Numerical Simulation of Particle Dispersion and Deposition in Turbulent Square Duct Flows

Large eddy simulation was applied to investigate particle dispersion and deposition in turbulent square duct flows at Reb=250 k with three particle size considered(50μm, 100μm, 500 μm). Simulation results for single phase agree well with the experimental data. Results obtained for particle field show that the turbulence-driven secondary flow appeared in square ducts plays a role in particle dispersion and deposition. Particle dispersion is found to decrease with particle size. For small particles, the secondary flow dominates their dispersion resulting in a relatively uniform distribution, and they tend to deposit on the central regions of duct floor under the comprehensive function of gravity. For large particles, gravity dominates their deposition and they tend to accumulate in the corner regions of duct due to the effect of secondary flow. The dynamic analysis indicates that it is the drag force that dominates the behavior of small particles, with large particles' motion mainly determined by gravity. © 2019, Science Press. All right reserved.