液态水相变发散冷却的实验

以液态水为冷却介质，采用高温合金粉末烧结多孔材料制造平板实验件，实验研究了具有液态水相变的发散冷却特性.用远红外热像系统记录实验平板热端表面温度分布，通过热电偶及压力传感器监控冷却腔内温度和压力变化，从而分析液态水的相变过程.实验表明:随着液态水注入率的增大，平均冷却效率不断提高；当液态水在暴露于高温主流的平板表面发生气液相变时，平均冷却效率趋于稳定且不再大幅上升；主流温度与液态水注入率决定了液态水的相变位置，并对冷却腔内压力变化产生影响. 

Experiment on transpiration cooling with phase change of liquid water

An experimental investigation of transpiration cooling characteristics with phase change of liquid water was carried out.The specimen used in the experiments was made of porous materials sintered by refractory steel powder.The surface temperature of the specimen was measured by an infrared thermal imaging system.The variety of pressure and temperature in coolant chamber detected by the thermocouples and pressure sensor were used to analyze the phase change process of cooling water.The results indicate that average cooling efficiency is improved gradually with the increase of cooling water injection rate;but when liquid vapor phase change happens on the specimen surface exposed in hot gas,average cooling efficiency tends gradually to be stable;main flow temperature and cooling water injection rate determine the phase change position of cooling water,thus affecting pressure variation in the coolant chamber.