Gas filling in closed vessel

chanfire · February 16, 2010, 09:28

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, 12:30

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, 13:41

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, 17:23

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.

February 16, 2010, 09:28	Gas filling in closed vessel	#1
chanfire New Member Sung Kim Join Date: Feb 2010 Posts: 2 Rep Power: 0	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.

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February 16, 2010, 12:30		#2
feizaghaee Senior Member moein Join Date: Dec 2009 Posts: 132 Rep Power: 16	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?

February 16, 2010, 13:41		#3
chanfire New Member Sung Kim Join Date: Feb 2010 Posts: 2 Rep Power: 0	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.

February 16, 2010, 17:23		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	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.