Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-18T20:41:01.954Z Has data issue: false hasContentIssue false
  • English
  • Français

Measurements of the mean force on a particle near a boundary in turbulent flow

Published online by Cambridge University Press:  21 April 2006

D. Hall
D. Hall
Affiliation:
CEGB Berkeley Nuclear Laboratories, Berkeley, Gloucestershire GL13 9PB, UK
Get access Rights & Permissions [Opens in a new window]

Abstract

The transport of particles through gaseous systems is controlled by three factors: their arrival to the surface; whether or not they bounce upon impact; and when (if ever) they are resuspended from the surface. One of the parameters required in determining whether or not a particle is suspended is the lift force acting on the particle. We demonstrate that the fluid lift forces acting on particles as small as 1 μm in diameter can be modelled by particles of several mm in diameter. However, the forces involved in modelling such small particles are around 10−8 N, which is several orders of magnitude smaller than reported in published measurements of fluid lift forces. A system to determine such lift forces has been developed and is described. Measurements of the mean force acting on particles on both rough and smooth surfaces are presented.

The data recorded here for the mean fluid lift force on a sphere on a smooth surface are in good agreement with the relationship \[ F^{+} = (20.90\pm 1.57)(a^{+})^{2.31\pm 0.02}, \] where F+ is the non-dimensional force and a+ the non-dimensional particle radius scaled on fluid-boundary-layer parameters. It was observed that surface roughness can change the force by up to a factor of six.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 187 , February 1988 , pp. 451 - 466
Copyright
© 1988 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bretherton, F. P. 1962 J. Fluid Mech. 14, 284–304.
British Standard 1042: Part 2A 1973 Method for the Measurement of Fluid Flow in Pipes. London: British Standards Institution.
Cleaver, J. W. & Yates, B. 1973 J. Colloid Interface Sci. 44, 464–474.
Goren, S. L. 1970 J. Fluid Mech. 41, 619–625.
Hall, D. 1982 CEGB Rep. TPRD/B/0102/N82.
Hall, D. 1984 CEGB Rep. TPRD/B/0516/N84.
Halow, J. S. 1973 Chem. Engng Sci. 28, 1–12.
Kay, J. M. & Nedderman, R. M. 1974 Fluid Mechanics and Heat Transfer, 3rd edn, p. 186. Cambridge University Press.
Leighton, D. & Acrivos, A. 1985 Z. Angew. Math. Phys. 36, 174–178.
O'Neill, M. E. 1968 Chem. Engng Sci. 23, 1293–1298.
Pirie, M. A. M. 1978 CEGB Rep. RD/B/N4227.
Reeks, M. W., Reed, J. & Hall, D. 1987 On the resuspension of small particles by a turbulent flow. J. Phys. D (accepted for publication).Google Scholar
Saffman, P. G. 1965 J. Fluid Mech. 22, 385–400 (and Corrigendum 31, 1968, 624).
Willetts, B. B. & Murray, C. G. 1981 J. Fluid Mech. 105, 487–505.