Numerical study on particle deposition in rough channels with large-scale irregular roughness

We studied particle deposition in rough channels, using the W-M fractal function to characterize a large-scale irregular surface with a root-mean-square roughness of 0.5mm. The flow was numerically investigated by Reynolds stress model, and the particles were tracked by a Lagrangian particle model. An analysis of the flow field in a rough channel shows that the roughness enhances the max flow velocity and the pressure drop in the channel. It induces several eddies in the concave of the rough surface. We also compared particle deposition in a rough channel with particle deposition in a smooth channel. This comparison shows that the roughness significantly enhances the particle deposition of small particles, but the enhancement decreases with the increase of particle size. Moreover, the particle deposition ratio decreases with increasing flow velocity.