CFD gas flow simulations in a DEM-resolved pebble bed reactor

This paper presents computational fluid dynamics (CFD) gas flow simulations within a segment of the pebble bed core. The realistic packing structure in an entire pebble bed reactor (PBR) is generated by discrete element method (DEM). The random packing structure of pebbles is crucial to CFD simulations results. While in CFD calculations, selection of the turbulence models have great importance in accuracy and capturing the details of the flow features, in our numerical simulations both large eddy simulation (LES) and Reynolds-averaged Navier-Stokes (RANS) models are employed to investigate the effects of different turbulence models on gas flow field and relevant heat transfer. The calculations indicate the complex flow structure within the voids between the pebbles. (author)