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-   -   Help needed in modelling a liquid-solid fluidized bed (http://www.cfd-online.com/Forums/main/105661-help-needed-modelling-liquid-solid-fluidized-bed.html)

 Jovan10 August 6, 2012 03:33

Help needed in modelling a liquid-solid fluidized bed

Hi all,

I am currently working on a University project which requires me to model a liquid-solid fluidized bed, 0.5m in diameter and 3m tall. I have no problems with geometry or meshing but am struggling with the addition of the solid phase.

My major problem is how to define the solid phase, i.e. initial bed height and packing. If there is some one to guide me through the process involved in designing this system, it would be greatly appreciated. If anymore information is required, please don't hesitate to ask me.

Cheers

 leflix August 6, 2012 10:40

Quote:
 Originally Posted by Jovan10 (Post 375536) Hi all, I am currently working on a University project which requires me to model a liquid-solid fluidized bed, 0.5m in diameter and 3m tall. I have no problems with geometry or meshing but am struggling with the addition of the solid phase. My major problem is how to define the solid phase, i.e. initial bed height and packing. If there is some one to guide me through the process involved in designing this system, it would be greatly appreciated. If anymore information is required, please don't hesitate to ask me. Cheers

what kind of code do you use for that ?

 Jovan10 August 6, 2012 11:03

I am using Ansys CFX for modelling purposes. I have defined volume fractions for the solid and liquid phases. But being a complete novice at CFD modelling, I'm unsure of how to proceed from there.

The main issue is that I haven't been able to model the initial bed height etc.

 leflix August 6, 2012 12:55

Quote:
 Originally Posted by Jovan10 (Post 375618) I am using Ansys CFX for modelling purposes. I have defined volume fractions for the solid and liquid phases.
volume fration for each phase are unknowns of your problem. In fact there is only one unknown because they are related by eps_sol + eps_liq = 1. So I don't know what you mean when you say that you have defined them?
You just have to set the initial conditions for these variables. After the program should compute the time and spatial evolution of the volume fractions

Quote:
 But being a complete novice at CFD modelling, I'm unsure of how to proceed from there. The main issue is that I haven't been able to model the initial bed height etc.
the initial bed height of you bed is an input data of your problem. It's up to you to decide what is the height of your bed according your problem specifications.
(number of particles,diameter of these particles, geometry of your column... )

 Jovan10 August 6, 2012 21:47

Hi leflix,

Thanks for your help. This is how I have defined the volume fractions for the problem:

Solid:
IniVoFSES = 0.35 #initial volume fraction#
SESVoF = IniVoFSES*step((yinitial-y)/1[m])
yinitial = 0.25 #initial bed height#

Liquid
WaterVoF = 1-VoFSES

Is this the way I am meant to go about defining the initial height of the bed? As I want it to be at 0.25m, also I do not know the number of particles, but the mean diameter of the particles is roughly 100microns.

Thanks again.

 leflix August 7, 2012 06:20

Quote:
 Originally Posted by Jovan10 (Post 375691) Is this the way I am meant to go about defining the initial height of the bed? As I want it to be at 0.25m, also I do not know the number of particles, but the mean diameter of the particles is roughly 100microns. Thanks again.
I do not know the specifications of CFX but I guess yes. Apparently it uses a Euler-Euler method. You just have to set the height of the bed you want.

 kavithailanagai August 14, 2012 12:22

CFD MODELING IN L-S FLUIDIZED BED PROJECT ,particularly in sof

Quote:
 Originally Posted by Jovan10 (Post 375536) Hi all, I am currently working on a University project which requires me to model a liquid-solid fluidized bed, 0.5m in diameter and 3m tall. I have no problems with geometry or meshing but am struggling with the addition of the solid phase. My major problem is how to define the solid phase, i.e. initial bed height and packing. If there is some one to guide me through the process involved in designing this system, it would be greatly appreciated. If anymore information is required, please don't hesitate to ask me. Cheers
I am also a M.Tech student working with CFD modeling in L_S fluidized bed particularly in software COMSOL,do u know anybody did or doing project same as me,pls send informations

Thank you

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