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Optimization of Deposition of Micro- and Nano Particles in Filters and Porous Media

Banihashemi Tehrani, Mostafa | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: English
  3. Document No: 47061 (58)
  4. University: Sharif University of Technology, International Campus, Kish Island
  5. Department: Science and Engineering
  6. Advisor(s): Moosavi, Ali; Sadrhosseini, Hani
  7. Abstract:
  8. This study is aimed at simulation of the flow of air and aerosol particles through a single square fibrous filter media made up of micro fiber as well as the importance and effect of different fiber’s cross-sectional shapes and arrangements on particle deposition and filtration efficiency. An understanding of the role of changing the laminar flow regime from laminar vortex shedding "(Re"=100" and Re"=200")" to subcritical flow "(Re"=1000")" developed for the first case. The study deals with parallel and staggered multi-fibrous filter media with circular, elliptical, and equilateral triangular micro fiber’s cross-sectional shape of the transient laminar vortex shedding flow "(Re"=200")" . Typically, 4000 particles were injected into the flow at the moment of wakes completely formed behind the fibers. The average time of simulation was 40 seconds in almost the cases. The procedure of finding the optimum number of particles is thoroughly discussed. The study also copes with modeling particle deposition (due to Drag force, Brownian diffusion, and Saffman lift force) and tracking particles with Lagrangian technique. By computing the air flow field and the traces of airborne particles in 2-D virtual geometries that present the internal microstructure of fibrous filter media, capture efficiency of micro-fiber filters are mocked and validated with the available numerical studies for the case of a single square cylinder in a filter. The results show that changing the flow regime can increase the collection efficiency drastically and parallel circular multi-fibrous filter with parameters of the third type is the optimum choice for fine particles
  9. Keywords:
  10. Optimization ; Filters ; Laminar Flow ; Air Particulate Matter ; Particles Deposition

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