NUMERICAL-SIMULATION OF AIR-FLOW AND INERTIAL DEPOSITION OF PARTICLES IN A BIFURCATING CHANNEL OF SQUARE CROSS-SECTION

Abstract

Air flow pattern and inertial deposition of particles in a bifurcating channel of square cross section have been studied numerically. The Navier-Stokes equation for the air flow are solved in an Eulerian grid system first, and then the particle trajectories are tracked in a Lagrangian coordinate system. The three dimensional flow pattern in a bifurcating airway is analysed, and the role played by the secondary flow is studied. Geometry of the channel, radius of curvature at the bend comer, bifurcation angle, particle size, average flow velocity and the velocity profile at the inlet are the important parameters considered in the present study. The roundness at the bend comer and the intensity of secondary flow were found to play an important role in both the air flow pattern and the particle deposition. The characteristics of particle deposition could be well explained by the flow characteristics. Under certain conditions, the present results are in good agreement with the experimental data in the literature, and the discrepancy existing under other conditions could also be explained by considering the characteristics of the secondary flow .