The effect of convective heat transfer mechanism on the wastewater pretreatment by the normal freezing cool thermal storage process was investigated. A mathematical model considering the heat and mass transfers in a normal freezing cool-thermal storage system using wastewater as the phase change material was developed and solved for the approximate solutions. A convective transport of heat in the water phase and constant heat sinking surface temperature of solid phase were considered and incorporated with the system equations to determine the temperature profiles of solid and liquid layers. The effects of system parameters on the solidification rate and the amount of solute removal were studied. The solidification rate would increase with increasing heat transfer coefficient in overall, but an inversed trend occurred initially. The optimal amount of thermal storage and the optimal solidification thickness had been determined. Differences around 10% in the optimum operating time and the cool-thermal storage would be made if different heat transfer mechanisms were assumed in the present aqueous system studied.
Tamkang Journal of Science and Engineering=淡江理工學刊 14(2), pp.115-122