多孔表面的液氮池沸腾实验研究  

Experimental research on pool boiling of liquid nitrogen on porous surfaces

作　　者：付鑫[1] 任小军[2] 张鹏[2] 江世臣[1] 

机构地区：[1]上海卫星工程研究所,上海200240 [2]上海交通大学制冷与低温工程研究所,上海200240

出　　处：《低温与超导》2014年第8期21-25,共5页Cryogenics and Superconductivity

基　　金：航天科技创新基金(SAST201212)

摘　　要：文中对颗粒烧结多孔表面和泡沫金属多孔表面上的液氮池沸腾换热特性进行了实验研究,并与光滑铜表面的试验结果进行了比较。结果表明,多孔表面成核条件更好,使得沸腾起始点相对于光滑表面提早;随着热流密度逐渐增大,气泡增多,且在多孔层内部连成一片,加热表面气泡离开受到多孔层的限制,热阻增加,换热系数大幅降低,整个沸腾进入表面沸腾阶段;多孔结构所产生的毛细抽力不断补充冷却流体,使表面沸腾能够持续较长时间,实验中未观测到临界热流密度现象。在实验基础上,文中描述了多孔表面不同池沸腾换热阶段的主要换热机理,并分析了流体工质、多孔层厚度、渗透系数、孔隙率等参数对多孔表面池沸腾换热的影响。The pool boiling heat transfer characteristics of liquid nitrogen on sintered porous surface and metal foam porous surface were experimentally studied, as well as the smooth copper surface which were done for comparison. The onset of nucleate boiling on the porous surface occured early compared to that on the smooth surfaces. As the heat flux increase, the increased bubbles coalesce together and the escape of bubbles were confined by porous surface configuration, which greatly reduced the heat transfer performance and it entered the surface boiling stage. Owing to the capillary suction force supplying the cooling fluid to the porous surface, the surface boiling could be sustained for a long time and the CHF phenomenon was not observed in the present study. The heat transfer mechanisms on the different heat transfer surfaces during different heat transfer stages were described, and the influences of working fluids, thickness, permeability and porosity were also analyzed.

关 键 词：多孔表面 液氮 池沸腾 

分 类 号：TK124[动力工程及工程热物理—工程热物理]