NUMERICAL STUDY ON COOLING PHENOMENON OF WATER WITH SUPERCOOLED REGION IN A HORIZONTAL CIRCULAR CYLINDER

Abstract

Ice formation in a horizontal circular has been studied numerically. From the numerical analysis results, it was found that there were three types of freezing patterns and that the freezing phenomenon was affected largely by density inversion and cooling rate. The type of freezing pattern largely depends on the secondary flow, which is generated by density inversion. When supercooling energy is released before the development of the secondary flow, an annular ice layer grows. If the energy is released when the secondary flow is considerably developed and the supercooled region is removed to the upper half part of the cylinder, an asymmetric ice layer grows. If the energy is released after perfect development of the secondary flow, instantaneous dendritic ice formation over the full region occurs. Furthermore, the secondary flow was found to have an effect on heat transfer characteristics. The heat transfer rate becomes small at the instant when the secondary flow is generated, but it becomes large with the development of the secondary flow. It is concluded that for the facilitation of heat transfer it is desirable to keep water, in its liquid phase until the secondary flow is perfectly developed. This study gives an instruction on the performance improvement of a capsule-type ice storage tank.