Characteristics of Solidification and Melting in the Water-Saturated Porous Medium Cooled from the Top (Response of Solid-Liquid Interface due to Time-Varying Cooling Temperature)

摘要

This paper describes the response of a solid-liquid interface in a water-saturated porous box to a time-varying cooling temperature. Spherical soda glass beads with an average diameter of 5 mm constitute a porous matrix. The lower boundary of the matrix is kept at 8℃ at all times during the experiments, while the upper plate is set at a temperature, lower than the liquids 0℃. After a steady state is reached, the cooling temperature is varied periodically with a fixed amplitude of 4℃. The solid-liquid interface positions are measured and the characteristic amplitudes and the phase delays are determined for different periods ranging from one hour to ten hours at four different cooling temperatures. It has been found that the amplitude of the interface is proportional to the cooling temperature period length, and that a thicker solid layer causes larger phase delays. The proposed one-dimensional model has been found appropriate for predicting the response of the horizontally averaged position of the solid-liquid interface.