Annex60.Fluid.MixingVolumes.Examples

This model demonstrates the use of the mixing volume with heat conduction to the ambient. The mixing volume is configured as a steady-state model.

Modelica definition

Name	Description
MixingVolumeHeatConduction	Test model for heat transfer to volume
MixingVolumeMoistAir	Test model for mixing volume with moist air input
MixingVolumePrescribedHeatFlowRate	Test model for heat transfer to volume

model MixingVolumeHeatConduction "Test model for heat transfer to volume" extends Modelica.Icons.Example; package Medium = Annex60.Media.Air; Modelica.Thermal.HeatTransfer.Components.ThermalConductor theCon(G=10) "Thermal conductor"; Modelica.Thermal.HeatTransfer.Sensors.HeatFlowSensor heaFlo "Heat flow sensor"; Modelica.Thermal.HeatTransfer.Sources.FixedTemperature TAmb(T=293.15) "Ambient temperature"; Modelica.Fluid.Sources.MassFlowSource_T sou( redeclare package Medium = Medium, use_m_flow_in=true, T=313.15, nPorts=1) "Flow source and sink"; Modelica.Fluid.Sources.FixedBoundary bou( redeclare package Medium = Medium, T=303.15, nPorts=1) "Boundary condition"; Annex60.Fluid.MixingVolumes.MixingVolume vol( V=1, redeclare package Medium = Medium, m_flow_nominal=0.01, energyDynamics=Modelica.Fluid.Types.Dynamics.SteadyState, massDynamics=Modelica.Fluid.Types.Dynamics.SteadyState, allowFlowReversal=true, nPorts=2); Modelica.Blocks.Sources.Ramp ramp( duration=1, offset=1, height=-2); Modelica.Blocks.Math.Gain gain(k=0.01); equation connect(TAmb.port, theCon.port_a); connect(heaFlo.port_b, vol.heatPort); connect(ramp.y, gain.u); connect(gain.y, sou.m_flow_in); connect(theCon.port_b, heaFlo.port_a); connect(sou.ports[1], vol.ports[1]); connect(vol.ports[2], bou.ports[1]); end MixingVolumeHeatConduction;

Annex60.Fluid.MixingVolumes.Examples.MixingVolumeMoistAir

Information

Parameters

Modelica definition

Type	Name	Default	Description
MassFlowRate	m_flow_nominal	0.001	Nominal mass flow rate [kg/s]

model MixingVolumeMoistAir "Test model for mixing volume with moist air input" extends Modelica.Icons.Example; package Medium = Annex60.Media.Air; parameter Modelica.SIunits.MassFlowRate m_flow_nominal = 0.001 "Nominal mass flow rate"; Annex60.Fluid.MixingVolumes.MixingVolumeMoistAir vol1( redeclare package Medium = Medium, V=1, nPorts=2, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, m_flow_nominal=m_flow_nominal) "Volume"; Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensor TSen "Temperature sensor"; Modelica.Blocks.Sources.Constant XSet(k=0.005) "Set point for water mass fraction"; Modelica.Thermal.HeatTransfer.Sources.PrescribedHeatFlow preHeaFlo; Modelica.Blocks.Sources.Constant TSet(k=273.15 + 20) "Set point for temperature"; Annex60.Utilities.Psychrometrics.pW_X humRat( use_p_in=false) "Conversion from humidity ratio to partial water vapor pressure"; Annex60.Utilities.Psychrometrics.TDewPoi_pW dewPoi "Dew point temperature"; Modelica.Thermal.HeatTransfer.Sensors.HeatFlowSensor heatFlowSensor; Modelica.Blocks.Continuous.Integrator QSen "Sensible heat transfer"; Modelica.Blocks.Continuous.Integrator QLat "Enthalpy of extracted water"; Modelica.Blocks.Sources.RealExpression QLat_flow(y=vol1.QLat_flow.y) "MoistAir heat flow rate"; Annex60.Fluid.Sources.MassFlowSource_T sou( redeclare package Medium = Medium, nPorts=1, T=293.15); Annex60.Fluid.Sources.Boundary_pT sin( redeclare package Medium = Medium, T=293.15, nPorts=1); Annex60.Controls.Continuous.LimPID PI( Ni=0.1, yMax=1000, k=1, Ti=1, Td=1, controllerType=Modelica.Blocks.Types.SimpleController.PI, wd=0, yMin=-1000); Annex60.Controls.Continuous.LimPID PI1( Ni=0.1, Ti=1, controllerType=Modelica.Blocks.Types.SimpleController.PI, k=10, yMax=1, yMin=-1, Td=1); Annex60.Fluid.Sensors.MassFlowRate mIn_flow(redeclare package Medium = Medium); Annex60.Fluid.Sensors.MassFlowRate mOut_flow(redeclare package Medium = Medium); Modelica.Blocks.Math.Add dM_flow(k2=-1); Modelica.Blocks.Math.Gain gai(k=200); Modelica.Blocks.Math.Gain gai1(k=0.1); Annex60.Fluid.FixedResistances.PressureDrop res1( redeclare each package Medium = Medium, from_dp=true, dp_nominal=2.5, m_flow_nominal=m_flow_nominal); equation connect(preHeaFlo.port, heatFlowSensor.port_a); connect(heatFlowSensor.Q_flow, QSen.u); connect(QLat_flow.y,QLat. u); connect(TSet.y, PI.u_s); connect(TSen.T, PI.u_m); connect(XSet.y, PI1.u_s); connect(mOut_flow.m_flow, dM_flow.u1); connect(mIn_flow.m_flow, dM_flow.u2); connect(gai.y, preHeaFlo.Q_flow); connect(PI1.y, gai1.u); connect(gai1.y, vol1.mWat_flow); connect(dewPoi.T, vol1.TWat); connect(vol1.X_w, PI1.u_m); connect(vol1.X_w, humRat.X_w); connect(sou.ports[1], mIn_flow.port_a); connect(heatFlowSensor.port_b, vol1.heatPort); connect(TSen.port, vol1.heatPort); connect(mIn_flow.port_b, vol1.ports[1]); connect(mOut_flow.port_a, vol1.ports[2]); connect(PI.y, gai.u); connect(humRat.p_w, dewPoi.p_w); connect(mOut_flow.port_b, res1.port_a); connect(res1.port_b, sin.ports[1]); end MixingVolumeMoistAir;

Annex60.Fluid.MixingVolumes.Examples.MixingVolumePrescribedHeatFlowRate

Information

This model demonstrates the use of the mixing volume with a prescribed heat flow rate. The mixing volume is configured as a steady-state model. The heat flow rate is set to a very small value. This model is used to test convergence for the case the prescribed heat flow rate should be zero, but due to numerical solutions, it may have a small error that causes the signal to be non-zero.

Modelica definition

model MixingVolumePrescribedHeatFlowRate "Test model for heat transfer to volume" extends Modelica.Icons.Example; package Medium = Annex60.Media.Air; Modelica.Thermal.HeatTransfer.Sensors.HeatFlowSensor heaFlo "Heat flow sensor"; Modelica.Fluid.Sources.MassFlowSource_T sou( nPorts=1, redeclare package Medium = Medium, use_m_flow_in=true, T=313.15) "Flow source and sink"; Modelica.Fluid.Sources.FixedBoundary bou( redeclare package Medium = Medium, nPorts=1, T=303.15) "Boundary condition"; Annex60.Fluid.MixingVolumes.MixingVolume vol( V=1, nPorts=2, redeclare package Medium = Medium, m_flow_nominal=0.01, energyDynamics=Modelica.Fluid.Types.Dynamics.SteadyState, massDynamics=Modelica.Fluid.Types.Dynamics.SteadyState, allowFlowReversal=true, prescribedHeatFlowRate=true); Modelica.Blocks.Sources.Ramp ramp( duration=1, offset=1, height=-2); Modelica.Blocks.Math.Gain gain(k=0.01); Modelica.Blocks.Sources.Constant const(k=0); Modelica.Thermal.HeatTransfer.Sources.PrescribedHeatFlow preHeaFlo "Prescribed heat flow rate"; equation connect(sou.ports[1], vol.ports[1]); connect(ramp.y, gain.u); connect(gain.y, sou.m_flow_in); connect(vol.ports[2], bou.ports[1]); connect(preHeaFlo.port, heaFlo.port_a); connect(preHeaFlo.Q_flow, const.y); connect(heaFlo.port_b, vol.heatPort); end MixingVolumePrescribedHeatFlowRate;