Evaluating turbulence models to predict the particle deposition in curved ducts

This study aims to evaluate the capability of eddy-viscosity and Reynolds stress models to describe the particle deposition efficiency of gas-solid turbulent flow in a square-sectioned curved duct using the Eulerian-Lagrangian approach. The air flows with a Reynolds number of 40,000 through a 90-deg bend of 0.08 m hydraulic diameter and a curvature ratio of 4. One cloud with 100,000 monodispersed particles of 2,500 kg/m3 density and particle diameter up to 100 μm was injected at once with the same local fluid velocity near the bend inlet and tracked until all the non-deposited particles crossed the bend outlet. Three Reynolds Averaged Navier-Stokes turbulence models were evaluated: two eddy-viscosity models (the Shear Stress Transport k-ω and the v2f models) and one Reynolds stress model (the Reynolds Stress Model of Launder, Reece, and Rodi). These turbulence models were compared in terms of mean gas-phase velocity profiles and particle deposition efficiency. The results showed that the eddy-viscosity models produced lower deviations as well as the Reynolds stress model regarding the gas-phase at the bend outlet with errors in the order of 10%. In addition, the Reynolds Stress Model of Launder, Reece, and Rodi performed better to reproduce the particle deposition efficiencies for the Stokes number between 0.1 and 3.