Learning Forum

[uxsarah]

I am using Polyflow to simulate the mould filling process of a chemical reaction flow, but the computation failed. I have attached the listing File, can any one help? many thanks.

 

 

[uxsarah]

 Running vof for T within [ 0.000E+00 , 2.000E+02 ]
  with dT-ini = 1.000E-01,
       dT-min = 1.000E-02, dT-max = 2.500E-01,
  with up to 2000 successful steps,
 
 
 
  ===> Starting VOF
         at T-ini = 0.000E+00
  =================================
 
 
 
 
**************************************************************************
      Initial volume     =  1.4103619E-04 / 4.1392274E-02
**************************************************************************

 Preprocessors  

 Convergence assumed : Rel. var. LT  1.00000E-04

 F.E.M. Task    

 Global divergence has occured. Diverg =  0.2000000E+04
 
 
**************************************************************************
    VOF Step #1                                 |   Progress bar(s)  |
      Time               =  0.0000000E+00       |>                   |
      Volume of fluid    =  1.4103619E-04       |>                   |
      Volume filled (%)  =  3.4073070E-01       |>                   |
      Step status : KO
          Solver divergence occured.
         New time step      =  5.0000000E-02
**************************************************************************

 Preprocessors  

 Convergence assumed : Rel. var. LT  1.00000E-04

 F.E.M. Task    


Divergence detected for field Carbondioxide: iterations cancelled by Expert System

Divergence detected for field Urethane: iterations cancelled by Expert System
 Global divergence has occured. Diverg =  0.2000000E+04
 
 
**************************************************************************
    VOF Step #1                                 |   Progress bar(s)  |
      Time               =  0.0000000E+00       |>                   |
      Volume of fluid    =  1.4103619E-04       |>                   |
      Volume filled (%)  =  3.4073070E-01       |>                   |
      Step status : KO
          Solver divergence occured.
         New time step      =  2.5000000E-02
**************************************************************************

 Preprocessors  

 Convergence assumed : Rel. var. LT  1.00000E-04

 F.E.M. Task    

           *** WARNING *** from [fpow]
          Negative local temperature for power law. Stop.
           *** WARNING *** from [mat162]
          Evaluation of the reaction rate has failed. Stop.
           *** WARNING *** from [MATRIX]
          Information about the above trouble...
          for problem Reaction rate 2D
          on domain: SURFACE_BODY.
            near location : ( 0.23946E+00 ,  0.92221E-01 )
         
         
 Global divergence has occured. Diverg =  0.2000000E+04
 
 
**************************************************************************
    VOF Step #1                                 |   Progress bar(s)  |
      Time               =  0.0000000E+00       |>                   |
      Volume of fluid    =  1.4103619E-04       |>                   |
      Volume filled (%)  =  3.4073070E-01       |>                   |
      Step status : KO
          Solver divergence occured.
         New time step      =  1.2500000E-02
**************************************************************************

 Preprocessors  

 Convergence assumed : Rel. var. LT  1.00000E-04

 F.E.M. Task    


Divergence detected for field Urea: iterations cancelled by Expert System
 Global divergence has occured. Diverg =  0.2000000E+04
 
 
**************************************************************************
    VOF Step #1                                 |   Progress bar(s)  |
      Time               =  0.0000000E+00       |>                   |
      Volume of fluid    =  1.4103619E-04       |>                   |
      Volume filled (%)  =  3.4073070E-01       |>                   |
      Step status : KO
          Solver divergence occured.
         New time step      =  6.2500000E-03
**************************************************************************

 Preprocessors  

 Convergence assumed : Rel. var. LT  1.00000E-04

 F.E.M. Task    

 Global divergence has occured. Diverg =  0.2000000E+04
 
 
**************************************************************************
    VOF Step #1                                 |   Progress bar(s)  |
      Time               =  0.0000000E+00       |>                   |
      Volume of fluid    =  1.4103619E-04       |>                   |
      Volume filled (%)  =  3.4073070E-01       |>                   |
      Step status : KO
          Solver divergence occured.
         New time step      =  3.1250000E-03
**************************************************************************


     *******************************
     *  Summary of the simulation  *
     *******************************

        The computation failed.


     *****************************
     *  Expert tool diagnostics  *
     *****************************

     Computation can not start, time step becomes too small at the first
     step.
     Maybe there is a problem is your set up. Please, review it.


     *****************************
     *  Expert tool diagnostics  *
     *****************************

     Out of convergence disk


     *****************************
     *  Expert tool diagnostics  *
     *****************************

     The problem F.E.M. Task     has not converged.


     *****************************
     *  Expert tool suggestions  *
     *****************************

     A serious internal error has occured (in printEndOfVof).
     Please, contact Ansys Polyflow support, and send us, if possible the
     mesh, data and listing files.
     We apologize for the inconvenience.

[uxsarah]

Is there anything wrong with my folling settings?

VOF iterative parameters:

Initial time value =0

Upper time limit= 2.000E2

Initial value of the time step= 1.000E-1

Min admissible value of the time-step = 1.000E-2

Max admissible value of the time-step = 2.500E-01

Accuracy of VOF scheme =2.500E-01

Max number of successful steps =2000