Flow visualization on SFR wire-wrapped 19-pin bundle geometry using MIR-PIV-PLIF and comparisons with RANS-based CFD analysis

In this study, measurement of turbulence intensity, pressure drop and local velocity field in the sodium fast reactor (SFR) wire-wrapped 19-pin bundle have been conducted to compare with the Reynolds averaged Navier-Stokes equations (RANS)-based computational fluid dynamics (CFD) simulations. The refractive indices between test section and working fluid, anise oil, were matched for the flow visualization. The turbulence intensity measurement showed that the transition of flow regime occurs at around Re = 13,800 at the test section. Pressure drop results revealed that the low-Re model showed the superior agreement with the experimental results. The particle image velocimetry (PIV) measurement was performed at the Reynolds numbers from 15,000 to 17,000. The velocity fields measured in the edge and interior subchannels. From the comparisons, it was found that the CFD simulation showed good agreement with the PIV measurement on specific flow characteristics such as vortex structure, swirl flow, and velocity direction change. (C) 2020 Elsevier Ltd. All rights reserved.