水滴结冰结霜及合成双射流除霜除冰实验研究

An experimental investigation on the process of droplet icing/frosting and defrosting/deicing using dual synthetic jet

对水滴结冰结霜过程及合成双射流除霜除冰过程进行了实验研究。实验中利用半导体制冷片作为实验板将温度从室温降低到-30℃,在水滴凝固结冰结霜后启动合成双射流激励器。采用电子显微镜观测水滴凝固结冰结霜过程及合成双射流除霜除冰过程。结果显示:在合成双射流的作用下,霜的结构迅速由细长针叶状变为短粗的柱状冰晶,霜的厚度变薄;随后,由于合成双射流强迫对流换热作用,凝固水滴上的冰晶及锥形冰尖发生融化,凝固水滴上冰晶高度缓慢下降,锥形冰尖变平滑,融化的液态水在沿凝固水滴向下流动时遇冷再冻结,与下游冰晶结为更加质密的小颗粒状白霜,凝固水滴变矮,与冷平面接触面积增大。

The processes of a droplet icing/frosting and defrosting/deicing using a dual synthetic jet actuator（DSJA）was experimentally studied.The temperature of a semiconductorcooled board was reduced to-30℃,and the DSJA was started after the droplet was frozen.The processes of the droplet icing,frosting,defrosting and deicing were observed by an electron microscope.The experimental results show that the structure of the frost changes quickly from needle to column,and then to granule.Meanwhile,the thickness of the frost attenuates.Later on,because the DSJ can enhance the heat transfer,the cone of the frozen droplet becomes flattish and the height of the frozen droplet decreases slowly.The thawed water flows downwards and freezes again.The interface area between the frozen droplet and the semiconductor-cooled board is increased.