基于数据同化的棒束流场湍流模型常数标定方法研究  

Turbulence Model Constant Calibration for Flow Field in Rod Bundle Based on Data Assimilation

作　　者：李逸 曲文海 熊进标[1] LI Yi;QU Wenhai;XIONG Jinbiao(School of Nuclear Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学核科学与工程学院,上海200240

出　　处：《原子能科学技术》2024年第7期1413-1423,共11页Atomic Energy Science and Technology

基　　金：国家重点研发计划(2022YFB1902200)。

摘　　要：为了提升压水堆棒束燃料组件内二次流预测精度,采用基于集合卡尔曼滤波算法的数据同化策略对非线性涡粘模型的关键模型系数进行标定。为了提升数据同化策略的收敛速度,降低模型常数的收敛残差,采用基于模型常数敏感性分析的定向抽样和基于空间相关长度的局部修正等方法,改进了数据同化策略和集合卡尔曼滤波算法。本文基于改进的数据同化策略,利用5×5棒束通道定位格架下游流场实验观测数据,标定了非线性涡粘模型。研究结果表明,与标准非线性涡粘模型相比,标定后的非线性涡粘模型对棒束通道定位格架下游二次流的预测精度显著提高,成功预测了标准模型常数未能准确预测的横截面涡结构。The paper presents a novel approach to enhancing the accuracy of turbulence modeling in nuclear reactor simulations,specifically addressing secondary flow in the fuel assembly of pressurized water reactors.The accurate prediction of secondary flow in the rod bundle channels of pressurized water reactors is crucial for the design and performance evaluation of nuclear fuel assemblies.Traditional numerical simulation methods have difficulty in striking a balance between computational cost and prediction accuracy.This paper addressed this challenge by calibrating the constants of the nonlinear eddy viscosity model(NLEVM)based on the high-fidelity flow field measurement data from a 5×5 rod bundle with a split mixing vaned spacer grid using a novel data assimilation strategy that incorporated the ensemble Kalman filter(EnKF)algorithm.This study enhanced the overall data assimilation strategy and the EnKF algorithm by introducing sensitivity-based deterministic sampling and correlation-length-based local adjustment,respectively.These modifications aimed to accelerate convergence and reduce residuals in the model constant calibration process.Besides,this study adopted the correlation coefficient between the predicted and measured flow fields as a criterion for judging whether the calibrated model constants improve the prediction accuracy of the secondary flow in the rod bundle channel,which is more in line with the actual phenomenon than the traditional relative error criterion.The calibrated NLEVM significantly improves the prediction accuracy of secondary flow in the rod bundle channels compared to the standard NLEVM.The similarity between the predicted flow field of the calibrated model and the experimentally observed flow field is improved,with the correlation coefficients of the full cross-section flow field improving to a greater extent the further away from the localized grids.The secondary flow structure of the subchannels predicted by the calibrated model agrees well with the experimental observations and can s

关 键 词：定位格架 二次流 非线性涡粘模型 集合卡尔曼滤波 数据同化 

分 类 号：TL334[核科学技术—核技术及应用]