高温相变储热单元模拟研究与计算

Numerical Simulation Studyof High-temperature Phase Change Thermal Energy Storage Cell

运用Fluent软件对圆形储热单元内部LiCl高温相变材料熔化过程进行二维数值模拟。模拟结果表明:不同位置的LiCl都会出现恒温"平台",其平台的长度和出现的时间间隔随空间位置的不同而有显著差异;随时间的增加,储热单元储热量在相变区明显增大,其储热功率也相应出现了最大值。相变材料的导热系数、相变储热单元的形状和空间尺度以及其恒温隔热装置是改善相变储热系统储热性能的关键性因素。

Two-dimensional numerical simulation on melting processes of high-temperature phase change material （LiC1） in a circular heat storage unit was conducted with Fluent software. The simulated results showed that the constant temperature ＂platform＂ appeared, and the length of the platform and the interval between the points with equidistance were significantly different with the different spatial position. The closer the position of phase change materials （PCM） to the hot side is, the faster the platform appears. PCM have high latent heat, the thermal storage of the cell increases significantly and the storage power enlarges to the maximum correspondingly during the phase change zone, then the increasing rate of the thermal storage slows and the storage power gradually reduces to the minimum. The thermal conductivity of the PCM, shape and space scale of the PCM heat storage unit, and constant temperature thermal insulation devices are the critical factors to improve the phase change thermal storage performance.