Numerical study of the fine particle deposition behaviors on three-dimensional random rough walls

Abstract

The collision and adhesion between the micron-sized particles and the wall play decisive roles in the particle deposition process. Therefore, the effect of wall roughness on the gas-solid two-phase flow should not have been neglected. In this paper, the Reynolds stress model together with the discrete particle model were employed to quantitatively study the fine particle deposition behaviors on three-dimensional random rough walls. The classical Weierstrass-Mandelbrot function was adopted to establish a model that can reflect the intrinsic characteristics of surface roughness. It is found that the turbulence kinetic energy in the near-wall regions of the rough wall is obviously stronger than that of the smooth wall, leading to an increase of 1–2 orders of magnitude in the deposition rate of small particles. Moreover, the slopes with different angles on the uneven wall endow the larger particles with an enhanced rebound effect. Furthermore, the airflow velocity exhibits multiple effects in increasing the kinetic energy of particles, enhancing the rebound effect, and improving the turbulent kinetic energy near the wall. This work not only broadens the research scope of particle deposition, but also provides technical references for the design of ventilation and dust removal pipelines.