EXPERIMENTAL RESEARCHES ON DYNAMIC ICE-MAKING BY S

Two factors to lead to icing in heat exchanger in dynamic ice-making system were investigated: supercooled degree of inner surface of tube wall and ice crystals entering into heat exchanger. Supercooled degrees of inner surface of tube wall could be divided into three zones according to possibility to lead to icing in the tube:stable zone , less stable zone , unstable zone. Dividing line of stable and less stable was not markedly related to Renolds number of water in tube when Renolds number in range of 0-9200. Ice crystals entering into heat exchanger was very likely to lead to icing although responding time was stochastically distributed.

Keys to keep stable running of dynamic ice-making by supercooling water were put forward: to keep temperature of outer surface of tube wall above certain value, to eliminate fully supercooling of water in ice tank and to eliminate completely ice crystals carried by water from ice tank before entering into heat exchanger. Dynamic ice -making apparatus by supercooling water was set up. It ran stable with temperature of water at inlet of heat exchanger of higher than 0.45℃ and temperature decline of water through heat exchanger of about 1℃.