通过数值模拟及分析可以得出,流量脉动对铅铋合金流动换热的影响很小,横向附加力是导致铅铋时域平均换热能力改变的主要原因。在正常海洋条件下,铅铋的流动特性不会受外力场的影响,但当附加外力场足够大,如本报告中假定的10倍附加力时,铅铋的流动与换热特性可以同时改变。通过与冷却剂水的比较,发现铅铋密度大,是摇摆易造成其径向二次流增强的主要原因,铅铋普朗特数高,是造成铅铋换热特性易受摇摆影响、加强的主要的原因,进而铅铋在摇摆条件下表现出与水不同的特性。倾斜对于铅铋合金流动换热的影响和忽略。起伏对于竖直通道内流动的流体来说仅会使流量波动,而流量波动不会造成流体流动和换热的时均特性产生变化。从数值模拟的结果来看,现有的静态条件下的铅铋流动传热关系式已经无法满足海洋环境下铅铋冷却反应堆的设计及安全分析,需进一步开展实验及数值模拟开发适用的模型,以方便开发海洋铅铋堆的专用分析研究工具。
Through numerical simulation and analysis, it can be concluded that the flow fluctuation has little effect on the flow heat transfer of lead-bismuth alloy, and the lateral additional force is the main reason for the change of the time domain average heat transfer capacity of lead-bismuth alloy. Under normal ocean conditions, the flow characteristics of lead-bismuth are not affected by the external force field, but when the additional force field is large enough, such as 10 times the assumed additional force in this report, the flow and heat transfer characteristics of lead-bismuth can be changed simultaneously. By comparing with the coolant water, it is found that the lead bismuth density is the main reason for the radial secondary flow enhancement easily caused by rocking, and the lead bismuth Prandtl number is high, which is the main reason for the lead bismuth heat transfer characteristics easily affected and strengthened by rocking, and then the lead bismuth shows different characteristics from the water under the rocking condition. Influence and neglect of tilt on flow heat transfer of lead-bismuth alloy. For the fluid flowing in the vertical channel, fluctuation will only cause the flow fluctuation, and the flow fluctuation will not cause the change of the time-uniform characteristics of fluid flow and heat transfer. It can be seen from the numerical simulation results that the existing static lead-bismuth flow heat transfer equation cannot satisfy the design and safety analysis of lead-bismuth cooled reactors in the Marine environment. Further experiments and numerical simulation should be carried out to develop suitable models to facilitate the development of special analytical tools for Marine lead-bismuth reactors.