Numerical Modelling of Flow Boiling in Expanding Microchannel with Non-Uniform Heat Flux

Abstract

Thermal management of high-power density electronic chips is vital for their safe operation and reliable performance. For efficient heat dissipation from electronic chip, liquid microchannel heat sink is preferred and is an effective option amongst the various available cooling technologies. In the recent past, flow boiling in microchannel has received considerable attention as an effective option for thermal management of high-power electronic devices. Flow boiling involves phase change and dissipates high heat fluxes for lower mass flow rate, when compared with single-phase flow. The commercial application of flow boiling microchannel for electronic cooling is hindered because of limited understanding of nonuniform wall temperature distribution, flow instabilities and flow reversal. In the recent past, more focus has been on numerical modelling and simulation of flow boiling in microchannel. In this work, numerical simulation of a 2D expanding microchannel heat sink with nonuniform heat flux has been considered and the simulations have been performed using ANSYS Fluent. Phase change heat transfer simulation has been performed using volume of fluid (VOF) model together with interfacial mass and energy transfer. The performance of expanding channel is then compared with the straight channel with similar heat flux distribution and the results are presented.