Simulation of multilayer particle resuspension in an obstructed channel flow

The present work deals with the multilayer resuspension of solid aerosol particles off a multilayer deposit exposed to a sudden gas flow increase. The heavy detachment of particles spans a wide range of industrial and non-industrial applications. It is used extensively in applications dealing with the resuspension of dust by wind, the resuspension of particles in ventilation ducts and the resuspension of radioactive graphite particles in high temperature reactors. A new numerical approach is suggested to simulate the particle resuspension off a multilayer deposit initially at rest in the cavity of horizontal obstructed turbulent channel flow. The present resuspension model is based on alternating iterations of a Large Eddy Simulation (LES) for the gas flow and of a Discrete Element Method (DEM) for the particle detachment. The combination of LES and DEM simulates the effect of a sudden increase in the turbulent gas flow on the topology of the granular interface, i.e. the surface separating the multilayer deposit from the turbulent gas phase. After tuning two parameters of a simple cluster re-entrainment criterion, results show good agreements with experimental data performed on-site. Both the shape and the wall roughness of the granular interface are predicted with a good level of accuracy. Findings from this study also confirm that the friction velocity is a major resuspension agent.