相变材料步冷过程模拟分析

Numerical analysis on step cooling process of phase change material

大部分的相变材料都具有一定的过冷度,这限制了相变材料的广泛应用。充分了解相变材料在凝固过程中的温度变化情况对于相变材料性能分析具有重要意义。基于集中参数法和等效比热容法建立了相变材料步冷过程温度变化模型,并通过实验验证了该模型。同时运用模型研究了相变材料过冷度与有效潜热值对其凝固过程中温度变化的影响并得出结论:相变材料开始凝固的时间与相变持续时间均与其过冷度呈指数关系;相变材料开始凝固的时间随着过冷度的增大而增长,相变持续时间随着过冷度的增大而缩短;相变材料开始凝固的时间与其有效潜热大小没有关系,而相变持续时间与其有效潜热值呈明显的线性正比关系。

Most phase change materials have the problem of supercooling,which affects the wide use of phase change materials.Therefore,it is very important to figure out the temperature variations during the solidifying process of phase change material.The numerical model of step cooling process of phase change material was built based on the lumped parameter method and the effective heat capacity method,and the model was verified by the experimental results.Meanwhile,the influences of the supercooling degree and the amount of latent heat of the phase change material on its temperature during the solidifying process were studied.It was found that the starting solidifying time of the phase change material and the total time of solidifying process both had the exponential relationship with the supercooling degree.The starting solidifying time was delayed with the increase of the supercooling degree,and the total time of solidifying process was decreased with the increase of the supercooling degree.The amount of latent heat had no influence on the starting solidifying time,but there was a linear relationship between the amount of latent heat and the total time of solidifying process.