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EOS1 - REDUCE TIME STEP error

Hello,

I am simulating the single-phase radial flow of water to a well during 13 days of pumping test. I am using EOS1 with MULTI (1,2,2.6).

After running the code, in the first iteration I have "PHASE TRANSITION TO TWO-PHASE" and then "REDUCE TIME STEP". 

...ITERATING...  AT [   1,  1] --- DELTEX = 0.864000E+05   MAX. RES. = 0.458172E+02  AT ELEMENT A1M22  EQUATION   1
                                    AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
 .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A17 2*   T =  0.15000E+02   P =  0.13209E+04   PS =  0.17039E+04
 .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A18 2*   T =  0.15000E+02   P =  0.71761E+03   PS =  0.17039E+04
 .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A19 2*   T =  0.15000E+02   P =  0.12257E+03   PS =  0.17039E+04
 ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A1A 2*      XX(M) = -0.46048E+03  0.15000E+02
 +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.216000E+05

Please see the attached file which are my input file (inp.txt), mesh file and INCON file for more details.

Here is also the structure of my model:

*inpradb* ... Pumping Test.
MESHMAKER1----*----2----*----3----*----4----*----5----*----6----*----7----*----8
XYZ
        0.
NX      41  19.51219
NY      43
  19.51219  19.51219  19.51219  19.51219  19.51219  19.51219  19.51219  19.51219
  19.51219  19.51219  19.51219  19.51219  19.51219  19.51219  19.51219  19.51219
  19.51219  19.51219  19.51219  19.51219   

9.74679 0.19620 9.56919  19.51219
  19.51219  19.51219  19.51219  19.51219  19.51219  19.51219  19.51219  19.51219
  19.51219  19.51219  19.51219  19.51219  19.51219  19.51219  19.51219  19.51219
  19.51219  19.51219  19.51219
NZ       1  7.0

ENDFI----1----*----2----*----3----*----4----*----5----*----6----*----7----*----8

I appreciate if anyone know and can help me to fix this problem.

Best Regards
Sara

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  • Sara,

    I have not run your input files, but the message simply indicates that the total pressure is lowered (due to pumping) below the saturated vapor pressure, thus inducing boiling. The induced non-linearity is too strong for the Newton-Raphson iteration to yield thermodynamically acceptable primary variables, so a time-step reduction is proposed. This may not be an "error", as you state, but the expected behavior. Does the simulation recover after that (i.e., after time-step reduction)? If it does not recover, make sure  your pumping rate is not too high for the given reservoir properties and conditions (i.e., leads to a drawdown that is too strong).

    Stefan

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  • Stefan,

    Thanks for the reply.
    1) There is no recovery after time-step reduction. I have"PHASE TRANSITION TO TWO-PHASE" and "REDUCE TIME STEP" in the next iterations as well.

    2) I run the model several times by decreasing and increasing the MASS productions (GX= -0.71 kg/s).

    Would you please have a look at let me know your idea?

    Here is the results:

    =====>  a)  GX= - 0.1      kg/s

     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.864000E+05   MAX. RES. = 0.645313E+01  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1F 4*   T =  0.15000E+02   P =  0.15825E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1G 4*   T =  0.15000E+02   P =  0.14143E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1H 4*   T =  0.15000E+02   P =  0.12710E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1I 4*   T =  0.15000E+02   P =  0.11557E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1J 4*   T =  0.15000E+02   P =  0.10712E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1K 4*   T =  0.15000E+02   P =  0.10196E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1L 4*   T =  0.15000E+02   P =  0.10065E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1M 4*   T =  0.15000E+02   P =  0.10065E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1N 4*   T =  0.15000E+02   P =  0.10066E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1O 4*   T =  0.15000E+02   P =  0.10194E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1P 4*   T =  0.15000E+02   P =  0.10708E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1Q 4*   T =  0.15000E+02   P =  0.11551E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1R 4*   T =  0.15000E+02   P =  0.12702E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1S 4*   T =  0.15000E+02   P =  0.14134E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1T 4*   T =  0.15000E+02   P =  0.15815E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1B 5*   T =  0.15000E+02   P =  0.15621E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1C 5*   T =  0.15000E+02   P =  0.12453E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1D 5*   T =  0.15000E+02   P =  0.94355E+03   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1E 5*   T =  0.15000E+02   P =  0.66108E+03   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1F 5*   T =  0.15000E+02   P =  0.40252E+03   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1G 5*   T =  0.15000E+02   P =  0.17271E+03   PS =  0.17039E+04
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A1H 5*      XX(M) = -0.23526E+02  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.216000E+05
     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.216000E+05   MAX. RES. = 0.161328E+01  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1H 5*   T =  0.15000E+02   P =  0.16851E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1I 5*   T =  0.15000E+02   P =  0.15722E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1J 5*   T =  0.15000E+02   P =  0.14889E+04   PS =  0.17039E+04
    

    ====>  b) GX= - 0.01   kg/s

    ...ITERATING...  AT [   1,  1] --- DELTEX = 0.864000E+05   MAX. RES. = 0.645313E+00  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1K17*   T =  0.15000E+02   P =  0.15918E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1L17*   T =  0.15000E+02   P =  0.15545E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1M17*   T =  0.15000E+02   P =  0.15544E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1N17*   T =  0.15000E+02   P =  0.15545E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1O17*   T =  0.15000E+02   P =  0.15909E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1I18*   T =  0.15000E+02   P =  0.15523E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1J18*   T =  0.15000E+02   P =  0.12733E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1K18*   T =  0.15000E+02   P =  0.10651E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1L18*   T =  0.15000E+02   P =  0.10061E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1M18*   T =  0.15000E+02   P =  0.10060E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1N18*   T =  0.15000E+02   P =  0.10062E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1O18*   T =  0.15000E+02   P =  0.10638E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1P18*   T =  0.15000E+02   P =  0.12711E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1Q18*   T =  0.15000E+02   P =  0.15497E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1H19*   T =  0.15000E+02   P =  0.15520E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1I19*   T =  0.15000E+02   P =  0.11460E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1J19*   T =  0.15000E+02   P =  0.74052E+03   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1K19*   T =  0.15000E+02   P =  0.40346E+03   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1L19*   T =  0.15000E+02   P =  0.29603E+03   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1M19*   T =  0.15000E+02   P =  0.29571E+03   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1N19*   T =  0.15000E+02   P =  0.29610E+03   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1O19*   T =  0.15000E+02   P =  0.40113E+03   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1P19*   T =  0.15000E+02   P =  0.73712E+03   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1Q19*   T =  0.15000E+02   P =  0.11424E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1R19*   T =  0.15000E+02   P =  0.15486E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1H20*   T =  0.15000E+02   P =  0.12692E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1I20*   T =  0.15000E+02   P =  0.73360E+03   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1J20*   T =  0.15000E+02   P =  0.13329E+03   PS =  0.17039E+04
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A1K20*      XX(M) = -0.45850E+03  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.216000E+05
     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.216000E+05   MAX. RES. = 0.161328E+00  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1J19*   T =  0.15000E+02   P =  0.14978E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1K19*   T =  0.15000E+02   P =  0.11756E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1L19*   T =  0.15000E+02   P =  0.10721E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1M19*   T =  0.15000E+02   P =  0.10718E+04   PS =  0.17039E+04
    

    ======> c) GX= - 20 kg/s

    ...ITERATING...  AT [   1,  1] --- DELTEX = 0.864000E+05   MAX. RES. = 0.129063E+04  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A12 2*      XX(M) = -0.12326E+05  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.216000E+05
     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.216000E+05   MAX. RES. = 0.322656E+03  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A12 2*      XX(M) = -0.57821E+04  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.540000E+04
     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.540000E+04   MAX. RES. = 0.806641E+02  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A13 2*      XX(M) = -0.25119E+03  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.135000E+04
     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.135000E+04   MAX. RES. = 0.201660E+02  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1D 3*   T =  0.15000E+02   P =  0.13867E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1E 3*   T =  0.15000E+02   P =  0.88470E+03   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1F 3*   T =  0.15000E+02   P =  0.38428E+03   PS =  0.17039E+04
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A1G 3*      XX(M) = -0.94587E+02  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.337500E+03
     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.337500E+03   MAX. RES. = 0.504150E+01  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1K11*   T =  0.15000E+02   P =  0.15688E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1L11*   T =  0.15000E+02   P =  0.14879E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1M11*   T =  0.15000E+02   P =  0.14877E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1N11*   T =  0.15000E+02   P =  0.14880E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1O11*   T =  0.15000E+02   P =  0.15671E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1H12*   T =  0.15000E+02   P =  0.10430E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1I12*   T =  0.15000E+02   P =  0.51327E+02   PS =  0.17039E+04
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A1J12*      XX(M) = -0.84570E+03  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.843750E+02
     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.843750E+02   MAX. RES. = 0.126038E+01  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1J17*   T =  0.15000E+02   P =  0.65488E+03   PS =  0.17039E+04
    

    ======> d) GX= - 80    kg/s

    ...ITERATING...  AT [   1,  1] --- DELTEX = 0.864000E+05   MAX. RES. = 0.516250E+04  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A12 2*      XX(M) = -0.64304E+05  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.216000E+05
     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.216000E+05   MAX. RES. = 0.129063E+04  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A12 2*      XX(M) = -0.38128E+05  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.540000E+04
     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.540000E+04   MAX. RES. = 0.322656E+03  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A12 2*      XX(M) = -0.54528E+04  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.135000E+04
     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.135000E+04   MAX. RES. = 0.806641E+02  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A19 2*   T =  0.15000E+02   P =  0.14037E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1A 2*   T =  0.15000E+02   P =  0.67226E+03   PS =  0.17039E+04
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A1B 2*      XX(M) = -0.13377E+03  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.337500E+03
     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.337500E+03   MAX. RES. = 0.201660E+02  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1J 9*   T =  0.15000E+02   P =  0.14060E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1K 9*   T =  0.15000E+02   P =  0.11146E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1L 9*   T =  0.15000E+02   P =  0.10377E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1M 9*   T =  0.15000E+02   P =  0.10374E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1N 9*   T =  0.15000E+02   P =  0.10379E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1O 9*   T =  0.15000E+02   P =  0.11129E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1P 9*   T =  0.15000E+02   P =  0.14026E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1G10*   T =  0.15000E+02   P =  0.11749E+04   PS =  0.17039E+04
     .....PHASE TRANSITION TO TWO-PHASE..... AT ELEMENT *A1H10*   T =  0.15000E+02   P =  0.16877E+03   PS =  0.17039E+04
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A1I10*      XX(M) = -0.83266E+03  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.843750E+02
     ...ITERATING...  AT [   1,  1] --- DELTEX = 0.843750E+02   MAX. RES. = 0.504150E+01  AT ELEMENT A1M22  EQUATION   1
                                        AT *A1M22* ...   DX1= 0.000000E+00 DX2= 0.000000E+00 T =  15.000 P =     5000. S = 0.000000E+00
     ++++++++++ EOS CANNOT FIND PARAMETERS AT ELEMENT *A1J16*      XX(M) = -0.61238E+03  0.15000E+02
     +++++++++ REDUCE TIME STEP AT (   1,  1) ++++++++++++++++   NEW DELT = 0.210938E+02
    
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  • Sara,

    I look at your files. I can only repeat what I said in my previous reply: The production rate is (way too) high for the specified initial conditions. Just look at element A1M22 after the first time step is complete; it is at a very low pressure (your system literally "cavitates", creating a strong vacuum on its way to absolute zero!)

    Your initial pressure is most likely wrong. You specified 5000 Pa! You probably wanted to specify 5 bar or 50 bar (I don't know what system you try to simulate). You have to go above 10 bars for the pumping to work for a while. Note that as soon as you induce boiling, a production rate of 0.7 kg/s means a huge volume is being extracted, so the pressure drops to zero very fast.

    Note, since you have uniform initial conditions, keep the INCON block empty, and specify initial conditions using a single line in block PARAM.4. You may also want to tighten RE1.

    Hope this helps.

     

    Stefan

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  • Thanks Stefan for the help. My problem was solved by changing the pressure.

    Best Regards

    Sara

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  • Hi Sara,

    I'm glad it worked. I also appreciate the feedback - should be helpful to those who follow this forum post.

    Best,

    Stefan

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