on the Finite Volume Method (FVM). The multiphasic Volume of Fluid (VOF) model is applied to tackle with the water-air interaction. The computational domain is represented by an OWC device coupled with the wave tank. The results led to a theoretical recommendation about the chamber geometry which maximizes the device performance, indicating that the higher efficiency (around 40 %) is obtained when H1/L = 0.13 and H3 = 9.50 m. On the other hand, the chamber geometry that generate the lower efficiency (around 4.4 %) is formed by H1/L = 0.03 and H3 = 9.00 m. One can note that the optimal shape is approximately 10 times more efficient than the worst geometry, showing the applicability and relevance of the Constructal Design method in the design of OWC-WEC.