Transition velocities in the riser of a circulating fluidized bed

N. Balasubramanian, C. Srinivasakannan, C. Ahmed Basha

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


We attempted to study the hydrodynamics and flow regime transitions in a circulating fluidized bed (CFB). In conventional gas-solids fluidization, the flow regimes include the fixed bed, bubbling fluidization and turbulent fluidization, in which the regimes mainly depend on the gas velocity. However, in a CFB, the flow regime depends on both the solids circulation rate and gas velocity. The flow regimes in a CFB include the high-velocity fluidized bed and pneumatic conveying. Experiments were conducted in a column of 0.052 m internal diameter and 1.2 m long covering a wide range of operating conditions. The transport velocity was estimated by emptying time and extrapolation techniques. It was noticed from the present experimental observations that Geldart B-type particles move more or less as individual particles, while Geldart A-type particles have a tendency to form clusters. Empirical correlations have been proposed for the transport velocity Utr and the chocking velocity Uch. A qualitative map of different flow regimes of a gas-solid fluidized bed has been proposed based transition velocities.

Original languageBritish English
Pages (from-to)247-260
Number of pages14
JournalAdvanced Powder Technology
Issue number3
StatePublished - 2005


  • Chocking velocity
  • Circulating fluidized bed
  • Flow regime transition
  • Transport velocity


Dive into the research topics of 'Transition velocities in the riser of a circulating fluidized bed'. Together they form a unique fingerprint.

Cite this