Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-20T22:23:50.209Z Has data issue: false hasContentIssue false
  • English
  • Français

An experimental study of the motion of concentrated suspensions in two-dimensional channel flow. Part 2. Bidisperse systems

Published online by Cambridge University Press:  25 May 1998

M. K. LYON  and
L. G. LEAL
M. K. LYON
Affiliation:
University of California, Santa Barbara, Department of Chemical Engineering, Santa Barbara, CA 93106, USA Present address: Department of Mechanical Engineering and Applied Mechanics, University of Michigan, Ann Arbor, MI 48109-2121, USA.
L. G. LEAL
Affiliation:
University of California, Santa Barbara, Department of Chemical Engineering, Santa Barbara, CA 93106, USA
Get access Rights & Permissions [Opens in a new window]

Abstract

In this paper we report experimental velocity and concentration profiles for suspensions possessing a bidisperse distribution of particle size undergoing pressure-driven flow through a parallel-wall channel. In addition to the overall concentration distributions determined by implementing the modified laser Doppler velocimetry method described in Part 1 (Lyon & Leal 1998), concentration profiles for the particles of each size were measured by sampling the position of marked tracer particles across 60% of the channel gap. Non-uniform overall particle concentration distributions and blunted velocity profiles were found at bulk particle volume fractions of 0.30 and 0.40, which were equal to the monodisperse data of Part 1, within experimental uncertainty. The large-particle concentration profiles were non-uniform down to a large-particle bulk volume fraction of 0.075, while non-uniform distributions of the small particles were only found when the volume fraction of small particles in the bulk was greater than or equal to 0.20. Experiments in which at least half the suspended particulate volume was occupied by large particles revealed enrichment of the large particles in the centreline region of the channel. This size segregation was found to increase as the total number of suspended particles decreased. Finally, the data from experiments in which a uniform small-particle concentration profile was measured were compared with suspension balance model (McTigue & Jenkins 1992; Nott & Brady 1994) predictions for parameter values that corresponded only to the large particles. While close agreement with the large-particle concentration profiles was found, this comparison also reflected the fact that the small particles bring the suspension viscosity to a regime that is more sensitive to the particle concentration, rather than simply providing an increment in background viscosity to the suspending liquid.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 363 , 25 May 1998 , pp. 57 - 77
Copyright
© 1998 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.)