Turbulent gas‐particle flow in vertical risers
Authors:
- 1 February 1994
- journal article
- fluid mechanics-and-transport-phenomena
- Published by Wiley in AIChE Journal
- Vol. 40 (2) , 215-228
Abstract
Many experimental studies on the cross‐sectional distribution of particles in vertical risers have revealed marked segregation of particles. These flows are inherently unsteady with large fluctuations in suspension density. In this article, we have analyzed the time‐smoothed equations for the motion of dense suspensions to demonstrate the role of these fluctuations on the occurrence of segregation. It is shown that the particles will congregate in regions where the kinetic energy of fluctuations associated with the particles is small. In the context of transport of small particles such as FCC, a simplified model based on the mixture velocity can be constructed. A speculative K‐ϵ model based on this velocity is analyzed to illustrate the extent of segregation of particles afforded by unsteady fluctuations.Keywords
This publication has 36 references indexed in Scilit:
- Instability of unbounded uniform granular shear flowJournal of Fluid Mechanics, 1992
- Bubble formation in dense fluidized bedsPhysics of Fluids A: Fluid Dynamics, 1991
- A thermodynamical formulation for dispersed multiphase turbulent flows—1International Journal of Multiphase Flow, 1990
- Gas‐particle flow in a vertical pipe with particle‐particle interactionsAIChE Journal, 1989
- An investigation into heat transfer in circulating fluidized bedsInternational Journal of Heat and Mass Transfer, 1987
- Turbulence models for near-wall and low Reynolds number flows - A reviewAIAA Journal, 1985
- Mechanisms of choking and entrainmentPowder Technology, 1982
- X-Ray Diffraction from Polymers with Mesomorphic Order1978
- On the Deposition of Small Particles From Turbulent StreamsJournal of Heat Transfer, 1970
- Experimental Determination of Statistical Properties of Two-Phase Turbulent MotionJournal of Basic Engineering, 1960