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采用焓-多孔介质模型对高温蓄热堆积床蓄热单元相变过程进行模拟,探讨不同的封装材料、相变材料、熔化温度和运动粘度对相变材料熔化过程的影响。结果表明:当封装材料的导热系数远大于相变材料的导热系数时,封装材料对相变的影响非常小,可忽略不计;通过对比不同相变材料的熔化时间和蓄热能力可知NaNO_3、KNO_3、LiNO_3的完全相变熔化时间相差不大;高粘度的相变材料在相变过程中自然对流较弱,低粘度有利于相变材料熔化过程中的自然对流;熔化温度范围越小,越有利于相变材料的熔化。
The enthalpy-porous media model was used to simulate the phase change process of the thermal storage unit in high temperature thermal storage bed, and the effects of different packaging materials, phase change materials, melting temperature and kinematic viscosity on the melting process of phase change material were discussed. The results show that when the thermal conductivity of the encapsulation material is much larger than the thermal conductivity of the phase change material, the influence of the encapsulation material on the phase transition is negligible. By comparing the melting time and thermal storage capacity of different phase change materials, it can be seen that NaNO_3, KNO_3 , The phase transformation melting time of LiNO_3 is almost the same; high viscosity phase change material in the phase transition process natural convection is weak, low viscosity is conducive to phase transition material melting process of natural convection; melting temperature range is smaller, the more Conducive to the phase change material melting.