Flow boiling in a counter flow straight microchannel pair: LBM study

Abstract

Heat dissipation of high-power electronics is a critical challenge nowadays. The microchannel heat sinks due to their higher heat removal capability and more uniform temperature distributions are one of the most promising options. Our former experimental studies have shown that the intrinsic shortcomings of microchannels can be improved significantly by an innovative counter flow design of microchannels through the significant channel-to-channel heat transfer mechanism. The current study aims to simulate the flow boiling heat transfer inside a Counter Flow Straight Microchannel (CFSM) pair and compare it with the Co-Current Straight Microchannel (CCSM) one using the MRT-based Pseudopotential model combined with a thermal phase change LB model. The simulation results reveal that the CFSM pair acquires a lower void fraction and demonstrates better heat transfer with a higher CHF than that of CCSM one. The simulation results on CHF for a CCSM pair agree well with the predictions form a well-established correlation in the literature. The simulations quantitatively provide the channel-to-channel heat transfer distribution in the axial direction. The results reveal that better overall heat transfer performance can be achieved with a higher CHF in the CFSM pair by increasing the Reynolds number and inlet subcooling through enhanced channel-to-channel heat transfer.