Validation of Particle-Laden Turbulent Flow Simulations Including Turbulence Modulation

Abstract

The objective of the present numerical study is the validation of wall-bounded, turbulent particle-laden air flow simulations for a wide range of flow and particle parameters (i.e., flow and particle Reynolds numbers, Stokes number, particle-to-fluid density ratio, ratio of particle diameter to turbulent length scale) covering the one-, two- and four-way coupling regimes. The applied computational fluid dynamics (CFD) model follows the Eulerian two-fluid approach in a Reynolds-Averaged Navier–Stokes (RANS) context and is based on the kinetic theory of granular flow (KTGF) for closures concerning the particulate phase. The fluid turbulence is modeled applying a low-Reynolds-number k–epsilon turbulence model. The main focus is put on the modeling of turbulence coupling between the fluid and the particle phase. Different from common practice, the choice of a model accounting for turbulence modulation is made dependent on the prevailing coupling regime. For the case of four-way coupling, a new modulation model is suggested that well predicts turbulence augmentation and attenuation. The predictive capabilities of the present approach are evaluated by comparing simulation results to experimental benchmark data of various pipe and channel flows. Very good agreement with reference data is obtained for the mean flow and turbulence profiles of both phases.