Effect of various parameters on bubble formation due to a single jet pulse in two-dimensional coarse-particle fluidized beds

2012 ◽  
Vol 23 (3) ◽  
pp. 398-405 ◽  
Author(s):  
Liang-wan Rong ◽  
Jie-min Zhan ◽  
Chun-liang Wu
Keyword(s):  
Fluidized Beds ◽  
Bubble Formation ◽  
Coarse Particle ◽  
Two Dimensional ◽  
Single Jet

Bubbling Flow in a Multi-Jet Fluidized Bed

2020 ◽  
Author(s):  
Liwu Wang ◽  
Sijun Zhang
Keyword(s):  
Fluidized Bed ◽  
Fluidized Beds ◽  
Fluid Model ◽  
Bubble Formation ◽  
Model Parameters ◽  
Phase Flow ◽  
Two Phase ◽  
Single Jet ◽  
Two Fluid Model ◽  
Two Fluid

Abstract This work concerns with numerical simulation of dense gas-particle two-phase flow in a fluidized bed in the framework of two-fluid model, where attention is given to the bubble formation in a single-jet and multi-jet fluidized beds. The kinetic theory is implemented in the model to avoid empirically determined model parameters. The validity of the approach is confirmed through the comparison between the computed results and the measurements in the literature. The results show that increasing the number of jets results in different behavior in bubble formation and the flow pattern in a multi-jet bed is much more complex than that in a single-jet bed.

Investigation of Fluid and Coarse-Particle Dynamics in a Two-Dimensional Spouted Bed

2004 ◽  
Vol 27 (9) ◽  
pp. 971-981 ◽  
Author(s):  
T. Swasdisevi ◽  
W. Tanthapanichakoon ◽  
T. Charinpanitkul ◽  
T. Kawaguchi ◽  
T. Tanaka ◽  
...  
Keyword(s):  
Particle Dynamics ◽  
Coarse Particle ◽  
Two Dimensional ◽  
Spouted Bed

Fully developed travelling wave solutions and bubble formation in fluidized beds

1997 ◽  
Vol 334 ◽  
pp. 157-188 ◽  
Author(s):  
B. J. GLASSER ◽  
I. G. KEVREKIDIS ◽  
S. SUNDARESAN
Keyword(s):  
Numerical Integration ◽  
Fluidized Beds ◽  
Bubble Formation ◽  
Travelling Wave ◽  
Numerical Continuation ◽  
Travelling Wave Solutions ◽  
Wave Solutions ◽  
Averaged Equations ◽  
Wide Range ◽  
Direct Numerical Integration

It is well known that most gas fluidized beds of particles bubble, while most liquid fluidized beds do not. It was shown by Anderson, Sundaresan & Jackson (1995), through direct numerical integration of the volume-averaged equations of motion for the fluid and particles, that this distinction is indeed accounted for by these equations, coupled with simple, physically credible closure relations for the stresses and interphase drag. The aim of the present study is to investigate how the model equations afford this distinction and deduce an approximate criterion for separating bubbling and non-bubbling systems. To this end, we have computed, making use of numerical continuation techniques as well as bifurcation theory, the one- and two-dimensional travelling wave solutions of the volume-averaged equations for a wide range of parameter values, and examined the evolution of these travelling wave solutions through direct numerical integration. It is demonstrated that whether bubbles form or not is dictated by the value of Ω = (ρsv3t/Ag) 1/2, where ρs is the density of particles, vt is the terminal settling velocity of an isolated particle, g is acceleration due to gravity and A is a measure of the particle phase viscosity. When Ω is large (> ∼ 30), bubbles develop easily. It is then suggested that a natural scale for A is ρsvtdp so that Ω2 is simply a Froude number.

Obstacle-induced voids in two-dimensional gas fluidized beds

1994 ◽  
Vol 49 (2) ◽  
pp. 233-244 ◽  
Author(s):  
G.R. Duursma ◽  
J.R. Ockendon ◽  
S.J. Hogan
Keyword(s):  
Fluidized Beds ◽  
Two Dimensional ◽  
Gas Fluidized Beds

Heat Transfer in Large Particle Bubbling Fluidized Beds

1984 ◽  
Vol 106 (1) ◽  
pp. 85-90 ◽  
Author(s):  
R. L. Adams
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Residence Time ◽  
Large Particle ◽  
Fluidized Beds ◽  
Horizontal Tube ◽  
Two Dimensional ◽  
Phase Contact ◽  
Emulsion Phase ◽  
Bubble Phase

The potential use of fluidized bed combustion of coal as a means of meeting air quality standards with high-sulfur fuels has motivated the development of theoretical models of heat transfer in large particle gas fluidized beds. Models of the separate contributions of emulsion and bubble phase heat transfer have been developed by Adams and Welty [1] and Adams [2, 3, 4] and have been substantiated by experimental data for a horizontal tube immersed in a two-dimensional cold bed obtained by Catipovic [5, 6]. The consolidation of these models to predict local and overall time-average heat transfer to immersed surfaces requires information regarding emulsion phase residence time and bubble phase contact fraction for the particular geometry of interest. The analytical procedure to consolidate these models is outlined in the present work, then applied to the case of a horizontal tube immersed in a two-dimensional atmospheric pressure cold bed. Measurements of emulsion phase residence time and bubble phase contact fraction obtained by Catipovic [5] are used in the calculations for particle diameters ranging from 1.3 to 6 mm. The results agree favorably with experimental data and further substantiate the fundamental assumptions of the model.

Asymmetric two-dimensional jet efflux from a channel

1977 ◽  
Vol 80 (1) ◽  
pp. 1-15
Author(s):  
C. Samuel Martin
Keyword(s):  
Experimental Data ◽  
Analytical Approach ◽  
Two Dimensional ◽  
Asymmetric Case ◽  
Hodograph Plane ◽  
Single Jet ◽  
Von Mises ◽  
Two Jets ◽  
Direct Use ◽  
Special Case

Irrotational flow of two-dimensional jets from a channel is treated without direct use of a logarithmic hodograph plane. An analytical approach is introduced for solving the general problem of two jets issuing from a channel with three end plates. Numerical values of the contraction coefficient and the angle of jet deflexion are obtained for the special case where the two jets are located symmetrically and all the end plates are in line. Limiting cases of the resulting single-jet problem are the symmetric and asymmetric configurations solved by von Mises. Results for the asymmetric case improve upon the theoretical values reported by von Mises, and compare favourably with existing experimental data.

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