水滴在撞击不同厚度水膜条件下产生的二次液滴特性

Characteristics of Secondary Droplets Produced During Impact Process of a Water Droplet on Water Film of Different Thicknesses

采用高速相机对水滴撞击水膜的飞溅过程进行了详细测量,分析了水滴撞击水膜的飞溅临界值、二次液滴的直径分布和二次液滴的速率等飞溅特性。结果表明,在实验参数范围内,当韦伯数增大时发生飞溅现象。此外,可以使用量纲为一参数K来描述飞溅临界值,K=We·Oh-0.4。当K值大于2 100时发生飞溅现象,二次液滴的量纲为一直径和二次液滴的量纲为一速率随着K值的增大而增大。水膜量纲为一厚度对二次液滴直径分布的影响不明显,但由冠状水花产生的二次液滴的平均量纲为一速率随水膜量纲为一厚度的增加而减小。

The splashing dynamics of a water droplet impacting a water film was experimentally investigated by a high-speed camera.The splashing limit,the size distribution of secondary droplets,and the velocity of secondary droplets were analyzed.The results show that within the range of the experimental parameters,the splashing occurs when the Weber number increases.The dimensionless parameter K(K=We·Oh-0.4)could be used to describe the splashing limit.When K>2100,splashing phenomenon happens.In addition,with the increase of the K number,both the dimensionless secondary droplet diameter and the dimensionless velocity of secondary droplets increase.The effect of dimensionless film thickness on the diameter distribution of secondary droplets is not significant.However,the average dimensionless velocity of secondary droplets produced by crown splashing decreases with the increment of dimensionless film thickness.