封闭式喷雾冷却传热特性的实验与理论研究

Experimental and Theoretical Analysis of Heat Transfer Characteristics of Spray Cooling in a Closed Loop

喷雾冷却是一种高效的高密度热流散热方式,在空间热控领域具有重要的应用前景。本文基于液膜动力学、气泡动力学和传热学的基本原理,建立了描述喷雾冷却传热特性的理论模型,模型分析结果和实验结果吻合良好;利用实验研究和模型模拟相结合的方法,对以水作为工质的封闭喷雾冷却系统的加热面温度分布、冷却曲线等特性进行了分析,分析结果显示,在封闭式喷雾冷却系统中,被冷却表面也仍然存在着温度分布的不均匀性,但是其最大温差小于5℃;由于喷雾腔内压力较低,喷雾曲线基本上处于两相区内,其换热能力远远高于常压下的换热能力。

Spray Cooling is a promising candidate to provide high rate heat flux removal in spacecraft thermal control.A mathematical model of spray cooling heat transfer characteristics is presented based on the fundamentals of bubble dynamics and heat transfer,and the predictions by the model coincide well with the experimental results in this paper.The heat transfer characteristics including spray cooling curve,temperature gradient on the heating surface and so on in a closed loop are obtained by both experiment and model simulation.The analyzed results show that：1） the temperature distribution on the heating surface is not uniform,however the maximal temperature difference is less than 5℃;2） spray cooling curves are almost in the two phase region,thus resulting in that the heat transfer in the closed loop system is stronger than that under the normal pressure condition due to the lower pressure in the spray chamber.