Initializing error :: OpenModelica

Initializing error

Mar-02-20 10:38:12

Hi,
I have been trying to teach myself Modelica by starting from the examples and changeing simple things here and there. Goal is to be able to create big thermohydraulic models for work.

My model compiles fine, but has multitudes of errors (division by zero) on initializing. It works fine when I uncomment the output definitions. However, I do not need these, and I do not understand why this creates an error.

Ideas anyone?

Code:

model OneMass "Cooling of one hot mass"

  extends Modelica.Icons.Example;



  parameter Modelica.SIunits.Temperature TAmb(displayUnit="degC")=293.15

    "Ambient temperature";

  parameter Modelica.SIunits.Temperature TMass(displayUnit="degC")=313.15

  "Initial temperature of mass";

//  output Modelica.SIunits.TemperatureDifference dTMass=

//    heatCapacitor.port.T-TAmb "Mass over Ambient";

//  output Modelica.SIunits.TemperatureDifference dTtoPipe=heatCapacitor.port.T-pipe.T_q

//    "Mass over Coolant";

//  output Modelica.SIunits.TemperatureDifference dTCoolant=pipe.dT

//    "Coolant's temperature increase";

  Modelica.Thermal.FluidHeatFlow.Sources.Ambient ambient1(

    constantAmbientPressure=0,constantAmbientTemperature=TAmb, medium=Modelica.Thermal.FluidHeatFlow.Media.Water(), useTemperatureInput = true)

    annotation (Placement(transformation(extent={{-60,-10},{-80,10}})));

  Modelica.Thermal.FluidHeatFlow.Sources.VolumeFlow pump(

    

    T0=TAmb,

    constantVolumeFlow=1,

    m= 1,medium=Modelica.Thermal.FluidHeatFlow.Media.Water(),

    useVolumeFlowInput= false)

    annotation (Placement(transformation(extent={{-40,-10},{-20,10}})));

  Modelica.Thermal.FluidHeatFlow.Components.Pipe pipe(

    

    T0=TAmb,

    T0fixed=true, V_flow(start = 1),

    V_flowLaminar=0.1,

    V_flowNominal=1,

    dpLaminar(displayUnit="Pa") = 0.1,

    dpNominal(displayUnit="Pa") = 1,

    h_g=0,

    m= 1,medium=Modelica.Thermal.FluidHeatFlow.Media.Water(),

    useHeatPort=true)

    annotation (Placement(transformation(extent={{0,-10},{20,10}})));

  Modelica.Thermal.FluidHeatFlow.Sources.Ambient ambient2(

    constantAmbientPressure=0,constantAmbientTemperature=TAmb, medium=Modelica.Thermal.FluidHeatFlow.Media.Water())

    annotation (Placement(transformation(extent={{40,-10},{60,10}})));

  Modelica.Thermal.HeatTransfer.Components.HeatCapacitor heatCapacitor(

    C= 10, T( fixed=true,start=TMass))

    annotation (Placement(transformation(

        origin={10,-60},

        extent={{10,-10},{-10,10}},

        rotation=180)));

  Modelica.Thermal.HeatTransfer.Components.ThermalConductor thermalConductor(G=1)

    annotation (Placement(transformation(

        origin={10,-30},

        extent={{-10,-10},{10,10}},

        rotation=90)));

  Modelica.Blocks.Sources.Ramp ramp(duration = 5, height = 10, offset = TAmb, startTime = 5) annotation(

    Placement(visible = true, transformation(origin = {-136, -6}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));

equation

  connect(ambient1.flowPort, pump.flowPort_a) annotation(

    Line(points = {{-60, 0}, {-40, 0}}, color = {255, 0, 0}));

  connect(pump.flowPort_b, pipe.flowPort_a) annotation(

    Line(points = {{-20, 0}, {0, 0}}, color = {255, 0, 0}));

  connect(pipe.flowPort_b, ambient2.flowPort) annotation(

    Line(points = {{20, 0}, {40, 0}}, color = {255, 0, 0}));

  connect(thermalConductor.port_a, heatCapacitor.port) annotation(

    Line(points = {{10, -40}, {10, -45}, {10, -50}}, color = {191, 0, 0}));

  connect(pipe.heatPort, thermalConductor.port_b) annotation(

    Line(points = {{10, -10}, {10, -20}}, color = {191, 0, 0}));

  connect(ambient1.ambientTemperature, ramp.y) annotation(

    Line(points = {{-80, -6}, {-124, -6}, {-124, -6}, {-124, -6}}, color = {0, 0, 127}));

  annotation(

    Documentation(info = "<html>

<p>

7th test example: OneMass

</p>

A thermal capacity is coupled with a coolant flow.

Different initial temperatures of thermal capacity and pipe's coolant get ambient's temperature,

the time behaviour depending on coolant flow.

</html>"),

    experiment(StopTime = 1.0, Interval = 0.001),

    uses(Modelica(version = "3.2.3")));

end OneMass;

BelgianJoris: 3 Posts; Thank you [ 0 ]

#9768 Permalink

Re: Initializing error

Mar-02-20 11:58:19

It seems strange, because I am getting no error with your model, just a traslation warning.
Which soft are you using?

CTG: 124 Posts; Thank you [ 28 ]

#9769 Permalink

Re: Initializing error

Mar-02-20 12:14:30

OMEdit Connected to OpenModelica v1.14.1 (64-bit)
OneMass.log

Attachments:

OneMass.log

BelgianJoris: 3 Posts; Thank you [ 0 ]

#9770 Permalink

Re: Initializing error

Mar-02-20 12:49:04

Hi,
I'm getting similar errors when using the new frontend, but no error with the old, that is the one I am using by default.
Could you try to go to Simulation Setup, Translation flags, and activate the check box Enable old frontend for code generation?

CTG: 124 Posts; Thank you [ 28 ]

#9771 Permalink

Re: Initializing error

Mar-02-20 12:57:15

CTG wrote:
Simulation Setup, Translation flags, and activate the check box Enable old frontend for code generation?

This seems to have done the trick. So something wrong with the new frontend?

BelgianJoris: 3 Posts; Thank you [ 0 ]

#9772 Permalink

Re: Initializing error

Mar-02-20 13:19:07

Well they are just changing now from the old frontend to the new, that is much faster in translation. But, till now, it seems more limited than the old one. We need to wait for its improvement.

CTG: 124 Posts; Thank you [ 28 ]