Non-uniform melting in packed beds of fine ice slurry

The melting process of packed beds of ice slurry consisting of aqueous solu tion and ice particles with a mean diameter of 0.2 mm, so-called liquid ice , was studied. The packed ice layer was melted with aqueous solution spraye d on top of it directly and indirectly. Experiments of the melting process were done by changing the mass of ice, the inlet temperature and the flow r ate. The time history of the outlet temperature of the bed was measured and the melting phenomenon was observed. During the melting, it was found that passages through the ice layer were formed and the aqueous solution spraye d on the top of the ice layer hardly permeated the ice layer, but flowed th rough the passages. Assuming that the flow rate of the solution through the passages was known, the melting process was analyzed. In the case of direc t spraying, the effects on the outlet temperature and the formation of pass age were clarified by changing the initial mass of ice, the how rate and th e inlet temperature. When the solution was sprayed on top of the ice layer directly (direct spraying), the outlet temperature was kept constant becaus e the heat exchange was enhanced by the mixing effects of spraying. On the contrary, when an obstacle was placed on top of the ice layer (indirect spr aying), the outlet temperature was higher than that in the case of direct s praying and was not kept constant. (C) 2001 Elsevier Science Ltd and IIR. A ll rights reserved.