CORRELATIONS OF INTERFACIAL HEAT TRANSFER COEFFICIENT AND THERMAL DISPERSION FOR TURBULENT CONVECTIVE FLOW IN POROUS MEDIUM

Abstract

Effective properties like interfacial heat transfer coefficient and longitudinal and transverse thermal dispersion play an important role in the up-scaled mathematical models of porous medium. However, most of the existing correlations are obtained by assuming that fluid flow in porous medium is laminar. Therefore, numerical simulations were conducted in the study to investigate interfacial heat transfer coefficient and longitudinal thermal dispersion for turbulent convective flow in porous medium. For the sake of simplification, a two-dimensional (2D) periodic array of square rods was chosen as physical geometry. Moreover, a low-Re turbulence model suitable for backward-facing step geometry was applied to better capture the turbulent characteristic in porous medium. By the exhausted numerical results, an interfacial heat transfer coefficient correlation was obtained. Furthermore, due to the inverse relationship between interfacial heat transfer coefficient and longitudinal thermal dispersion, the expression of longitudinal thermal dispersion was derived. By comparing with existing experimental data and correlations in the literature, the correlations of interfacial heat transfer coefficient and longitudinal and transverse thermal dispersion were validated. In light of the proposed correlations, it is feasible to establish a more reliable macroscopic mathematical model of porous medium.