A random-walk simulation of thermophoretic particle deposition in a turbulent boundary layer

A random-walk simulation of thermophoretic particle deposition in a turbulent boundary layer Deposition of log-normally distributed particles in isothermal and heated turbulent boundary layers is studied via Lagrangian random-walk simulations. The velocity and temperature fields and the thermophoretic force are considered to be Gaussian random fields. Their mean values were obtained from law-of-the wall relations (velocity and temperature) and from a Knudsen number dependent expression for the thermophoretic force; their rms fluctuations were determined by polynomial fits to experimental data. The effect of aerodynamic (Saffman) lift and crossing trajectories on particle deposition is examined. We find that for particle sizes in the diffusion–impaction deposition regime the mean thermophoretic force gives the dominant contribution to total particle deposition, whereas the thermophoretic fluctuating force has only a limited contribution. The effect of lift and crossing trajectories on deposition is small with respect to the effect of the mean thermophoretic force, comparable to the effect of the fluctuating thermophoretic force, and dependent on the mean particle size. The effect of crossing trajectories (in the presence of lift) is small in isothermal flows. A limited number of particle runs was found sufficient to obtain steady-state total deposition velocities in simulations of log-normal particle-size distributions. Simulation results are compared to experimental data: we find reasonable agreement for total deposition velocity, deposited mass, and axial location of maximum deposition. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png International Journal of Multiphase Flow Elsevier

A random-walk simulation of thermophoretic particle deposition in a turbulent boundary layer

Loading next page...
 
/lp/elsevier/a-random-walk-simulation-of-thermophoretic-particle-deposition-in-a-DFhzFjbd41
Publisher
Elsevier
Copyright
Copyright © 2000 Elsevier Science Ltd
ISSN
0301-9322
DOI
10.1016/S0301-9322(99)00092-0
Publisher site
See Article on Publisher Site

Abstract

Deposition of log-normally distributed particles in isothermal and heated turbulent boundary layers is studied via Lagrangian random-walk simulations. The velocity and temperature fields and the thermophoretic force are considered to be Gaussian random fields. Their mean values were obtained from law-of-the wall relations (velocity and temperature) and from a Knudsen number dependent expression for the thermophoretic force; their rms fluctuations were determined by polynomial fits to experimental data. The effect of aerodynamic (Saffman) lift and crossing trajectories on particle deposition is examined. We find that for particle sizes in the diffusion–impaction deposition regime the mean thermophoretic force gives the dominant contribution to total particle deposition, whereas the thermophoretic fluctuating force has only a limited contribution. The effect of lift and crossing trajectories on deposition is small with respect to the effect of the mean thermophoretic force, comparable to the effect of the fluctuating thermophoretic force, and dependent on the mean particle size. The effect of crossing trajectories (in the presence of lift) is small in isothermal flows. A limited number of particle runs was found sufficient to obtain steady-state total deposition velocities in simulations of log-normal particle-size distributions. Simulation results are compared to experimental data: we find reasonable agreement for total deposition velocity, deposited mass, and axial location of maximum deposition.

Journal

International Journal of Multiphase FlowElsevier

Published: Aug 1, 2000

References

  • Turbulent dispersion of particle using eddy interaction models
    Graham, D.I.; James, P.W.
  • Analytical approach to derive the fine particle dispersion properties inherent in numerical particle trajectory models
    Lin, C.-H.; Chang, L.-F.W.
  • Thermophoretic deposition of small particles in a direct numerical simulation of turbulent channel flow
    Thakurta, D.G.; Chen, M.; McLaughlin, J.B.; Kontomaris, K.
  • On the role of the lift force in turbulence simulations of particle deposition
    Wang, Q.; Squires, K.D.; Chen, M.; McLaughlin, J.B.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create folders to
organize your research

Export folders, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off