Particle-resolved turbulent flow in a packed bed: RANS, LES, and DNS simulations

Packed bed reactors are widely used to perform solid-catalyzed gas-phase reactions and local turbulence is known to influence heat and mass transfer characteristics. We have investigated turbulence characteristics in a packed bed of 113 spherical particles by performing particle-resolved Reynolds-averaged Navier–Stokes (RANS) simulations, Large Eddy Simulation (LES), and Direct Numerical Simulation (DNS). The predictions of the RANS and LES simulations are validated with the lattice Boltzmann method (LBM)–based DNS at particle Reynolds number (Re _p) of 600. The RANS and LES simulations can predict the velocity, strain rate, and vorticity with a reasonable accuracy. Due to the dominance of enhanced wall-function treatment, the turbulence characteristics predicted by the ε-based models are found to be in a good agreement with the DNS. The ω-based models under-predicted the turbulence quantities by several orders of magnitude due to their inadequacy in handling strongly wall-dominated flows at low Re _p. Using the DNS performed at different Re _p, we also show that the onset of turbulence occurs between (Formula presented.).