Thermal-hydraulic performance of a 5 x 5 rod bundle with spacer grid in a nuclear reactor

摘要

The turbulent flow behavior and heat transfer performance of the rod bundle with spacer grid have significant effect on the thermal-hydraulic characteristics in Pressurized Water Reactor (PWR). The complex structure of the spacer grid includes dimple, mixing vane and spring. In-this paper, different turbulence models are coupled with the Computational Fluid Dynamics (CFD) analysis for the complex flow in rod bundle, and the numerical results are compared with the expetimental results with temperature distribution at outlet. This paper focuses on thermal-hydraulic behavior downstream of the spacer grid mused by mixing vane, dimple and spring. Two types of rod bundles are investigated, including with spacer grid and without spacer grid. According to the numerical study, the strong secondary flow induced by-the spacer grid gradually decay along the rod bundle after the mixing vane, and this secondary flow has significant effect on the heat transfer. In addition, a normalized Nusselt number (Nu) and swirl factor are defined to investigate the thermal-hydraulic performance of the rod bundle. (C) 2016 Elsevier Ltd. All rights reserved.