Effect of flow regime on convective heat transfer in porous copper manufactured by lost carbonate sintering

Abstract

The fluid flow hydrodynamics and forced convective heat transfer in porous Cu samples manufactured by the Lost Carbonate Sintering process, with pore size 425–710 μm and porosities 0.6–0.8, have been investigated experimentally. Pressure drop and heat transfer coefficient were measured for pore-based Reynolds numbers in the range of 0.5–380. Five flow regimes, namely pre-Darcy, transition to Darcy, Darcy, transition to non-Darcy and non-Darcy, were identified. The Reynolds numbers for the flow regime boundaries increased nearly linearly with porosity. The permeability of the porous Cu samples increased and the form drag coefficient decreased with increasing porosity. Both the friction factor and the heat transfer coefficient depended strongly on the flow rate. The relationship between Nusselt number and Reynolds number showed three sections, with each section fitting well with the correlation Nu=CTRen with different CT and n values. The value of n was largely independent of porosity, except at the lowest porosity. The flow regimes had a strong effect on the heat transfer performance. The three sections of the Nusselt number vs Reynolds number curves broadly corresponded to the pre-Darcy, Darcy and non-Darcy regimes.