氨饱和压力对喷雾相变冷却特性的影响  

Effects Saturation Pressure on Spray Cooling with Ammonia

作　　者：王宏[1] 余勇胜[1] 朱恂[1] 孙少鹏[1] 廖强[1] 丁玉栋[1] 杨宝海[1] 

机构地区：[1]重庆大学工程热物理研究所,重庆400030

出　　处：《中国激光》2011年第7期21-25,共5页Chinese Journal of Lasers

基　　金：国家自然科学基金(50906102);"211工程"三期建设项目(S-09101);中央高校基本科研业务费(CDJRC10150002)资助课题

摘　　要：喷雾相变冷却是一种具有高热流密度散热特点的冷却方式。采用紫铜棒加热器作为热源,通过调节背压阀改变喷淋室压力,重点研究了在高热流密度散热需求下,以液氨为工质的双喷嘴阵列在不同饱和压力下的喷雾相变冷却传热特性。实验结果表明,随着液氨饱和压力的增大,液氨气化潜热的降低有利于喷雾相变由单相强制对流换热向核态沸腾换热的转变;在相同热流密度下,随着液氨饱和压力的增加,热表面温度升高,过热度降低,换热系数增大,冷却能力得到大幅度提高;当热流密度为310 W/cm2,喷淋室压力为4.01×105Pa时,热表面温度仅为19.5℃,换热系数可达1.48×105W/(m2.K),为高热流密度散热实现较低温度的冷却技术提供了参考。Spray cooling is an efficient high heat flux cooling method.In this study,the heat transfer characteristics of the spray cooling with ammonia as coolant are experimentally investigated under different ammonia saturation pressures.The cylindrical copper acts as the heat sources with seven cartridge heaters,and two-nozzles arrays are specifically designed to spray with ammonia.Experimental results indicate that the latent heat of ammonia decreases with the saturation pressure increasing,it is useful to promote the single-phase convection to convert to the nucleate boiling at the lower superheat temperature.The surface temperature and heat transfer coefficient increase with the saturation pressure of ammonia increasing but the variation trend of the superheat reverses.The maximum heat transfer coefficient of 1.48×105 W/（m2·K） is achieved with the heat flux of 310 W/cm2,the spray chamber pressure of 4.01×105 Pa and the surface temperature only of 19.5 ℃.Meanwhile,this study provides a reference in the engineering application for the high heat flux cooling technology.

关 键 词：激光技术 喷雾冷却 液氨 饱和压力 高热流密度 

分 类 号：TK124[动力工程及工程热物理—工程热物理]