Pool boiling heat transfer of R141b on surfaces covered copper foam with circular-shaped channels

Abstract

The pool boiling heat transfer performance on surfaces covered copper foam with and without circular-shaped channels were experimentally studied at atmospheric pressure and within a range of 0–250 kW/m2 heat fluxes using refrigerant R141b as the working fluid. The pore density, porosity and thickness of the copper foam were fixed at 110 PPI (pores per inch), 98%, and 2 mm in this paper. The influences of copper foam with and without channels on boiling heat transfer were investigated and the results were compared with the plain copper surface. The results showed that the copper foam without channels enhanced the boiling heat transfer below 179 kW/m2, but it deteriorated the heat transfer at relatively high heat fluxes compared with that of the plain surface. However, the boiling heat transfer coefficients of the copper foams with channels were all improved and increased with increasing heat flux compared with that of the plain surface for the entire range of measured data. The boiling heat transfer enhancement of the copper foam with channels varied with different channel diameters, channel numbers, and heat fluxes. The present results showed that the boiling heat transfer coefficient of the copper foam covered surface could be increased by manufacturing channels with appropriate channel diameter and number through the foam especially at high heat fluxes.