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Design, simulation, and characterization of a radial opposed migration ion and aerosol classifier (ROMIAC)

Mui, Wilton and Mai, Huajun and Downard, Andrew J. and Seinfeld, John H. and Flagan, Richard C. (2017) Design, simulation, and characterization of a radial opposed migration ion and aerosol classifier (ROMIAC). Aerosol Science and Technology, 51 (7). pp. 801-823. ISSN 0278-6826. doi:10.1080/02786826.2017.1315046.

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We present the design, simulation, and characterization of the radial opposed migration ion and aerosol classifier (ROMIAC), a compact differential electrical mobility classifier. We evaluate the performance of the ROMIAC using a combination of finite element modeling and experimental validation of two nearly identical instruments using tetra-alkyl ammonium halide mass standards and sodium chloride particles. Mobility and efficiency calibrations were performed over a wide range of particle diameters and flow rates to characterize ROMIAC performance under the range of anticipated operating conditions. The ROMIAC performs as designed, though performance deviates from that predicted using simplistic models of the instrument. The underlying causes of this non-ideal behavior are found through finite element simulations that predict the performance of the ROMIAC with greater accuracy than the simplistic models. It is concluded that analytical performance models based on idealized geometries, flows, and fields should not be relied on to make accurate a priori predictions about instrumental behavior if the actual geometry or fields deviate from the ideal assumptions. However, if such deviations are accurately captured, finite element simulations have the potential to predict instrumental performance. The present prototype of the ROMIAC maintains its resolution over nearly three orders of magnitude in particle mobility, obtaining sub-20 nm particle size distributions in a compact package with relatively low flow rate operation requirements.

Item Type:Article
Related URLs:
URLURL TypeDescription
Mui, Wilton0000-0003-3065-1296
Mai, Huajun0000-0002-0616-1986
Seinfeld, John H.0000-0003-1344-4068
Flagan, Richard C.0000-0001-5690-770X
Additional Information:© 2017 American Association for Aerosol Research. Received 5 June 2016. Accepted 1 February 2017. Accepted author version posted online: 04 Apr 2017. Published online: 04 Apr 2017. Editor: Jian Wang. The authors thank Daniel Thomas, Amanda Grantz, Ranganathan Gopalakrishnan, Paula Popescu, Johannes Leppä, and Natasha Hodas for helpful discussions. Andrew Metcalf and Xerxes López-Yglesias are acknowledged for their assistance with the particle trajectory simulations and LabView controls. This research was supported by National Science Foundation Grant No. CBET-1236909 and a National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469 (W.M.), and the Jacobs Institute for Molecular Engineering for Medicine (R.C.F. and A.J.D.).
Funding AgencyGrant Number
NSF Graduate Research FellowshipDGE-1144469
Jacobs Institute for Molecular Engineering for MedicineUNSPECIFIED
Issue or Number:7
Record Number:CaltechAUTHORS:20170515-102340363
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:77445
Deposited By: Ruth Sustaita
Deposited On:16 May 2017 02:45
Last Modified:15 Nov 2021 17:31

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