Experimental Investigation on Water Droplet Impacting Liquid Film on Inclined Wetted Surface

Abstract

The secondary carry-over of the droplet and liquid film in the steam-water separator can influence the separation efficiency of the separator. The generation of the secondary droplets resulting from droplets impacting the water film of the wetted surface is one of the mechanisms of secondary carry-over. Therefore, the experimental investigation on water droplet impacting liquid film on inclined wetted surface is conducted through high-speed video camera. The subsequent form and evolution process once the droplet colliding with the inclined liquid film are obtained. The droplet splashing phenomenon and mechanism are explained. The qualitative analysis of influence of the initial droplet diameter, velocity and the inclination angle of the wet surface on the splashing behavior is conducted. The results reveal that with increasing angle of inclination of the wet surface, the critical velocity to generate the splashing phenomenon increases accordingly; the increasing initial droplet diameter leads to decreasing critical velocity; the splashing phenomenon is more likely to appear in cases with higher impacting velocity, larger initial droplet diameter and smaller inclination angle, under which conditions the number of secondary droplets generated increases and the splashing phenomenon is more obvious. The obtained experimental results are significant to the study of steam-water separation and can lay basis on design of the separator.