Theoretical Modeling of Ice Formation Using Direct Contact Heat Exchange

Theoretical modeling of a column type of direct contact heat exchanger was performed to predict the refrigerant evaporation and ice formation processes. There are a number of factors influencing the heat transfer rate-dependent evaporation of refrigerant and formation of ice. Among these are the size of the refrigerant droplets as injected, the local temperature and pressure, the heat transfer coefficient, and the temperature difference between the fluids. Differential equations are written for a general location in the flow, which express the conservation of energy and mass for the various species in the multiphase flow. The equations are solved stepwise from the initial injection location of the refrigerant to the location at which the entire refrigerant has become vapor. The theoretical modeling of the refrigerant evaporation and ice crystal growth processes is performed to determine the refrigerant bubble growth rate and the ice crystal growth rate in order to predict the refrigerant evaporation time and the size of the ice crystals.