A Model for Predicting Airborne Dust Concentrations within a Ventilated Airspace

Abstract

A random flight model is used to predict mean concentrations of 1μm diameter particles within mechanically ventilated airspace, an experimental section of a typical UK intensive livestock building. The model is used in conjunction with the statistical properties of air flow predicted by thek-ϵmodel, a standard computational fluid dynamics (CFD) model. The patterns of predicted mean particle concentrations are shown to be in accord wtih experimental findings. Particularly well predicted are the locations of maximum particle concentration and the shape of contours of constant particle concentration. The root mean square differences between predicted and measured normalized mean particle concentrations are 0·38 and 0·49, for two different locations of the particle source. These differences are shown to be 16% and 23% smaller than those obtained using a simple random flight model which is widely available within CFD packages.