Estimation of dispersion coefficient in a solid-liquid fluidised bed system

Md Shakhaoath Khan, Ifsana Karim, Geoffrey Evans, Elham Doroodchi, JB Joshi, Subhasish Mitra

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Particle dispersion behaviour in a solid liquid fluidised system leads to interesting outcomes such as mixing and segregation which are often quantified by an empirical dispersion coefficient. The present study aims at providing a better estimation of particle dispersion behaviour from a fundamental definition analogous to diffusion coefficient. By tracking a tracer particle using high speed image analysis, fluctuating velocity components (Vi/) were determined in a solid-liquid fluidised bed comprising glass particles (dS = 8 mm, ρS = 2230 kg m−3) and water as a fluidising medium. Both inter-particle and particle-wall collisions were determined from the time varying jerk data. The particle mean-free path (λ) was then estimated as a distance between two successive peaks in the jerk profile. Finally, dispersion efficient D was computed based on the product of λ and V. Estimated dispersion coefficients were compared with the available correlations and reasonable agreement was obtained.
Original languageEnglish
Pages (from-to)560-576
Number of pages17
JournalPowder Technology
Publication statusPublished - Sept 2020


  • Fluidisation
  • Particle technology
  • Multiphase flow
  • Dispersion coefficient

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