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Title: Particle filter based on thermophoretic deposition from natural convection flow

Abstract

We present an analysis of particle migration in a natural convection flow between parallel plates and within the annulus of concentric tubes. The flow channel is vertically oriented with one surface maintained at a higher temperature than the other. Particle migration is dominated by advection in the vertical direction and thermophoresis in the horizontal direction. From scale analysis it is demonstrated that particles are completely removed from air flowing through the channel if its length exceeds L[sub c] = (b[sup 4]g/24K[nu][sup 2]), where b is the width of the channel, g is the acceleration of gravity, K is a thermophoretic coefficient of order 0.5, and [nu] is the kinematic viscosity of air. Precise predictions of particle removal efficiency as a function of system parameters are obtained by numerical solution of the governing equations. Based on the model results, it appears feasible to develop a practical filter for removing smoke particles from a smoldering cigarette in an ashtray by using natural convection in combination with thermophoresis. 22 refs., 8 figs., 1 tab.

Authors:
;  [1];  [2]
  1. Univ. of California, Berkeley, CA (United States)
  2. Lawrence Berkeley Lab., CA (United States)
Publication Date:
OSTI Identifier:
7301185
Resource Type:
Journal Article
Journal Name:
Aerosol Science and Technology; (United States)
Additional Journal Information:
Journal Volume: 20:3; Journal ID: ISSN 0278-6826
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; FILTRATION; MATHEMATICAL MODELS; SMOKES; AIR POLLUTION ABATEMENT; CONVECTION; FILTERS; INDOOR AIR POLLUTION; NUMERICAL ANALYSIS; PLATES; THERMOPHORESIS; TOBACCO PRODUCTS; TUBES; AEROSOLS; AIR POLLUTION; COLLOIDS; DISPERSIONS; ENERGY TRANSFER; HEAT TRANSFER; MASS TRANSFER; MATHEMATICS; POLLUTION; POLLUTION ABATEMENT; RESIDUES; SEPARATION PROCESSES; SOLS; 420400* - Engineering- Heat Transfer & Fluid Flow; 420200 - Engineering- Facilities, Equipment, & Techniques; 990200 - Mathematics & Computers

Citation Formats

Sasse, A G.B.M., Nazaroff, W W, and Gadgil, A J. Particle filter based on thermophoretic deposition from natural convection flow. United States: N. p., 1994. Web. doi:10.1080/02786829408959679.
Sasse, A G.B.M., Nazaroff, W W, & Gadgil, A J. Particle filter based on thermophoretic deposition from natural convection flow. United States. https://doi.org/10.1080/02786829408959679
Sasse, A G.B.M., Nazaroff, W W, and Gadgil, A J. 1994. "Particle filter based on thermophoretic deposition from natural convection flow". United States. https://doi.org/10.1080/02786829408959679.
@article{osti_7301185,
title = {Particle filter based on thermophoretic deposition from natural convection flow},
author = {Sasse, A G.B.M. and Nazaroff, W W and Gadgil, A J},
abstractNote = {We present an analysis of particle migration in a natural convection flow between parallel plates and within the annulus of concentric tubes. The flow channel is vertically oriented with one surface maintained at a higher temperature than the other. Particle migration is dominated by advection in the vertical direction and thermophoresis in the horizontal direction. From scale analysis it is demonstrated that particles are completely removed from air flowing through the channel if its length exceeds L[sub c] = (b[sup 4]g/24K[nu][sup 2]), where b is the width of the channel, g is the acceleration of gravity, K is a thermophoretic coefficient of order 0.5, and [nu] is the kinematic viscosity of air. Precise predictions of particle removal efficiency as a function of system parameters are obtained by numerical solution of the governing equations. Based on the model results, it appears feasible to develop a practical filter for removing smoke particles from a smoldering cigarette in an ashtray by using natural convection in combination with thermophoresis. 22 refs., 8 figs., 1 tab.},
doi = {10.1080/02786829408959679},
url = {https://www.osti.gov/biblio/7301185}, journal = {Aerosol Science and Technology; (United States)},
issn = {0278-6826},
number = ,
volume = 20:3,
place = {United States},
year = {Fri Apr 01 00:00:00 EST 1994},
month = {Fri Apr 01 00:00:00 EST 1994}
}