方腔内相变材料固液相变传热研究

基于相变材料(PCM,phase change material)的相变储能设备具有储能密度高的特点。本文建立了基于相变储能元件伪焓模型的固液相变格子Boltzmann模型,研究了内部管道位置、方腔倾斜角度对PCM融化过程的影响规律。结果表明,在内管道靠近方腔上部时,由于上部界面(固液相变界面或上壁面)对自然对流阻碍作用,使PCM的融化速率减慢。但是,在此时使方腔发生倾斜,会改变管道热流体到上部界面的距离,强化PCM的热质传递过程,使融化加快。

Investigation of Heat Transfer for Solid-liquid Phase Change in a Square Cavity

The phase change thermal energy storage unit based on phase change material(PCM) possesses the characteristic of high energy storage density.In this paper,the solid-liquid phase change lattice Boltzmann model based on quasi-enthalpy for phase change thermal energy storage unit has been established.The effects of the inner channel location and inclination angle on phase change process of PCM are investigated.The results show that when the channel is in the upper region of cavity,the natural convection is weakened by the upper boundary(upper wall of cavity or solid-liquid phase change interface),leading to the lower melting rate of PCM.However,in the meanwhile,inclining the cavity will change the distance between inner channel and upper boundary,resulting in enhancement of heat and mass transfer and acceleration of phase change process.