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-   -   Mass fraction via Cel file at outlet (http://www.cfd-online.com/Forums/cfx/19563-mass-fraction-via-cel-file-outlet.html)

Jens April 6, 2003 15:53

Mass fraction via Cel file at outlet
 
Hi,

I have a problem when I would like to calculate the averaged mass fraction of a mixture at thought the outlet.

The case is mixing two fluids in a large tank. The fluid is extracted using an outlet with a pump and then injected at another possition in the tank.

How can I calculate the averaged mass fraction thought the outlet area and then use this to specify the mass fraction at the inlet ???

Thanks.

Regards

Jens

Robin April 7, 2003 10:49

Re: Mass fraction via Cel file at outlet
 
Hi Jens,

Assuming a multicomponent fluid called "Fluid", a component named "componentA", and you are measuring flow at a boundary named "Outlet", the following expression will do the trick:

massFlowAve(Fluid.componentA.mf)@Outlet

Regards, Robin

windhair April 7, 2003 11:54

Re: Mass fraction via Cel file at outlet
 
In CFX 4, you can write a output file using Command file:
:>PATCH DATA PATCH NAME 'OUTLET' FILE NAME 'OUTLETAVERAGE.DAT' AVERAGE SPEICES1 EACH TIME STEP

Jens April 28, 2003 09:14

Re: Mass fraction via Cel file at outlet
 
Hi

I am having some problem setting the mass fraction using the method you describe.

I keep getting error:

"and then error found at item: massFlowAve

unrecognised name

Error processing expression: Mass Fraction = scAn error has occurred in cfx5solve: "

I define the massfraction in the cel file as:

sc = massFlowAve(Mixture.SodiumChlorite.mf)@outlettop

Can you give me any hints on what the problem is ???

Thanks

Regards

Jens



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