LARGE EDDY SIMULATIONS OF PARTICLE DEPOSITION IN A TURBULENT SQUARE DUCT FLOW

The deposition of heavy solid particles in a downward, fully developed turbulent square duct flow al Reτ = 360, based on average friction velocity and duct width, is studied using large eddy simulations. The continuous and the dispersed phases are treated using the Eulerian and Lagrangian approaches, respectively. A finite volume based second-order accurate fractional step scheme is used to integrate the incompressible form of the unsteady, three-dimensional Navier-Stokes equations on an 80×80×128 grid. A dynamic subgrid kinetic energy-model is used to account for the subgrid scales. The particle equation of motion includes drag, lift, and gravity Ibices and is integrated using the fourth-order accurate Runge-Kutta method, fable 1 lists the details of the particle properties. Three approaches are used in this work. First, simulations are carried out assuming that the particle-particle interactions are negligible and that the particles do not modify the fluid phase momentum (one-way coupling). Second, simulations are carried out for representative cases with the inclusion of particle-particle collisions as well as particle feedback effects on the fluid phase (four-way coupling). Third, collisions are neglected but the particle feedback effect is retained (two-way coupling) for a select case to determine if the observed trends are due to collisions or due to two-way coupling. Variation in the probability distribution function (PDF) of the deposition location with particle Stokes number is presented. The average stream wise and wall-normal deposition velocities are also presented. Collisions are seen to increase the deposition rates.