A numerical study of the bubble induced pressure fluctuation in gas-fluidized beds

2017 ◽  
Vol 314 ◽  
pp. 387-399 ◽  
Author(s):  
Yuli Zhang ◽  
Rui Xiao ◽  
Mao Ye ◽  
Zhongmin Liu
Keyword(s):  
Pressure Fluctuation ◽  
Fluidized Beds ◽  
Numerical Study ◽  
Gas Fluidized Beds

Onset of cohesive behaviour in gas fluidized beds: a numerical study using DEM simulation

2001 ◽  
Vol 56 (14) ◽  
pp. 4433-4438 ◽  
Author(s):  
M.J Rhodes ◽  
X.S Wang ◽  
M Nguyen ◽  
P Stewart ◽  
K Liffman
Keyword(s):  
Fluidized Beds ◽  
Numerical Study ◽  
Dem Simulation ◽  
Gas Fluidized Beds

A numerical study on gas-fluidized beds of wet flexible fibers

2021 ◽  
pp. 117094
Author(s):  
Lixiang Zhong ◽  
Dandan Xu ◽  
Yiyang Jiang ◽  
Yu Guo
Keyword(s):  
Fluidized Beds ◽  
Numerical Study ◽  
Flexible Fibers ◽  
Gas Fluidized Beds

Expulsion of particles from a buoyant blob in a fluidized bed

1994 ◽  
Vol 278 ◽  
pp. 63-81 ◽  
Author(s):  
G. K. Batchelor ◽  
J. M. Nitsche
Keyword(s):  
Fluidized Bed ◽  
Fluidized Beds ◽  
Particle Concentration ◽  
Small Concentration ◽  
Numerical Calculations ◽  
Significant Feature ◽  
Average Particle ◽  
Remarkable Property ◽  
Gas Fluidized Beds ◽  
Secondary Instabilities

It is a significant feature of most gas-fluidized beds that they contain rising ‘bubbles’ of almost clear gas. The purpose of this paper is to account plausibly for this remarkable property first by supposing that primary and secondary instabilities of the fluidized bed generate compact regions of above-average or below-average particle concentration, and second by invoking a mechanism for the expulsion of particles from a buoyant compact blob of smaller particle concentration. We postulate that the rising of such an incipient bubble generates a toroidal circulation of the gas in the bubble, roughly like that in a drop of liquid rising through a second liquid of larger density, and that particles in the blob carried round by the fluid move on trajectories which ultimately cross the bubble boundary. Numerical calculations of particle trajectories for practical values of the relevant parameters show that a large percentage of particles, of such small concentration that they move independently, are expelled from a bubble in the time taken by it to rise through a distance of several bubble diameters.Similar calculations for a liquid-fluidized bed show that the expulsion mechanism is much weaker, as a consequence of the larger density and viscosity of a liquid, which is consistent with the absence of observations of relatively empty bubbles in liquid-fluidized beds.It is found to be possible, with the help of the Richardson-Zaki correlation, to adjust the results of these calculations so as to allow approximately for the effect of interaction of particles in a bubble in either a gas- or a liquid-fluidized bed. The interaction of particles at volume fractions of 20 or 30 % lengthens the expulsion times, although without changing the qualitative conclusions.

Experimental and numerical study of solids circulation in gas-vibro fluidized beds

2013 ◽  
Vol 248 ◽  
pp. 153-160 ◽  
Author(s):  
C. Zeilstra ◽  
M.A. van der Hoef ◽  
J.A.M. Kuipers
Keyword(s):  
Fluidized Beds ◽  
Numerical Study
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