Correlation of. critical heat flux and two-phase friction factor for subcooled convective boiling in structured surface microchannels

摘要

Critical heat flux (CHF) and pressure drop of subcooled flow boiling are measured for a microchannel heat sink containing 75 parallel 100 μm × 200 μm structured surface channels. The heated surface is made of a Cu metal sheet with/without 2 μm thickness diamond film. Tests and measurements are conducted with de-ionized water, de-ionized water +1 vol.% MCNT additive solution, and FC-72 fluids over a mass velocity range of 820-1600 kg/m~2 s, with inlet temperatures of 15(8.6)℃, 25(13.6)℃, 44(24.6)℃, and 64(36.6)℃ for DI water (FC-72), and heat fluxes up to 600 W/cm~2. The CHF of subcooled flow boiling of the test fluids in the microchannels is measured parametrically. The two-phase pressure drop is also measured. Both CHF and the two-phase friction factor correlation for one-side heating with two other side-structured surface microchannels are proposed and developed in terms of the relevant parameters.