Characteristics On Freezing Of Water Droplet Due To Evaporation

Developing cool thermal energy storage technology is an important measure to realize shifting electrical energy demand from peak period to off-peak period. The vacuum ice slurry making technology which operates on freezing of water droplet due to evaporation under vacuum environment, is an energy efficient and novelty cool thermal energy storage technology and thus will has a large number of application prospects in China.The objective of the present dissertation is to investigate the crystallization characteristics of heat and mass transport. The layout of the dissertation is as follows:firstly, the loss of mass and transfer of heat at vacuum environmental pressure in the processes of freezing of a water droplet due to evaporation is numerically studied.Temperature variation of water droplet with different droplet size and different chamber pressure is subsequently investigated in the following chapter, the results show that ice can be produced by water vapor absorbing the latent heat from the droplet with an initial ambient temperature under conditions of a sufficiently small droplet size, a long enough residence time of the droplet in the chamber, and a chamber pressure far enough below the triple point.In addition, for the reason that capture of water vapor producing in the evaporation-freezing process can not satisfied the need of owners, a novel chamber structure with a feature of interspaces including vacuum chamber is brought forward. The influences of major parameters on the vacuum ice slurry making system performance are respectively discussed. The results obtained in this paper are of great importance for the optimal design of the vacuum ice slurry making unit.