系统压力影响下的喷雾冷却特性及温度均匀性

Effect of system pressure on spray cooling heat transfer and surface temperature uniformity

喷雾冷却是一种新型的高热通量换热方式。对以水为工质的封闭式喷雾冷却进行了实验研究,并结合实验现象对不同系统压力下喷雾冷却的换热特性及表面温度不均匀性进行了分析,并给出了相应的量纲1压力换热关联式。实验结果显示:由于系统压力较低,喷雾工质在较低的温度下进入两相区,其换热能力远远高于常压下的换热能力,且换热性能随系统压力减小呈指数性增大关系;在实验条件中,可以实现在85℃的平均壁面温度下,热通量达到360W.cm-2;低压下喷雾冷却被冷却壁面的温度不均匀性小于常压下温度不均匀性。

Spray cooling is a new type of high heat flux heat transfer.The spray cooling in a closed loop was investigated by the experimental method,in which distilled water was used as the working fluid.The heat transfer characteristics including the spray cooling curve,the temperature non-uniformity on the cooled surface,and the corresponding non-dimensional correlation were obtained by experimental analyses.The experimental results show that：the spray cooling heat transfer in the low system pressure is stronger than that in the normal system pressure,because the spray cooling curves are almost in the two-phase region under the low system pressure.The heat flux curve shows an exponential growth with the decrease of the system pressure in the spray chamber.For the average surface temperature of 85℃,the heat flux reached 360 W.cm-2.The surface temperature non-uniformity on the cooled surface in the low system pressure is lower than that in the normal system pressure.