Applied Scientific Research

, Volume 48, Issue 3–4, pp 315–328 | Cite as

Hydrodynamic scaling relationships for fluidisation

  • P. U. Foscolo
  • L. G. Gibilaro
  • R. Di Felice


The scaling rules for fluidisation are obtained from a closed formulation of the equations of change that incorporates a fluid dynamic mechanism for particle pressure. The rules are compatible with previous ones, based on formulations that omit particle pressure, thereby extending their validity to gas fluidised fine powders and liquid systems that display a region of stable homogeneous behaviour.


fluidisation scale-up particle pressure 



Archimedes number: Ar =gd ρ 3 ρ f 2 u f 2


drag coefficient


particle diameter, m


density number: De =ρfp


particle phase elastic modulus, Nm−2


fluid-particle interaction force, Nm−3


flow number: Fl =u/ut


Froude number: Fr =gdp/u t 2


gravitational field strength, N kg−1


characteristic length dimension, m


length number: Le =L/dp


exponent in Richardson-Zaki relationship


fluid and particle pressure, N m−2


Reynolds number: Re =utdpρff


time, s


fluid and particle velocities, ms−1


total volumetric flux, ms−1


volumetric flux of fluid at distributor, ms−1


terminal settling velocity of a single particle, ms−1




void fraction


minimum bubbling and minimum fluidisation void fraction


fluid viscosity, N sm−2


fluid and particle density, kg m−3


signifies a dimensionless variable


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Copyright information

© Kluwer Academic Publishers 1991

Authors and Affiliations

  • P. U. Foscolo
    • 1
  • L. G. Gibilaro
    • 2
  • R. Di Felice
    • 1
  1. 1.Dipartimento di Chimica, Ingegneria Chimica e MaterialiUniversità di l'AquilaL'AquilaItaly
  2. 2.Department of Chemical and Biochemical EngineeringUniversity College LondonLondonEngland

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