抄録
An experimental study has been performed to investigate the freezing characteristics of an aqueous binary solution droplet on a cooled wall. Pure water, ethylene-glycol aqueous solutions of 1to 10 mass%, and NaCl aqueous solutions of 1 to 15 mass% in concentration were adopted as the testing solutions. The droplet was frozen under a variety of cooling conditions such as wall temperature, air temperature, air velocity, and solute concentration in both the static atmosphere and the cold air flow. The observations on both the freezing characteristics and the morphologies of the droplet were extensively carried out. In addition, the inside flow of the droplets were observed. It was found that the morphology of the droplet on the cooled wall varied markedly depending on the solution, which appears to be mainly caused by the difference in the surface tension of the solution. On the other hand, under the conditions with a cold air flow, initial freezing point of the droplet was found to be mainly owing to the cooling rate between the cooled wall and the cold air.
