Calculation of Turbulent Kinetic Energy Budgets for Flow Through a Pebble Bed Using DNS

Abstract

Pebble bed high temperature reactors (PBR) are currently being investigated as a potential successor for light water reactor based designs in the future. Past analyses of flows through PBR cores using Reynolds averaged Navier-Stokes (RANS) approaches have had limited success. Due to a lack of available high fidelity experimental or computational data, optimization of RANS closure models for these geometries has not been extensively done. In the present study, direct numerical simulation (DNS) is employed to develop a high fidelity data set which may be used for the optimization of RANS closure models for pebble bed flows. Calculated parameters include turbulence statistics, as well as values for the turbulent kinetic energy (TKE) budget terms. A well documented, single face centered cubic domain with periodic boundaries was used. Flow was simulated at a Reynolds number of 9308. Tests were conducted to ensure sufficient spatial and temporal resolution for conforming to the requirements for DNS. A selection of the generated statistics and TKE budget terms is presented here.