AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
A New Instrument to Classify Particles by Their Aerodynamic Size
Farzan Tavakoli, Jonathan Symonds, JASON OLFERT, University of Alberta
Abstract Number: 121 Working Group: Instrumentation and Methods
Abstract A new aerosol particle classifier, the Aerodynamic Aerosol Classifier (AAC), is presented. Aerosol classifiers are used to produce a monodisperse aerosol, that is, they select a narrow range of particles from a larger distribution of particles. The instrument uses centrifugal force and a sheath flow between two concentric rotating cylinders to produce a monodisperse aerosol classified by aerodynamic diameter. The instrument does not rely on particle charging so it produces a true monodisperse aerosol without classifying multiply-charged particles like other classifiers. This work reports the theoretical and experimental results of the new instrument.
A diffusion model and a non-diffusion model have been used to predict the performance of the AAC. From the analytical model the normalized transfer function was obtained as a function of the particle relaxation time and the particle aerodynamic diameter. The transfer function has been studied for different flow rates. The analytical model of the AAC does not include particle diffusion. Thus, the diffusion model has been developed by solving the convective-diffusion equation for the AAC which has been solved using the Crank-Nicolson method. The diffusion effect has been studied for different particle density and particle size. Also, the experimental results will be compared to the theoretical models.