Modelling particle dispersion in three dimensional turbulent duct flow using CFD

Résumé

To reduce the potential health effects of exposure to aerosol particles, it is important to use an effective ventilation system. The main objective of this study was to investigate the effects of the duct aspect ratio (α), Reynolds number (Re) and particle diameter (dp) on the particles behaviour and their deposition in order to select the most effective ventilation scenario. Computational Fluid Dynamic (CFD) was used to predict the airflow pattern and particle behaviour. Code-Saturne was chosen as the CFD software. Particle dispersion and depositions were modelled by an Eulerian-Lagrangian approach. A mathematical model based on the Reynolds Averaged Navier-Stocks equations was chosen to simulate the airflow. The numerical results of airflow simulations obtained by Code-Saturne were compared and validated against numerical results and empirical equations available in the literature. To validate the Code-Saturne capability to predict the particle deposition, the nondimensional deposition velocity of particles with 0.1 < dp < 10 μmin a 2D turbulent channel was obtained by Code-Saturne and was compared with empirical results. Also the percentage of the particles deposited on the channel walls calculated from simulation results was compared with the one obtained by a correlation available in the literature. To analyze the simulation results and select the most effective ventilation, the percentage of the deposited particles on the duct surfaces was calculated from the average concentration of particles at different distances from the duct inlet. It was concluded that for a given particle size, depositions can be reduced by increasing the Reynolds number. It was also found that itis beneficial to use a duct with larger aspect ratio to reduce the particle deposition.

Date	22 juil. 2016
langue originale	Anglais américain
Établissement diplômant	École de technologie supérieure
Superviseur	François Morency (Directeur(-trice)) & Stéphane Hallé (Codirecteur(-trice))