Analysis of the characteristics of the gas–liquid mixed artificial snow-making

Abstract

This study investigates the heat and mass transfer of liquid droplets freezing in the process of artificial snow-making, and emphatically analyses the effects of droplet size, ambient temperature and relative humidity on the evaporative cooling and freezing of liquid droplets by establishing a theoretical model. On this basis, the critical droplet size for snow-making under different environmental conditions is obtained, and the accuracy of the droplet freezing model was verified by artificial snow-making experiments. Finally, by analyzing the density of artificial snow under different environmental conditions, the optimum gas-liquid mixing mass ratio (GLR) suitable for snow-making is obtained. The results show that the liquid droplets could be frozen under the action of self-evaporation and convection heat transfer with ambient. The time required for the droplet to be frozen completely shows a positive correlation with ambient temperature, relative humidity and droplet size. In the evaporation cooling stage, the droplet cooling rate increases with the decrease of ambient temperature, and in the phase transition stage, the time for the droplet resists the latent heat of phase transition increases with the increase of the droplet size. When the droplet size is smaller than the critical size for snow-making, the artificial snow can be achieved at a maximum temperature of 3 °C. The snow density decreases with the increase of GLR. And when the GLR is greater than 0.15, the snow density tends to be stable.