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-   -   OpenFOAM - Reverse flow occur while (https://www.cfd-online.com/Forums/openfoam-solving/183379-openfoam-reverse-flow-occur-while.html)

ozgunoglu February 2, 2017 17:15

OpenFOAM - Reverse flow occur while
 
Dear all,

I am trying to stabilize flame in Stagnation Point Reverse Flow Combustor (SPRF) using reactingFoam.

I ignited the flame using high temperature 1300 K fuel inlet then I am lowering to temperature to 330 K and expecting a continuous flame.

Actually, there is no problem about getting stable flame, however there seems a revers flow at the outlet which is fixed pressure boundary condition with a 101325 Pa.

The first thing I thought that existence of the low pressure products make the entire domain weaker than 101325 Pa outlet boundary condition.

How do you think that I can prevent reverse flow ?
What type of pressure boundary condition should I apply to the outlet?

I also attached pressure, temperature and Ux figures which shows the reverse flow at the outlet.

Thanks.

http://i65.tinypic.com/2h5jwo5.png
http://i64.tinypic.com/23h8w9l.png
http://i67.tinypic.com/2je729z.png

matejfor February 6, 2017 07:21

Hi,
the standard solution for outflow BC is to use inletOutlet BC.
It sets the zeroGradient for outflow situation and fixedValue for inflow situation.
You can use this one for velocity, temp and scalars to prescribe the fixed value if things go wrong.
http://www.openfoam.com/documentatio...d.html#details


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