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-   -   Case of fixed inlet total pressure and fixed outlet static pressure (http://www.cfd-online.com/Forums/openfoam/116314-case-fixed-inlet-total-pressure-fixed-outlet-static-pressure.html)

 Sunxing April 16, 2013 23:30

Case of fixed inlet total pressure and fixed outlet static pressure

2 Attachment(s)
Hi foamers,

I want to simulate a turbine cascade case. The boundary conditions are:
1, inlet: fixed total pressure and total temperature
2, outlet: fixed static pressure.
This was one case calculated by fluent. Now I want to simulate it using OpenFOAM, however, I don't know which solver should I choose and how to set the initial and boundary conditions.
Do anyone have similar case or any suggestions?

Here is the calculating region:

 akashjangid September 7, 2013 02:49

Boundary condition.

Hello,

I have the same problem. I am doing simulations on stator blade. The boundary conditions are the same as by Sunxing
Inlet - total pressure - 411.8 kPa, total inlet temp 517.5 K
Outlet - static pressure 367 kPA

I am using rhosimplecfoam, but the results are not good, may be some problems with the boundary condition and initial condition, any suggestion for this ?
and how should i specify k, omega value IN PRESSURE BASED solver

Thanks

 Sunxing September 7, 2013 22:18

2 Attachment(s)
Quote:
 Originally Posted by akashjangid (Post 450319) Hello, I have the same problem. I am doing simulations on stator blade. The boundary conditions are the same as by Sunxing Inlet - total pressure - 411.8 kPa, total inlet temp 517.5 K Outlet - static pressure 367 kPA I am using rhosimplecfoam, but the results are not good, may be some problems with the boundary condition and initial condition, any suggestion for this ? and how should i specify k, omega value IN PRESSURE BASED solver Thanks
Hi,

These are my 0 and system folders:

Regards

Sunxing

 akashjangid September 10, 2013 04:18

Reference pressure

hello Sunxing

I still have one doubt. how do you specify the total pressure at inlet and outlet or do we have to specify the reference pressure somewhere and change this accordingly

In my case i have total pressure at inlet 411800 Pa and 367000 Pa at outlet, but with these conditions my velocity variation is coming very high from expected values

Inlet
{
type totalPressure;
gamma 1.4;
p0 uniform 411800;
value uniform 411800;
}
Outlet
{
type fixedValue;
value 367000;
}

I think problem is with the reference pressure.
How to figure out that ?

Thanks

 Sunxing September 10, 2013 04:31

I‘m a little confused with your question, what reference pressure do you want? As I offer at #3, I have set the same inlet and outlet pressure conditions with yours. And my case works out well.

 akashjangid September 10, 2013 04:55

a) I want to know that, is there anything here as reference pressure or it is automatically zero when we specify a fixed value to outlet and inlet.

b) If i know my static pressure at inlet(355617.5 from fluent), what changes should i make in the total pressure BC at inlet.

 Sunxing September 10, 2013 06:23

Quote:
 Originally Posted by akashjangid (Post 450861) a) I want to know that, is there anything here as reference pressure or it is automatically zero when we specify a fixed value to outlet and inlet. b) If i know my static pressure at inlet(355617.5 from fluent), what changes should i make in the total pressure BC at inlet.
I don't think that there is any reference pressure.
If you want to set the static pressure at inlet, then just set it as：
type fixedValue;
value 355617.5;

 cleoo September 12, 2016 10:09

Quote:
 Originally Posted by Sunxing (Post 450440) Hi, These are my 0 and system folders: I hope that can help you. Sunxing
Hi Sunxing,
I was looking over your folder and i was wondering how did you determine the interal feild value for pressue?

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