ibpsa · mwetter · Oct 12, 2021 · Jul 12, 2021 · Jul 12, 2021 · Jul 12, 2021
diff --git a/IBPSA/Fluid/FixedResistances/BaseClasses/PlugFlowTransportDelay.mo b/IBPSA/Fluid/FixedResistances/BaseClasses/PlugFlowTransportDelay.mo
@@ -23,12 +23,13 @@ model PlugFlowTransportDelay "Delay time for given normalized velocity"
     if initDelay and (abs(m_flow_start) > 1E-10*m_flow_nominal)
      then min(-length/m_flow_start*(rho*dh^2/4*Modelica.Constants.pi), 0) else 0
     "Initial value of input time at outlet";
-
+  final parameter Real conUM(unit="1/kg") = 4/rho/dh/dh/Modelica.Constants.pi/length
+    "Constant to convert mass flow rate into velocity normalized by the pipe length";
   Modelica.SIunits.Time time_out_rev "Reverse flow direction output time";
   Modelica.SIunits.Time time_out_des "Design flow direction output time";
 
   Real x(start=0) "Spatial coordinate for spatialDistribution operator";
-  Modelica.SIunits.Frequency u "Normalized fluid velocity (1/s)";
+  Real u(unit="1/s") "Normalized fluid velocity (1/s)";
 
   Modelica.Blocks.Interfaces.RealInput m_flow "Mass flow of fluid" annotation (
       Placement(transformation(extent={{-140,-20},{-100,20}}),
@@ -48,8 +49,7 @@ initial equation
   t0 = time;
 
 equation
-  u = m_flow/(rho*(dh^2)/4*Modelica.Constants.pi)/length;
-
+  u = m_flow * conUM;
   der(x) = u;
   (time_out_rev, time_out_des) = spatialDistribution(
     time,
@@ -119,17 +119,14 @@ function. This components requires the mass flow through the pipe and the pipe
 dimensions in order to derive information about the fluid propagation.
 </p>
 <p>
-The component calculates the delay time at both in/outlet ports of the pipe
-and therefore has two outlets. During forward flow, only the forward
-<a href=\"modelica://IBPSA.Fluid.FixedResistances.BaseClasses.PlugFlowTransportDelay\">
-IBPSA.Fluid.FixedResistances.BaseClasses.PlugFlowTransportDelay</a> component in
-<a href=\"modelica://IBPSA.Fluid.FixedResistances.BaseClasses.PlugFlowCore\">
-IBPSA.Fluid.FixedResistances.BaseClasses.PlugFlowCore</a>
-will be active and uses the forward output of PlugFlowTransportDelay.
-During reverse, the opposite is true and only the reverse output is used.
+The component calculates the delay time at the inlet and the outlet port of the pipe.
+For the forward flow, the time delay is exposed at the output <code>tau</code>,
+and for the backward flow, the time delay is exposed at the output <code>tauRev</code>.
 </p>
 <h4>Assumption</h4>
-<p>It is assumed that no axial mixing takes place in the pipe. </p>
+<p>
+No axial mixing takes place in the pipe.
+</p>
 </html>", revisions="<html>
 <ul>
 <li>

diff --git a/IBPSA/Fluid/FixedResistances/BaseClasses/package.order b/IBPSA/Fluid/FixedResistances/BaseClasses/package.order
@@ -1,5 +1,3 @@
 PlugFlow
-PlugFlowCore
 PlugFlowHeatLoss
 PlugFlowTransportDelay
-Validation
diff --git a/IBPSA/Fluid/FixedResistances/Examples/PlugFlowPipe.mo b/IBPSA/Fluid/FixedResistances/Examples/PlugFlowPipe.mo
@@ -3,67 +3,124 @@ model PlugFlowPipe "Simple example of plug flow pipe"
   extends Modelica.Icons.Example;
   replaceable package Medium = IBPSA.Media.Water "Medium in the pipe" annotation (
       choicesAllMatching=true);
+
+  final parameter Modelica.SIunits.MassFlowRate m_flow_nominal=3
+    "Mass flow rate";
+
   Modelica.Blocks.Sources.Ramp Tin(
     height=20,
     duration=0,
     offset=273.15 + 50,
     startTime=100) "Ramp pressure signal"
-    annotation (Placement(transformation(extent={{-92,-6},{-72,14}})));
+    annotation (Placement(transformation(extent={{-100,-10},{-80,10}})));
   Sources.Boundary_pT sin(
     redeclare package Medium = Medium,
     T=273.15 + 10,
-    nPorts=1,
+    nPorts=2,
     p(displayUnit="Pa") = 101325) "Pressure boundary condition"
-    annotation (Placement(transformation(extent={{82,-10},{62,10}})));
+    annotation (Placement(transformation(extent={{100,-10},{80,10}})));
   IBPSA.Fluid.FixedResistances.PlugFlowPipe pip(
     redeclare package Medium = Medium,
-    nPorts=1,
     dh=0.1,
     length=100,
     dIns=0.05,
     kIns=0.028,
-    m_flow_nominal=1,
+    m_flow_nominal=m_flow_nominal,
     cPip=500,
     thickness=0.0032,
     initDelay=true,
-    m_flow_start=1,
+    m_flow_start=m_flow_nominal,
     rhoPip=8000,
     T_start_in=323.15,
     T_start_out=323.15) "Pipe"
-    annotation (Placement(transformation(extent={{0,-10},{20,10}})));
-  Modelica.Thermal.HeatTransfer.Sources.FixedTemperature bou(T=283.15)
+    annotation (Placement(transformation(extent={{0,10},{20,30}})));
+  Modelica.Thermal.HeatTransfer.Sources.FixedTemperature bou[2](each T=283.15)
     "Boundary temperature"
     annotation (Placement(transformation(extent={{-40,60},{-20,80}})));
   IBPSA.Fluid.Sources.MassFlowSource_T sou(
-    nPorts=1,
     redeclare package Medium = Medium,
     use_T_in=true,
-    m_flow=3) "Flow source"
-    annotation (Placement(transformation(extent={{-60,-10},{-40,10}})));
+    m_flow=m_flow_nominal,
+    nPorts=1) "Flow source"
+    annotation (Placement(transformation(extent={{-60,10},{-40,30}})));
 
   IBPSA.Fluid.Sensors.TemperatureTwoPort senTemOut(
     redeclare package Medium = Medium,
-    m_flow_nominal=1,
+    m_flow_nominal=m_flow_nominal,
+    tau=0,
     T_start=323.15) "Temperature sensor"
-    annotation (Placement(transformation(extent={{30,-10},{50,10}})));
+    annotation (Placement(transformation(extent={{40,10},{60,30}})));
   IBPSA.Fluid.Sensors.TemperatureTwoPort senTemIn(
     redeclare package Medium = Medium,
-    m_flow_nominal=1,
+    m_flow_nominal=m_flow_nominal,
+    tau=0,
+    T_start=323.15) "Temperature sensor"
+    annotation (Placement(transformation(extent={{-30,10},{-10,30}})));
+  Sensors.TemperatureTwoPort senTemInNoMix(
+    redeclare package Medium = Medium,
+    m_flow_nominal=m_flow_nominal,
+    tau=0,
     T_start=323.15) "Temperature sensor"
-    annotation (Placement(transformation(extent={{-30,-10},{-10,10}})));
+    annotation (Placement(transformation(extent={{-30,-30},{-10,-10}})));
+  IBPSA.Fluid.FixedResistances.PlugFlowPipe pipNoMix(
+    have_pipCap=false,
+    redeclare package Medium = Medium,
+    dh=0.1,
+    length=100,
+    dIns=0.05,
+    kIns=0.028,
+    m_flow_nominal=m_flow_nominal,
+    cPip=500,
+    thickness=0.0032,
+    initDelay=true,
+    m_flow_start=m_flow_nominal,
+    rhoPip=8000,
+    T_start_in=323.15,
+    T_start_out=323.15) "Pipe"
+    annotation (Placement(transformation(extent={{0,-30},{20,-10}})));
+  Sensors.TemperatureTwoPort senTemOutNoMix(
+    redeclare package Medium = Medium,
+    m_flow_nominal=m_flow_nominal,
+    tau=0,
+    T_start=323.15) "Temperature sensor"
+    annotation (Placement(transformation(extent={{40,-30},{60,-10}})));
+  Sources.MassFlowSource_T souNoMix(
+    redeclare package Medium = Medium,
+    use_T_in=true,
+    m_flow=m_flow_nominal,
+    nPorts=1) "Flow source"
+    annotation (Placement(transformation(extent={{-60,-30},{-40,-10}})));
 equation
-  connect(bou.port, pip.heatPort)
-    annotation (Line(points={{-20,70},{10,70},{10,10}}, color={191,0,0}));
   connect(Tin.y, sou.T_in)
-    annotation (Line(points={{-71,4},{-62,4}}, color={0,0,127}));
-  connect(pip.ports_b[1], senTemOut.port_a)
-    annotation (Line(points={{20,0},{30,0}}, color={0,127,255}));
+    annotation (Line(points={{-79,0},{-68,0},{-68,24},{-62,24}},
+                                               color={0,0,127}));
+  connect(pip.port_b, senTemOut.port_a)
+    annotation (Line(points={{20,20},{40,20}},
+                                             color={0,127,255}));
   connect(senTemOut.port_b, sin.ports[1])
-    annotation (Line(points={{50,0},{62,0}}, color={0,127,255}));
-  connect(sou.ports[1], senTemIn.port_a)
-    annotation (Line(points={{-40,0},{-30,0}}, color={0,127,255}));
+    annotation (Line(points={{60,20},{76,20},{76,-1},{80,-1}},
+                                             color={0,127,255}));
   connect(senTemIn.port_b, pip.port_a)
-    annotation (Line(points={{-10,0},{0,0}}, color={0,127,255}));
+    annotation (Line(points={{-10,20},{0,20}},
+                                             color={0,127,255}));
+  connect(senTemInNoMix.port_b, pipNoMix.port_a)
+    annotation (Line(points={{-10,-20},{0,-20}}, color={0,127,255}));
+  connect(pipNoMix.port_b, senTemOutNoMix.port_a)
+    annotation (Line(points={{20,-20},{40,-20}}, color={0,127,255}));
+  connect(senTemOutNoMix.port_b, sin.ports[2]) annotation (Line(points={{60,-20},
+          {76,-20},{76,1},{80,1}},   color={0,127,255}));
+  connect(bou[1].port, pip.heatPort)
+    annotation (Line(points={{-20,70},{-4,70},{-4,40},{10,40},{10,30}},
+                                                        color={191,0,0}));
+  connect(bou[2].port, pipNoMix.heatPort) annotation (Line(points={{-20,70},{-4,
+          70},{-4,0},{10,0},{10,-10}},     color={191,0,0}));
+  connect(sou.ports[1], senTemIn.port_a) annotation (Line(points={{-40,20},{-30,
+          20}},               color={0,127,255}));
+  connect(souNoMix.ports[1], senTemInNoMix.port_a)
+    annotation (Line(points={{-40,-20},{-30,-20}}, color={0,127,255}));
+  connect(Tin.y, souNoMix.T_in) annotation (Line(points={{-79,0},{-68,0},{-68,
+          -16},{-62,-16}},
+                      color={0,0,127}));
   annotation (
     __Dymola_Commands(file=
           "Resources/Scripts/Dymola/Fluid/FixedResistances/Examples/PlugFlowPipe.mos"
@@ -72,12 +129,17 @@ equation
     Documentation(info="<html>
 <p>Basic test of model
 <a href=\"modelica://IBPSA.Fluid.FixedResistances.PlugFlowPipe\">
-IBPSA.Fluid.FixedResistances.PlugFlowPipe</a>.
+IBPSA.Fluid.FixedResistances.PlugFlowPipe</a> with and without outlet mixing volume.
 This test includes an inlet temperature step under a constant mass flow rate.
 </p>
 </html>", revisions="<html>
 <ul>
+<li>July 27, 2021 by Baptiste Ravache<br/>Add case without mixing volume</li>
+</ul>
+<ul>
 <li>September 8, 2017 by Bram van der Heijde<br/>First implementation</li>
 </ul>
-</html>"));
+</html>"),
+    Diagram(coordinateSystem(extent={{-120,-100},{120,100}})),
+    Icon(coordinateSystem(extent={{-100,-100},{100,100}})));
 end PlugFlowPipe;