Hi Adrpo
Thank you so much for your help. It is quite hard to beginning alone with openmodelica. My goal is to try o simulate the approach system of a paper machine. So, still a long way to do ...
Now the model is well checked.
Nevertheless, when I try to simulate (after changing some parameters of the pump and others equipments, the message bellow came.
I've understood that it comes from the initial parameter but  how to do to have access to the information "Use -d=bltdump to get more information"

<<
[1] 10:38:50 Scripting Warning
Requested package Modelica of version 3.2.2, but this package was already loaded with version 3.2.3. You might experience problems if these versions are incompatible.

[2] 10:38:50 Symbolic Warning
The model contains alias variables with conflicting start and/or nominal values. It is recommended to resolve the conflicts, because otherwise the system could be hard to solve. To print the conflicting alias sets and the chosen candidates please use -d=aliasConflicts.

[3] 10:38:50 Translation Error
Internal error IndexReduction.pantelidesIndexReduction failed! System is structurally singulare and cannot handled because number of unassigned equations is larger than number of states. Use -d=bltdump to get more information.

[4] 10:38:50 Translation Error
post-optimization module replaceHomotopyWithSimplified (initialization) failed.

[5] 10:38:50 Translation Error
No system for the symbolic initialization was generated

One more question:
I want to add a sink has an overflow of the tank one.
But there are error messages. Where should I redeclare the classMedium ?

testje3.mo

With the number of processor = 1, it works.
Thank you,

When simulating your model testje2, I have the scripting error:
Internal error: no tokens left to replace %s with.
Given message was: System.launchParallelTasks: Failed to create thread: %s

How to solve that problem.

I have the same problem => did you find a solution ?
Regards

I try to simulate the draining of a tank through a valve.

So the system is as mentioned below :
The error messages are :
[1] 08:50:32 Scripting Warning
Requested package Modelica of version 3.2.2, but this package was already loaded with version 3.2.3. You might experience problems if these versions are incompatible.
[2] 08:50:32 Translation Notification
[Modelica.Fluid.Interfaces: 508:19-510:49]: From here:
[3] 08:50:32 Translation Error
[test: 4:3-5:114]: component tank contains the definition of a partial class Medium.
Please redeclare it to any package compatible with Modelica.Media.Interfaces.PartialMedium.
[4] 08:50:32 Translation Error
Error occurred while flattening model test

I have not found where and how to change the "class.Medium"
Thanks for your help.
Raphaêl

model test
  Modelica.Fluid.Sources.FixedBoundary sink(T = system.T_ambient,nPorts = 1, p = system.p_ambient)  annotation(
    Placement(visible = true, transformation(origin = {74, -44}, extent = {{-10, -10}, {10, 10}}, rotation = 180)));
  Modelica.Fluid.Vessels.OpenTank tank(crossArea = 1, height = 2, level(fixed = true, start = 2), use_portsData = true)  annotation(
    Placement(visible = true, transformation(origin = {-64, 62}, extent = {{-20, -20}, {20, 20}}, rotation = 0)));
  Modelica.Fluid.Valves.ValveLinear UserValve annotation(
    Placement(visible = true, transformation(origin = {32, 14}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  Modelica.Blocks.Sources.Constant OuvertureVanne(k = 0.5)  annotation(
    Placement(visible = true, transformation(origin = {12, 80}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  inner Modelica.Fluid.System system annotation(
    Placement(visible = true, transformation(origin = {-86, -82}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
equation
  connect(tank.ports[1], UserValve.port_a) annotation(
    Line(points = {{-64, 42}, {22, 42}, {22, 14}}, color = {0, 127, 255}));
  connect(UserValve.port_b, sink.ports[1]) annotation(
    Line(points = {{42, 14}, {61, 14}, {61, -12}, {88, -12}, {88, -24}, {64, -24}, {64, -44}}, color = {0, 127, 255}));
  connect(OuvertureVanne.y, UserValve.opening) annotation(
    Line(points = {{23, 80}, {23, 56.5}, {41, 56.5}, {41, 59}, {32, 59}, {32, 22}}, color = {0, 0, 127}));

annotation(
    uses(Modelica(version = "3.2.3")));
end test;

Hi,
I try to use OpenModelica to simulate a part (the approch system) of a papermachine.
But I meet problems when I try to use examples of Fluid package (see below the error messages).
Furthermore, I have not found good readings about the modelisation of water system (how to manage connections, tanks, pumps and so on).If you have suggestion ?
If somebody can help me...
Thanks in advance
Best Regards
Raphaël
<<<
Example of trying to use PulpingSystem => messages occuring after clicking the "simulation" button
in Message Broswer

[1] 08:08:59 Scripting Notification
Linear iteration variables with predefined start attributes that are unrelevant in NLSJac28. (2)
========================================
1: userValve.m_flow:VARIABLE(min = max(-100000.0, max(-1e+060, max(0.0, max(0.0, 0.0)))) max = min(100000.0, min(1e+060, min(100000.0, min(100000.0, 100000.0)))) start = 0.0 unit = "kg/s" )  "Mass flow rate in design flow direction" type: Real
2: userValve.dp:VARIABLE(start = userValve.dp_start unit = "Pa" )  "Pressure difference between port_a and port_b (= port_a.p - port_b.p)" type: Real

Info: Only non-linear iteration variables in non-linear eqation systems require start values. All other start values have no influence on convergence and are ignored. Use "-d=dumpLoops" to show all loops. In OMEdit Tools->Options->Simulation->OMCFlags, in OMNotebook call setCommandLineOptions("-d=dumpLoops")


Linear iteration variables with predefined start attributes that are unrelevant in NLSJac29. (2)
========================================
1: pipe.flowModel.m_flows[1]:VARIABLE(min = max(0.0, max(-100000.0, max(-1e+060, max(-1e+060, -1e+060)))) max = min(100000.0, min(100000.0, min(100000.0, min(100000.0, 100000.0)))) start = 0.0 unit = "kg/s" )  "mass flow rates between states" type: Real [1]
2: pipe.flowModel.dps_fg[1]:VARIABLE(start = pipe.flowModel.p_a_start - pipe.flowModel.p_b_start unit = "Pa" )  "pressure drop between states" type: Real [1]

Info: Only non-linear iteration variables in non-linear eqation systems require start values. All other start values have no influence on convergence and are ignored. Use "-d=dumpLoops" to show all loops. In OMEdit Tools->Options->Simulation->OMCFlags, in OMNotebook call setCommandLineOptions("-d=dumpLoops")

[2] 08:08:59 Scripting Warning
Requested package Modelica of version 3.2.2, but this package was already loaded with version 3.2.3. You might experience problems if these versions are incompatible.

[3] 08:08:59 Symbolic Warning
The model contains alias variables with conflicting start and/or nominal values. It is recommended to resolve the conflicts, because otherwise the system could be hard to solve. To print the conflicting alias sets and the chosen candidates please use -d=aliasConflicts.

Message in the window which open during the simulation
C:/Users/passasr/AppData/Local/Temp/OpenModelica/OMEdit/Modelica.Fluid.Examples.PumpingSystem/Modelica.Fluid.Examples.PumpingSystem.exe -port=58194 -logFormat=xmltcp -override=startTime=0,stopTime=2000,stepSize=0.4,tolerance=1e-06,solver=dassl,outputFormat=mat,variableFilter=.* -r=C:/Users/passasr/AppData/Local/Temp/OpenModelica/OMEdit/Modelica.Fluid.Examples.PumpingSystem/Modelica.Fluid.Examples.PumpingSystem_res.mat -w -lv=LOG_STATS -inputPath=C:/Users/passasr/AppData/Local/Temp/OpenModelica/OMEdit/Modelica.Fluid.Examples.PumpingSystem -outputPath=C:/Users/passasr/AppData/Local/Temp/OpenModelica/OMEdit/Modelica.Fluid.Examples.PumpingSystem
The simulation finished successfully.
The following assertion has been violated at time 0.000000
pipe.flowModel.m_flows[1] >= 0.0 and pipe.flowModel.m_flows[1] <= 100000.0
Variable violating min/max constraint: 0.0 <= pipe.flowModel.m_flows[1] <= 100000.0, has value: -141.424
The initialization finished successfully without homotopy method.
The following assertion has been violated at time 200.000000
valveOpening.y >= 0.0 and valveOpening.y <= 1.0
Variable violating min/max constraint: 0.0 <= valveOpening.y <= 1.0, has value: 1
Warning: maximal number of iteration reached but no root found
Warning: maximal number of iteration reached but no root found
### STATISTICS ###