Influences of various vortex structures on the dispersion and deposition of small ash particles

Numerical simulations were conducted to study the influences of various vortex structures on the dispersion and deposition processes of 1 μm to 10 μm diameter fly ash particles on the rear side surface of a boiler tube. Turbulent gas flow was simulated with detached eddy simulation (DES) method and vortex structures in the wakes were modeled. Results suggested that the motions of particles in the near wake region were controlled by different vortex structures, and the impact efficiency and deposit concentration on the rear side surface induced by the vortices varied considerably at different velocities. The results of volume percentages distribution of the deposited particles with various diameters simulated were in good agreement with the experimental data.