Buildings.Fluid.Interfaces

Package with interfaces for fluid models

Information

This package contains basic classes that are used to build component models that change the state of the fluid. The classes are not directly usable, but can be extended when building a new model.

Extends from Modelica.Fluid.Icons.BaseClassLibrary (Icon for library).

Package Content

Name Description

FourPortFlowResistanceParameters Parameters for flow resistance for models with four ports

PartialDynamicFourPortTransformer Partial model transporting two fluid streams between four ports with storing mass or energy

PartialDynamicTwoPortTransformer Partial model transporting one fluid stream with storing mass or energy

PartialFourPort Partial model with four ports

PartialLumpedVolume Lumped volume with mass and energy balance

PartialStaticFourPortHeatMassTransfer Partial model transporting two fluid streams between four ports without storing mass or energy

PartialStaticFourPortInterface Partial model transporting fluid between two ports without storing mass or energy

PartialStaticTwoPortHeatMassTransfer Partial model transporting fluid between two ports without storing mass or energy

PartialStaticTwoPortInterface Partial model transporting fluid between two ports without storing mass or energy

TwoPortFlowResistanceParameters Parameters for flow resistance for models with two ports

Name	Description
FourPortFlowResistanceParameters	Parameters for flow resistance for models with four ports
PartialDynamicFourPortTransformer	Partial model transporting two fluid streams between four ports with storing mass or energy
PartialDynamicTwoPortTransformer	Partial model transporting one fluid stream with storing mass or energy
PartialFourPort	Partial model with four ports
PartialLumpedVolume	Lumped volume with mass and energy balance
PartialStaticFourPortHeatMassTransfer	Partial model transporting two fluid streams between four ports without storing mass or energy
PartialStaticFourPortInterface	Partial model transporting fluid between two ports without storing mass or energy
PartialStaticTwoPortHeatMassTransfer	Partial model transporting fluid between two ports without storing mass or energy
PartialStaticTwoPortInterface	Partial model transporting fluid between two ports without storing mass or energy
TwoPortFlowResistanceParameters	Parameters for flow resistance for models with two ports

Buildings.Fluid.Interfaces.FourPortFlowResistanceParameters

Parameters for flow resistance for models with four ports

Information

This class contains parameters that are used to compute the pressure drop in components that have two fluid streams. Note that the nominal mass flow rate is not declared here because the model PartialStaticFourPortInterface already declares it.

Parameters

Type Name Default Description

Nominal condition

Pressure dp1_nominal Pressure [Pa]

Pressure dp2_nominal Pressure [Pa]

Flow resistance

Medium 1

Boolean computeFlowResistance1 true =true, compute flow resistance. Set to false to assume no friction

Boolean from_dp1 true = true, use m_flow = f(dp) else dp = f(m_flow)

Boolean linearizeFlowResistance1 false = true, use linear relation between m_flow and dp for any flow rate

Real deltaM1 0.1 Fraction of nominal flow rate where flow transitions to laminar

Medium 2

Boolean computeFlowResistance2 true =true, compute flow resistance. Set to false to assume no friction

Boolean from_dp2 true = true, use m_flow = f(dp) else dp = f(m_flow)

Boolean linearizeFlowResistance2 false = true, use linear relation between m_flow and dp for any flow rate

Real deltaM2 0.1 Fraction of nominal flow rate where flow transitions to laminar

Type	Name	Default	Description
Nominal condition
Pressure	dp1_nominal		Pressure [Pa]
Pressure	dp2_nominal		Pressure [Pa]
Flow resistance
Medium 1
Boolean	computeFlowResistance1	true	=true, compute flow resistance. Set to false to assume no friction
Boolean	from_dp1	true	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance1	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM1	0.1	Fraction of nominal flow rate where flow transitions to laminar
Medium 2
Boolean	computeFlowResistance2	true	=true, compute flow resistance. Set to false to assume no friction
Boolean	from_dp2	true	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance2	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM2	0.1	Fraction of nominal flow rate where flow transitions to laminar

Modelica definition

record FourPortFlowResistanceParameters 
  "Parameters for flow resistance for models with four ports"


  parameter Boolean computeFlowResistance1 = true 
    "=true, compute flow resistance. Set to false to assume no friction";

  parameter Boolean from_dp1 = true 
    "= true, use m_flow = f(dp) else dp = f(m_flow)";
  parameter Modelica.SIunits.Pressure dp1_nominal(min=0, displayUnit="Pa") 
    "Pressure";
  parameter Boolean linearizeFlowResistance1 = false 
    "= true, use linear relation between m_flow and dp for any flow rate";
  parameter Real deltaM1 = 0.1 
    "Fraction of nominal flow rate where flow transitions to laminar";
  parameter Boolean computeFlowResistance2 = true 
    "=true, compute flow resistance. Set to false to assume no friction";

  parameter Boolean from_dp2 = true 
    "= true, use m_flow = f(dp) else dp = f(m_flow)";
  parameter Modelica.SIunits.Pressure dp2_nominal(min=0, displayUnit="Pa") 
    "Pressure";
  parameter Boolean linearizeFlowResistance2 = false 
    "= true, use linear relation between m_flow and dp for any flow rate";
  parameter Real deltaM2 = 0.1 
    "Fraction of nominal flow rate where flow transitions to laminar";
end FourPortFlowResistanceParameters;

Buildings.Fluid.Interfaces.PartialDynamicFourPortTransformer

Partial model transporting two fluid streams between four ports with storing mass or energy

Buildings.Fluid.Interfaces.PartialDynamicFourPortTransformer

Information

This component transports two fluid streams between four ports. It provides the basic model for implementing a dynamic heat exchanger. It is used by HeatExchangers.BaseClasses.HexElement. The variable names follow the conventions used in Modelica.Fluid.HeatExchangers.BasicHX.

Extends from Buildings.Fluid.Interfaces.PartialStaticFourPortInterface (Partial model transporting fluid between two ports without storing mass or energy), Buildings.Fluid.Interfaces.FourPortFlowResistanceParameters (Parameters for flow resistance for models with four ports). Parameters Type Name Default Description replaceable package Medium1 PartialMedium Medium 1 in the component replaceable package Medium2 PartialMedium Medium 2 in the component MixingVolumeDryAir vol2 redeclare Buildings.Fluid.Mi... Volume for fluid 2 Nominal condition MassFlowRate m1_flow_nominal Nominal mass flow rate [kg/s] MassFlowRate m2_flow_nominal m1_flow_nominal Nominal mass flow rate [kg/s] Pressure dp1_nominal Pressure [Pa] Pressure dp2_nominal Pressure [Pa] Time tau1 60 Time constant at nominal flow [s] Time tau2 60 Time constant at nominal flow [s] Initialization MassFlowRate m1_flow.start 0 Mass flow rate from port_a1 to port_b1 (m1_flow > 0 is design flow direction) [kg/s] Pressure dp1.start 0 Pressure difference between port_a1 and port_b1 [Pa] MassFlowRate m2_flow.start 0 Mass flow rate from port_a2 to port_b2 (m2_flow > 0 is design flow direction) [kg/s] Pressure dp2.start 0 Pressure difference between port_a2 and port_b2 [Pa] Assumptions Boolean allowFlowReversal1 system.allowFlowReversal = true to allow flow reversal in medium 1, false restricts to design direction (port_a -> port_b) Boolean allowFlowReversal2 system.allowFlowReversal = true to allow flow reversal in medium 2, false restricts to design direction (port_a -> port_b) Advanced MassFlowRate m1_flow_small 1E-4*m1_flow_nominal Small mass flow rate for regularization of zero flow [kg/s] MassFlowRate m2_flow_small 1E-4*m2_flow_nominal Small mass flow rate for regularization of zero flow [kg/s] Diagnostics Boolean show_V_flow false = true, if volume flow rate at inflowing port is computed Initialization AbsolutePressure p_a1_start system.p_start Guess value for inlet pressure [Pa] AbsolutePressure p_b1_start p_a1_start Guess value for outlet pressure [Pa] AbsolutePressure p_a2_start system.p_start Guess value for inlet pressure [Pa] AbsolutePressure p_b2_start p_a2_start Guess value for outlet pressure [Pa] Flow resistance Medium 1 Boolean computeFlowResistance1 true =true, compute flow resistance. Set to false to assume no friction Boolean from_dp1 true = true, use m_flow = f(dp) else dp = f(m_flow) Boolean linearizeFlowResistance1 false = true, use linear relation between m_flow and dp for any flow rate Real deltaM1 0.1 Fraction of nominal flow rate where flow transitions to laminar Medium 2 Boolean computeFlowResistance2 true =true, compute flow resistance. Set to false to assume no friction Boolean from_dp2 true = true, use m_flow = f(dp) else dp = f(m_flow) Boolean linearizeFlowResistance2 false = true, use linear relation between m_flow and dp for any flow rate Real deltaM2 0.1 Fraction of nominal flow rate where flow transitions to laminar Connectors Type Name Description FluidPort_a port_a1 Fluid connector a1 (positive design flow direction is from port_a1 to port_b1) FluidPort_b port_b1 Fluid connector b1 (positive design flow direction is from port_a1 to port_b1) FluidPort_a port_a2 Fluid connector a2 (positive design flow direction is from port_a2 to port_b2) FluidPort_b port_b2 Fluid connector b2 (positive design flow direction is from port_a2 to port_b2) Modelica definition partial model PartialDynamicFourPortTransformer "Partial model transporting two fluid streams between four ports with storing mass or energy" extends Buildings.Fluid.Interfaces.PartialStaticFourPortInterface; extends Buildings.Fluid.Interfaces.FourPortFlowResistanceParameters( final computeFlowResistance1=true, final computeFlowResistance2=true); import Modelica.Constants; Buildings.Fluid.MixingVolumes.MixingVolume vol1( redeclare package Medium = Medium1, nPorts = 2, V=m1_flow_nominal*tau1/rho1_nominal, medium(T(stateSelect=StateSelect.always)), final use_HeatTransfer=true, redeclare model HeatTransfer = Modelica.Fluid.Vessels.BaseClasses.HeatTransfer.IdealHeatTransfer) "Volume for fluid 1"; replaceable Buildings.Fluid.MixingVolumes.MixingVolumeDryAir vol2( redeclare package Medium = Medium2, nPorts = 2, V=m2_flow_nominal*tau2/rho2_nominal, final use_HeatTransfer=true, redeclare model HeatTransfer = Modelica.Fluid.Vessels.BaseClasses.HeatTransfer.IdealHeatTransfer(surfaceAreas={1})) constrainedby Buildings.Fluid.MixingVolumes.BaseClasses.PartialMixingVolumeWaterPort "Volume for fluid 2"; parameter Modelica.SIunits.Time tau1 = 60 "Time constant at nominal flow"; parameter Modelica.SIunits.Time tau2 = 60 "Time constant at nominal flow"; Modelica.SIunits.HeatFlowRate Q1_flow= if vol1.use_HeatTransfer then sum(vol1.heatPort.Q_flow) else 0 "Heat flow rate into medium 1"; Modelica.SIunits.HeatFlowRate Q2_flow= if vol2.use_HeatTransfer then sum(vol2.heatPort.Q_flow) else 0 "Heat flow rate into medium 2"; protected parameter Medium1.ThermodynamicState sta1_nominal=Medium1.setState_pTX( T=Medium1.T_default, p=Medium1.p_default, X=Medium1.X_default); parameter Modelica.SIunits.Density rho1_nominal=Medium1.density(sta1_nominal) "Density, used to compute fluid volume"; parameter Medium2.ThermodynamicState sta2_nominal=Medium2.setState_pTX( T=Medium2.T_default, p=Medium2.p_default, X=Medium2.X_default); parameter Modelica.SIunits.Density rho2_nominal=Medium2.density(sta2_nominal) "Density, used to compute fluid volume"; public FixedResistances.FixedResistanceDpM preDro1( redeclare package Medium = Medium1, final use_dh=false, final m_flow_nominal=m1_flow_nominal, final deltaM=deltaM1, final allowFlowReversal=allowFlowReversal1, final m_flow_small=m1_flow_small, final show_T=false, final show_V_flow=show_V_flow, final from_dp=from_dp1, final linearized=linearizeFlowResistance1, final dp_nominal=dp1_nominal, final dh=1, final ReC=4000) "Pressure drop model for fluid 1"; FixedResistances.FixedResistanceDpM preDro2( redeclare package Medium = Medium2, final use_dh=false, final m_flow_nominal=m2_flow_nominal, final deltaM=deltaM2, final allowFlowReversal=allowFlowReversal2, final m_flow_small=m2_flow_small, final show_T=false, final show_V_flow=show_V_flow, final from_dp=from_dp2, final linearized=linearizeFlowResistance2, final dp_nominal=dp2_nominal, final dh=1, final ReC=4000) "Pressure drop model for fluid 2"; equation assert(vol1.use_HeatTransfer == true, "Wrong parameter for vol1."); assert(vol2.use_HeatTransfer == true, "Wrong parameter for vol2."); connect(vol1.ports[2], port_b1); connect(vol2.ports[2], port_b2); connect(port_a1, preDro1.port_a); connect(preDro1.port_b, vol1.ports[1]); connect(port_a2, preDro2.port_a); connect(preDro2.port_b, vol2.ports[1]); end PartialDynamicFourPortTransformer; Buildings.Fluid.Interfaces.PartialDynamicTwoPortTransformer Partial model transporting one fluid stream with storing mass or energy Information This component transports one fluid stream. It provides the basic model for implementing a dynamic heater such as a boiler. It is used by Buildings.Fluid.Boilers.BoilerPolynomial. The variable names follow the conventions used in Modelica.Fluid.HeatExchangers.BasicHX. Extends from Buildings.Fluid.Interfaces.PartialStaticTwoPortInterface (Partial model transporting fluid between two ports without storing mass or energy), Buildings.Fluid.Interfaces.TwoPortFlowResistanceParameters (Parameters for flow resistance for models with two ports). Parameters Type Name Default Description replaceable package Medium PartialMedium Medium in the component Nominal condition MassFlowRate m_flow_nominal Nominal mass flow rate [kg/s] Pressure dp_nominal Pressure [Pa] Time tau 300 Time constant at nominal flow [s] Initialization MassFlowRate m_flow.start 0 Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s] Pressure dp.start 0 Pressure difference between port_a and port_b [Pa] Assumptions Boolean allowFlowReversal system.allowFlowReversal = true to allow flow reversal, false restricts to design direction (port_a -> port_b) Dynamics Dynamics energyDynamics system.energyDynamics Formulation of energy balance Dynamics massDynamics energyDynamics Formulation of mass balance Advanced MassFlowRate m_flow_small 1E-4*m_flow_nominal Small mass flow rate for regularization of zero flow [kg/s] Diagnostics Boolean show_V_flow false = true, if volume flow rate at inflowing port is computed Initialization AbsolutePressure p_a_start system.p_start Guess value for inlet pressure [Pa] AbsolutePressure p_b_start p_a_start Guess value for outlet pressure [Pa] AbsolutePressure p_start system.p_start Start value of pressure [Pa] Boolean use_T_start true = true, use T_start, otherwise h_start Temperature T_start if use_T_start then system.T... Start value of temperature [K] SpecificEnthalpy h_start if use_T_start then Medium.s... Start value of specific enthalpy [J/kg] MassFraction X_start[Medium.nX] Medium.X_default Start value of mass fractions m_i/m [kg/kg] ExtraProperty C_start[Medium.nC] fill(0, Medium.nC) Start value of trace substances Flow resistance Boolean computeFlowResistance true =true, compute flow resistance. Set to false to assume no friction Boolean from_dp true = true, use m_flow = f(dp) else dp = f(m_flow) Boolean linearizeFlowResistance false = true, use linear relation between m_flow and dp for any flow rate Real deltaM 0.1 Fraction of nominal flow rate where flow transitions to laminar Connectors Type Name Description FluidPort_a port_a Fluid connector a (positive design flow direction is from port_a to port_b) FluidPort_b port_b Fluid connector b (positive design flow direction is from port_a to port_b) Modelica definition partial model PartialDynamicTwoPortTransformer "Partial model transporting one fluid stream with storing mass or energy" extends Buildings.Fluid.Interfaces.PartialStaticTwoPortInterface; extends Buildings.Fluid.Interfaces.TwoPortFlowResistanceParameters( final computeFlowResistance=true); import Modelica.Constants; Buildings.Fluid.MixingVolumes.MixingVolume vol( redeclare package Medium = Medium, nPorts = 2, V=m_flow_nominal*tau/rho_nominal, final use_HeatTransfer=true, redeclare model HeatTransfer = Modelica.Fluid.Vessels.BaseClasses.HeatTransfer.IdealHeatTransfer, final energyDynamics=energyDynamics, final massDynamics=massDynamics, final p_start=p_start, final use_T_start=use_T_start, final T_start=T_start, final h_start=h_start, final X_start=X_start, final C_start=C_start) "Volume for fluid stream"; parameter Modelica.SIunits.Time tau = 300 "Time constant at nominal flow"; // Assumptions parameter Modelica.Fluid.Types.Dynamics energyDynamics=system.energyDynamics "Formulation of energy balance"; parameter Modelica.Fluid.Types.Dynamics massDynamics=energyDynamics "Formulation of mass balance"; final parameter Modelica.Fluid.Types.Dynamics substanceDynamics=massDynamics "Formulation of substance balance"; final parameter Modelica.Fluid.Types.Dynamics traceDynamics=massDynamics "Formulation of trace substance balance"; // Initialization parameter Medium.AbsolutePressure p_start = system.p_start "Start value of pressure"; parameter Boolean use_T_start = true "= true, use T_start, otherwise h_start"; parameter Medium.Temperature T_start= if use_T_start then system.T_start else Medium.temperature_phX(p_start,h_start,X_start) "Start value of temperature"; parameter Medium.SpecificEnthalpy h_start= if use_T_start then Medium.specificEnthalpy_pTX(p_start, T_start, X_start) else Medium.h_default "Start value of specific enthalpy"; parameter Medium.MassFraction X_start[Medium.nX] = Medium.X_default "Start value of mass fractions m_i/m"; parameter Medium.ExtraProperty C_start[Medium.nC]( quantity=Medium.extraPropertiesNames)=fill(0, Medium.nC) "Start value of trace substances"; Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensor temSen( T(final quantity="ThermodynamicTemperature", final unit = "K", displayUnit = "degC", min=0)) "Temperature sensor of metal"; protected parameter Medium.ThermodynamicState sta_nominal=Medium.setState_pTX( T=Medium.T_default, p=Medium.p_default, X=Medium.X_default); parameter Modelica.SIunits.Density rho_nominal=Medium.density(sta_nominal) "Density, used to compute fluid volume"; public Buildings.Fluid.FixedResistances.FixedResistanceDpM preDro( redeclare package Medium = Medium, final use_dh=false, final m_flow_nominal=m_flow_nominal, final deltaM=deltaM, final allowFlowReversal=allowFlowReversal, final m_flow_small=m_flow_small, final show_T=false, final show_V_flow=show_V_flow, final from_dp=from_dp, final linearized=linearizeFlowResistance, final dp_nominal=dp_nominal) "Pressure drop model"; equation assert(vol.use_HeatTransfer == true, "Wrong parameter for vol."); connect(temSen.port, vol.heatPort); connect(vol.ports[2], port_b); connect(port_a, preDro.port_a); connect(preDro.port_b, vol.ports[1]); end PartialDynamicTwoPortTransformer; Buildings.Fluid.Interfaces.PartialFourPort Partial model with four ports Information This partial model defines an interface for components with two ports. The treatment of the design flow direction and of flow reversal are predefined based on the parameter allowFlowReversal. m1_flow (or m2_flow) defines the mass flow rate in design direction, which is port_a1.m_flow. An extending model providing direct access to internal storage of mass or energy through port_a or port_b (or port_a2 and port_b2) should redefine the protected parameters port_a1_exposesState and port_b1_exposesState appropriately. This will be visualized at the port icons, in order to improve the understanding of fluid model diagrams. This partial model is identical to Assumptions BooleanallowFlowReversal1system.allowFlowReversal= true to allow flow reversal in medium 1, false restricts to design direction (port_a -> port_b) BooleanallowFlowReversal2system.allowFlowReversal= true to allow flow reversal in medium 2, false restricts to design direction (port_a -> port_b) Connectors Type Name Description FluidPort_a port_a1 Fluid connector a1 (positive design flow direction is from port_a1 to port_b1) FluidPort_b port_b1 Fluid connector b1 (positive design flow direction is from port_a1 to port_b1) FluidPort_a port_a2 Fluid connector a2 (positive design flow direction is from port_a2 to port_b2) FluidPort_b port_b2 Fluid connector b2 (positive design flow direction is from port_a2 to port_b2) Modelica definition partial model PartialFourPort "Partial model with four ports" import Modelica.Constants; outer Modelica.Fluid.System system "System wide properties"; replaceable package Medium1 = Modelica.Media.Interfaces.PartialMedium "Medium 1 in the component"; replaceable package Medium2 = Modelica.Media.Interfaces.PartialMedium "Medium 2 in the component"; parameter Boolean allowFlowReversal1 = system.allowFlowReversal "= true to allow flow reversal in medium 1, false restricts to design direction (port_a -> port_b)"; parameter Boolean allowFlowReversal2 = system.allowFlowReversal "= true to allow flow reversal in medium 2, false restricts to design direction (port_a -> port_b)"; Modelica.Fluid.Interfaces.FluidPort_a port_a1( redeclare package Medium = Medium1, m_flow(min=if allowFlowReversal1 then -Constants.inf else 0)) "Fluid connector a1 (positive design flow direction is from port_a1 to port_b1)"; Modelica.Fluid.Interfaces.FluidPort_b port_b1( redeclare package Medium = Medium1, m_flow(max=if allowFlowReversal1 then +Constants.inf else 0)) "Fluid connector b1 (positive design flow direction is from port_a1 to port_b1)"; Modelica.Fluid.Interfaces.FluidPort_a port_a2( redeclare package Medium = Medium2, m_flow(min=if allowFlowReversal2 then -Constants.inf else 0)) "Fluid connector a2 (positive design flow direction is from port_a2 to port_b2)"; Modelica.Fluid.Interfaces.FluidPort_b port_b2( redeclare package Medium = Medium2, m_flow(max=if allowFlowReversal2 then +Constants.inf else 0)) "Fluid connector b2 (positive design flow direction is from port_a2 to port_b2)"; // Model structure, e.g. used for visualization protected parameter Boolean port_a1_exposesState = false "= true if port_a1 exposes the state of a fluid volume"; parameter Boolean port_b1_exposesState = false "= true if port_b1 exposes the state of a fluid volume"; parameter Boolean port_a2_exposesState = false "= true if port_a1 exposes the state of a fluid volume"; parameter Boolean port_b2_exposesState = false "= true if port_b1 exposes the state of a fluid volume"; end PartialFourPort; Buildings.Fluid.Interfaces.PartialLumpedVolume Lumped volume with mass and energy balance Information Interface and base class for an ideally mixed fluid volume with the ability to store mass and energy. The following boundary flow and source terms are part of the energy balance and must be specified in an extending class: Qb_flow , e.g. convective or latent heat flow rate across segment boundary, and Wb_flow , work term, e.g. p*der(fluidVolume) if the volume is not constant. The component volume fluidVolume is an input that needs to be set in the extending class to complete the model. Further source terms must be defined by an extending class for fluid flow across the segment boundary: Hb_flow , enthalpy flow, mb_flow , mass flow, mbXi_flow , substance mass flow, and mbC_flow , trace substance mass flow. Note: This model is identical to Modelica.Fluid.Interfaces.PartialLumpedVolume, except for the assert statement, which has been removed in this model the final keyword for the declaration of the the substance and trace substance balance. These modifications have been made to allow modeling the air humidity using a differential equation, while modeling the total mass balance as a steady-state equation. Parameters Type Name Default Description Assumptions Dynamics Dynamics energyDynamics system.energyDynamics Formulation of energy balance Dynamics massDynamics system.massDynamics Formulation of mass balance Dynamics substanceDynamics energyDynamics Formulation of substance balance Dynamics traceDynamics energyDynamics Formulation of trace substance balance Initialization AbsolutePressure p_start system.p_start Start value of pressure [Pa] Boolean use_T_start true = true, use T_start, otherwise h_start Temperature T_start if use_T_start then system.T... Start value of temperature [K] SpecificEnthalpy h_start if use_T_start then Medium.s... Start value of specific enthalpy [J/kg] MassFraction X_start[Medium.nX] Medium.X_default Start value of mass fractions m_i/m [kg/kg] ExtraProperty C_start[Medium.nC] fill(0, Medium.nC) Start value of trace substances Modelica definition partial model PartialLumpedVolume "Lumped volume with mass and energy balance" import Modelica.Fluid.Types; import Modelica.Fluid.Types.Dynamics; outer Modelica.Fluid.System system "System properties"; replaceable package Medium = Modelica.Media.Interfaces.PartialMedium "Medium in the component"; // Inputs provided to the volume model input Modelica.SIunits.Volume fluidVolume "Volume"; // Assumptions parameter Types.Dynamics energyDynamics=system.energyDynamics "Formulation of energy balance"; parameter Types.Dynamics massDynamics=system.massDynamics "Formulation of mass balance"; /* Original formulation final parameter Types.Dynamics substanceDynamics=massDynamics "Formulation of substance balance" annotation(Evaluate=true, Dialog(tab = "Assumptions", group="Dynamics")); final parameter Types.Dynamics traceDynamics=massDynamics "Formulation of trace substance balance" annotation(Evaluate=true, Dialog(tab = "Assumptions", group="Dynamics")); */ parameter Types.Dynamics substanceDynamics=energyDynamics "Formulation of substance balance"; parameter Types.Dynamics traceDynamics=energyDynamics "Formulation of trace substance balance"; // Initialization parameter Medium.AbsolutePressure p_start = system.p_start "Start value of pressure"; parameter Boolean use_T_start = true "= true, use T_start, otherwise h_start"; parameter Medium.Temperature T_start= if use_T_start then system.T_start else Medium.temperature_phX(p_start,h_start,X_start) "Start value of temperature"; parameter Medium.SpecificEnthalpy h_start= if use_T_start then Medium.specificEnthalpy_pTX(p_start, T_start, X_start) else Medium.h_default "Start value of specific enthalpy"; parameter Medium.MassFraction X_start[Medium.nX] = Medium.X_default "Start value of mass fractions m_i/m"; parameter Medium.ExtraProperty C_start[Medium.nC]( quantity=Medium.extraPropertiesNames)=fill(0, Medium.nC) "Start value of trace substances"; Medium.BaseProperties medium( preferredMediumStates=true, p(start=p_start), h(start=h_start), T(start=T_start), X(start=X_start[1:Medium.nX]), Xi(start=X_start[1:Medium.nXi])); Modelica.SIunits.Energy U "Internal energy of fluid"; Modelica.SIunits.Mass m "Mass of fluid"; Modelica.SIunits.Mass[Medium.nXi] mXi "Masses of independent components in the fluid"; Modelica.SIunits.Mass[Medium.nC] mC "Masses of trace substances in the fluid"; // C need to be added here because unlike for Xi, which has medium.Xi, // there is no variable medium.C Medium.ExtraProperty C[Medium.nC] "Trace substance mixture content"; // variables that need to be defined by an extending class Modelica.SIunits.MassFlowRate mb_flow "Mass flows across boundaries"; Modelica.SIunits.MassFlowRate[Medium.nXi] mbXi_flow "Substance mass flows across boundaries"; Medium.ExtraPropertyFlowRate[Medium.nC] mbC_flow "Trace substance mass flows across boundaries"; Modelica.SIunits.EnthalpyFlowRate Hb_flow "Enthalpy flow across boundaries or energy source/sink"; Modelica.SIunits.HeatFlowRate Qb_flow "Heat flow across boundaries or energy source/sink"; Modelica.SIunits.Power Wb_flow "Work flow across boundaries or source term"; protected parameter Boolean initialize_p = not Medium.singleState "= true to set up initial equations for pressure"; equation /* statement from original model assert(not (energyDynamics<>Dynamics.SteadyState and massDynamics==Dynamics.SteadyState) or Medium.singleState, "Bad combination of dynamics options and Medium not conserving mass if fluidVolume is fixed."); */ // Total quantities m = fluidVolume*medium.d; mXi = m*medium.Xi; U = m*medium.u; mC = m*C; // Energy and mass balances if energyDynamics == Dynamics.SteadyState then 0 = Hb_flow + Qb_flow + Wb_flow; else der(U) = Hb_flow + Qb_flow + Wb_flow; end if; if massDynamics == Dynamics.SteadyState then 0 = mb_flow; else der(m) = mb_flow; end if; if substanceDynamics == Dynamics.SteadyState then zeros(Medium.nXi) = mbXi_flow; else der(mXi) = mbXi_flow; end if; if traceDynamics == Dynamics.SteadyState then zeros(Medium.nC) = mbC_flow; else der(mC) = mbC_flow; end if; initial equation // initialization of balances if energyDynamics == Dynamics.FixedInitial then if use_T_start then medium.T = T_start; else medium.h = h_start; end if; elseif energyDynamics == Dynamics.SteadyStateInitial then if use_T_start then der(medium.T) = 0; else der(medium.h) = 0; end if; end if; if massDynamics == Dynamics.FixedInitial then if initialize_p then medium.p = p_start; end if; elseif massDynamics == Dynamics.SteadyStateInitial then if initialize_p then der(medium.p) = 0; end if; end if; if substanceDynamics == Dynamics.FixedInitial then medium.Xi = X_start[1:Medium.nXi]; elseif substanceDynamics == Dynamics.SteadyStateInitial then der(medium.Xi) = zeros(Medium.nXi); end if; if traceDynamics == Dynamics.FixedInitial then C = C_start[1:Medium.nC]; elseif traceDynamics == Dynamics.SteadyStateInitial then der(C) = zeros(Medium.nC); end if; end PartialLumpedVolume; Buildings.Fluid.Interfaces.PartialStaticFourPortHeatMassTransfer Partial model transporting two fluid streams between four ports without storing mass or energy Information This component transports two fluid streams between four ports, without storing mass or energy. It is similar to Buildings.Fluid.Interfaces.PartialStaticTwoPortHeatMassTransfer, but it has four ports instead of two. See the documentation of Buildings.Fluid.Interfaces.PartialStaticTwoPortHeatMassTransfer for how to use this partial model. Extends from Buildings.Fluid.Interfaces.PartialStaticFourPortInterface (Partial model transporting fluid between two ports without storing mass or energy), Buildings.Fluid.Interfaces.FourPortFlowResistanceParameters (Parameters for flow resistance for models with four ports). Parameters Type Name Default Description replaceable package Medium1 PartialMedium Medium 1 in the component replaceable package Medium2 PartialMedium Medium 2 in the component Nominal condition MassFlowRate m1_flow_nominal Nominal mass flow rate [kg/s] MassFlowRate m2_flow_nominal m1_flow_nominal Nominal mass flow rate [kg/s] Pressure dp1_nominal Pressure [Pa] Pressure dp2_nominal Pressure [Pa] Initialization MassFlowRate m1_flow.start 0 Mass flow rate from port_a1 to port_b1 (m1_flow > 0 is design flow direction) [kg/s] Pressure dp1.start 0 Pressure difference between port_a1 and port_b1 [Pa] MassFlowRate m2_flow.start 0 Mass flow rate from port_a2 to port_b2 (m2_flow > 0 is design flow direction) [kg/s] Pressure dp2.start 0 Pressure difference between port_a2 and port_b2 [Pa] Assumptions Boolean allowFlowReversal1 system.allowFlowReversal = true to allow flow reversal in medium 1, false restricts to design direction (port_a -> port_b) Boolean allowFlowReversal2 system.allowFlowReversal = true to allow flow reversal in medium 2, false restricts to design direction (port_a -> port_b) Advanced MassFlowRate m1_flow_small 1E-4*m1_flow_nominal Small mass flow rate for regularization of zero flow [kg/s] MassFlowRate m2_flow_small 1E-4*m2_flow_nominal Small mass flow rate for regularization of zero flow [kg/s] Diagnostics Boolean show_V_flow false = true, if volume flow rate at inflowing port is computed Initialization AbsolutePressure p_a1_start system.p_start Guess value for inlet pressure [Pa] AbsolutePressure p_b1_start p_a1_start Guess value for outlet pressure [Pa] AbsolutePressure p_a2_start system.p_start Guess value for inlet pressure [Pa] AbsolutePressure p_b2_start p_a2_start Guess value for outlet pressure [Pa] Flow resistance Medium 1 Boolean computeFlowResistance1 true =true, compute flow resistance. Set to false to assume no friction Boolean from_dp1 true = true, use m_flow = f(dp) else dp = f(m_flow) Boolean linearizeFlowResistance1 false = true, use linear relation between m_flow and dp for any flow rate Real deltaM1 0.1 Fraction of nominal flow rate where flow transitions to laminar Medium 2 Boolean computeFlowResistance2 true =true, compute flow resistance. Set to false to assume no friction Boolean from_dp2 true = true, use m_flow = f(dp) else dp = f(m_flow) Boolean linearizeFlowResistance2 false = true, use linear relation between m_flow and dp for any flow rate Real deltaM2 0.1 Fraction of nominal flow rate where flow transitions to laminar Connectors Type Name Description FluidPort_a port_a1 Fluid connector a1 (positive design flow direction is from port_a1 to port_b1) FluidPort_b port_b1 Fluid connector b1 (positive design flow direction is from port_a1 to port_b1) FluidPort_a port_a2 Fluid connector a2 (positive design flow direction is from port_a2 to port_b2) FluidPort_b port_b2 Fluid connector b2 (positive design flow direction is from port_a2 to port_b2) Modelica definition partial model PartialStaticFourPortHeatMassTransfer "Partial model transporting two fluid streams between four ports without storing mass or energy" extends Buildings.Fluid.Interfaces.PartialStaticFourPortInterface; extends Buildings.Fluid.Interfaces.FourPortFlowResistanceParameters( final computeFlowResistance1=true, final computeFlowResistance2=true); import Modelica.Constants; Modelica.SIunits.HeatFlowRate Q1_flow "Heat transfered into the medium 1"; Medium1.MassFlowRate mXi1_flow[Medium1.nXi] "Mass flow rates of independent substances added to the medium 1"; Modelica.SIunits.HeatFlowRate Q2_flow "Heat transfered into the medium 2"; Medium2.MassFlowRate mXi2_flow[Medium2.nXi] "Mass flow rates of independent substances added to the medium 2"; equation // Energy balance (no storage, no heat loss/gain) port_a1.m_flow*port_a1.h_outflow + port_b1.m_flow*inStream(port_b1.h_outflow) = -Q1_flow; port_a1.m_flow*port_b1.h_outflow + port_b1.m_flow*inStream(port_a1.h_outflow) = Q1_flow; port_a2.m_flow*port_a2.h_outflow + port_b2.m_flow*inStream(port_b2.h_outflow) = -Q2_flow; port_a2.m_flow*port_b2.h_outflow + port_b2.m_flow*inStream(port_a2.h_outflow) = Q2_flow; // Mass balance (no storage) port_a1.m_flow + port_b1.m_flow = -sum(mXi1_flow); port_a2.m_flow + port_b2.m_flow = -sum(mXi2_flow); port_a1.m_flow*port_a1.Xi_outflow + port_b1.m_flow*inStream(port_b1.Xi_outflow) = -mXi1_flow; port_a1.m_flow*port_b1.Xi_outflow + port_b1.m_flow*inStream(port_a1.Xi_outflow) = mXi1_flow; port_a2.m_flow*port_a2.Xi_outflow + port_b2.m_flow*inStream(port_b2.Xi_outflow) = -mXi2_flow; port_a2.m_flow*port_b2.Xi_outflow + port_b2.m_flow*inStream(port_a2.Xi_outflow) = mXi2_flow; // Transport of trace substances port_a1.C_outflow = inStream(port_b1.C_outflow); port_b1.C_outflow = inStream(port_a1.C_outflow); port_a2.C_outflow = inStream(port_b2.C_outflow); port_b2.C_outflow = inStream(port_a2.C_outflow); // Pressure drop calculation // Medium 1 if computeFlowResistance1 then if from_dp1 then m1_flow = Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_dp( dp=dp1, k=m1_flow_nominal/sqrt(dp1_nominal), m_flow_turbulent=deltaM1 * m1_flow_nominal, linearized=linearizeFlowResistance1); else dp1 = Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_m_flow( m_flow=m1_flow, k=m1_flow_nominal/sqrt(dp1_nominal), m_flow_turbulent=deltaM1 * m1_flow_nominal, linearized=linearizeFlowResistance1); end if; else dp1 = 0; end if; // Medium 2 if computeFlowResistance2 then if from_dp2 then m2_flow = Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_dp( dp=dp2, k=m2_flow_nominal/sqrt(dp2_nominal), m_flow_turbulent=deltaM2 * m2_flow_nominal, linearized=linearizeFlowResistance2); else dp2 = Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_m_flow( m_flow=m2_flow, k=m2_flow_nominal/sqrt(dp2_nominal), m_flow_turbulent=deltaM2 * m2_flow_nominal, linearized=linearizeFlowResistance2); end if; else dp2 = 0; end if; end PartialStaticFourPortHeatMassTransfer; Buildings.Fluid.Interfaces.PartialStaticFourPortInterface Partial model transporting fluid between two ports without storing mass or energy Information This component defines the interface for models that transport two fluid streams between four ports. It is similar to , but it has four ports instead of two. The model is used by other models in this package that add heat transfer, mass transfer and pressure drop equations. Extends from Buildings.Fluid.Interfaces.PartialFourPort (Partial model with four ports). Parameters Type Name Default Description replaceable package Medium1 PartialMedium Medium 1 in the component replaceable package Medium2 PartialMedium Medium 2 in the component Nominal condition MassFlowRate m1_flow_nominal Nominal mass flow rate [kg/s] MassFlowRate m2_flow_nominal m1_flow_nominal Nominal mass flow rate [kg/s] Assumptions Boolean allowFlowReversal1 system.allowFlowReversal = true to allow flow reversal in medium 1, false restricts to design direction (port_a -> port_b) Boolean allowFlowReversal2 system.allowFlowReversal = true to allow flow reversal in medium 2, false restricts to design direction (port_a -> port_b) Advanced MassFlowRate m1_flow_small 1E-4*m1_flow_nominal Small mass flow rate for regularization of zero flow [kg/s] MassFlowRate m2_flow_small 1E-4*m2_flow_nominal Small mass flow rate for regularization of zero flow [kg/s] Diagnostics Boolean show_V_flow false = true, if volume flow rate at inflowing port is computed Initialization AbsolutePressure p_a1_start system.p_start Guess value for inlet pressure [Pa] AbsolutePressure p_b1_start p_a1_start Guess value for outlet pressure [Pa] AbsolutePressure p_a2_start system.p_start Guess value for inlet pressure [Pa] AbsolutePressure p_b2_start p_a2_start Guess value for outlet pressure [Pa] Modelica definition partial model PartialStaticFourPortInterface "Partial model transporting fluid between two ports without storing mass or energy" import Modelica.Constants; extends Buildings.Fluid.Interfaces.PartialFourPort( port_a1( p(start=p_a1_start), m_flow(min = if allowFlowReversal1 then -Constants.inf else 0)), port_b1( p(start=p_b1_start), m_flow(max = if allowFlowReversal1 then +Constants.inf else 0)), port_a2( p(start=p_a2_start), m_flow(min = if allowFlowReversal2 then -Constants.inf else 0)), port_b2( p(start=p_b2_start), m_flow(max = if allowFlowReversal2 then +Constants.inf else 0))); parameter Modelica.SIunits.MassFlowRate m1_flow_nominal(min=0) "Nominal mass flow rate"; parameter Modelica.SIunits.MassFlowRate m2_flow_nominal(min=0) = m1_flow_nominal "Nominal mass flow rate"; parameter Medium1.MassFlowRate m1_flow_small(min=0) = 1E-4*m1_flow_nominal "Small mass flow rate for regularization of zero flow"; parameter Medium2.MassFlowRate m2_flow_small(min=0) = 1E-4*m2_flow_nominal "Small mass flow rate for regularization of zero flow"; // Initialization parameter Medium1.AbsolutePressure p_a1_start=system.p_start "Guess value for inlet pressure"; parameter Medium1.AbsolutePressure p_b1_start=p_a1_start "Guess value for outlet pressure"; parameter Medium2.AbsolutePressure p_a2_start=system.p_start "Guess value for inlet pressure"; parameter Medium2.AbsolutePressure p_b2_start=p_a2_start "Guess value for outlet pressure"; // Diagnostics parameter Boolean show_V_flow = false "= true, if volume flow rate at inflowing port is computed"; Modelica.SIunits.VolumeFlowRate V1_flow= m1_flow/Modelica.Fluid.Utilities.regStep(m1_flow, Medium1.density(state_a1_inflow), Medium1.density(state_b1_inflow), m1_flow_small) if show_V_flow "Volume flow rate at inflowing port (positive when flow from port_a1 to port_b1)"; Modelica.SIunits.VolumeFlowRate V2_flow= m2_flow/Modelica.Fluid.Utilities.regStep(m2_flow, Medium2.density(state_a2_inflow), Medium2.density(state_b2_inflow), m2_flow_small) if show_V_flow "Volume flow rate at inflowing port (positive when flow from port_a2 to port_b2)"; Medium1.MassFlowRate m1_flow(start=0) "Mass flow rate from port_a1 to port_b1 (m1_flow > 0 is design flow direction)"; Modelica.SIunits.Pressure dp1(start=0, displayUnit="Pa") "Pressure difference between port_a1 and port_b1"; Medium2.MassFlowRate m2_flow(start=0) "Mass flow rate from port_a2 to port_b2 (m2_flow > 0 is design flow direction)"; Modelica.SIunits.Pressure dp2(start=0, displayUnit="Pa") "Pressure difference between port_a2 and port_b2"; Medium1.ThermodynamicState sta_a1= Medium1.setState_phX(port_a1.p, actualStream(port_a1.h_outflow), actualStream(port_a1.Xi_outflow)) "Medium properties in port_a1"; Medium1.ThermodynamicState sta_b1= Medium1.setState_phX(port_b1.p, actualStream(port_b1.h_outflow), actualStream(port_b1.Xi_outflow)) "Medium properties in port_b1"; Medium2.ThermodynamicState sta_a2= Medium2.setState_phX(port_a2.p, actualStream(port_a2.h_outflow), actualStream(port_a2.Xi_outflow)) "Medium properties in port_a2"; Medium2.ThermodynamicState sta_b2= Medium2.setState_phX(port_b2.p, actualStream(port_b2.h_outflow), actualStream(port_b2.Xi_outflow)) "Medium properties in port_b2"; protected Medium1.ThermodynamicState state_a1_inflow= Medium1.setState_phX(port_a1.p, inStream(port_a1.h_outflow), inStream(port_a1.Xi_outflow)) "state for medium inflowing through port_a1"; Medium1.ThermodynamicState state_b1_inflow= Medium1.setState_phX(port_b1.p, inStream(port_b1.h_outflow), inStream(port_b1.Xi_outflow)) "state for medium inflowing through port_b1"; Medium2.ThermodynamicState state_a2_inflow= Medium2.setState_phX(port_a2.p, inStream(port_a2.h_outflow), inStream(port_a2.Xi_outflow)) "state for medium inflowing through port_a2"; Medium2.ThermodynamicState state_b2_inflow= Medium2.setState_phX(port_b2.p, inStream(port_b2.h_outflow), inStream(port_b2.Xi_outflow)) "state for medium inflowing through port_b2"; equation // Design direction of mass flow rate m1_flow = port_a1.m_flow; m2_flow = port_a2.m_flow; // Pressure difference between ports dp1 = port_a1.p - port_b1.p; dp2 = port_a2.p - port_b2.p; end PartialStaticFourPortInterface; Buildings.Fluid.Interfaces.PartialStaticTwoPortHeatMassTransfer Partial model transporting fluid between two ports without storing mass or energy Information This component transports fluid between its two ports, without storing mass or energy. It is based on Modelica.Fluid.Interfaces.PartialTwoPortTransport but it does use a different implementation for handling reverse flow because in this component, mass flow rate can be added or removed from the medium. Depending on the parameter settings, this component computes pressure drop due to flow friction. The pressure drop is defined by a quadratic function that goes through the point (m_flow_nominal, dp_nominal). At |m_flow| < deltaM * m_flow_nominal, the pressure drop vs. flow relation is linearized. If the parameter linearizeFlowResistance is set to true, then the whole pressure drop vs. flow resistance curve is linearized. When using this partial component, an equation for the energy and mass balances need to be added, such as mWat_flow = u * m_flow_nominal; Q_flow = Medium.enthalpyOfLiquid(TWat) * mWat_flow; for i in 1:Medium.nXi loop mXi_flow[i] = if ( i == Medium.Water) then mWat_flow else 0; end for; Extends from Buildings.Fluid.Interfaces.PartialStaticTwoPortInterface (Partial model transporting fluid between two ports without storing mass or energy), Buildings.Fluid.Interfaces.TwoPortFlowResistanceParameters (Parameters for flow resistance for models with two ports). Parameters Type Name Default Description replaceable package Medium PartialMedium Medium in the component Nominal condition MassFlowRate m_flow_nominal Nominal mass flow rate [kg/s] Pressure dp_nominal Pressure [Pa] Initialization MassFlowRate m_flow.start 0 Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s] Pressure dp.start 0 Pressure difference between port_a and port_b [Pa] Assumptions Boolean allowFlowReversal system.allowFlowReversal = true to allow flow reversal, false restricts to design direction (port_a -> port_b) Advanced MassFlowRate m_flow_small 1E-4*m_flow_nominal Small mass flow rate for regularization of zero flow [kg/s] Diagnostics Boolean show_V_flow false = true, if volume flow rate at inflowing port is computed Initialization AbsolutePressure p_a_start system.p_start Guess value for inlet pressure [Pa] AbsolutePressure p_b_start p_a_start Guess value for outlet pressure [Pa] Flow resistance Boolean computeFlowResistance true =true, compute flow resistance. Set to false to assume no friction Boolean from_dp true = true, use m_flow = f(dp) else dp = f(m_flow) Boolean linearizeFlowResistance false = true, use linear relation between m_flow and dp for any flow rate Real deltaM 0.1 Fraction of nominal flow rate where flow transitions to laminar Connectors Type Name Description FluidPort_a port_a Fluid connector a (positive design flow direction is from port_a to port_b) FluidPort_b port_b Fluid connector b (positive design flow direction is from port_a to port_b) Modelica definition partial model PartialStaticTwoPortHeatMassTransfer "Partial model transporting fluid between two ports without storing mass or energy" extends Buildings.Fluid.Interfaces.PartialStaticTwoPortInterface; extends Buildings.Fluid.Interfaces.TwoPortFlowResistanceParameters( final computeFlowResistance=true); import Modelica.Constants; Modelica.SIunits.HeatFlowRate Q_flow "Heat transfered into the medium"; Medium.MassFlowRate mXi_flow[Medium.nXi] "Mass flow rates of independent substances added to the medium"; equation // Energy balance (no storage, no heat loss/gain) port_a.m_flow*port_a.h_outflow + port_b.m_flow*inStream(port_b.h_outflow) = -Q_flow; port_a.m_flow*port_b.h_outflow + port_b.m_flow*inStream(port_a.h_outflow) = Q_flow; // Mass balance (no storage) port_a.m_flow + port_b.m_flow = -sum(mXi_flow); port_a.m_flow*port_a.Xi_outflow + port_b.m_flow*inStream(port_b.Xi_outflow) = -mXi_flow; port_a.m_flow*port_b.Xi_outflow + port_b.m_flow*inStream(port_a.Xi_outflow) = mXi_flow; // Transport of trace substances port_a.C_outflow = inStream(port_b.C_outflow); port_b.C_outflow = inStream(port_a.C_outflow); // Pressure drop calculation if computeFlowResistance then if from_dp then m_flow = Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_dp( dp=dp, k=m_flow_nominal/sqrt(dp_nominal), m_flow_turbulent=deltaM * m_flow_nominal, linearized=linearizeFlowResistance); else dp = Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_m_flow( m_flow=m_flow, k=m_flow_nominal/sqrt(dp_nominal), m_flow_turbulent=deltaM * m_flow_nominal, linearized=linearizeFlowResistance); end if; else dp = 0; end if; end PartialStaticTwoPortHeatMassTransfer; Buildings.Fluid.Interfaces.PartialStaticTwoPortInterface Partial model transporting fluid between two ports without storing mass or energy Information This component defines the interface for models that transports a fluid between two ports. It is similar to Modelica.Fluid.Interfaces.PartialTwoPortTransport, but it does not include the species balance port_b.Xi_outflow = inStream(port_a.Xi_outflow); . Thus, it can be used as a base class for a heat and mass transfer component The model is used by other models in this package that add heat transfer, mass transfer and pressure drop equations. See for example Buildings.Fluid.Interfaces.PartialStaticTwoPortHeatMassTransfer. Extends from Modelica.Fluid.Interfaces.PartialTwoPort (Partial component with two ports). Parameters Type Name Default Description replaceable package Medium PartialMedium Medium in the component Nominal condition MassFlowRate m_flow_nominal Nominal mass flow rate [kg/s] Assumptions Boolean allowFlowReversal system.allowFlowReversal = true to allow flow reversal, false restricts to design direction (port_a -> port_b) Advanced MassFlowRate m_flow_small 1E-4*m_flow_nominal Small mass flow rate for regularization of zero flow [kg/s] Diagnostics Boolean show_V_flow false = true, if volume flow rate at inflowing port is computed Initialization AbsolutePressure p_a_start system.p_start Guess value for inlet pressure [Pa] AbsolutePressure p_b_start p_a_start Guess value for outlet pressure [Pa] Modelica definition partial model PartialStaticTwoPortInterface "Partial model transporting fluid between two ports without storing mass or energy" import Modelica.Constants; extends Modelica.Fluid.Interfaces.PartialTwoPort( port_a( p(start=p_a_start), m_flow(min = if allowFlowReversal then -Constants.inf else 0)), port_b( p(start=p_b_start), m_flow(max = if allowFlowReversal then +Constants.inf else 0))); parameter Medium.MassFlowRate m_flow_nominal(min=0) "Nominal mass flow rate"; parameter Medium.MassFlowRate m_flow_small(min=0) = 1E-4*m_flow_nominal "Small mass flow rate for regularization of zero flow"; // Initialization parameter Medium.AbsolutePressure p_a_start=system.p_start "Guess value for inlet pressure"; parameter Medium.AbsolutePressure p_b_start=p_a_start "Guess value for outlet pressure"; // Diagnostics parameter Boolean show_V_flow = false "= true, if volume flow rate at inflowing port is computed"; Modelica.SIunits.VolumeFlowRate V_flow= m_flow/Modelica.Fluid.Utilities.regStep(m_flow, Medium.density(state_a_inflow), Medium.density(state_b_inflow), m_flow_small) if show_V_flow "Volume flow rate at inflowing port (positive when flow from port_a to port_b)"; /* Medium.Temperature port_a_T= Modelica.Fluid.Utilities.regStep(port_a.m_flow, Medium.temperature(state_a), Medium.temperature(Medium.setState_phX(port_a.p, port_a.h_outflow, port_a.Xi_outflow)), m_flow_small) if show_T "Temperature close to port_a, if show_T = true"; Medium.Temperature port_b_T= Modelica.Fluid.Utilities.regStep(port_b.m_flow, Medium.temperature(state_b), Medium.temperature(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow)), m_flow_small) if show_T "Temperature close to port_b, if show_T = true"; */ Medium.MassFlowRate m_flow(start=0) "Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction)"; Modelica.SIunits.Pressure dp(start=0, displayUnit="Pa") "Pressure difference between port_a and port_b"; Medium.ThermodynamicState sta_a= Medium.setState_phX(port_a.p, actualStream(port_a.h_outflow), actualStream(port_a.Xi_outflow)) "Medium properties in port_a"; Medium.ThermodynamicState sta_b= Medium.setState_phX(port_b.p, actualStream(port_b.h_outflow), actualStream(port_b.Xi_outflow)) "Medium properties in port_b"; protected Medium.ThermodynamicState state_a_inflow= Medium.setState_phX(port_a.p, inStream(port_a.h_outflow), inStream(port_a.Xi_outflow)) "state for medium inflowing through port_a"; Medium.ThermodynamicState state_b_inflow= Medium.setState_phX(port_b.p, inStream(port_b.h_outflow), inStream(port_b.Xi_outflow)) "state for medium inflowing through port_b"; equation // medium_a.state=sta_a; // medium_a.Xi = actualStream(port_a.Xi_outflow); // Design direction of mass flow rate m_flow = port_a.m_flow; // Pressure difference between ports dp = port_a.p - port_b.p; end PartialStaticTwoPortInterface; Buildings.Fluid.Interfaces.TwoPortFlowResistanceParameters Parameters for flow resistance for models with two ports Information This class contains parameters that are used to compute the pressure drop in models that have one fluid stream. Note that the nominal mass flow rate is not declared here because the model PartialStaticTwoPortInterface already declares it. Parameters Type Name Default Description Nominal condition Pressure dp_nominal Pressure [Pa] Flow resistance Boolean computeFlowResistance true =true, compute flow resistance. Set to false to assume no friction Boolean from_dp true = true, use m_flow = f(dp) else dp = f(m_flow) Boolean linearizeFlowResistance false = true, use linear relation between m_flow and dp for any flow rate Real deltaM 0.1 Fraction of nominal flow rate where flow transitions to laminar Modelica definition record TwoPortFlowResistanceParameters "Parameters for flow resistance for models with two ports" parameter Boolean computeFlowResistance = true "=true, compute flow resistance. Set to false to assume no friction"; parameter Boolean from_dp = true "= true, use m_flow = f(dp) else dp = f(m_flow)"; parameter Modelica.SIunits.Pressure dp_nominal(min=0, displayUnit="Pa") "Pressure"; parameter Boolean linearizeFlowResistance = false "= true, use linear relation between m_flow and dp for any flow rate"; parameter Real deltaM = 0.1 "Fraction of nominal flow rate where flow transitions to laminar"; end TwoPortFlowResistanceParameters; HTML-documentation generated by Dymola Sat Feb 6 17:39:01 2010.

Type	Name	Default	Description
replaceable package Medium1		PartialMedium	Medium 1 in the component
replaceable package Medium2		PartialMedium	Medium 2 in the component
MixingVolumeDryAir	vol2	redeclare Buildings.Fluid.Mi...	Volume for fluid 2
Nominal condition
MassFlowRate	m1_flow_nominal		Nominal mass flow rate [kg/s]
MassFlowRate	m2_flow_nominal	m1_flow_nominal	Nominal mass flow rate [kg/s]
Pressure	dp1_nominal		Pressure [Pa]
Pressure	dp2_nominal		Pressure [Pa]
Time	tau1	60	Time constant at nominal flow [s]
Time	tau2	60	Time constant at nominal flow [s]
Initialization
MassFlowRate	m1_flow.start	0	Mass flow rate from port_a1 to port_b1 (m1_flow > 0 is design flow direction) [kg/s]
Pressure	dp1.start	0	Pressure difference between port_a1 and port_b1 [Pa]
MassFlowRate	m2_flow.start	0	Mass flow rate from port_a2 to port_b2 (m2_flow > 0 is design flow direction) [kg/s]
Pressure	dp2.start	0	Pressure difference between port_a2 and port_b2 [Pa]
Assumptions
Boolean	allowFlowReversal1	system.allowFlowReversal	= true to allow flow reversal in medium 1, false restricts to design direction (port_a -> port_b)
Boolean	allowFlowReversal2	system.allowFlowReversal	= true to allow flow reversal in medium 2, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRate	m1_flow_small	1E-4*m1_flow_nominal	Small mass flow rate for regularization of zero flow [kg/s]
MassFlowRate	m2_flow_small	1E-4*m2_flow_nominal	Small mass flow rate for regularization of zero flow [kg/s]
Diagnostics
Boolean	show_V_flow	false	= true, if volume flow rate at inflowing port is computed
Initialization
AbsolutePressure	p_a1_start	system.p_start	Guess value for inlet pressure [Pa]
AbsolutePressure	p_b1_start	p_a1_start	Guess value for outlet pressure [Pa]
AbsolutePressure	p_a2_start	system.p_start	Guess value for inlet pressure [Pa]
AbsolutePressure	p_b2_start	p_a2_start	Guess value for outlet pressure [Pa]
Flow resistance
Medium 1
Boolean	computeFlowResistance1	true	=true, compute flow resistance. Set to false to assume no friction
Boolean	from_dp1	true	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance1	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM1	0.1	Fraction of nominal flow rate where flow transitions to laminar
Medium 2
Boolean	computeFlowResistance2	true	=true, compute flow resistance. Set to false to assume no friction
Boolean	from_dp2	true	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance2	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM2	0.1	Fraction of nominal flow rate where flow transitions to laminar

Type	Name	Description
FluidPort_a	port_a1	Fluid connector a1 (positive design flow direction is from port_a1 to port_b1)
FluidPort_b	port_b1	Fluid connector b1 (positive design flow direction is from port_a1 to port_b1)
FluidPort_a	port_a2	Fluid connector a2 (positive design flow direction is from port_a2 to port_b2)
FluidPort_b	port_b2	Fluid connector b2 (positive design flow direction is from port_a2 to port_b2)

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Pressure	dp_nominal		Pressure [Pa]
Time	tau	300	Time constant at nominal flow [s]
Initialization
MassFlowRate	m_flow.start	0	Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]
Pressure	dp.start	0	Pressure difference between port_a and port_b [Pa]
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Dynamics
Dynamics	energyDynamics	system.energyDynamics	Formulation of energy balance
Dynamics	massDynamics	energyDynamics	Formulation of mass balance
Advanced
MassFlowRate	m_flow_small	1E-4*m_flow_nominal	Small mass flow rate for regularization of zero flow [kg/s]
Diagnostics
Boolean	show_V_flow	false	= true, if volume flow rate at inflowing port is computed
Initialization
AbsolutePressure	p_a_start	system.p_start	Guess value for inlet pressure [Pa]
AbsolutePressure	p_b_start	p_a_start	Guess value for outlet pressure [Pa]
AbsolutePressure	p_start	system.p_start	Start value of pressure [Pa]
Boolean	use_T_start	true	= true, use T_start, otherwise h_start
Temperature	T_start	if use_T_start then system.T...	Start value of temperature [K]
SpecificEnthalpy	h_start	if use_T_start then Medium.s...	Start value of specific enthalpy [J/kg]
MassFraction	X_start[Medium.nX]	Medium.X_default	Start value of mass fractions m_i/m [kg/kg]
ExtraProperty	C_start[Medium.nC]	fill(0, Medium.nC)	Start value of trace substances
Flow resistance
Boolean	computeFlowResistance	true	=true, compute flow resistance. Set to false to assume no friction
Boolean	from_dp	true	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM	0.1	Fraction of nominal flow rate where flow transitions to laminar

Type	Name	Description
FluidPort_a	port_a	Fluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_b	port_b	Fluid connector b (positive design flow direction is from port_a to port_b)