Effects of the shape and height of artificial 2D roughness elements on deposition of nano and microparticles in the turbulent gas flow inside a horizontal channel

In this paper, deposition of the particles in turbulent incompressible gas flow inside a horizontal channel with different two-dimensional artificial roughness shapes and heights is studied. The Eulerian-Lagrangian method is used for numerical simulation of the particulate gas flow. The Reynolds stress model (RSM) with enhanced wall treatment is applied to simulate the anisotropic turbulence in the gas flow. The Lagrangian equation of the particles motion includes drag, gravity, Saffman lift, and Brownian forces. Discrete phase simulations are compared with the available correlations for a smooth channel to show the validation of the simulations. The results show that the rate of deposition for small particles is affected significantly by the flow pattern in the space between two roughness elements. For small particles (τ+<10), deposition of the particles depends on the v component of the gas velocity. Gravity force is assumed to be perpendicular to the main flow direction. For large particles (τ+>10), the gravity force is more effective on the deposition velocity.