短程逆流式微通道内的流动沸腾传热特性实验研究

Experimental investigation on flow boiling heat transfer characteristics in short flow passage counter-flow microchannels

微通道内的流动沸腾被公认为是一种极具潜力的高功率密度微电子设备/器件散热技术,但微通道的极限散热能力依赖于其下游的状态。为了进一步提升流动沸腾过程的传热特性并从根本上解决下游过早干涸的问题,基于逆流式微通道的概念,将传统顺流平行微通道(CPM)分为两段,提出并设计了短程逆流式微通道(SFCM)。实验研究了去离子水在质量流速为118~219 kg/(m^(2)·s)时,过冷度为50℃下的流动沸腾传热特性,并与传统顺流平行微通道的实验结果进行了对比。研究发现,与传统顺流平行微通道相比,短程逆流式微通道的临界热通量(CHF)和平均传热系数(HTC_(ave))分别实现了160.6%~204.4%和91.2%~115.4%的提升。同时,相较于传统顺流平行微通道,短程逆流式微通道的压降和泵功分别降低了76.9%~80.4%和44.9%~48.2%。更重要的是,短程逆流式微通道实现了沸腾不稳定性的有效抑制。

In order to further improve the heat transfer characteristics of the flow boiling process and fundamentally solve the problem of premature drying out downstream,in this study,the short flow passage counter-flow microchannels(SFCM)is proposed and designed based on the concept of counter-flow microchannels by dividing the conventional parallel-flow microchannel(CPM)into two segments.The flow boiling heat transfer characteristics of deionized water are experimentally investigated at the mass flux of 118—219 kg/(m^(2)·s)with inlet subcooling of 50℃,and the results are compared with the CPM.It is found that the critical heat flux(CHF)and average heat transfer coefficient(HTC_(ave))can achieve a 160.6%—204.4%and 91.2%—115.4%enhancement,respectively.Meanwhile,compared with CPM,the pressure drop and pumping power of SFCM are reduced by 76.9%—80.4%and 44.9%—48.2%,respectively.More importantly,flow boiling instabilities can be effectively suppressed in SFCM.