等速入口三喷口流动的温度振荡数值模拟

Numerical Investigation on Temperature Fluctuation in Triple-Jet Flow With Isovelocity Inlet Conditions

由于来自核反应堆堆芯不同通道冷却剂的温度存在差异,它们在上腔室混合后将产生复杂的温度振荡现象,可能干扰堆芯出口的温度测量,也可能造成周围固体结构的热疲劳破坏。本文基于FLU-ENT软件,采用大涡模拟湍流模型(LES)对三维平行三喷口流动进行数值模拟,并与实验结果进行了比较。结果表明:随着入口速度的增加,流体混合越来越剧烈,同时温度振荡的最大振幅逐渐减小,而相应的频率则逐渐增加。

The temperature fluctuation phenomenon caused by the mixed coolant flows out of the core with different temperatures in upper plenum, may not only interfere with the temperature measuring in the outlet of the core, but also cause thermal fatigue of the solid structure in upper plenum. In this paper, the three-dimensional triple-jet flow was simulated by the software FLUENT with large eddy simulation （LES）. The numerical results are in good agreement with the experimental ones. The results show that the mixing of fluids becomes more and more intense with the inlet velocity increasing. The maximum amplitude of temperature fluctuation decreases obviously, while its corre- sponding frequency increases in the case.