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Claudia March 31, 2010 12:54

droplet absorption diameter

I have a subdomain in which I want to remove particles from the domain. I know that I can use the "Absortion diameter". But now my question:

The absorption diameter depends on the gas velocity, is it possible to implement this dependency? I tried to do something like

absorption diameter = function of Velocity w,

but the following error occurs:

"Velocity w is not available for use in this term"

Does anyone has an idea?

Thanks in advance

ghorrocks March 31, 2010 18:07

The message is quite clear - you can't make absorption diameter a function of W velocity. Some variables can only be constants or functions of a subset of variables and I think you have found one. If you really need to do this talk to CFX support and they may be able to find a work around for you.

a.m. April 1, 2010 02:15

try to create an expression in cfx pre like absorption diameter = f(velocity w), then use this expression in subdomain.

in expression you should use direct difinition, e.g.
"massflowave(Velocity W)@inlet*1[s]"
it means than your absorption diameter will be equal average velocity w in inlet BC

Claudia April 1, 2010 07:30

Thanks, Glenn for your answer. So I have to tell the support about it and I hope they will find a workaround.

ghorrocks April 2, 2010 06:14

Yes, that's right. There will be a reason the absorption diameter cannot be set as a function of velocity. If you bypass the check, it may or may not affect your results - so talk to them and try to find out.

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