Modeling of Heat Transfer Effective Coefficient of Ceramic Porous Media by Self-Consistent Method

Abstract

Providing a comprehensive model for effective heat transfer coefficient using effective medium approximation and with regard to the homogeneity and isotropic thermal insulation materials is very useful in the design process and also to appropriately assess the porous media at different temperature conditions. This case has been studied and presented by many scientists, including Ohm, Russell, Maxwell and etc. However most of them have neglected the direct effect of the fluid within the cavity. In this study, the possibility of generalized self-consistent model with the ability to accurately estimate the effective coefficient of heat transfer in porous media that the 3 parameters of apparent conduction heat transfer coefficient of air, conduction heat transfer coefficients matrix and porosity are considered analytically was examined for the porous material. Apparent conduction heat transfer coefficient of air would indirectly include the effect of the size and shape of the pores, the temperature gradient, the average film temperature, thermo-physical properties of air trapped in the matrix and the dispersed phase. Finally, effective heat transfer coefficient for porous media ceramic insulators that avoid heat dissipation in heating furnace petrochemical olefin units, were calculate using the software Fluent and the results were compared with experimental results. Good agreement between experimental and theoretical results was obtained with a standard deviation of approximately 1%.