基于热焓方程的相变材料凝固时间分析

Analysis of Phase Change Time of PCM Based on the Heat Enthalpy Equation

对相变导热的研究,以往大多集中于固液边界层的移动速率,间接推导相变时间。对相变材料焓值与温度建立数学模型,并基于数学模型和热力学第一定律,建立一种新的相变导热热焓方程。运用该方程,可直观分析相变材料发生相变凝固所需时间,并分析影响固液相变时间的具体因素。计算表明,在零维非稳态导热中,相变时间与相变材料质量、相变潜热、换热面积、对流换热系数、相变材料与周围冷却介质温差有关。

Most of the researches on the PCM （Phase change material） are mainly focused on the movement rate of the liquid-solid boundary layer, and then the phase change time could be derived indirectly. In this paper, a new PCM enthalpy equation is introduces based on the first law of thermodynamics and a mathematic model of temperature and the enthalpy value of the PCM. The phase change time and its influence factors could be analyzed according to this equation directly. The results show that, in zero-dimensional model, the phase change time is related to the quality of the material, the latent heat, the convective heat transfer coefficient and the area of heat exchange. Also, the temperature difference between the PCM and the medium around the material is another influence factor.