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-   -   Species concentration at the flow exit (https://www.cfd-online.com/Forums/fluent/36733-species-concentration-flow-exit.html)

Kavitha May 22, 2005 02:06

Species concentration at the flow exit
 
Hi, I do species conservation modeling in Fluent 6.2.

I write UDFs for each of these species using DEFINE_SOURCE macro which I hook to the sources in Fluid panel.

But when it comes to the fluid exit ( I assign a pressure-outlet at this boundary) Fluent asks me for species concentration at this boundary,which I dont know and expect Fluent to do it for me.Given that I know inlet species concentration, how should i overcome this?

Should I write a UDF using DEFINE_PROFILE macro that calculates the species concentration (using C_YI(c,t,i)) at this boundary? Will this work?

Please help,

Kavitha.

yhpcgame May 22, 2005 04:31

Re: Species concentration at the flow exit
 
I have the same question........

kyung May 24, 2005 00:15

Re: Species concentration at the flow exit
 
I get the same problem. How do I solve this? Can I use outflow? then what is the flow rate weighting gonna be?

us May 24, 2005 15:21

Re: Species concentration at the flow exit
 
No knowledge of perticular multispecies flow. However, would "OUTFLOW" boundary condition where you don't need to specify anything help? -US

Shiju G,Thomas May 26, 2005 07:16

Re: Species concentration at the flow exit
 
I think fluent asks only for backflow species concentration on a pressure outlet.I have not yet used Fluent 6.2 but have used 6.1.

SIVAKUMAR May 28, 2005 08:24

Re: Species concentration at the flow exit
 
Hai,

please give me some idea to write udf for combustion of solid fuel. bcz i'm struggling with this problem.

help me please.



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