Numerical Study of the Performance of a Magnetic Passive Aerosol Sampler
QISHENG OU, Ta-Chi Hsiao, Pengfei Gao, Da-Ren Chen
Washington University in St. Louis
Abstract Number: 630
Working Group: Control Technology
Last modified: April 4, 2011
A multi-domain “quarter-sized” magnetic passive aerosol sampler (MPAS) was developed by NIOSH for the evaluation of particle penetration through protective ensembles. Studies on the MPAS performance, conducted in NIOSH, has shown that by using multi-domain magnets the sampler is able to collect a measureable mass of submicron magnetic particles in a short period of time comparing to conventional passive samplers; to significantly improve the uniformity of particle deposition on the sample substrate; and to confine the sampling of aerosol at the sampler opening to minimize the interference resulted from the sampling of aerosol beyond the opening space.
In this study a comprehensive numerical model was constructed to calculate the performance of the MPAS. In this model, the flow and the magnetic fields were calculated by a numerical finite element method using COMSOL Multiphysics; while the particle trajectory and deposition on the sampling substrate were modeled by the particle tracking method, solving the Langevin equation via Matlab. The normalized particle deposition velocity/sampling efficiency of MPAS was then calculated based on the numerical result. Upon the model verification detail investigation for the effects of particle size, and external flow direction and velocity on the collection efficiency of the MPAS was further performed. The detail result of this investigation will be presented in this talk.