Div by zero error in simple heat flow model

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Div by zero error in simple heat flow model

Div by zero error in simple heat flow model

May-15-20 18:51:41

Hi! I'm trying to run the simple model below in OpenModelica. But I get an error like below. I can't fingure out what I'm doing wrong. Any ideas?

Error:
solver will try to handle division by zero at time 0: if (-pump.flowPort_a.m_flow) >= 0.0 then -pump.flowPort_a.m_flow else -0.0

Code:

model test

    parameter Modelica.Thermal.FluidHeatFlow.Media.Medium medium=Modelica.Thermal.FluidHeatFlow.Media.Medium()

    "Cooling medium"

    annotation(choicesAllMatching=true);

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

    "Ambient temperature";

  Modelica.Thermal.FluidHeatFlow.Sources.Ambient ambient2(constantAmbientPressure = 0, constantAmbientTemperature = TAmb, medium = medium) annotation(

    Placement(visible = true, transformation(extent = {{40, -10}, {60, 10}}, rotation = 0)));

  Modelica.Thermal.FluidHeatFlow.Sources.Ambient ambient1(constantAmbientPressure = 0, constantAmbientTemperature = TAmb, medium = medium) annotation(

    Placement(visible = true, transformation(extent = {{-60, -10}, {-80, 10}}, rotation = 0)));

  Modelica.Thermal.FluidHeatFlow.Components.Pipe pipe(T0 = TAmb, T0fixed = true, V_flowLaminar = 0.1, V_flowNominal = 1, dpLaminar(displayUnit = "Pa") = 0.1, dpNominal(displayUnit = "Pa") = 1, h_g = 0, m = 0.1, medium = medium, useHeatPort = false) annotation(

    Placement(visible = true, transformation(extent = {{0, -10}, {20, 10}}, rotation = 0)));

  Modelica.Thermal.FluidHeatFlow.Sources.VolumeFlow pump(T0 = TAmb, constantVolumeFlow = 1, m = 0, medium = medium, useVolumeFlowInput = true) annotation(

    Placement(visible = true, transformation(extent = {{-40, -10}, {-20, 10}}, rotation = 0)));

  Modelica.Blocks.Sources.Constant volumeFlow(k = 1) annotation(

    Placement(visible = true, transformation(extent = {{-60, 10}, {-40, 30}}, rotation = 0)));

equation

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

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

  connect(volumeFlow.y, pump.volumeFlow) annotation(

    Line(points = {{-39, 20}, {-30, 20}, {-30, 10}}, color = {0, 0, 127}));

  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}));

  annotation(

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

end test;