Bubble departure diameter determination for pool boiling on surface with microchannels

Abstract

The paper presents visualization investigations into pool boiling heat transfer for open microchannel surfaces. The experiments were carried out with saturated water, ethanol, FC-72 and Novec-649 at atmospheric pressure. Parallel microchannels fabricated by machining copper sample were about 0.2 to 0.5 mm wide and 0.2 to 0.5 mm deep. The diameter of departing bubble was calculated for the microchannel surface on the basis of buoyancy force and surface tension force balance. The visualization carried out was aimed at determining the diameters of the departing bubbles at various heat fluxes for four working fluids.