modelLoopBreaker
Extends from ThermofluidStream.Utilities.DropOfCommonsPlus (Extend this to use 'dropOfCommons', 'instanceName', 'displayInstanceName' and 'displayParameters').
Information
Combination of ThermofluidStream.Source with Sink_free to artificially close a loop. Cyclic loops without a loop breaker lead to algebraic loops which can make the system unsolvable. The loop-breaker acts as both a source and a sink, defining a beginning (source) and an end (sink) in the loop, breaking the algebraic equations.
The model is locally underdetermined (1 equation missing) and therefore must be connected to an overdetermined one (e.g., MassFlowRate) to ensure that the overall system is balanced.
Inlet and outlet states of the loop breaker are independent of each other. The outlet state of the loop breaker is prescribed, while the user must ensure that the inlet state is consistent. Any deviation is indicated by a warning.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| String | instanceName (from DropOfCommonsPlus) | getInstanceName() | Instance name |
| String | name | getInstanceName() | |
| Layout | |||
| Boolean | displayInstanceName (from DropOfCommonsPlus) | dropOfCommons.displayInstanceNames | = true, if instance name is displayed |
| Boolean | displayParameters (from DropOfCommonsPlus) | dropOfCommons.displayParameters | = true, if displaying parameters is enabled |
| Pressure | |||
| ValueSpecification | pSpec | ThermofluidStream.Types.ValueSpecification.Fixed | Specifies whether the outlet pressure is fixed or prescribed |
| Medium.AbsolutePressure | p_out_fixed | Medium.p_default | Fixed outlet pressure |
| Thermal | |||
| ThermalSpecification | thermalSpec | ThermofluidStream.Types.ThermalSpecification.Temperature | Thermal quantity used to define the outlet state |
| ValueSpecification | thermalValueSpec | ThermofluidStream.Types.ValueSpecification.Fixed | Specifies whether the outlet thermal quantity is fixed or prescribed |
| Medium.Temperature | T_out_fixed | Medium.T_default | Fixed outlet temperature |
| Medium.SpecificEnthalpy | h_out_fixed | Medium.h_default | Fixed outlet specific enthalpy |
| Mass fractions | |||
| ValueSpecification | XiSpec | ThermofluidStream.Types.ValueSpecification.Fixed | Specifies whether the outlet mass fractions are fixed or prescribed |
| Medium.MassFraction[Medium.nXi] | Xi_out_fixed | Medium.X_default[1:Medium.nXi] | Fixed outlet mass fractions |
| Advanced | |||
| Boolean | considerInertance | dropOfCommons.considerInertance | =true, if transient momentum (inertance) term is considered; disable only for advanced use |
| ThermofluidStream.Utilities.Units.Inertance | L | dropOfCommons.L | Inertance |
| Advanced › Accepted errors | |||
| AssertionLevel | assertionLevel | AssertionLevel.warning | Assertion level |
| SI.PressureDifference | tol_p | 1e-5*Medium.p_default | Absolute tolerance for pressure p_in, p_out |
| SI.SpecificEnthalpy | tol_h | 500 | Absolute tolerance for specific enthalpy h_in, h_out |
| SI.MassFlowRate | tol_m_flow | 1e-3 | Absolute tolerance for mass flow rate m_flow_in, m_flow_out |
| SI.MassFlowRate | tol_Xi | 1e-5 | Absolute tolerance for mass fractions Xi_in, Xi_out |
| Layout › Display parameters | |||
| Boolean | showPressure | true | = true to show the fixed outlet pressure value p_out_fixed |
| Boolean | showThermalSpecification | true | = true to show the fixed outlet thermal specification value (either T_out_fixed or h_out_fixed) |
| Boolean | showMassFractions | false | = true to show the fixed outlet mass fraction values Xi_out_fixed |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput | p_out_prescribed | Prescribed outlet pressure [Pa] | |
| Modelica.Blocks.Interfaces.RealInput | T_out_prescribed | Prescribed outlet temperature [K] | |
| Modelica.Blocks.Interfaces.RealInput | h_out_prescribed | Prescribed outlet specific enthalpy [J/kg] | |
| Modelica.Blocks.Interfaces.RealInput[Medium.nXi] | Xi_out_prescribed | Prescribed outlet mass fractions [kg/kg] | |
| ThermofluidStream.Interfaces.Inlet | inlet | ||
| ThermofluidStream.Interfaces.Outlet | outlet |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| SI.MassFlowRate | m_flow_in | inlet.m_flow | Mass flow rate |
| Medium.AbsolutePressure | p_in | Medium.pressure(inlet.state) | Inlet pressure |
| Medium.SpecificEnthalpy | h_in | Medium.specificEnthalpy(inlet.state) | Inlet specific enthalpy |
| Medium.MassFraction[Medium.nXi] | Xi_in | Medium.massFraction(inlet.state) | Inlet mass fractions |
| SI.MassFlowRate | m_flow_out | -outlet.m_flow | Mass flow rate outlet |
| SI.MassFlowRate | dm_flow | Mass flow rate difference | |
| SI.Pressure | dp | Pressure difference | |
| SI.SpecificEnthalpy | dh | Specific enthalpy difference | |
| ThermofluidStream.Units.MassFractionDifference[Medium.nXi] | dXi | Mass fraction difference |
Contents
| Name | Description |
|---|---|
 Medium | Medium model |
Revisions
-
2026, by Raphael Gebhart (raphael.gebhart@dlr.de):
Initial version.