Package Modelica.Fluid.InterfacesInterfaces for steady state and unsteady, mixed-phase, multi-substance, incompressible and compressible flow
Package Modelica.Fluid.Interfaces
Extends from Modelica.Icons.InterfacesPackage (Icon for packages containing interfaces).
| Name | Description |
|---|---|
FluidPort | Interface for quasi one-dimensional fluid flow in a piping network (incompressible or compressible, one or more phases, one or more substances) |
FluidPort_a | Generic fluid connector at design inlet |
FluidPort_b | Generic fluid connector at design outlet |
FluidPorts_a | Fluid connector with filled, large icon to be used for vectors of FluidPorts (vector dimensions must be added after dragging) |
FluidPorts_b | Fluid connector with outlined, large icon to be used for vectors of FluidPorts (vector dimensions must be added after dragging) |
HeatPorts_a | HeatPort connector with filled, large icon to be used for vectors of HeatPorts (vector dimensions must be added after dragging) |
HeatPorts_b | HeatPort connector with filled, large icon to be used for vectors of HeatPorts (vector dimensions must be added after dragging) |
PartialDistributedFlow | Base class for a distributed momentum balance |
PartialDistributedVolume | Base class for distributed volume models |
PartialHeatTransfer | Common interface for heat transfer models |
PartialLumpedFlow | Base class for a lumped momentum balance |
PartialLumpedVolume | Lumped volume with mass and energy balance |
PartialPressureLoss | Base flow model for pressure loss functions with the same area at port_a and at port_b |
PartialTwoPort | Partial component with two ports |
PartialTwoPortTransport | Partial element transporting fluid between two ports without storage of mass or energy |
Connector Modelica.Fluid.Interfaces.FluidPort| Type | Name | Description |
|---|---|---|
flow MassFlowRate | m_flow | Mass flow rate from the connection point into the component |
AbsolutePressure | p | Thermodynamic pressure in the connection point |
stream SpecificEnthalpy | h_outflow | Specific thermodynamic enthalpy close to the connection point if m_flow < 0 |
stream MassFraction | Xi_outflow[Medium.nXi] | Independent mixture mass fractions m_i/m close to the connection point if m_flow < 0 |
stream ExtraProperty | C_outflow[Medium.nC] | Properties c_i/m close to the connection point if m_flow < 0 |
Connector Modelica.Fluid.Interfaces.FluidPort_aExtends from Modelica.Fluid.Interfaces.FluidPort (Interface for quasi one-dimensional fluid flow in a piping network (incompressible or compressible, one or more phases, one or more substances)).
| Type | Name | Description |
|---|---|---|
flow MassFlowRate | m_flow | Mass flow rate from the connection point into the component |
AbsolutePressure | p | Thermodynamic pressure in the connection point |
stream SpecificEnthalpy | h_outflow | Specific thermodynamic enthalpy close to the connection point if m_flow < 0 |
stream MassFraction | Xi_outflow[Medium.nXi] | Independent mixture mass fractions m_i/m close to the connection point if m_flow < 0 |
stream ExtraProperty | C_outflow[Medium.nC] | Properties c_i/m close to the connection point if m_flow < 0 |
Connector Modelica.Fluid.Interfaces.FluidPort_bExtends from Modelica.Fluid.Interfaces.FluidPort (Interface for quasi one-dimensional fluid flow in a piping network (incompressible or compressible, one or more phases, one or more substances)).
| Type | Name | Description |
|---|---|---|
flow MassFlowRate | m_flow | Mass flow rate from the connection point into the component |
AbsolutePressure | p | Thermodynamic pressure in the connection point |
stream SpecificEnthalpy | h_outflow | Specific thermodynamic enthalpy close to the connection point if m_flow < 0 |
stream MassFraction | Xi_outflow[Medium.nXi] | Independent mixture mass fractions m_i/m close to the connection point if m_flow < 0 |
stream ExtraProperty | C_outflow[Medium.nC] | Properties c_i/m close to the connection point if m_flow < 0 |
Connector Modelica.Fluid.Interfaces.FluidPorts_aExtends from Modelica.Fluid.Interfaces.FluidPort (Interface for quasi one-dimensional fluid flow in a piping network (incompressible or compressible, one or more phases, one or more substances)).
| Type | Name | Description |
|---|---|---|
flow MassFlowRate | m_flow | Mass flow rate from the connection point into the component |
AbsolutePressure | p | Thermodynamic pressure in the connection point |
stream SpecificEnthalpy | h_outflow | Specific thermodynamic enthalpy close to the connection point if m_flow < 0 |
stream MassFraction | Xi_outflow[Medium.nXi] | Independent mixture mass fractions m_i/m close to the connection point if m_flow < 0 |
stream ExtraProperty | C_outflow[Medium.nC] | Properties c_i/m close to the connection point if m_flow < 0 |
Connector Modelica.Fluid.Interfaces.FluidPorts_bExtends from Modelica.Fluid.Interfaces.FluidPort (Interface for quasi one-dimensional fluid flow in a piping network (incompressible or compressible, one or more phases, one or more substances)).
| Type | Name | Description |
|---|---|---|
flow MassFlowRate | m_flow | Mass flow rate from the connection point into the component |
AbsolutePressure | p | Thermodynamic pressure in the connection point |
stream SpecificEnthalpy | h_outflow | Specific thermodynamic enthalpy close to the connection point if m_flow < 0 |
stream MassFraction | Xi_outflow[Medium.nXi] | Independent mixture mass fractions m_i/m close to the connection point if m_flow < 0 |
stream ExtraProperty | C_outflow[Medium.nC] | Properties c_i/m close to the connection point if m_flow < 0 |
Partial Model Modelica.Fluid.Interfaces.PartialTwoPort
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.
The component may transport fluid and may have internal storage for a given fluid Medium.
An extending model providing direct access to internal storage of mass or energy through port_a or port_b
should redefine the protected parameters port_a_exposesState and port_b_exposesState appropriately.
This will be visualized at the port icons, in order to improve the understanding of fluid model diagrams.
| Type | Name | Default | Description |
|---|---|---|---|
Boolean | allowFlowReversal | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| 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) |
Partial Model Modelica.Fluid.Interfaces.PartialTwoPortTransport
This component transports fluid between its two ports, without storing mass or energy.
Energy may be exchanged with the environment though, e.g., in the form of work.
PartialTwoPortTransport is intended as base class for devices like orifices, valves and simple fluid machines.
Three equations need to be added by an extending class using this component:
dp and the mass flow rate m_flow,port_b.h_outflow for flow in design direction, andport_a.h_outflow for flow in reverse direction.Moreover appropriate values shall be assigned to the following parameters:
dp_start for a guess of the pressure dropm_flow_small for regularization of zero flow.Extends from Modelica.Fluid.Interfaces.PartialTwoPort (Partial component with two ports).
| Type | Name | Default | Description |
|---|---|---|---|
Boolean | allowFlowReversal | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
AbsolutePressure | dp_start | 0.01 * system.p_start | Guess value of dp = port_a.p - port_b.p |
MassFlowRate | m_flow_start | system.m_flow_start | Guess value of m_flow = port_a.m_flow |
MassFlowRate | m_flow_small | if system.use_eps_Re then system.eps_m_flow * system.m_flow_nominal else system.m_flow_small | Small mass flow rate for regularization of zero flow |
Boolean | show_T | true | = true, if temperatures at port_a and port_b are computed |
Boolean | show_V_flow | true | = true, if volume flow rate at inflowing port is computed |
| 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) |
Connector Modelica.Fluid.Interfaces.HeatPorts_a
Extends from Modelica.Thermal.HeatTransfer.Interfaces.HeatPort (Thermal port for 1-dim. heat transfer).
| Type | Name | Description |
|---|---|---|
Temperature | T | Port temperature |
flow HeatFlowRate | Q_flow | Heat flow rate (positive if flowing from outside into the component) |
Connector Modelica.Fluid.Interfaces.HeatPorts_b
Extends from Modelica.Thermal.HeatTransfer.Interfaces.HeatPort (Thermal port for 1-dim. heat transfer).
| Type | Name | Description |
|---|---|---|
Temperature | T | Port temperature |
flow HeatFlowRate | Q_flow | Heat flow rate (positive if flowing from outside into the component) |
Partial Model Modelica.Fluid.Interfaces.PartialHeatTransfer
This component is a common interface for heat transfer models. The heat flow rates Q_flows[n] through the boundaries of n flow segments
are obtained as function of the thermodynamic states of the flow segments for a given fluid Medium,
the surfaceAreas[n] and the boundary temperatures heatPorts[n].T.
The heat loss coefficient k can be used to model a thermal isolation between heatPorts.T and T_ambient.
An extending model implementing this interface needs to define one equation: the relation between the predefined fluid temperatures Ts[n],
the boundary temperatures heatPorts[n].T, and the heat flow rates Q_flows[n].
| Type | Name | Default | Description |
|---|---|---|---|
Integer | n | 1 | Number of heat transfer segments |
Boolean | use_k | false | = true to use k value for thermal isolation |
CoefficientOfHeatTransfer | k | 0 | Heat transfer coefficient to ambient |
Temperature | T_ambient | system.T_ambient | Ambient temperature |
| Type | Name | Description |
|---|---|---|
HeatPorts_a | heatPorts[n] | Heat port to component boundary |
Partial Model Modelica.Fluid.Interfaces.PartialLumpedVolume
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, andWb_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, andmbC_flow, trace substance mass flow.| Type | Name | Default | Description |
|---|---|---|---|
Dynamics | energyDynamics | system.energyDynamics | Formulation of energy balance |
Dynamics | massDynamics | system.massDynamics | Formulation of mass balance |
final Dynamics | substanceDynamics | massDynamics | Formulation of substance balance |
final Dynamics | traceDynamics | massDynamics | Formulation of trace substance balance |
AbsolutePressure | p_start | system.p_start | Start value of pressure |
Boolean | use_T_start | true | = true, use T_start, otherwise h_start |
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 |
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 |
MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m |
ExtraProperty | C_start[Medium.nC] | Medium.C_default | Start value of trace substances |
Partial Model Modelica.Fluid.Interfaces.PartialLumpedFlow
Interface and base class for a momentum balance, defining the mass flow rate m_flow
of a given Medium in a flow model.
The following boundary flow and force terms are part of the momentum balance and must be specified in an extending model (to zero if not considered):
Ib_flow, the flow of momentum across model boundaries,F_p[m], pressure force, andF_fg[m], friction and gravity forces.
The length of the flow path pathLength is an input that needs to be set in an extending class to complete the model.
| Type | Name | Default | Description |
|---|---|---|---|
Boolean | allowFlowReversal | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction (m_flow >= 0) |
Dynamics | momentumDynamics | system.momentumDynamics | Formulation of momentum balance |
MassFlowRate | m_flow_start | system.m_flow_start | Start value of mass flow rates |
Partial Model Modelica.Fluid.Interfaces.PartialDistributedVolume
Interface and base class for n ideally mixed fluid volumes with the ability to store mass and energy.
It is intended to model a one-dimensional spatial discretization of fluid flow according to the finite volume method.
The following boundary flow and source terms are part of the energy balance and must be specified in an extending class:
Qb_flows[n], heat flow term, e.g., conductive heat flows across segment boundaries, andWb_flows[n], work term.
The component volumes fluidVolumes[n] are an input that needs to be set in an extending class to complete the model.
Further source terms must be defined by an extending class for fluid flow across the segment boundary:
Hb_flows[n], enthalpy flow,mb_flows[n], mass flow,mbXi_flows[n], substance mass flow, andmbC_flows[n], trace substance mass flow.| Type | Name | Default | Description |
|---|---|---|---|
Integer | n | 2 | Number of discrete volumes |
Dynamics | energyDynamics | system.energyDynamics | Formulation of energy balances |
Dynamics | massDynamics | system.massDynamics | Formulation of mass balances |
final Dynamics | substanceDynamics | massDynamics | Formulation of substance balances |
final Dynamics | traceDynamics | massDynamics | Formulation of trace substance balances |
AbsolutePressure | p_a_start | system.p_start | Start value of pressure at port a |
AbsolutePressure | p_b_start | p_a_start | Start value of pressure at port b |
final AbsolutePressure | ps_start[n] | if 1 < n then linspace(p_a_start, p_b_start, n) else {0.5 * (p_a_start + p_b_start)} | Start value of pressure |
Boolean | use_T_start | true | Use T_start if true, otherwise h_start |
Temperature | T_start | if use_T_start then system.T_start else Medium.temperature_phX(0.5 * (p_a_start + p_b_start), h_start, X_start) | Start value of temperature |
SpecificEnthalpy | h_start | if use_T_start then Medium.specificEnthalpy_pTX(0.5 * (p_a_start + p_b_start), T_start, X_start) else Medium.h_default | Start value of specific enthalpy |
MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m |
ExtraProperty | C_start[Medium.nC] | Medium.C_default | Start value of trace substances |
Partial Model Modelica.Fluid.Interfaces.PartialDistributedFlow
Interface and base class for m momentum balances, defining the mass flow rates m_flows[m]
of a given Medium in m flow segments.
The following boundary flow and force terms are part of the momentum balances and must be specified in an extending model (to zero if not considered):
Ib_flows[m], the flows of momentum across segment boundaries,Fs_p[m], pressure forces, andFs_fg[m], friction and gravity forces.
The lengths along the flow path pathLengths[m] are an input that needs to be set in an extending class to complete the model.
| Type | Name | Default | Description |
|---|---|---|---|
Boolean | allowFlowReversal | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction (m_flows >= zeros(m)) |
Integer | m | 1 | Number of flow segments |
Dynamics | momentumDynamics | system.momentumDynamics | Formulation of momentum balance |
MassFlowRate | m_flow_start | system.m_flow_start | Start value of mass flow rates |
Partial Model Modelica.Fluid.Interfaces.PartialPressureLoss
This component transports fluid between its two ports, without storing mass or energy.
Energy may be exchanged with the environment though, e.g., in the form of work.
PartialTwoPortTransport is intended as base class for devices like orifices, valves and simple fluid machines.
Three equations need to be added by an extending class using this component:
dp and the mass flow rate m_flow,port_b.h_outflow for flow in design direction, andport_a.h_outflow for flow in reverse direction.Moreover appropriate values shall be assigned to the following parameters:
dp_start for a guess of the pressure dropm_flow_small for regularization of zero flow.Extends from Modelica.Fluid.Interfaces.PartialTwoPortTransport (Partial element transporting fluid between two ports without storage of mass or energy).
| Type | Name | Default | Description |
|---|---|---|---|
Boolean | allowFlowReversal | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
AbsolutePressure | dp_start | 0.01 * system.p_start | Guess value of dp = port_a.p - port_b.p |
MassFlowRate | m_flow_start | system.m_flow_start | Guess value of m_flow = port_a.m_flow |
MassFlowRate | m_flow_small | if system.use_eps_Re then system.eps_m_flow * system.m_flow_nominal else system.m_flow_small | Small mass flow rate for regularization of zero flow |
Boolean | show_T | true | = true, if temperatures at port_a and port_b are computed |
Boolean | show_V_flow | true | = true, if volume flow rate at inflowing port is computed |
| 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) |