On the prediction of particle deposition in turbulent channel flow using large eddy simulation

Particle deposition in fully-developed turbulent channel flow has been examined using large eddy simulation (LES) of the incompressible Navier-Stokes equations. Calculations were performed at channel flow Reynolds numbers of 3,200 and 21,900 (based on centerline velocity and channel half width); subgrid-scale stresses were parameterized using the dynamic eddy viscosity model. Particle deposition rates obtained from the LES calculations are in reasonable agreement with the direct numerical simulation results of McLaughlin (1989). For particles with identical relaxation times scaled in wall units, deposition rates in the high Reynolds number channel were nearly identical to those in the low Reynolds number channel flow. Simulations performed using the Saffman lift force in the particle equation of motion were found to over-predict the dependence of the deposition rate on particle relaxation time. Use of forms for particle lift derived by Vasseur and Cox (1977) and Cherukat and McLaughlin (1994) yield deposition rates exhibiting a dependence on relaxation time in good agreement with experiments (τ⁺²). However, it is also found that neglect of the lift force altogether leads to a similar result.