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Research Abstracts Online
January - December 2011

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University of Minnesota Twin Cities
College of Science and Engineering
Department of Mechanical Engineering

PI: David Y.H. Pui, Associate Fellow

Numerical Study of Particle Filtration

These researchers are using MSI resources for four projects. In the first, they are developing a model for the design of pleated filters with particle loading with the aid of numerical simulation. They are calculating particle deposition on filter media from the interaction of gas flow field and particle trajectory. The simulation will help to understand the performance of pleated filters with dust cake buildup and lead to new design criteria for this condition.

The second project is a numerical assessment of the effect of upstream flow non-uniformity to particle deposition pattern and filter performance under particle loading. The project aims to understand the flow field under non-uniform flow conditions and the particle transportation properties under it. This work will be important for filtration systems and filter design in practical applications.

The objective of the third project is to perform numerical simulations of airborne particle diffusion across protective garment fabrics under zero and low air-flow conditions. For low air-flow conditions, the flow field will be modeled using CFX. For both zero- and low-flow conditions, particle diffusion can be simulated by the heat transfer module based on the heat and mass transfer analogy. Transient thermal module in ANSYS workbench will be used for the zero-flow case.

The fourth project involves modeling the charging efficiency of nanoparticle agglomerates. The charging efficiency of aerosols plays a significant role in particle precipitation, filtration, electrical measurement, and many other applications. The charging study of agglomerates that have complicated structures is challenging. Charging efficiency is dependent on the particle properties such as the electrical capacitance, surface area, and possibly other parameters. Numerical calculation of the electrical capacitance may be carried out by a variational method that seeks to minimize the electrical potential energy. Difficulties in the calculations arise in the particle structure, polydispersity of the primary particles, and necking between the primary particles. After the electrical capacitance is computed, it can be combined with other parameters to give the charging efficiency.

Group Members

Christof Asbach, Institut für Energie- und Umwelttechnik (IUTA), Duisburg, Germany
Tsz Yan Ling, Graduate Student
Chaolong Qi, Research Associate
Weon Gyu Shin, Research Associate
Jimmy Jing Wang, Research Associate