Investigation of the processes of heat and mass transfer during cooling and crystallization of droplet nuclei of hail

The regularities of crystallization of water droplets in an air stream and the processes of heat and mass transfer have been investigated. Theoretical calculations for determining the time of complete solidification of a drop are presented. Calculation formulas are given for determining the Reynolds number and wind coefficient, as well as comparative curves of theoretical and experimental studies of the average time of complete freezing of drops. It is shown that the theoretical calculations are in agreement with the experimental data. It was found that with intense blowing, the droplet crystallizes in a regime in which its surface is maintained at a constant temperature. An ice crust forms in the form of a dendrite when supercooled droplets crystallize. On the basis of numerous experiments, it has been established that the character of droplet crystallization substantially depends on the external conditions under which the crystallization process takes place.