盐水液滴撞击固体壁面接触特性实验研究

Experimental Research on Contact Characteristics After Droplet Impacting Onto Solid Surface

采用高速摄像仪对不同浓度盐水液滴撞击水平固体表面的现象进行了观测并记录,总结了接触角、铺展系数和无量纲高度的变化规律,并对其影响参数进行了分析。结果表明:在液滴铺展阶段,盐水液滴的动态接触角大于纯水液滴的,在回缩阶段,其动态接触角反而小于纯水液滴的;液滴铺展系数随盐浓度的增加而减小;液滴直径增大,其最大铺展系数增大,铺展系数变化的震荡频率减弱;对于较大直径液滴,在铺展阶段,盐浓度对液滴动态铺展特性影响较小;随液滴撞击速度增加,液滴的铺展系数增大,而回缩到最小铺展直径所用时间缩短,液滴震荡越易受到抑制;相对于速度而言,液滴直径大小更能影响液滴的震荡频率。

The phenomena and behaviors of different droplets impacting on the solid flat surface were observed and recorded with a high-speed camera, then dynamic contact angle, dynamic spreading coefficient and dimensionless height were measured and the effects of the parameters on the droplet impacting were studied. The results show that during the spreading process, the higher concentration of droplet has bigger dynamic contact angles, while during the receding process, the dynamic angles of the brine are smaller than that of the pure water. Spread coefficient decreases with rise of the concentration of droplet. With increase of droplet diameter, the maximum spreading coefficient increases, and the oscillation frequency of droplet decreases. For the bigger droplet, the concentration has little effect on the dynamic spreading characteristics during the spreading process. When the impact velocity increases, the spreading coefficient rises, and the period of receding to the minimum spreading coefficient is shortened. Compared to the impact velocity, the droplet diameter is more likely to affect the oscillation frequency of the droplet.