Kinetic wetting characteristics of droplet on the surface of spherical dust

The phenomenon of droplet impinging and wetting on dust exists widely in the process of spray dedusting.The wetting process has obvious dynamic characteristics.In order to further understand the kinetic wetting phenomenon in the process of droplet to spherical dust,this study took droplet morphology as a research target.In Eulerian framework,the VOF numerical simulation method was used to track the droplet surface.Droplet deformation and kinetic wetting characteristics were studied.The effects of droplet impact velocity,particle size ratio on dimensionless spreading coefficient and droplet center height were analyzed.The results show that when approaching the dust particle,as particle size ratio increases,the droplet deformation decreases.The greater droplet velocity,the greater deformation.With the decrease of particle size,the resistance of droplet to deformation is gradually enhanced.After the droplets hit the dust particle,bubbles appear at the interface,which prevent the droplet from wetting the dust particle,and can be broken later.The greater droplet velocity,the faster bubbles is broken by pressure and shear stress.In the droplet spreading process,the larger velocity,the easier to reach the maximum spreading coefficient and the minimum droplet center height.As the particle size ratio increases,the initial dimensionless droplet center height increases.After the droplet hits the dust particle,the dimensionless droplet center height gradually decreases,and the curve changes from steep to gentle.When dust particle size is 20,200 and 2 000 μm respectively,the dimensionless spreading coefficient decreases with the increase of the particle size ratio.When the particle size ratio is greater than 1,increasing the droplet diameter will not improve the wettability.After the spreading,a small part of the droplet will remain on dust particle surface.When the dust particle size is 2 μm and the particle size ratio is between 0.5~1.5,the droplet spreading process is obviously inhibited.Although the maximum value of dimensionless spreading coefficient increases slightly when the particle size ratio is greater than 1,the increase is very small.After the spreading,the droplet remains on the dust particle surface completely.