中文摘要：

单罐填充床蓄热是一种重要的高温蓄热方式,而在充放热过程中不发生黏性指进现象,保持斜温层的稳定是蓄热系统是否可行的重要依据。本文对充放热过程中熔盐的流动方向、熔盐的密度和黏度对黏性指进的影响进行了详细的理论分析。结果表明熔盐自上而下流动,热熔盐置换冷熔盐时,熔盐流速不能超过临界流速;冷熔盐置换热熔盐时,熔盐流速要大于临界流速才能维持斜温层的稳定。熔盐自下而上流动,热熔盐置换冷熔盐时,必然会发生黏性指进;冷熔盐置换热熔盐时,没有流速的限制,斜温层能自然保持稳定。

英文摘要：

A single tank thermal energy storage（TES） is a kind of important thermal energy storage method.During the operation of charging and discharging a TES tank,the stability of thermocline is important basis for the feasibility of the system.In this paper,the influence of direction of flow,density and viscosity of the molten salt on the viscous fingering was analyzed theoretically.Some conclusions were obtained.When the direction of molten salt is top-down flow and the hot molten salt displaces the cold one,the molten salt velocity can not exceed the critical velocity;When the cold hot molten salt displaces the hot one,molten salt velocity need to be larger than the critical velocity in order to maintain a stable thermocline.When the direction of molten salt is Bottom-up flow and the hot molten salt displaces the cold one,it is bound to happen viscous fingering;when the cold molten salt displaces the hot one,there is no limit of velocity and the thermocline is stable naturally.