Improved CFD transport and boundary conditions models for low-inertia particles

Abstract

This paper presents a simple aerosol transport model together with specific boundary conditions, which can be easily implemented in a CFD code in order to calculate particulate concentrations at any point in a dilute gas-particle flow. The low-inertia of the particles considered (aerodynamic diameter less than 50 μm) enables a simplified Eulerian model to be proposed (“diffusion–inertia”), which consists of a single transport equation of aerosol concentration considering sedimentation, deviation from fluid streamlines and migration effects. Specific study of deposition has made it possible to develop a new boundary condition approach at smooth walls based on semi-empirical deposition laws, which determines the particle flux towards the wall in the boundary layer for any deposition regime and any surface orientation from the computed CFD variables. These transport and deposition models can be used for a very wide range of geometries (from elementary devices to rooms of various volumes), in industrial applications dealing with particulate contamination. In this paper, the models are validated for simple geometries, by comparing published data to the CFD results.