Dynamics of fluidized suspensions of spheres of finite size

P. Singh, D. D. Joseph

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

We propose a one-dimensional theory of fluidized suspensions in which the fluids and solids momentum equations are decoupled by using a new mean drag law for the particles. Our mean drag law differs from the standard drag laws frequently used in that the drag is assumed to depend on the area fraction rather than the number density. For a monodisperse suspension of spheres of radius R, the area fraction and the number density are related by a simple geometrical construction that takes into account the area of intersection of the spheres with a plane perpendicular to the flow. For the linearized theory uniformly fluidized suspension is unstable but not Hadamard unstable. However, there is a distinguished set of marginally stable modes belonging to a countable set of blocked wave numbers α: α = 4.493 R, 7.7253 R, 10.904 R,... The nonlinear theory contains bounded solutions when a certain dimensionless "growth rate" parameter is below a critical value. The power spectrum of these bounded solutions is broad banded in both space and time, and is very low for the wave numbers that are marginally stable in the linear theory. These results agree with our experiments, as well as witht he previous experimental results from diffraction studies.

Original languageEnglish (US)
Pages (from-to)1-26
Number of pages26
JournalInternational Journal of Multiphase Flow
Volume21
Issue number1
DOIs
StatePublished - Jan 1995
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Physics and Astronomy(all)
  • Fluid Flow and Transfer Processes

Keywords

  • Hodamard instability
  • bounded solutions
  • bubbling instability
  • fluidized suspensions
  • particle phase theories
  • radial and area-averaged distributions

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