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-   -   Gas filling in closed vessel (http://www.cfd-online.com/Forums/cfx/72726-gas-filling-closed-vessel.html)

chanfire February 16, 2010 10:28

Gas filling in closed vessel
 
I am trying to simulate the fueling process of gas cylinder using CFX.
My concern is the pressure rising during the filling of gas into the closed vessel. So, the computational domain is very simple, consist of a pressure boundary condition as inlet and walls without any outlet.

After CFX-pre, I have an error in a few iterations(3 iterations), and the solving has been stopped.
Do I need any technique to model the compress flow in a closed vessel ?
I already got some results with FLUENT model considering operating pressure option. But I can not find such option in CFX model.

the error message was as follows:
"The ANSYS CFX solver could not be started, or exited with return code 255:", ". No results file has been created."

Thanks in advance.

feizaghaee February 16, 2010 13:30

it's a general error. is there any different error?
check the residuls. maybe they diverge?
what version do you use?
do you use parallel solving?

chanfire February 16, 2010 14:41

Thanks for your fast response.
I am using CFX version 12 and serial solving.
There is no special error message.
The follows are some of out file.

----------------------------------------------------------------------
COEFFICIENT LOOP ITERATION = 2 CPU SECONDS = 6.281E+00
----------------------------------------------------------------------
| Equation | Rate | RMS Res | Max Res | Linear Solution |
+----------------------+------+---------+---------+------------------+
| U-Mom | 0.00 | 7.0E-15 | 1.3E-13 | 2.9E+10 * |
| V-Mom | 0.00 | 2.9E-15 | 6.9E-14 | 7.8E+10 * |
| W-Mom | 0.00 | 2.9E-15 | 6.9E-14 | 1.1E+11 * |
| P-Mass | 0.00 | 0.0E+00 | 7.6E-27 | 8.9 9.6E+10 * |
+----------------------+------+---------+---------+------------------+

+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| The ANSYS CFX solver could not be started, or exited with return |
| code 255: . No results file has been created. |
+--------------------------------------------------------------------+

End of solution stage.

ghorrocks February 16, 2010 18:23

The linear solver has diverged and the solver has crashed. You need to improve the stability of the simulation. Are you sure your physics is correct? If so then consider reducing the time step.


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