Three-dimensional simulation of multilayer particle deposition in an obstructed channel flow

A large variety of systems are subject to slow and lengthy processes of solid aerosol particle deposition in turbulent flows. As a result of a long exposure to deposition, a multilayer particle bed eventually forms over time. Notable examples are the formation of multilayer deposits in ventilation ducts, in nuclear reactors or on earth surfaces subject to atmospheric sedimentation. Simulations are of great importance to predict the multilayer deposition of solid aerosol particles. Theoretical models are quite limited since their complexity rapidly increases when the flow becomes turbulent and the surface geometry complex. The present study proposes a new three-dimensional approach to reproduce the growth of a multilayer deposit in a turbulent obstructed channel flow at Reynolds number Re = 10,000. Computational Fluid Dynamics and Computational Granular Dynamics are brought together to simulate 4 h of real deposition. A detached eddy simulation is employed to predict particle deposition while self-organised criticality is employed to reproduce the slow growth of the multilayer deposit. The three dimensional shape of the multilayer deposit matches remarkably well the experimental data.