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Old   August 6, 2012, 03:33
Default Help needed in modelling a liquid-solid fluidized bed
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Jovan
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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

Last edited by Jovan10; August 6, 2012 at 03:37. Reason: Addition of information
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Old   August 6, 2012, 10:40
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Quote:
Originally Posted by Jovan10 View Post
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 ?
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Old   August 6, 2012, 11:03
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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.
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Old   August 6, 2012, 12:55
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Quote:
Originally Posted by Jovan10 View Post
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... )
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Old   August 6, 2012, 21:47
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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.
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Old   August 7, 2012, 06:20
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Originally Posted by Jovan10 View Post
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.
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Old   August 14, 2012, 12:22
Default CFD MODELING IN L-S FLUIDIZED BED PROJECT ,particularly in sof
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Quote:
Originally Posted by Jovan10 View Post
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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