A1 Journal article (refereed), original research

Flow characteristics of circulating fluidized beds near terminal velocity: Eulerian model of a lab-scale apparatus


Publication Details
Authors: Jalali Payman, Nikku Markku, Ritvanen Jouni, Hyppänen Timo
Publisher: Elsevier
Publication year: 2018
Language: English
Related Journal or Series Information: Powder Technology
Volume number: 339
Start page: 569
End page: 584
Number of pages: 16
ISSN: 0032-5910
eISSN: 1873-328X
JUFO-Level of this publication: 1
Open Access: Not an Open Access publication

Abstract

The hydrodynamic characteristics of gas and solid flows in circulating fluidized

beds (CFB) can also influence other processes. To investigate various features of flows and

mass circulation in CFB, a computational study was performed with the support of

experiments measured in the riser section of a lab-scale apparatus of CFB. The fluidization

velocity was slightly below the terminal velocity to avoid a major solid entrainment. The

Gidaspow’s model was used to calculate the gas-solid drag term in computational cells,

which led to a good agreement with the experimental data of pressure profile. The gas inlet

conditions were shown to be uninfluential in the hydrodynamics of major part of the upper

riser, and the solid inlet (return) imposed non-uniformity in radial and tangential directions.

The time-averaged profiles presented a good indication of the wall layer formation. The rate

of circulating mass in the riser from simulations was obtained 25 percent lower than the

experiments. The coefficient of restitution was a parameter with notable influence on the

hydrodynamics and the present study suggests that a variable coefficient of restitution in

Eulerian models can describe the behavior of CFB system more accurately.


Last updated on 2019-13-03 at 12:00