HIGH HEAT-FLUX ABSORPTION UTILIZING POROUS MATERIALS WITH 2-PHASE HEAT-TRANSFER

By combining two-phase hear transfer with forced convective flow throu gh a porous material, a new heat transfer scheme emerges with the abil ity to absorb high heat fluxes without the corresponding temperature i ncrease encountered in single-phase systems. In general, flow-through sintered metals are characterized by high thermal conductivity due to the metallic media, and a fluid flow which on the macro scale can be d escribed as slug flow in nature. These same characteristics are exhibi ted by liquid metal flow cooling systems. To predict the heat transfer attributes of this two-phase flow process, a semi-analytical model wa s developed using the conservation equations of mass, momentum and ene rgy along with the apparent physical properties of the composite mater ial. The results indicate that when a heat flux is applied to one side of the bounding surface and adiabatic conditions exist on the remaini ng sides, the surface temperature asymptotically approaches the same v alue regardless of the mass flow rate. In addition to the analytical r esults, definitions for the convection coefficient and Nusselt number for flow-through porous materials with phase change are presented.