Hydrodynamic Performance Study on Flow Field in Rod Bundles With Spacer Grids

With the dramatic progress in the computational fluid dynamics (CFD) methodology, this technology can be used in researching the knowledge of thermal–hydraulic characteristics in the rod bundles, particularly with the spacer grids. These characteristics, including fluid flow, turbulence, and heat transfer and so on, all of this information can be applied in design and the improvement of rod bundles. This paper calculated the single-phase flow field in rod bundles with different spacer grids respectively by numerical method, which was based on the experiment performed by Korea Atomic Energy Research Institute (KAERI). Two types of grid designs are used, including the Split-type and Swirl-type, respectively. By analyzing the calculated results, discussing the feasibility of computational fluid dynamics (CFD) methodology in thermal-hydraulic analysis of nuclear reactor, and obtaining the hydrodynamic performance of the two different types of spacer grids. The result showed that both of the two spacer grids led to intense cross-flow in the channel, and the cross-flow intensity decayed with the increasing of downstream distance after the spacer grids. Axial velocities were distributed uniformly in the channel.