"The computation failed" when I use Polyflow to simulate filling process of chemical reaction flow

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  • Last Post 29 November 2018
uxsarah posted this 29 November 2018

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.

 

 

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uxsarah posted this 29 November 2018

 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 posted this 29 November 2018

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

Numerical paramters for iterations:

Modify the max number of iterations =30

Modify the convergence test =2.00000E-3

Modify the divergence test = 2.00000E+4

Modify the convergence test for species = 5.000000E-3

Modify the solver aggressivity =2 (very robust)

===> solver type=AMF direct solver

 

Modify the max number of iterations =30

Modify the convergence test =2.00000E-3

Modify the divergence test = 2.00000E+4

Modify the convergence test for species = 5.000000E-3

Modify the solver aggressivity =2 (very robust)

===> solver type=AMF direct solver

 

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