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-   -   Different combustion models in two domains-how? (http://www.cfd-online.com/Forums/cfx/24616-different-combustion-models-two-domains-how.html)

tony October 2, 2007 10:08

Different combustion models in two domains-how?
 
Hi, all,

I want to simulate a gas burner which consists of venturi and burner. Fuel and 50% of air enter the venturi and goes to burner ports. In reality, combustion is ignited by a spark near the burner ports (outer side of the burner).

I setup two domains: inner burner and outer burner. inner burner is where the mixing happens and should be a cold flow without combustion. Inner burner and outer burner domains are connected with GGI fluid-fluid interface at ports.

The problem is that CFX only allow one same combustion model in these two domains. I can't even specify different parameter values for these two domains. So combustion occurs in the inner burner domain, which is not correct.

Anyone has similar experience? Can you guide me on this?

Thanks.

Tony

opaque October 2, 2007 11:03

Re: Different combustion models in two domains-how
 
Dear Tony,

Changing physical models across domain is not for the faint of heart. What models are you trying to activate in the different domains?, or what parameters do you want to make different on each domain.

Opaque


tony October 2, 2007 12:09

Re: Different combustion models in two domains-how
 
Hi, Opaque,

Thank you for your reply.

What I want to model is fuel and air first mix in the venturi and then combust at burner ports. However, with EDM combustion model, the mixture combusts right after they enter the venturi. So I want to specify two different values of combustion model parameters like extinction temperature for two domains so that combustion is not allowed in the venturi(extinction temperature=5000K), but allowed in the outer domain(300K).

Please give some advice.

Thanks.


opaque October 2, 2007 13:13

Re: Different combustion models in two domains-how
 
Dear Tony,

If you turn off the constant physics checks in CFX-Pre, you can set different values the EDM parameters in each domain.

If you are using ANSYS CFX 11.0, this can be done in the Edit/Options/Pre/Automatic Physics Update

Opaque.



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