单相4×4棒束流动试验的CFD方法验证

Validation of CFD Method for Benchmark Experiment of Single-Phase 4×4 Rod Bundle Flow

为研究计算流体力学(CFD)方法预测棒束通道内流场分布的准确性,基于网格敏感性分析所确定的网格方案,采用标准k-ε模型(SKE)、可实现k-ε模型(RKE)、标准k-ω模型(SKW)和剪切应力传输模型(SST模型)对单相棒束流动进行模拟,并将横向速度与轴向速度与试验结果进行量化比较。结果表明:4种湍流模型均能较好地预测棒束通道内的流场分布,其中SKE与RKE的在横向速度预测上相对偏差较小,为19.6%;对于近格架区域的横向流场分析,SKE模拟较优,反之RKE模拟较优;对于轴向速度的预测,SKE的相对偏差最小为4.9%;4种湍流模型均低估均方根(RMS)速度,但能够预测棒束通道内RMS速度的分布规律,近格架区域采用RKE,反之SST较优。本文的计算结果可为单相棒束流动CFD分析的最佳实践导则建立提供参考。

In order to study the accuracy of the prediction of flow field distribution in bundle channels using Computational Fluid Dynamics(CFD) methods, STAR-CCM+ code is utilized to analyze the single-phase 4×4 bundle flow experiments conducted by Korea Atomic Energy Research Institute. Based on generating meshing scheme determined by meshing sensitivity study, standard k-ε(SKE), realized k-ε(RKE), standard k-ω(SKW) and SST turbulence model are adopted to simulate the bundle flow, and comparisons are conducted for the simulation results and experimental data for lateral and axial velocity. The results show that, four turbulence models can well predict velocity field distribution inside the bundle channels, the relative deviation for SKE and RKE is 19.6% to predict the lateral velocity, and SKE is better for simulating the lateral velocity analysis at zone near grids, otherwise RKE is better. For axial velocity prediction, SKE simulation is with the minimum relative deviation of 4.9%. All four models underestimate RMS velocities, but can predict RMS velocity distribution law inside the bundle channels, and RKE is suitable for near-grid zone, otherwise SST is suitable. The results provide references to the set-up of best practice guide for CFD analysis of single-phase bundle flow.