Prediction of Particle Deposition in Rectangular Ventilation Ducts

The accurate prediction of particle deposition in ventilation ducts is an important step in estimating the exposure risk of building occupants to particulate matter. In this paper a mathematical model for predicting particle deposition in rectangular ventilation duct flow by incorporating existing theoretical and experimental results is presented. The influences of Brownian diffusion, turbulent diffusion and gravity on particle deposition are considered. Model equations are presented for calculating the deposition velocities on vertical surfaces and the floor and ceiling of ducts. Results of calculations are compared with the experimental results of Sippola (2002) and a good agreement of the deposition velocity of particles on the floor is shown. For the deposition velocity of particles on the vertical walls, the results obtained by this model have the same tendency as those observed by Sippola (2002). In the case of ceiling deposition, this model did not match the observation in some cases.