The influence of the mass flow rate on the critical heat flux during subcooled deionized water boiling in a microchannel cooling system

We have experimentally studied the influence of the mass flow rate on the critical heat flux (CHF) during the boiling of deionized water underheated relative to the saturation temperature in a microchannel cooling system. The experimental unit comprised a copper-based block with two 0.36-mm-deep microchannels of 2 mm width and 16 mm length. The mass flow rate ranged from 100 to 600 kg/(m$^2$ s) and the initial subcooling was varied from 30 to 70$^{\circ}$C. It was found that the character of boiling crisis changed with increasing mass flow rate and the CHF significantly increased upon complete condensation of vapor in the distribution chamber of the cooling system.