建立了高温熔融盐壳管式相变换热器的同心套管模型.采用Fluent软件,分析了在考虑相变区域自然对流条件下,熔融盐流体与相变材料的物性参数、内管进口温度与进口流向等因素对液相率与熔化时间的影响,并在熔融盐传热-蓄热实验平台上进行了试验研究.发现：考虑相变区域自然对流时,总的熔化时间减少16.2%;模拟得到的壳侧相变材料温度随时间的变化趋势与实验结果趋于一致.结果表明,可采用熔融盐相变区域特殊测点温度超过相变材料的熔点,并升至与内管流体进口温度相近时所耗费的时间作为壳管式相变换热器内相变材料完全熔化的判据.

In this paper,first,a concentric circular tube model for the shell-tube heat exchanger with molten-salt phase change materials（PCMs） is established.Then,the liquid fraction and the total melting time,which are affected by the thermal-physical parameters of the molten salt fluid and the PCMs as well as by the inlet velocity and the flow direction of the inner tube,are analyzed with Fluent,by taking into consideration the natural convection in the PCMs region.Finally,some experiments are carried out on a test platform of molten-salt heat transfer.The results show that the total melting time nearly decreases by 16.2% considering the natural convection in the PCMs region,and that the simulated temperature of PCMs at the shell side varies with time,which has a tendency similar to that of the experimental results.Thus,it comes to the conclusion that,when the temperature of the specific measu-ring point in the PCMs region exceeds the melting point of PCMs and rises to the tube inlet temperature,the corresponding time cost can be used as the criterion of melting ending of PCMs.