AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Effect of Wall Shear Stress on Aerodynamic Particle Resuspension
Patrick Fillingham, KALYAN KOTTAPALLI, Xiaolin Zhan, Igor Novosselov, Harikrishna Murali, University of Washington
Abstract Number: 697 Working Group: Aerosol Physics
Abstract Particle resuspension from surfaces due to aerodynamic forces is of interest in various applications, including trace material detection, surface cleaning and the study of the fate of radioactive particles. Particle removal from surfaces depends on the balance of forces acting on the particle; in an aerodynamic resuspension scenario, the structure of the boundary layer is especially important. Wall shear stress can be used to define the boundary layer flow at the surface. We combine the use of particle removal data from a controlled flow cell experiment with Computational Fluid Dynamics (CFD) modeling to study the effect of wall shear stress on particle resuspension in the constant wall shear stress environment of the flow cell.
In addition, a computational model is developed for the wall shear stress from high-pressure impinging jets. An experimental setup using an oblique rectangular slit nozzle impinging jet is used for particle resuspension study. This experimental setup uses pressures ranging from 5 to 20 psig for the resuspension of silica glass microsphere particles on a glass substrate ranging in size from 8 to 50 microns. The test substrate is subjected to a range of wall shear stress from 10-500 pascals by varying the jet pressure and standoff distance. The experimental removal efficiency data together with the CFD models yields a correlation between wall shear stress and particle removal. This correlation allows for the prediction of particle resuspension in a variety of aerodynamic removal scenarios.