Numerical and Experimental Studies of Heat Transfer in Porous Media

Rajesh N P

The subject of heat transfer through porous media is an area of rapid growth in contemporary research. Porous media consists of solid matrix and fluid matrix. The void matrix in the porous media is filled with fluids or gases. Heat transfer through porous media includes conduction, convection and radiation. The objective of this study is to determine the thermal response of a porous media under varying heating conditions. In the present study only one mode of heat transfer, heat conduction, is used to determine the thermal response of a porous media. For this analysis effective properties of porous media are used and the effective properties are determined using correlations. An explicit finite difference scheme is used for numerical formulation of the problem. The numerical model can be augmented by experimental results, which is also included in the scope of this work. Porous materials are used to protect the reentry space shuttle from failure due to aerodynamic heating. Silica tiles, which are essentially a porous material, made from pure silica fibre are used to protect the space shuttle. The experiments were carried out on silica tiles in a facility having capability to simulate time varying heating conditions and studied the thermal response of the material. The experiments were repeated for different specimens with variation in thickness at varying heating conditions. Experimental results are found to be in good match with the numerical results.