Identifying what causes fuel assembly vibrations downstream of Mixing Vane Grids (MVG) in Pressurized Water reactor (PWR) is of paramount importance for nuclear community to understand grid-to-rod fretting wear. Experiments, called CALIFS, were carried out by the Atomic Energy Commission (CEA) on a 5 × 5 MVG at a hydraulic Reynolds number of 66,000, in order to measure the flow velocity and the pressure along the central rod. In parallel, a benchmark for Large Eddy Simulation (LES) was setup to compare the predictions of three different CFD codes: Star-CCM+, Code_Saturne and TrioCFD to experimental measurements. The computational domain is representative of a span of CALIFS mockup, composed of a 5 × 5 rod bundle with a MVG. The three computations overall give very satisfactory results, independently from the mesh created and the modelling options selected. It seems to suggest that whatever the software used, this kind of calculations has reached a significant level of robustness and accuracy. Nonetheless, some discrepancies remain concerning the predictions of pressure standard deviation decay far downstream of the mixing vane grid.

确定导致压水反应堆 (PWR) 中混合叶片网格 (MVG) 下游燃料组件振动的原因对于核界了解网格到杆的微动磨损至关重要。名为 CALIFS 的实验由原子能委员会 (CEA) 在 5 × 5 MVG 上以 66,000 的液压雷诺数进行，以测量沿中心杆的流速和压力。同时，设置了大涡模拟 (LES) 的基准来比较三种不同 CFD 代码的预测：Star-CCM+、Code_Saturne和 TrioCFD 到实验测量。计算域代表 CALIFS 模型的跨度，由 5 × 5 棒束和 MVG 组成。这三个计算总体上给出了非常令人满意的结果，独立于创建的网格和选择的建模选项。这似乎表明，无论使用什么软件，这种计算都达到了相当高的稳健性和准确性。尽管如此，关于混合叶片网格下游的压力标准偏差衰减的预测仍然存在一些差异。