ABSTRACT Flow boiling heat transfer in a microchannel heat sink is experimentally investigated. The microchannels considered are 275 µm wide and 636 µm deep, and the experiments are conducted at inlet water temperatures in the range of 66 to 95°C and mass fluxes of 341 to 936 kg/m 2 s. Convective boiling heat transfer coefficients are measured and compared to predictions from correlations proposed for larger channels. While an existing correlation was found to provide satisfactory prediction of the heat transfer coefficient in subcooled boiling in the microchannels, saturated boiling was not well predicted by the correlations for macrochannels. A new heat transfer model is developed to correlate the data in the saturated boiling regime. Good agreement with the experimental measurements indicates that this correlation is suitable for use in the design of twophase microchannel heat sinks
