Validation of Local Thermal Equilibrium (LTE) in Porous Media for Variation in Flow rate and Permeability: Transient Analysis

Abstract

The usage of porous media is one of the effective ways to augment the heat transfer in micro-to-mini scale channels due to its enormously high surface area, enhanced thermophysical properties, and dispersion effect to transfer the thermal energy between the heated channel wall and fluid at a faster rate. However, there is ambiguity associated with the extent of thermal equilibrium between the solid and fluid phases, and therefore, also in the selection of suitable heat transfer model. In the current study, the numerical analysis of thermo-hydrodynamics for the porous media filled in the channel for incompressible laminar forced convective flow with varying Reynolds number and Darcy number is delt. The validity of the local thermal equilibrium (LTE) condition is performed for transient case to study the effects of the parameters that governs the flow and thermal effects, i.e., Reynolds number (Re) in the range of 10 < Re < 1000 and Darcy number (Da) in the range of 10^-6 < Da < 10^0 . The results of the present study show that for higher range of flow rate (Re > 100), the LTE assumption is valid for all ranges of Da, however, for the lower range of flow rate (Re < 100), the LTE assumption deviates for higher Da