Numerical Modeling of the Performance of High Flow DMAs to Classify Sub-2 nm Particles


While there are several computational studies on differential mobility analyzers (DMA), there is none for high flow DMA to classify nanoparticles less than 3 nm. A specific design of a high flow DMA, a half mini DMA, is investigated to predict its performance through numerical modeling in the incompressible flow regime. The governing equations for flow field, electric field and aerosol transport are solved using COMSOL 5.3. The transfer function of the half mini DMA is compared with that of a nano DMA (TSI 3085). The results show that both the height of the transfer function and resolution (R) of the half mini DMA are much better than those of nano DMA in sub-2 nm particle size range. Finally, the transfer function of half mini DMA is evaluated for different values of aerosol flow rate to the sheath flow rate (q/Q). Comparison of the simulated transfer function with existing models from Knutson—Whitby and Stolzenburg is also elucidated. It is found that the former model overestimates the resolution; whereas the latter is close to the simulation results for q/Q above 0.067. This work provides a useful method to study the flow regimes and transfer function of a high flow DMA.


Civil, Architectural and Environmental Engineering


The work was supported by a grant from the National Science Foundation, SusChEM: Ultrafine Particle Formation in Advanced Low Carbon Combustion Processes; CBET 1705864. Huang Zhang was supported by the Natural Science Foundation of Beijing [Grant No. 3184051].

Keywords and Phrases

Aerosols; Atmospheric movements; Electric fields; Incompressible flow; Numerical models; Particle size; Aerosol flow; Aerosol transport; Computational studies; Differential mobility analyzers; Flow regimes; Governing equations; Particle size ranges; Sheath flows; Transfer functions; Adiabaticity; Aerosol; Air; Air temperature; Article; Boundary layer; Calculation; Comparative study; Flow; Flow rate; Particle size; Priority journal; Kihong Park

International Standard Serial Number (ISSN)

0278-6826; 1521-7388

Document Type

Article - Journal

Document Version


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© 2019 American Association for Aerosol Research, All rights reserved.

Publication Date

01 Jan 2019