关键词: 相变, 热传导, 自然对流, 蓄/放热, 数值模拟

Abstract:

Ternary composite phase change material is prepared from sodium acetate, stearic acid and stearyl alcohol. Composite material could effectively reduce the phase separation and supercooling degree of inorganic phase change material and improve the thermal conductivity of organic phase change material. The performance of charging and discharging of the ternary composite phase charge material with sodium acetate, stearic acid and stearyl alcohol is investigated in a double-pipe heat exchanger. The effect of the temperature and flow of hot water on the process of heat charge and discharge is studied. The movement of phase interface is also analyzed, based on the results of CFD numerical simulation and experiment. The experimental results show that natural convection is the dominant way of heat transfer during the heat charge, but heat conduction plays the leading role during the heat discharge. The time required for heat charge is less than that for heat discharge. The upper phase interface of the phase change material moves significantly faster than the lower one during the heat charge process, while both the upper and the lower phase interfaces uniformly moves in the radial direction during the heat discharge process.

Key words: phase change, heat conduction, natural convection, heat charge and discharge, numerical simulation