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Old   November 22, 2010, 11:23
Question Total mass flow
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Enio Carpi
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Hi Folks

I'm simulating a chamber pumpdown using a getter. The pumpdown speed depends on the total mass sorbed by the getter (I have the model for that).

What would be the variable for the cumulative mass flow through an outlet? Or would it be possible to integrate over time?

thx for the help
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Old   November 22, 2010, 17:00
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You could do a numerical integration via a CEL expression. Not sure on the variable though - I have no knowledge in this area.
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Old   November 22, 2010, 18:29
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Glenn Horrocks
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Sorry, but no. You cannot do time integrals in CEL. If you have to do time integrals you will need to do it in fortran.
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Old   November 22, 2010, 18:57
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So CFX does not have an internal time value that can be used/addressed?
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Old   November 22, 2010, 19:10
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Yes, CFX does have a time value. But CEL values do not persist between time steps so there is no way to accumulate over time. You could make a fortran CEL function to do the accumulation over time and normal CEL to do everything else. This is not too hard to do.
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Old   November 23, 2010, 06:41
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Enio Carpi
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Thanks for the comments. So, it seems I'm stuck here. I'll work on something. Thank you again
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Old   November 24, 2010, 12:59
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So fa rthe only solution is to use "mass()@domain". The total mass out of the domain is initial mass - mass()@domain. It seems to work. Now I just need the folks from SAES to send me some data.

Take care
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