Research on Optimization Design by CFD in Complex Fuel Assembly
A Computational Fluid Dynamics(CFD)based simulation analysis of the complex fuel assem-bly with helical cruciform fuel rods using the realizable k-ε model is conducted.The internal complex structural features and small gap features of the fuel assembly are retained.Based on the numerical re-sults data,a multi-parameter optimization model of structural parameters was established.The hydraulic optimization study of the fuel assembly conducts the uniform design experimentation,the second-order response surface methodology and the genetic algorithms.Results indicate that a smaller diameter D of the central area of flow distribution disc and a larger length H of the guide head derives a better performance.The optimized design for the fuel assembly with 6 holes flow distribution disc reduces pressure drop by 8.61%,while for it with 4 holes one reduces pressure drop by 22.23%.Meanwhile,the optimized de-sign of the fuel assembly with 4 holes flow distribution disc exhibits advantages in velocity uniformity of flow.