Species concentration at the flow exit

May 22, 2005, 01:06

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.

May 22, 2005, 03:31

I have the same question........

May 23, 2005, 23:15

I get the same problem. How do I solve this? Can I use outflow? then what is the flow rate weighting gonna be?

May 24, 2005, 14:21

No knowledge of perticular multispecies flow. However, would "OUTFLOW" boundary condition where you don't need to specify anything help? -US

May 26, 2005, 06:16

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.

May 28, 2005, 07:24

Hai,

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

help me please.

May 22, 2005, 01:06	Species concentration at the flow exit	#1
Kavitha Guest Posts: n/a	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.

May 22, 2005, 03:31	Re: Species concentration at the flow exit	#2
yhpcgame Guest Posts: n/a	I have the same question........

May 23, 2005, 23:15	Re: Species concentration at the flow exit	#3
kyung Guest Posts: n/a	I get the same problem. How do I solve this? Can I use outflow? then what is the flow rate weighting gonna be?

May 24, 2005, 14:21	Re: Species concentration at the flow exit	#4
us Guest Posts: n/a	No knowledge of perticular multispecies flow. However, would "OUTFLOW" boundary condition where you don't need to specify anything help? -US

May 26, 2005, 06:16	Re: Species concentration at the flow exit	#5
Shiju G,Thomas Guest Posts: n/a	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.

May 28, 2005, 07:24	Re: Species concentration at the flow exit	#6
SIVAKUMAR Guest Posts: n/a	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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