On the apparent viscosity of a fluidized bed

L. G. Gibilaro, K. Gallucci, R. Di Felice, P. Pagliai

Research output: Contribution to journalArticlepeer-review

58 Citations (Scopus)


The fluid-dynamic analogy of a typical spherical particle in a fluidized bed as the same particle suspended under terminal conditions in a pseudo-fluid (composed of the fluid and all the other suspended particles) is shown to yield predictive estimates for the apparent viscosity of fluidized beds, in good quantitative agreement with reported experimental measurements for particle concentrations of up to ∼ 40 %. For higher concentrations the predictions fall progressively below measured values, leading to order-of-magnitude underestimates for dense beds at close to minimum fluidization conditions. This latter phenomenon might be ascribable to the dominance, under these conditions, of particle-particle interactions. At high particle concentrations, these would give rise to the observed phenomenon of liquid- and gas-fluidized bed apparent viscosities approaching very similar values, and gas pressure having no influence at all.

Original languageEnglish
Pages (from-to)294-300
Number of pages7
JournalChemical Engineering Science
Issue number1-2
Publication statusPublished - Jan 2007


  • Apparent viscosity
  • Fluidization
  • Pseudo-fluid

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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