Numerical simulation of single aluminum droplet evaporation based on VOF method

Abstract

In order to explore the law of single aluminum droplet evaporation process in argon, based on the VOF method, this paper carried out a corresponding two-dimensional transient multiphase flow numerical simulation. The evaporation process of droplet behavior in forced convection environment is compared and analyzed, and the influences of gas velocity on evaporation rate, the change of the droplet temperature and concentration boundary layer, and the variation of the velocity field around the droplet are studied. The research results showed that droplet evaporation can be divided into transient variation period and steady-state period. As the gas velocity increased from 2 m/s to 5 m/s, the evaporation rate at the transient variation period of aluminum droplets was increased by 22%–36%, and the evaporation rate at the steady-state stage was increased by 16%–33%; At 2 m/s, the temperature boundary layer on the windward and leeward sides of the droplet was thicker than the concentration boundary layer, indicating that the temperature diffusion was greater than the concentration diffusion; In addition, when the airflow around the droplet, the double row of vortices periodically fell off from the upper and lower sides of the droplet with opposite rotation direction and regular arrangement. With the mutual interference and influence between shedding vortices, Karman vortex street was formed, and the formation of the Karman vortex street became more obvious with the increase of the Reynolds number. The research results of this paper could provide reference for the unsteady numerical simulation of aluminum droplets combustion with chemical reaction in the future.