Measurement of salt entrapment during the directional solidification of brine under forced mass convection

In practical slurry ice-making applications, ice crystals are produced during the solidification of brine under non-linear non-equilibrium conditions.High speeds of growth combined with the irregular morphology of dendritic branched ice crystals result in the entrapment of pockets of highly concentrated brine within the ice matrix. Measurements of the brine concentration in a growing ice layer have been made for the case where ice grows on a vertical refrigerated plate wetted by a falling film of brine. These measurements show that the lower the plate temperature, the higher the concentration of brine trapped in the ice layer, and as the ice layer thickens the local concentration of entrapped brine falls.The process of crystallisation of ice from brine in a falling film system is influenced by both heat and mass transfer effects, and a simple model is used to predict conditions for the maximum rate of ice film growth when either the heat or mass transfer diffusion processes are controlling.