modelThreeWayEqualPercentageLinear

Three way valve with equal percentage and linear characteristics
Diagram of ThreeWayEqualPercentageLinearOpen the diagram
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Extends from BaseClasses.PartialThreeWayValve (Partial three way valve).

Information

Three way valve with equal percentage characteristics between port_1 and port_2 and linear opening characteristic between port_3 and port_2. Such opening characteristics were typical for valves from Landis & Gyr (now Siemens).

This model is based on the partial valve models Buildings.Fluid.Actuators.BaseClasses.PartialThreeWayValve and Buildings.Fluid.Actuators.BaseClasses.PartialTwoWayValve. See Buildings.Fluid.Actuators.BaseClasses.PartialThreeWayValve for the implementation of the three way valve and see Buildings.Fluid.Actuators.BaseClasses.PartialTwoWayValve for the implementation of the regularization near the origin.

Parameters

TypeNameDefaultDescription
BooleanhomotopyInitialization (from PartialThreeWayValve)true= true, use homotopy method
RealfraK (from PartialThreeWayValve)0.7Fraction Kv(port_3→port_2)/Kv(port_1→port_2)
Reall (from PartialThreeWayValve){0.0001, 0.0001}Valve leakage, l=Kv(y=0)/Kv(y=1)
RealR50Rangeability, R=50...100 typically
Realdelta00.01Range of significant deviation from equal percentage law
Dynamics › Conservation equations
Modelica.Fluid.Types.DynamicsenergyDynamics (from LumpedVolumeDeclarations)Modelica.Fluid.Types.Dynamics.DynamicFreeInitialType of energy balance: dynamic (3 initialization options) or steady state
Modelica.Fluid.Types.DynamicssubstanceDynamics (from LumpedVolumeDeclarations)energyDynamicsType of independent mass fraction balance: dynamic (3 initialization options) or steady state
Modelica.Fluid.Types.DynamicstraceDynamics (from LumpedVolumeDeclarations)energyDynamicsType of trace substance balance: dynamic (3 initialization options) or steady state
Modelica.Units.SI.MassFlowRatemDyn_flow_nominal (from PartialThreeWayResistance)Nominal mass flow rate for dynamic momentum and energy balance
Advanced › Dynamics
Modelica.Fluid.Types.DynamicsmassDynamics (from LumpedVolumeDeclarations)energyDynamicsType of mass balance: dynamic (3 initialization options) or steady state, must be steady state if energyDynamics is steady state
Initialization
Medium.AbsolutePressurep_start (from LumpedVolumeDeclarations)Medium.p_defaultStart value of pressure
Medium.TemperatureT_start (from LumpedVolumeDeclarations)Medium.T_defaultStart value of temperature
Medium.MassFraction[Medium.nX]X_start (from LumpedVolumeDeclarations)Medium.X_defaultStart value of mass fractions m_i/m
Medium.ExtraProperty[Medium.nC]C_start (from LumpedVolumeDeclarations)fill(0, Medium.nC)Start value of trace substances
Medium.ExtraProperty[Medium.nC]C_nominal (from LumpedVolumeDeclarations)fill(1E-2, Medium.nC)Nominal value of trace substances. (Set to typical order of magnitude.)
Dynamics
RealmSenFac (from LumpedVolumeDeclarations)1Factor for scaling the sensible thermal mass of the volume
Dynamics › Nominal condition
Modelica.Units.SI.Timetau (from PartialThreeWayResistance)10Time constant at nominal flow for dynamic energy and momentum balance
Advanced
Booleanfrom_dp (from PartialThreeWayResistance)true= true, use m_flow = f(dp) else dp = f(m_flow)
Modelica.Fluid.Types.PortFlowDirectionportFlowDirection_1 (from PartialThreeWayResistance)Modelica.Fluid.Types.PortFlowDirection.BidirectionalFlow direction for port_1
Modelica.Fluid.Types.PortFlowDirectionportFlowDirection_2 (from PartialThreeWayResistance)Modelica.Fluid.Types.PortFlowDirection.BidirectionalFlow direction for port_2
Modelica.Fluid.Types.PortFlowDirectionportFlowDirection_3 (from PartialThreeWayResistance)Modelica.Fluid.Types.PortFlowDirection.BidirectionalFlow direction for port_3
BooleanverifyFlowReversal (from PartialThreeWayResistance)false=true, to assert that the flow does not reverse when portFlowDirection_* does not equal Bidirectional
Modelica.Units.SI.MassFlowRatem_flow_small (from PartialThreeWayResistance)Small mass flow rate for checking flow reversal
Booleanlinearized (from PartialThreeWayValve){false, false}= true, use linear relation between m_flow and dp for any flow rate
Dynamics › Actuator position
Booleanuse_strokeTime (from ActuatorSignal)trueSet to true to continuously open and close valve using strokeTime
Modelica.Units.SI.TimestrokeTime (from ActuatorSignal)120Time needed to fully open or close actuator
Modelica.Blocks.Types.Initinit (from ActuatorSignal)Modelica.Blocks.Types.Init.InitialOutputType of initialization (no init/steady state/initial state/initial output)
Realy_start (from ActuatorSignal)1Initial position of actuator
Flow Coefficient
Buildings.Fluid.Types.CvTypesCvData (from ValveParameters)Buildings.Fluid.Types.CvTypes.OpPointSelection of flow coefficient
RealKv (from ValveParameters)Kv (metric) flow coefficient [m3/h/(bar)^(1/2)]
RealCv (from ValveParameters)Cv (US) flow coefficient [USG/min/(psi)^(1/2)]
Modelica.Units.SI.AreaAv (from ValveParameters)Av (metric) flow coefficient
Pressure-flow linearization
RealdeltaM (from ValveParameters)0.02Fraction of nominal flow rate where linearization starts, if y=1
Nominal condition
Modelica.Units.SI.MassFlowRatem_flow_nominal (from ValveParameters)Nominal mass flow rate
Modelica.Units.SI.PressureDifferencedpValve_nominal (from ValveParameters)Nominal pressure drop of fully open valve, used if CvData=Buildings.Fluid.Types.CvTypes.OpPoint
Modelica.Units.SI.PressureDifference[2]dpFixed_nominal (from PartialThreeWayValve){0, 0}Nominal pressure drop of pipes and other equipment in flow legs at port_1 and port_3
Advanced › Nominal condition
Modelica.Units.SI.DensityrhoStd (from ValveParameters)Inlet density for which valve coefficients are defined

Connectors

TypeNameDefaultDescription
Modelica.Fluid.Interfaces.FluidPort_aport_1 (from PartialThreeWayResistance)First port, typically inlet
Modelica.Fluid.Interfaces.FluidPort_bport_2 (from PartialThreeWayResistance)Second port, typically outlet
Modelica.Fluid.Interfaces.FluidPort_aport_3 (from PartialThreeWayResistance)Third port, can be either inlet or outlet
Modelica.Blocks.Interfaces.RealInputy (from ActuatorSignal)Actuator position (0: closed, 1: open)
Modelica.Blocks.Interfaces.RealOutputy_actual (from ActuatorSignal)Actual actuator position

Components

TypeNameDefaultDescription
Buildings.Fluid.Interfaces.PartialTwoPortInterfaceres1 (from PartialThreeWayResistance)
Buildings.Fluid.Interfaces.PartialTwoPortInterfaceres2 (from PartialThreeWayResistance)
Buildings.Fluid.Interfaces.PartialTwoPortInterfaceres3 (from PartialThreeWayResistance)
Buildings.Fluid.Delays.DelayFirstOrdervol (from PartialThreeWayResistance)Fluid volume to break algebraic loop

Revisions

  • March 7, 2022, by Michael Wetter:
    Set final massDynamics=energyDynamics.
    This is for #1542.
  • June 10, 2021, by Michael Wetter:
    Changed implementation of the filter and changed the parameter order to a constant as most users need not change this value.
    This is for #1498.
  • February 21, 2020, by Michael Wetter:
    Changed icon to display its operating stage.
    This is for #1294.
  • November 5, 2019, by Michael Wetter:
    Moved assignment of leakage from Buildings.Fluid.Actuators.BaseClasses.PartialThreeWayValve to the parent classes.
    This is for #1227.
  • February 20, 2012 by Michael Wetter:
    Renamed parameter dp_nominal to dpValve_nominal, and added new parameter dpFixed_nominal. See Buildings.Fluid.Actuators.UsersGuide.
  • February 14, 2012 by Michael Wetter:
    Added filter to approximate the travel time of the actuator.
  • March 25, 2011, by Michael Wetter:
    Added homotopy method.
  • June 16, 2008 by Michael Wetter:
    First implementation.