Chen Linhui,Tian Huaizhang,Wang Shi,Chen Jingliang
(School of Energy and Power Engineering,Xi'an Jiaotong University,Xi'an ¡¡710049,China)
Abstract:An effective thermal conductivity was introduced to consider the effect of natural convection on heat transfer of solidª²liquid phase change,and then the mathematic model on the energy storage system with solid-liquid phase change was simplified so that it was described by the energy equation only£®The present model was solved with the apparent heat capacity method and the normal distribution model of liquid fraction£® The comparison between the stearic energy storage experiment results and the calculations data shows that the effect of natural convection on heat transfer with phase change can not be neglected.The corrected empirical formula of effective thermal conductivity can describe the solid-liquid phase change with constant heat flux more exactly.The moving velocity of solid-liquid interface decreases with time in constant temperature boundary and increases with time in constant heat flux boundary£®
Keywords:energy storage system with solid-liquid phase change;the second boundary condition;effective thermal conductivity