流量分配对逆流微通道内流动沸腾影响的研究

Study on the Effect of Flow Distribution on Flow Boiling in Counter-flow Microchannels

微通道内的沸腾两相流动是解决高热流密度下微电子设备散热最有潜力的手段之一。本文基于逆流式微通道热沉设计,实验研究了不同流量调配下逆流式微通道内的流动沸腾特性。讨论了流量分配对微通道内流动沸腾过程中传热特性、压降分布和壁面温度演化规律的影响。实验结果表明:当逆流式通道两侧的质量流量相同时,壁面呈现较好的温度均匀性,且两侧流动压降基本保持一致。两侧流量相差越大,其对应最大两相压降偏差越大。逆流式微通道的壁面温度分布和局部热点的位置可以通过改变两侧质量流量的大小实现有效控制。同时,微通道内流体的演化周期同样可以根据两侧质量流量的高低实现调控。

Boiling two-phase flow within microchannels is the most promising approach to address micro-electronic devices’heat dissipation challenges at high heat fluxes.Based on the design of the counter-flow microchannel heat sink,the flow boiling characteristics in bidirectional counter-flow microchannels with different mass flux distributions are experimentally investigated.The effects of flow distribution on the heat transfer characteristics,pressure drop distributions,and wall temperature evolutions during the flow boiling process are investigated.The experimental results reveal that when the mass fluxes on both sides of the counter-flow microchannels are the same,the wall shows better temperature uniformity,and the pressure drop on both sides of the microchannels basically remains equal.The deviation of the maximum two-phase pressure drop on both sides increases with the deviation of the mass flux.The wall temperature distributions and location of the hot spots on the counter-flow microchannel can also be effectively controlled by changing the mass flux magnitude on both sides.Meanwhile,the periodic evolution pattern of the fluid in the counter-flow microchannels can also be regulated according to the mass fluxes on both sides.