Impact Behavior of Hydrophilic Micron Particles on a Planar Gas-Liquid Interface

The behavior of hydrophilic micron particles impacting on the gas-liquid interface has been further experimentally studied using a high-speed camera at different surface tensions and dynamic viscosities of liquids. The results show that the impact behavior exhibits suspension and submergence modes, whose boundary cannot be clearly identified because the overlap between the impact velocity ranges occurs because of the unstable pinning of the three-phase contact line on the surface of hydrophilic particles. The liquid properties have little effect on the wettability of hydrophilic particles but greatly influence the hydrodynamic and capillary force exerted on the particles, leading to the expansion of the suspension mode range. In addition, the penetration probability changes little with the decrease in surface tension, while it significantly reduces with the increase in dynamic viscosity. A penetration probability model is predicted as an exponential function of the inertial and supporting forces, and the experimental values agree well with the predicted values. The outcomes of this research will be helpful for understanding the mechanism of particle-interface interaction and providing guidance for enhancing the separation of hydrophilic fine ash via a bubble scrubbing system.