氟化物熔盐冷冻壁形成工艺研究

Experimental research on formation of fluoride molten salt frozen-wall

采用空气冷却的方式,在FLi Na K熔盐体系中开展了熔盐冷冻壁的形成工艺实验,考察了冷冻壁形成状态、温度分布及传热规律等。结果表明,冷冻壁形成过程中熔盐凝固界面沿逆热流方向逐渐推进,厚度增长速率与冷却热流量正相关,径向温度分布及传热规律均符合理论预期,但不同高度上换热不均导致轴向上冷冻壁厚度有一定差异,需考虑熔盐自然对流的影响并优化容器外壁换热方式。研究结果可为配置冷冻壁功能设备的设计尤其是换热器结构的优化提供数据支撑。

The experiment on the formation of molten salt frozen wall is conducted in FLi Na K molten salt system by means of air cooling.The forming status of frozen wall,temperature distribution and heat transfer law are investigated.The results show that the solidifying interface in molten salt has gradually been moving along the inverse heat flow direction during the formation of frozen wall. The growth rate of thickness of frozen wall is positively related to the cooling efficiency.The radial temperature distribution and heat transfer law are both in line with theoretical expectations. But the thicknesses of frozen wall are not axial uniform because the heat transfer is not uniform at different heights.So the effect of natural convection of molten salt shall be considered and the heat exchange method of vessel outer wall needs to be optimized.The research results can provide data supports for the design of the frozen wall functional equipment,especially for the optimization of heat exchanger structure.