Fluids

Fluids

Non-zero exit code while simulating Compressor flow

    • lizm
      Subscriber

      I have been getting a non-zero exit code : 2 when I try to run CFX solution. I used Ansys 15.0 tutorial on centrifugal compressor. What could be the problem? The mesh and set-up have updated but when it comes to solution it gives me the error.

    • DrAmine
      Ansys Employee

      Hi, 


      Can you carry out the tutorial on centrifugal pump once again? Perhaps you missed a thing. For the CFX Tutorials, you can play a *.pre session in order to end up with the finalized settings.


      A.

    • lizm
      Subscriber

      Thank you, let me try it.

    • lizm
      Subscriber

      @abenhadj, I re-did the centrifugal compressor tutorial and still ended up with the error. 


      My procedure was as follows:


      I used Vista CCD to design the compressor; it had 24 blades and the inlet temp was 298. I kept the other values at default. I transfered the information from Vista CCD to BladeGen. I had already un-selected Merge Blade Topology and Create Fluid Zones. in the mesh, the Topology set did not have  H/J/C/L grid topology, so I continued with the other changes. In Mechanical Model, the default settings of physical references remained. I defined the virtual topology and control methods. In CFX, I configured the basic setting to Centrifugal compressor and followed the instructions given.  On running the solution, I got the error.


      I do not know where I am going wrong.

    • DrAmine
      Ansys Employee

      On which tutorial are you working? The tutorial I was actually referencing is "Aerodynamic and Structural Performance of a


      Centrifugal Compressor" 

    • lizm
      Subscriber

      I was working on that one.


      I have been experiencing the error even when using fluent and CFX. I am working on centrifugal compressor flow and was using the tutorial as a guide. in fluent, I had used Vista CCD, kept the default settings in duty and aerodynamic data but changed the geometry to vaneless, and main blades to 7 without splitter. In the set-up, I select steady-state, energy model with viscous model SST. The material that I use is Air. For CFX, I input 1 bar as inlet pressure with a mass flow of 0.6kg/s.


      i honestly do not know where I am going wrong.

    • DrAmine
      Ansys Employee

      Please elaborate a bit on the issue: Are you experiencing problems with the tutorial itself?

    • lizm
      Subscriber

      Yes, I am having a problem with the tutorial. I cannot pin point where the error is arising from. 

    • DrAmine
      Ansys Employee

      At which stage?

    • lizm
      Subscriber

      The solution part in CFX. I am not able to pin point the source of non-zero exit code:2.

    • DrAmine
      Ansys Employee

      Does the error occur immediately? 

    • lizm
      Subscriber

      At the solution stage in CFX. 

    • lizm
      Subscriber

      It does not occur immediately. It starts to solve then after some seconds it stops and gives a message of the error.

    • DrAmine
      Ansys Employee

      Can you past some relevant lines from the out file before the error message is printed out? Are there any error messages written in the out file?

    • lizm
      Subscriber

       ======================================================================


       OUTER LOOP ITERATION =    3                    CPU SECONDS = 4.657E+01


       



       |       Equation       | Rate | RMS Res | Max Res |  Linear Solution |


       +


      +
      +
      +
      +
      +


       | U-Mom                |99.99 | 2.3E-03 | 1.9E-01 |       3.4E-04  OK|


       | V-Mom                |99.99 | 4.4E-03 | 3.9E-01 |       2.6E-04  OK|


       | W-Mom                |99.99 | 2.6E-04 | 3.7E-02 |       6.5E-03  OK|


       | P-Mass               |40.89 | 1.4E-08 | 6.1E-06 |  9.3  3.6E+00  F |


       +


      +
      +
      +
      +
      +


       | H-Energy             | 1.20 | 3.1E-03 | 7.5E-01 |  5.9  3.5E-02  OK|


       +


      +
      +
      +
      +
      +


       | K-TurbKE             | 0.72 | 2.6E-03 | 5.8E-01 |  5.9  1.7E-02  OK|


       | E-Diss.K             | 0.55 | 4.2E-03 | 1.0E+00 | 45.9  4.1E-09  OK|


       +


      +
      +
      +
      +
      +


       +


      +


       | Notice: The maximum Mach number is  3.108E+04.                     |


       +


      +


       


       ======================================================================


       OUTER LOOP ITERATION =    4                    CPU SECONDS = 6.725E+01


       



       |       Equation       | Rate | RMS Res | Max Res |  Linear Solution |


       +


      +
      +
      +
      +
      +


       


       +


      +


       | ERROR #004100018 has occurred in subroutine FINMES.                |


       | Message:                                                           |


       | Fatal overflow in linear solver.                                   |


       +


      +


       


       +


      +


       |                An error has occurred in cfx5solve:                 |


       |                                                                    |


       | The ANSYS CFX solver exited with return code 1.   No results file  |


       | has been created.                                                  |


       +


      +


       


      End of solution stage.


       


       +


      +


       | The following user files have been saved in the directory          |


       | DTHESIS/Compressor_pending/dp0_CFX_Solution/CFX_002:             |


       |                                                                    |


       | mon                                                                |


       +


      +


       


       


       +


      +


       | For CFX runs launched from Workbench, the final locations of       |


       | directories and files generated may differ from those shown.       |


       +


      +


       


       


      This run of the ANSYS CFX Solver has finished.

    • DrAmine
      Ansys Employee

      Please double check the settings and go through the tutorial one more. I have done the tutorial but only the CFX part without Mechanical and It is working for me. 

    • lizm
      Subscriber

      How do I check the setting? Where do I go?

    • DrAmine
      Ansys Employee

      First of all you work only on the CFX component disregard the Mechanical part. Just create the interfaces in CFX and include the interface for the internal GGI inerface (tip). You can just connect the CFX to Turbo Grid and work then this out.

    • lizm
      Subscriber

      Could you please elaborate more on the GGI  inerface (tip)?

    • DrAmine
      Ansys Employee

      Here the interfaces I have 



       


      and here the internal interface which connects the shroud tip sides (created in TurboGrid)


       



       

    • lizm
      Subscriber

      Hi,


      I started simulation again and it worked for one day. the next day I tried simulating the same conditions I got the following error:


       OUTER LOOP ITERATION =    7                    CPU SECONDS = 7.014E+01


       



       |       Equation       | Rate | RMS Res | Max Res |  Linear Solution |


       +


      +
      +
      +
      +
      +


       


       +


      +


       | ERROR #001100279 has occurred in subroutine ErrAction.             |


       | Message:                                                           |


       | Floating point exception: Overflow                                 |


       |                                                                    |


       |                                                                    |


       |                                                                    |


       |                                                                    |


       |                                                                    |


       +


      +


       


       +


      +


       | ERROR #001100279 has occurred in subroutine ErrAction.             |


       | Message:                                                           |


       | Stopped in routine FPX: C_FPX_HANDLER                            

    • lizm
      Subscriber

      Is it a computer problem or ....

    • lizm
      Subscriber

       ERROR #001100279 has occurred in subroutine ErrAction.             |


       | Message:                                                           |


       | Floating point exception: Overflow                                 |


       |                                                                    |


       |                                                                    |


       |                                                                    |


       |                                                                    |


       |                                                                    |


       +


      +


       


       +


      +


       | ERROR #001100279 has occurred in subroutine ErrAction.             |


       | Message:                                                           |


       | Stopped in routine FPX: C_FPX_HANDLER           

    • Surya Deb
      Ansys Employee

      Hi,


      Are you using Double Precision as Solver Settings?


      If not, then could you please try using DP?


      Regards,


       


       


       


       

    • anmehta
      Ansys Employee

      HI ,


          Just went through all the conversation and i would like to share some points to check on set up . 


       You are getting errors such as fatal overflow in linear solver or Overflow error even notification of max mach number going too high . These all errors can be generated due to


      a) improper initialization (Kindly check the reference pressure values in domain settings - units we are using ) - this may lead to unrealistic values of mass flow and properties in first few iterations only .  Check if we need to provide domain initialization values of pressure . 


      b)floating point overflow error can be due to memory requirement for the job to run on available RAM machine . In CFX solver manager --> you can slightly increase memory allocation factor from default 1 to 1.2 or 1.4 in solver as shown below . This will increase the memory allocation for this job by 1.2 times .



      I hope this will help . 


       


       

    • lizm
      Subscriber

      @Surya the double precision is still bringing an error.

    • lizm
      Subscriber

      @anmehta, I increased the memory allocation factor to 1.4. The error changed to as below:


       ERROR #004100018 has occurred in subroutine FINMES.                |


       | Message:                                                           |


       | Fatal overflow in linear solver.                                   |


       +


      +


       


       +


      +


       |                An error has occurred in cfx5solve:                 |


       |                                                                    |


       | The ANSYS CFX solver exited with return code 1.   No results file  |


       | has been created.                                                  |

    • lizm
      Subscriber

      I have been working on the conditions and so far the iterations have increased.

    • anmehta
      Ansys Employee

      HI ,


       You can check the point a) shared on initialization. You can also check the units of the reference pressure specified . 


        If you are running compressor case with very high value of rotation , i would prefer you to give some ramp up of RPM value . 


       


      Regards,


      Anup Mehta  

    • lizm
      Subscriber

      What is the purpose of the reference pressure?

    • lizm
      Subscriber

       ERROR #001100279 has occurred in subroutine ErrAction.             |


       | Message:                                                           |


       | SYMASS_CS_ELIM : The solver ran out of temporary space while buil- |


       | ding a linked list for a domain.  Try setting the expert paramete- |


       | r "topology estimate factor" to a value greater than 1.0.  Values  |


       | higher than 1.2 should not be necessary.

    • lizm
      Subscriber

      I increased the memory allocation factor to 1.4. Still getting the above error. What could be the source?


       


      Where do I get "topology estimate factor"?

    • lizm
      Subscriber

      I was able to find it in flow analysis solver.

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