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-   -   Boundary condition setting for non-premixed combustion using reactingFoam (http://www.cfd-online.com/Forums/openfoam/76360-boundary-condition-setting-non-premixed-combustion-using-reactingfoam.html)

skyopener May 23, 2010 22:55

Boundary condition setting for non-premixed combustion using reactingFoam
 
Hello, Foamers,
I am new with OpenFOAM .
I am trying to simulating turbulent jet combustion from Sandia.gov..and I have some problems on the setting of boundary condition. After having been tried many settings, I am lost. So I hope someone can help me, any hints would be appreciated!

Following is the simulation condition.
It is non-premixed combustion. So I use the reactingFoam solver.
So k-epsilon model is used to the turbulent flow.
It has 2 inlets and 1 outlet, one inlet is for the fuel, the other for coflow..
inlet1: H2/N2, width--2.285mm,velocity--107m/s,T--305k
coflow: Air, radius--288mm,velocity--3.5m/s,T--1045k
It is a 2-D geometry, the top is the outlet, vertical is the surround, the lower has two inlets.

so the boundary condition was setted as follow initially:
>----p
internalField uniform 1e+5;
boundaryField
{
nozzle
{
type zeroGradient;
}
coflow
{
type zeroGradient;
}
out
{
type fixedValue;
value uniform 1e+5;
}
surround
{
type zeroGradient;
}

frontAndBack
{
type empty;
}
>------------U
internalField uniform (0 0 0);
boundaryField
{
nozzle
{
type fixedValue;
value uniform (0 107 0);
}
coflow
{
type fixedValue;
value uniform (0 3.5 0);
}
out
{
type inletOutlet;
inletValue uniform (0 0 0);
value uniform (0 0 0);
}
surround
{
// type fixedValue;
//value uniform (0 0 0);
type zeroGradient;
}

frontAndBack
{
type empty;
}
>----------------T

internalField uniform 1045;



boundaryField


{


nozzle


{


type fixedValue;


value uniform 305;


}


coflow


{


type fixedValue;


value uniform 1045;


}



out


{


//type fixedValue;


//value uniform 800;


type zeroGradient;


}



surround


{


//type fixedValue;


//value uniform 800;


type zeroGradient;


}





frontAndBack


{


type empty;


}

>--------------N2

internalField uniform 0.745;



boundaryField


{


nozzle


{


type fixedValue;


value uniform 0.977;


}


coflow


{


type fixedValue;


value uniform 0.75;


}



out


{


type zeroGradient;


}



surround


{


type zeroGradient;


}





frontAndBack


{


type empty;


}

>------------------K

internalField uniform 1;



boundaryField


{


nozzle


{


type fixedValue;


value uniform 1;


}


out


{


type zeroGradient;


}


surround


{


type zeroGradient;


}


coflow


{


type fixedValue;


value uniform 1;


}



frontAndBack


{


type empty;


}

>-------------------------epsilon

internalField uniform 90;



boundaryField


{


nozzle


{


type fixedValue;


value uniform 90;


}


out


{


type zeroGradient;


}


surround


{


type zeroGradient;


}


coflow


{


type fixedValue;


value uniform 90;


}



frontAndBack


{


type empty;


}



These are the boundary condition settings


But the result is far away from the real world..


The problem must be focused on the boundary setting. Although many settings have been tried, the results are always terrible.


Could someone give me any hint?


Could some hearted person attach his similar cases setting or email it to me. The address is skyopener@sina.com


Great thanks to you.


Liang shi


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