Ultrasonic measurements in ice slurry generation by direct contact evaporation
Important reductions of refrigerant amounts can be achieved by using secondary refrigeration fluids. Ice slurry is a two-phase fluid and thus, compared to single phase secondary refrigeration fluids, offers the advantage of the latent heat of fusion when the ice phase melts during heat exchange. Therefore, the challenges that the introduction of ice slurry as a common thermal fluid is facing are, in the first place, how to generate ice slurry in an efficient and ecological way. Optimal design of a direct contact ice slurry generator requires studying the injection and the mechanisms of the evaporation of the refrigerant in the aqueous solution. The evaporation chamber is the main domain of our investigations presented in this paper. Some aspects of the evolution of the liquid-to-gas phase-change of the refrigerant, and of the liquid to solid phase-change of the water are presented in this article. Basic theory, velocity profiles achieved by Ultrasonic Doppler Method (UDM), and extracted values from measurements help to understand how to optimise the process of ice creation by an expanding jet of refrigerant in a column of water.