Case of fixed inlet total pressure and fixed outlet static pressure

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April 17, 2013, 00:30
Case of fixed inlet total pressure and fixed outlet static pressure
#1
Member

sqing
Join Date: Sep 2012
Location: Dalian
Posts: 77
Rep Power: 9
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:
Attached Images
 1.jpg (31.2 KB, 131 views) 捕获.GIF (96.7 KB, 136 views)

 September 7, 2013, 03:49 Boundary condition. #2 New Member   Akash Sharma Join Date: May 2013 Location: Paris Posts: 15 Rep Power: 8 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

September 7, 2013, 23:18
#3
Member

sqing
Join Date: Sep 2012
Location: Dalian
Posts: 77
Rep Power: 9
Quote:
 Originally Posted by akashjangid 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
Attached Files
 0.tar.gz (48.8 KB, 402 views) system.tar.gz (5.8 KB, 147 views)

 September 10, 2013, 05:18 Reference pressure #4 New Member   Akash Sharma Join Date: May 2013 Location: Paris Posts: 15 Rep Power: 8 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

 September 10, 2013, 05:31 #5 Member   sqing Join Date: Sep 2012 Location: Dalian Posts: 77 Rep Power: 9 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.

 September 10, 2013, 05:55 #6 New Member   Akash Sharma Join Date: May 2013 Location: Paris Posts: 15 Rep Power: 8 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.

September 10, 2013, 07:23
#7
Member

sqing
Join Date: Sep 2012
Location: Dalian
Posts: 77
Rep Power: 9
Quote:
 Originally Posted by akashjangid 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;

September 12, 2016, 11:09
#8
Member

annn
Join Date: Jun 2016
Posts: 40
Rep Power: 5
Quote:
 Originally Posted by Sunxing 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?

 September 9, 2019, 06:56 #9 New Member   马崇宾 Join Date: Apr 2019 Posts: 1 Rep Power: 0 hi Sunxing Thank you very much for your folders.May I ask you some question. I used tol T and tol P at inlet,and fixValue P at outlet. U in inlet is pressureDirectedInletVelocity and outlet type is inletOutlet. Why doesn't my case have any change in temperature,pressure and velocity?it just rotation. Thank you

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