Analysis of Heat Transfer in Transient Regime in Anisotropic Materials Applying the BEM
Miélle Silva Pestana1; Guilherme Vaz Ferreira1
1 Universidade de Brasília
doi:10.20906/CPS/COB-2015-0387
Resumo
This paper presents a study on effective thermal conductivity of porous media in transient heat transfer. The microporosity of the material is represented by the insertion of holes in the domain of the geometry. The Boundary Element Method (BEM) is employed to solve the differential equations governing the potential problems in the transient regime. The analysis was performed using Representative Volume Elements (RVE's), which is a method that applies the theory Midfields to find the effective properties (macroscopic) of this micro-porous material. Both the diameters of the holes as well as the volume fraction of the material are pre-determined. The thermal conductivity is evaluated locally by the ratio between the average volumetric heat flux and volumetric average temperature gradient of the field. The technique used for isotropic materials is extended to the study of the behavior of heat conduction in anisotropic media using the method known as domain mapping or linear transformation. Some numerical examples are evaluated by checking the behavior of the effective thermal conductivity in isotropic and anisotropic materials.
Palavras-chave: Heat transfer; effective thermal conductivity; Boundary Element Method; Isotropy; Anisotropy