modelPCV

Pressure and pressure-drop control valve

Extends from ThermofluidStream.Interfaces.SISOFlow (Base Model with basic flow eqautions for SISO).

Information

This component can be used to emulate a pressure-drop or output-pressure regulated control valve, depending on the chosen valve mode.

Depending on the parameter mode, either the pressure at the outlet p_out or the pressure difference dp between inlet and outlet can be stipulated. This is done either by parameter pressure_set_par or via input connector pressure_set_var when setting pressureFromInput = true. The resulting mass flow will be determined by its usual dynamics.

Setting dp instead of p_out has advantages, when p_out is determined by a volume at the outlet (for instance an accumulator).

The pressure difference dp is normalized, such that it cannot create pressure and it is zero for zero or negative mass flow.

If the desired pressure drop or outlet pressure, i.e. the target pressure drop in either case, can't be reached, a red dot shows up on the icon.

Parameters

TypeNameDefaultDescription
StringinstanceName (from DropOfCommonsPlus)getInstanceName()Instance name
ModemodeThermofluidStream.FlowControl.Internal.Types.PressureControlValveMode.dropValve mode
SI.Pressureeps1Threshold for visual warning
Layout
BooleandisplayInstanceName (from DropOfCommonsPlus)dropOfCommons.displayInstanceNames= true, if instance name is displayed
BooleandisplayParameters (from DropOfCommonsPlus)dropOfCommons.displayParameters= true, if displaying parameters is enabled
Advanced
BooleanconsiderInertance (from SISOFlow)dropOfCommons.considerInertance=true, if transient momentum (inertance) term is considered; disable only for advanced use
Utilities.Units.InertanceL (from SISOFlow)dropOfCommons.LInertance
StateSelectm_flowStateSelect (from SISOFlow)StateSelect.defaultState selection for mass flow rate
Booleanclip_p_out (from SISOFlow)= false, if dr_corr=0 (correction of inertial pressure difference)
Medium.AbsolutePressurep_min (from SISOFlow)dropOfCommons.p_minMinimum steady-state output pressure
SI.MassFlowRatem_flow_regdropOfCommons.m_flow_regRegularization mass flow
Initialization › Mass flow rate
InitializationMethodsinitM_flow (from SISOFlow)ThermofluidStream.Utilities.Types.InitializationMethods.noneInitialization method for mass flow rate
SI.MassFlowRatem_flow_0 (from SISOFlow)0Initial value for mass flow rate
Utilities.Units.MassFlowAccelerationm_acceleration_0 (from SISOFlow)0Initial value for derivative of mass flow rate
Pressure setpoint
BooleanpressureFromInputfalseIf true, pressure input connector is enabled
SI.AbsolutePressurepressure_set_par0Setpoint for pressure / pressure difference

Connectors

TypeNameDefaultDescription
Inletinlet (from SISOFlow)
Outletoutlet (from SISOFlow)
Modelica.Blocks.Interfaces.RealInputpressure_set_varPressure input connector [Pa]

Components

TypeNameDefaultDescription
SI.MassFlowRatem_flow (from SISOFlow)inlet.m_flowMass flow rate
SI.Pressuredr_corr (from SISOFlow)Correction of inertial pressure difference
SI.Pressuredp (from SISOFlow)Pressure difference
Medium.AbsolutePressurep_in (from SISOFlow)Medium.pressure(inlet.state)Inlet pressure
Medium.SpecificEnthalpyh_in (from SISOFlow)Medium.specificEnthalpy(inlet.state)Inlet specific enthalpy
Medium.MassFraction[Medium.nXi]Xi_in (from SISOFlow)Medium.massFraction(inlet.state)Inlet mass fractions
Medium.AbsolutePressurep_out (from SISOFlow)Outlet pressure
Medium.SpecificEnthalpyh_out (from SISOFlow)Outlet specific enthalpy
Medium.MassFraction[Medium.nXi]Xi_out (from SISOFlow)Outlet mass fractions
SI.Pressuredp_rawNot normalized desired dp