Local thermal non-equilibrium effects on the onset of convection in an internally heated layered porous medium with vertical throughflow

Abstract

We investigated how local thermal non-equilibrium and vertical throughflow affect the stability of an internally heated fluid-saturated porous layer. In order to investigate the effects of heterogeneity, we considered a system composed of two horizontal porous layers with different properties. This allowed us to investigate the effects of vertical variation of various parameters. Due to a large number of parameters, our primary goal was to investigate which parameters have a significant effect on the stability of the system. We have found that heterogeneity of permeability and fluid thermal conductivity have a major effect, heterogeneity of interphase heat transfer coefficient and porosity have a lesser effect, while heterogeneity of solid thermal conductivity is relatively unimportant. At the same time we investigated the variation of both upward and downward throughflow, and variation of heat source strength between the layers and between the fluid and solid phases. Downward throughflow is destabilizing, while upward throughflow is stabilizing. The stability is strongly affected by the solid-to-fluid heat source strength ratio.