The Effect of Thermal Interaction Between Boiling Parallel Microchannels on Flow Distribution

Abstract

Component packages in today’s high-performance electronic devices feature high-power densities where the utilization of intermediate heat spreaders to smear out the uneven heat flux profiles is not effective. Instead, the ultimate heat sink often experiences the uneven heat flux generated from the temperature variations in the package due to multiple components and devices. A key hydrodynamic implication of uneven heating on the flow boiling in microchannels is the tendency of the flow to distribute unequally between the channels. Flow maldistribution is undesirable in heat sinks as the channels that are starved of the flow may undergo an untimely dry-out and impair its heat transfer performance. While the heat transfer performance implications of uneven heating in boiling parallel microchannels are well studied, its key cause which is flow maldistribution is largely unmapped. In this study, a two-phase flow distribution model is used to investigate the effect of streamwise uneven heating and different levels of thermal connectedness between the channels on the flow distribution characteristics. It is demonstrated that the flow is noticeably maldistributed for channels that are thermally isolated compared to the channels that are strongly thermally interacting. In the latter case, the range of total flow rates with flow maldistribution is markedly reduced, the most severe flow maldistribution is damped, and the range of total flow rates with this most severe flow maldistribution is also reduced. These trends of these three flow distribution metrics are assessed as a function of increasing total input power. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.