Cavitation Enhanced Heat Transfer in Microchannels

Abstract

Heat transfer has been investigated in the presence of hydrodynamic cavitation instigated by 20-μm wide inlet micro-orifices entrenched inside 227-μm hydraulic diameter microchannels. Average surface temperatures, heat transfer coefficients, and pressure drops have been obtained over effective heat fluxes ranging from 39 to 558W∕cm2 at mass flux of 1814kg∕m2s under noncavitating and three cavitating conditions. Significant heat transfer enhancement has been recorded during supercavitating flow conditions in comparison to noncavitating flows with minimal pressure drop penalty. Once supercavitating conditions were reached, no apparent heat transfer augmentation was detected with the reduction of the cavitation index. Visualization of the flow morphology and the heat transfer coefficient characteristics aided in the evaluation of the dominant heat transfer mechanism under various thermal-hydraulic conditions.