In this research, the numerical simulation and analysis of flow behavior in 5 × 5 fuel rod bundle with consideration of spacer grid has been conducted. ANSYS FLUENT 19.0 with the consideration of the transition SST (Shear-Stress Transport) with SAS (Scale-Adaptive Simulation) turbulence model is used for the numerical simulation. The obtained simulation results are reasonable compared with the experimental data based on the comparison in the aspect of velocity distribution. The effect of the spacer grid on the flow behavior in the fuel rod bundle has also been investigated. The mixing vanes in the spacer grid can cause various strong flow branches; these flow branches develop and cause the complex flow behavior in the fuel rod bundle. Additionally, the secondary flow, the swirling factor and the mixing factor were investigated for the quantitative analysis of the spacer grid effect on the flow mixing behavior in fuel rod bundle.

在这项研究中，进行了5×5燃料棒束中考虑间隔栅的流动行为的数值模拟和分析。数值模拟中考虑了带有SAS（比例自适应模拟）湍流模型的过渡SST（剪切-应力传输）的ANSYS FLUENT 19.0。基于速度分布方面的比较，所获得的仿真结果与实验数据相比是合理的。还研究了隔栅对燃料棒束中流动行为的影响。间隔栅中的混合叶片会引起各种强烈的流动分支；这些流动分支发展并导致燃料棒束中复杂的流动行为。此外，次要流程