AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Experimental Study of Mini-Plate Differential Mobility Analyzers (Mini-plate DMAs) with Expansion/Contraction Flow Channel
QIAOLING LIU, Da-Ren Chen, Virginia Commonwealth University
Abstract Number: 425 Working Group: Instrumentation and Methods
Abstract To conduct the tempo-spatial ultrafine particle monitoring either on the ground/unmanned aerial vehicles, or even at the personal level, miniature, cost-effective ultrafine particle sizers based on the particle electrical mobility technique, i.e., mini-plate DMA, has recently been developed and its performance has been evaluated in our laboratory. To further extend the measurable particle size range of a mini-plate DMA without increasing its overall size much, two prototype mini-plate DMAs, one with the expansion flow channel and the other with the contraction flow channel, were designed constructed and tested in this study.
Two studied prototypes are in the plate-to-plate configuration, where polydisperse aerosol and clean sheath flows travel in the spacing (of 1/16”) between two parallel metal plates. One of two plates is on a High DC voltage and the other on the electrical ground to establish an electrical field for particle classification/sizing. The overall particle classification length in the two studied DMAs is 2 1/16”. In the expansion flow version the width of particle classification channel in the DMA is the same width as the length of aerosol entrance slit in the first half of the channel and the channel width is increased in the last half of the flow channel. The length of aerosol exit slit is designed the same as that of the entrance slit. The opposite flow channel geometry with the identical dimensions as the expansion flow channel DMA was designed in the contraction flow version of mini-plate DMA. Tandem DMA (TDMA) experiments were performed to evaluate the performance of two prototypes at different particle sizes and aerosol-to-sheath flowrate ratios. The piecewise-linear deconvolution scheme (Li et al., 2006) was applied to obtain the real transfer function of studied mini-plate DMAs. The detail result of this study will be presented in this talk.