熔盐吸热管非稳态对流换热特性

实验研究了高温熔盐吸热管的非稳态对流换热特性。研究发现：加热热通量与熔盐流量变化将引起吸热管内熔盐的非稳态对流换热过程，熔盐出口温度与管壁温度变化趋势一致但变化速度较慢。熔盐进口温度越低时，熔盐黏度越大，非稳态过程进行得越慢；热通量变化量增大时，温度变化速率加大，但非稳态持续时间变化不大；熔盐流量变化的影响最为显著，熔盐流量增大时，非稳态过程显著加快。吸热管有保温层时，熔盐的非稳态对流换热特性与无保温层时基本一致，但管壁温度相对较高。

Unsteady convective heat transfer performances of molten salt in receiver tube

The unsteady convective heat transfer performances of molten salt in receiver tube were experimentally investigated.When the heat flux or molten salt flow rate varied，the unsteady convective heat transfer appeared.During the unsteady process，the molten salt outlet temperature varied slower than the wall temperature，but their variation trends were similar.For lower inlet temperature，the viscosity of molten salt was higher，and the heat transfer process varied slower.For larger heat flux variation，the temperature varied more quickly，but the unsteady duration changed very little.The unsteady convective heat transfer process was remarkably affected by molten salt flow rate，and it can be significantly accelerated by flow rate rising.In addition，the unsteady heat transfer performances of the receiver tube with insulation layer were similar to those without insulation layer，but the wall temperature was higher.