水滴撞击固体表面实验研究

Experimental study of water droplet impacted onto solid surfaces

为了研究水滴撞击固体表面的影响因素,利用高速摄影仪记录了水滴撞击不同固体表面的形态变化过程,记录速度为2000f/s.实验是在常温大气环境中进行的,水滴的初始直径固定在(1.8±0.05)mm.对不同材料和不同表面粗糙度的固体表面以及不同撞击角度进行了实验观察,并采用图像处理技术获得不同条件对液滴撞击固体表面行为的影响.实验结果表明:不同固体表面、不同表面粗糙度和撞击角度对液滴撞击固体表面后的润湿行为有非常显著的影响.随着We由50增大到300,液滴撞击在非润湿性表面上会出现部分反弹、反弹甚至飞溅现象;相同固体表面的表面粗糙度增大使撞击过程的接触角变小.

In order to investigate the effect factors of water droplet impacted on the solid surfaces, the impaction process was recorded using a high-speed digital camera at 2 000 f/s. All experiments were performed in atmospheric air, and the initial droplet diameter was fixed at （1.8 ± 0.05） mm. When the droplet impacts on the solid surfaces with the different physical characteristics, the effects of different surface roughness and impact angles were separately researched in the experiment. An image processing technique was applied to analyze the effect of different factors. The experimental results indicate that there are remarkable influences of the different solid surfaces, the surface roughness and impact angle on the impaction process. When Weber number increases from 50 to 300, the droplet respectively experiences partly rebound, rebound and splash change after impacting on a hydrophobic surface. The rougher the same solid surface is, the smaller the contact angle of the impaction process is.