High heat flux flow boiling of refrigerant R236fa in parallel microchannels

Abstract

This paper presents the results of an experimental study of the heat transfer during flow boiling of refrigerant R236fa in a horizontal microchannel heat sink. The experiments were performed using closed loop that re-circulates coolant. Microchannel heat exchanger that contains two microchannels with 2x0.4 mm cross-section was used as the test section. The dependence of average heat flux on wall superheat and critical heat flux were measured in the range of mass fluxes from 600 to 1600 kg/m 2 s and in the range of heat fluxes from 5 to 120 W/cm 2 . For heat flux greater than 60 W/cm 2 , nucleate boiling suppression has significant effect on the flow boiling heat transfer, and this leads to decrease of the heat transfer coefficient with heat flux grows.