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Jane February 19, 2008 00:51

Validation of CFD data
 
Can anyone advise on any available technique to validate CFD model for rotary dryer? I am interested in the knowing the gas & particle velocities. Likewise the particle size distribution . Of interest will be to see how to validate the temperature profile inside this dryer.

Glenn Horrocks February 19, 2008 17:33

Re: Validation of CFD data
 
Hi,

Technique 1: Stick some instruments in a rotary dryer. Take some measurements. Compare to CFD results.

Technique 2: Go to library. Do literature survey on rotary dryers. Hopefully find some good published results relevant to what you are doing. Compare to CFD results.

Glenn Horrocks

Jane February 19, 2008 19:34

Re: Validation of CFD data
 
It's so unfortunate that there is no CFD work on rotary dryers in the literature. As a result, there is no experimental data in this regard. These are my thoughts:

Can I use Particle Image Velocimetry to measure the velocity of the particles. Or I use Laser Doppler Anemometry? I am just interested in the flowfield.

CheeOnn February 20, 2008 09:56

Re: Validation of CFD data
 
It is possible to use PIV or LDA to capture the flow field provided you make the dryer casing as transparent in order the laser can pass thru.

Bart February 20, 2008 10:53

Re: Validation of CFD data
 
Jane,

A quick glance with google on rotary dryers has learned me that it is mainly about solids tumbling and colliding with each other and a flow (the drying gas) in between. I do not think you can do this with CFD alone. You might want to have a look at Discrete Element Modeling (see EDEM) in combination with CFD. The interaction of the solids bouncing around is not typicaly something you do with CFD. But I'm no expert on rotary driers (my wife is more into that).

Bart

Glenn Horrocks February 20, 2008 17:46

Re: Validation of CFD data
 
Hi,

Colliding particles is not currently handled in CFX but the rumour is it is being looked at for V12. If you want powerful particle interaction modelling you need to look at software like EDEM (http://www.dem-solutions.com/) I believe it can be coupled to CFX, not sure how I have never done it.

Glenn Horrocks

Glenn Horrocks February 20, 2008 17:48

Re: Validation of CFD data
 
Hi,

Yes, PIV or LDA can give you the particle motion. Bear in mind you are then measuring the particles, not the flow and that may mean you need to properly model the particle/fluid and possibly particle/particle interaction.

Glenn Horrocks

Bart February 21, 2008 06:18

Re: Validation of CFD data
 
Glenn,

EDEM can be coupled with Fluent (I've seen it) and I think at present also with CFX. We use EDEM (not coupled by the way).

Bart


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