modelConductionElement

Model of quasi-stationary mass and heat transfer

Extends from Internal.PartialConductionElement (Partial model of quasi-stationary mass and heat transfer).

Information

This model represents an element with a fixed volume (fig. 1). The mass inside the volume is assumed quasi-stationary, meaning it is computed statically using the volume and density, and the inlet mass flow is coupled to the outlet mass flow.

Because of this, the ConductionElement cannot be used as a loop breaker.

The advantage of this approach is that multiple ConductionElements can be connected in series without causing oscillations or fast eigenvalues between their masses. The ConductionElement implements conservation of mass and energy equations for the fluid contained within the component.

For further details, see the documentation of the base class Internal.PartialConductionElement.

The useHeatTransferPropertyInput option can be selected to enable input connectors for the overall heat transfer coefficient U or the thermal conductance k = U*A. The resistanceFromAU checkbox determines which quantity is activated:

  • useHeatTransferPropertyInput = true and resistanceFromAU = true: enables the U input (overall heat transfer coefficient)
  • useHeatTransferPropertyInput = true and resistanceFromAU = false: enables the k input (thermal conductance)
  • useHeatTransferPropertyInput = false and resistanceFromAU = true: enables the U parameter (overall heat transfer coefficient)
  • useHeatTransferPropertyInput = false and resistanceFromAU = false: enables the k parameter (thermal conductance)

Parameters

TypeNameDefaultDescription
StringinstanceName (from DropOfCommonsPlus)getInstanceName()Instance name
SI.VolumeV (from PartialConductionElement)0.001Volume
BooleandisplayAnythingdisplayParameters and (displayVolume or displayConduction)
StringparameterStringif displayParameters and displayVolume and displayConduction then "V=%V, " + conductionString elseif displayParameters and displayVolume and not displayConduction then "V=%V" elseif displayParameters and not displayVolume and displayConduction then conductionString else ""
StringconductionStringif useHeatTransferPropertyInput and resistanceFromAU then "A=%A" elseif not useHeatTransferPropertyInput and resistanceFromAU then "A=%A, U=%U" elseif not useHeatTransferPropertyInput and not resistanceFromAU then "k=%k_par" else ""
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
Medium.Densityrho_min (from PartialConductionElement)dropOfCommons.rho_minMinimal density
BooleanneglectPressureChanges (from PartialConductionElement)true=true, if pressure changes are neglected
SI.MassFlowRatem_flow_assert (from PartialConductionElement)-dropOfCommons.m_flow_regAssertion threshold for negative massflows
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
Initialization › Specific enthalpy
Internal.InitializationMethodsCondElementinit (from PartialConductionElement)ThermofluidStream.Processes.Internal.InitializationMethodsCondElement.inletInitialization for specific enthalpy
Medium.TemperatureT_0 (from PartialConductionElement)Medium.T_defaultInitial Temperature
Medium.SpecificEnthalpyh_0 (from PartialConductionElement)Medium.h_defaultInitial specific enthalpy
Advanced › Global energy conservation
Booleanenforce_global_energy_conservation (from PartialConductionElement)false= true, if global conservation of energy is enforced
Advanced › global energy conservation
SI.TimeT_e (from PartialConductionElement)100Time constant for global conservation of energy
Thermal Conductance
BooleanuseHeatTransferPropertyInputfalse= true, if input connector for either U or k_par is enabled
BooleanresistanceFromAUtrue= true, if thermal conductance is given by U*A
SI.AreaA1Heat transfer area
SI.CoefficientOfHeatTransferU200Overall heat transfer coefficient
SI.ThermalConductancek_par200Thermal conductance
Layout › Display parameters
BooleandisplayVolumetrue= true, if volume V is displayed
BooleandisplayConductiontrue= true, if thermal conductance is displayed

Connectors

TypeNameDefaultDescription
Inletinlet (from SISOFlow)
Outletoutlet (from SISOFlow)
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_aheatPort (from PartialConductionElement)
Modelica.Blocks.Interfaces.RealInputU_varOverall heat transfer coefficient input connector [W/(m2.K)]
Modelica.Blocks.Interfaces.RealInputk_varThermal conductance input connector [W/K]

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
Medium.SpecificEnthalpyh (from PartialConductionElement)Volume? specific enthalpy
Medium.ThermodynamicStatestate (from PartialConductionElement)Medium.setState_phX(p_in, h, Xi_in)Volume thermodynamic state
Medium.TemperatureT (from PartialConductionElement)Medium.temperature(state)Volume temperature
SI.ThermalConductancek (from PartialConductionElement)Thermal conductance
SI.EnergydeltaE_system (from PartialConductionElement)Energy difference between m_flow*(h_in-h_out) and Q_flow
SI.MassM (from PartialConductionElement)Mass (of the volume)