A Numerical Calculation of the Transfer Function of the Fluted Centrifugal Particle Mass Analyzer

Abstract

A new particle mass classifier called the Fluted Centrifugal Particle Mass Analyzer (CPMA) is presented and compared to the Aerosol Particle Mass (APM) Analyzer and the Couette CPMA. These particle mass classifiers use electrostatic and centrifugal forces to classify particles by their mass-to-charge ratio. The Fluted CPMA uses reversed ‘scooped’ sections to create a stable system of forces in the radial direction but not in the angular direction. The stable forces in the radial direction improve the transfer function of the classifier. A Lagrangian model (neglecting diffusion) of the Fluted CPMA is derived from which the transfer function of the classifier is found. The model shows that, like the APM and Couette CPMA, a single non-dimensional number determines the shape of the transfer function. The comparison of the classifiers shows that the Couette CPMA outperforms the Fluted CPMA and APM. However, the Fluted CPMA outperforms the APM over a wide range of operating conditions and may be easier to manuf...