熔盐储罐冷却过程的瞬态分析

Transient analyses of a molten salt heat storage tanks

太阳能热发电易于和储热系统结合,通过储热系统,能够使电站平稳输出电力,因此是一种非常有前景的发电方式。熔盐储罐是储热系统中的重要设备,本工作建立了熔盐储罐冷却过程的模型,通过FLUENT计算,获得了熔盐储罐在不同情况下的散热量及熔盐储罐中熔盐温度下降的规律。计算发现,整个熔盐储罐中熔盐温度比较平均,但接近底部的熔盐发生了温度分层的现象;相同条件下,熔盐液位越高,熔盐发生凝固所需的时间越长,低温罐低液位(290℃,0.9 m)时所需凝固时间最短,只要3.8天开始凝固,19.3天后便完全凝固。

In this work, a computational fluid dynamics model is developed to analyze the cooling process of a molten salt tank during a standby period. The heat losses and temperature distribution under different conditions are obtained through the calculations. It is shown that the temperature distribution in the tank is mostly homogeneous, except for a temperature stratification closed to the bottom of the tank. Under the same conditions, the higher the level of molten salt, the longer time needed for the solidification of molten salt. For the cold tank at low molten salt level（290 ℃, 0.9 m）, the estimated onset of solidification occurs in 3.8 days, and all the molten salt is solidified in 19.3 days.