过冷大水滴撞击结冰特性实验研究

Experimental study on impacting icing characteristics of supercooled large droplets

对过冷大水滴(Supercooled large droplets,SLD)在不同粒径、过冷度、撞击速度及壁面温度下的撞击结冰特性进行了实验研究。设计了一套SLD发生装置,通过高速摄像机记录SLD撞击结冰过程,分析了各因素对SLD撞击结冰特性及冻结时间的影响。实验结果表明:SLD撞击壁面后呈现出摊开-回缩后结冰、摊开-回缩时结冰和摊开的过程中结冰3种典型结冰特性,水滴的过冷度及壁面温度对SLD的结冰特性具有显著的影响;SLD撞击后的冻结时间随着水滴直径的减小、过冷度的降低、撞击速度的增加和壁面温度的降低而减小。

Experimental studies on impacting icing characteristics of supercooled large droplets(SLD)were carried out with different droplet sizes,supercooling degrees,impact velocities and wall temperatures.A SLD generation device was designed,which was equipped with a high-speed camera to record the SLD impacting icing process.The influence of various factors on the impacting icing characteristics and freezing time of SLD were analyzed.The results show that the SLD exhibits three typical icing characteristics after impacting the wall:icing after spreading-retraction,icing during spreading-retraction,and icing during spreading,which are all significantly influenced by supercooling degree of droplet and wall temperature.The freezing time of SLD gradually become shorter with smaller droplet diameter,lower supercooling degree,lower wall temperature,and the higher impacting velocity.