Experiment study on the pressure drop of evaporative water flow in microchannels

The two phase pressure drop of the evaporative water flow in microchannel heat sink is studied in this paper. Sixty One 200μm×550μm×52mm (W×D×L) parallel microchannels with hydraulic diameter of 0.293mm machined on the surface of a brass block by EDM (Electric Discharge Machining) are composed to a set of experiment facility for the experiment of evaporative flow pressure drop and heat transfer. The pressures and the temperatures in the inlet and outlet reservoirs are measured, and the temperatures beneath the channels are measured to calculate the heat flux and exit qualities. The experiments are carried out with the volume flow rate ranges from 20ml/min to 80ml/min and the effective heat flux ranges from 5 W/cm² to 50W/cm², and the resulted outlet vapor qualities ranges from 0 to 0.8. The relations of the two phase pressure drop with heat flux and exit vapor quality under different mass flux are analyzed according to the results. The experiment pressure drops are compared with the prediction of latest developed correlations to validate the effectiveness of later.