微结构表面喷雾冷却性能试验研究  

Heat Transfer Characteristics of Spray Cooling on Micro-structured Surface

作　　者：刘妮[1] 李丽荣[1] 钟泽民[1] 

机构地区：[1]上海理工大学能源与动力工程学院,上海200093

出　　处：《机械工程学报》2017年第6期158-165,共8页Journal of Mechanical Engineering

摘　　要：搭建一套封闭式喷雾冷却试验系统,使用水作为冷却工质,结合高速摄像仪对试验进行可视化研究,分析对比光滑表面和微结构表面喷雾冷却换热特性。结果发现,相比光滑表面,不同几何形貌的微结构表面都能提高喷雾冷却的换热能力,其中换热最好的是方形肋表面,直肋表面次之,扇形肋表面较差,但均优于光滑表面。微结构表面的润湿性强于光滑表面,微结构的存在能够提高喷雾冷却热流密度,使喷雾冷却提前进入两相区,避免了沸腾的滞后性。不同形式的微结构表面表现出不同的换热效果,主要是因为微结构表面对换热的强化不仅和面积增幅有关,还与微槽的紧密程度和排列方式有关。此外,试验中发现喷雾冷却存在温度不均匀现象,且微结构表面温度不均匀性大于光滑表面,但是降低系统压力,这种温度不均匀性可以得到明显改善。Experiments are conducted to study the heat transfer characteristics of micro-structure and fiat surface in spray cooling. The micro-structured surfaces including square pin fins, straight rectangular fins and fan fins along with a referenced flat surface are tested in a closed loop system with water as the working fluid. The experimental results indicate that the fin arrangement rather than a simple increased wetted area plays significant role on the spray cooling performance of the micro-structure surface. Using a fiat surface as reference, the micro-structured surface produced more or less enhancement in spray cooling than the flat surface. The micro-structure is indicated can improve the heat flux, acquired higher CHF. In addition, to improve heat transfer, the micro-structure surface provides other advantages such as reducing the time of transition to two phase regime. And the micro-structure surface with square pin fins outperformed the surface with straight rectangular fins and fan fins. However, there exists a relative more serious temperature non-uniformity phenomenon on the enhanced surface than fiat surface, and it can be improved by reducing the system pressure.

关 键 词：喷雾冷却 微结构表面 CHF 温度不均匀性 

分 类 号：TK124[动力工程及工程热物理—工程热物理]