Numerical Simulation of Particle Deposition in Turbulent Duct Flows

Abstract

Particle deposition in fully developed turbulent square duct flows is simulated using large eddy simulation combined with Lagrangian particle tracking under conditions of one-way coupling, with the particle equation of motion solved with Stokes drag, lift, buoyancy, and gravitational force terms. The flow considered has bulk Re = 83 K, with three particle sizes 50, 100, 500 μm. Results obtained for the fluid phase show good agreement with the experimental data and the predictions of direct numerical simulations. The predictions for particles demonstrate that the turbulent-driven secondary flows within the duct plays an important role in the particle deposition process. Under the secondary flow effect, most particles tend to deposit close to the corners of the duct floor. It is shown that the flow particle size, drag force, shear-induced lift force, and gravity affect the particle deposition. The particle deposition velocity is found to increase with particle size, with the tendency for deposition at the duct corners increasing with the variable. From dynamic analysis, gravity most significantly affects particle deposition in the vertical direction, while drag force dominates particle deposition in the horizontal direction. The effect of the lift force becomes more significant when a particle is large or close to the duct wall. The lift force is also a contributing factor causing particles to accumulate at the corners of the duct.