Numerical Research on 3-D Flow Field in 5×5 Rod Bundles With Spacer Grids

3-D single-phase flow field in 5×5 rod bundles with spacer grids was studied by numerical method. Using hybrid grids technique, SST k-ω model and SIMPLEC algorithm, the Reynolds averaged mass conservation and momentum conservation equations were solved, and the pressure and velocity field were obtained. The simulation results show that the spacer grids leads to intense lateral flow in rod bundles channel, and it submitted parabola distributing raw; axial velocities were distributed uniformly in the channel; drag coefficient decreased as inlet Reynolds number increased. Calculated results agreed with experiment data well, it shows that numerical methods employed in this paper is suitable to study flow field in 5×5 rod bundles.