AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Performance of a Prototype Radial Opposed Migration Ion/Aerosol Classifier (ROMIAC)
WILTON MUI, Andrew Downard, Daniel Thomas, Huajun Mai, Amanda Grantz, Jesse Beauchamp, John Seinfeld, Richard Flagan, California Institute of Technology
Abstract Number: 451 Working Group: Instrumentation and Methods
Abstract The radial opposed migration ion/aerosol classifier (ROMIAC) is a novel differential mobility analyzer that was designed for classification of sub-20 nm particles. Initial design simulations were based on 2-dimensional finite element and Monte-Carlo particle tracing simulations. Here we report on 3-dimensional, finite element simulations that that have been performed to explore particle transmission through the ROMIAC. The modeled performance of the ROMIAC is verified through mobility and transmission efficiency calibration measurements with two nominally identical ROMIACs in tandem classifier methods. The measurements were performed at non-diffusive resolving powers (R$_(nd)) ranging from 4 to 20 using 1 to 20 nm diameter tetra-alkyl ammonium halide ions and sodium chloride particles. Particle mobilities transmitted show direct relationships to the applied voltage and operating cross flow rate, while particle transmission efficiency is related to the operating resolution. Measured transmission efficiencies and resolution agreed well with modeled predictions, including observations of relative resolutions (R/R$_(nd)) that slightly exceed unity. Reasons for this seemingly counterintuitive performance will be discussed.