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Research Abstracts Online
January 2008 - March 2009

University of Minnesota Twin Cities
Institute of Technology
Department of Mechanical Engineering

PI: Peter H. McMurry, Associate Fellow

Numerical Analysis of Particle Transport Through Various Aerosol Instruments

Numerical simulations of the flow field and particle transport in an aerosol instrument can provide useful information on the performance of the instrument and help to optimize its design. These researchers used software package FLUENT and its supporting software to calculate flow and particle motion in various aerosol instruments, such as an aerodynamic lens system, a Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS) and, in a new application, the Cluster-Chemical Ionization Mass Spectrometer (Cluster-CIMS).

The aerodynamics lens system can focus particles into a collimated narrow beam for applications such as particle delivery in mass spectrometer and micro-fabrications. The researchers are developing particle trajectory simulations that incorporate the repulsion force due to space charge, rather than assuming that the particles are electrically neutral.

The TDCIMS can measure the chemical composition of particles as small as 4 nm. In this instrument, aerosols are charged and then collected by electrostratic deposition on a metal filament. The challenges are to design proper parameters such as flowrate, filament length, and electric field, and to calculate the corresponding particle collection efficiency.

In the inlet of the Cluster-CIMS, fresh nucleated clusters are charged and their trajectories controlled by electrostatic force. The challenges are to design proper parameters such as the inlet configuration, the gas flow rate, and the electric field, and to calculate the corresponding cluster sampling efficiency. The cluster-free flow field and the electric field are solved at different conditions. Then a Lagrangian approach can be used to track the clusters and to determine the sampling efficiency.

Group Members

Modi Chen, Graduate Student
Raganathan Gopalakrishnan, Graduate Student
Dave Hanson, Faculty Collaborator
Jingkun Jiang, Research Associate
Chongman Kim, Graduate Student
Chongai Kuang, Graduate Student
Jacob H. Scheckman, Research Associate
Mari Titcombe, Graduate Student
Xiaoliang Wang, TSI Incorporated, Shoreview, Minnesota
Brent Williams, Research Associate