基于 CFD 方法的铅铋堆组件操作头射流搅混特性研究

In the upper chamber of the Lead-Bismuth Eutectic (LBE) cooled reactor, fluid temperature fluctuations during the LBE mixing process from different power assemblies may lead to thermal fatigue of the solid structure, threatening the safety of LBE reactor operation. Based on the Computational Fluid Dynamics (CFD) method, this paper established a computational model suitable for the jet simulation of the LBE reactor assembly head and validated it through experimental data. Then, simulations of jet flow conditions with various inlet parameters were carried out. The research results show that the increase in the inlet temperature difference will lead to a significant increase in the temperature distribution inhomogeneity on the axial section downstream of the assembly head, and the influence range continues to the position of the measuring column. Within the calculation range, when the temperature difference decreases by 20 K, the root mean square temperature of each downstream section decreases by approximately 23.5%. The increase in inlet velocity causes the secondary flow to increase, but the intensity of the secondary flow will decrease. Within the calculation range, the degree of mixing first decreases and then increases as the inlet velocity increases. This paper can provide reference for research on flow field analysis downstream of the assembly head, structural optimization design of the assembly head, and LBE reactor core flow distribution design.