Single Phase CFD Method Validation Based on PIV Experimental Data

The present paper aims to verify the existing CFD method and determine the optimal combination of the models and parameters. Single phase 5 × 5 bundle flow field is analyzed and validated based on the Particle image velocimetry (PIV) experimental data. By comparing the fluid velocity distributions at different sections and positions downstream of the grid, the effects of different grid basic sizes, mesh refinement in grid area and turbulence model on the calculation results are investigated. The results show that, when the mesh is refined to a certain extent, the change of calculation results tends to be stable, and the basic size of 0.4mm is used for subsequent calculation. Mesh refinement in grid area only has a certain influence on the flow calculation at zone near grid (1 D_h). In the 4 ∼ 20 D_h downstream of the grid, the simulated values under different turbulence models are different, the simulated values for standard quadratic k-ε (SKE) and realizable k-ε (RKE) are larger, while the improved quadratic k-ε is better for simulating the velocity analysis. All three turbulence models overestimate velocity at other zones. The results provide references to the establishment of a systematic and reliable high-precision numerical method for simulating the flow and heat transfer performance in the fuel rod bundle.