modelJunction
Fluid junction with zero pressure drop
Extends from Fluid.FixedResistances.Junction (Flow splitter with fixed resistance at each port).
Information
This is a model of a fluid junction with zero pressure drop. By default the model is configured in steady-state.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | homotopyInitialization (from Junction) | true | = true, use homotopy method |
| Real | n (from Junction) | 2 | Flow exponent, n=1 for laminar, n=2 for turbulent |
| Dynamics › Conservation equations | |||
| Modelica.Fluid.Types.Dynamics | energyDynamics (from LumpedVolumeDeclarations) | Modelica.Fluid.Types.Dynamics.DynamicFreeInitial | Type of energy balance: dynamic (3 initialization options) or steady state |
| Modelica.Fluid.Types.Dynamics | substanceDynamics (from LumpedVolumeDeclarations) | energyDynamics | Type of independent mass fraction balance: dynamic (3 initialization options) or steady state |
| Modelica.Fluid.Types.Dynamics | traceDynamics (from LumpedVolumeDeclarations) | energyDynamics | Type of trace substance balance: dynamic (3 initialization options) or steady state |
| Modelica.Units.SI.MassFlowRate | mDyn_flow_nominal (from PartialThreeWayResistance) | Nominal mass flow rate for dynamic momentum and energy balance | |
| Advanced › Dynamics | |||
| Modelica.Fluid.Types.Dynamics | massDynamics (from LumpedVolumeDeclarations) | energyDynamics | Type of mass balance: dynamic (3 initialization options) or steady state, must be steady state if energyDynamics is steady state |
| Initialization | |||
| Medium.AbsolutePressure | p_start (from LumpedVolumeDeclarations) | Medium.p_default | Start value of pressure |
| Medium.Temperature | T_start (from LumpedVolumeDeclarations) | Medium.T_default | Start value of temperature |
| Medium.MassFraction[Medium.nX] | X_start (from LumpedVolumeDeclarations) | Medium.X_default | Start value of mass fractions m_i/m |
| Medium.ExtraProperty[Medium.nC] | C_start (from LumpedVolumeDeclarations) | fill(0, Medium.nC) | Start value of trace substances |
| Medium.ExtraProperty[Medium.nC] | C_nominal (from LumpedVolumeDeclarations) | fill(1E-2, Medium.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Dynamics | |||
| Real | mSenFac (from LumpedVolumeDeclarations) | 1 | Factor for scaling the sensible thermal mass of the volume |
| Dynamics › Nominal condition | |||
| Modelica.Units.SI.Time | tau (from PartialThreeWayResistance) | 10 | Time constant at nominal flow for dynamic energy and momentum balance |
| Advanced | |||
| Boolean | from_dp (from PartialThreeWayResistance) | true | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Modelica.Fluid.Types.PortFlowDirection | portFlowDirection_1 (from PartialThreeWayResistance) | Modelica.Fluid.Types.PortFlowDirection.Bidirectional | Flow direction for port_1 |
| Modelica.Fluid.Types.PortFlowDirection | portFlowDirection_2 (from PartialThreeWayResistance) | Modelica.Fluid.Types.PortFlowDirection.Bidirectional | Flow direction for port_2 |
| Modelica.Fluid.Types.PortFlowDirection | portFlowDirection_3 (from PartialThreeWayResistance) | Modelica.Fluid.Types.PortFlowDirection.Bidirectional | Flow direction for port_3 |
| Boolean | verifyFlowReversal (from PartialThreeWayResistance) | false | =true, to assert that the flow does not reverse when portFlowDirection_* does not equal Bidirectional |
| Modelica.Units.SI.MassFlowRate | m_flow_small (from PartialThreeWayResistance) | Small mass flow rate for checking flow reversal | |
| Boolean | linearized (from Junction) | false | = true, use linear relation between m_flow and dp for any flow rate |
| Nominal condition | |||
| Modelica.Units.SI.MassFlowRate | m_flow_nominal (from Junction) | Mass flow rate. Set negative at outflowing ports. | |
| Modelica.Units.SI.Pressure | dp_nominal (from Junction) | Pressure drop at nominal mass flow rate, set to zero or negative number at outflowing ports. | |
| Transition to laminar | |||
| Real | deltaM (from Junction) | 0.3 | Fraction of nominal mass flow rate where transition to turbulent occurs |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_1 (from PartialThreeWayResistance) | First port, typically inlet | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_2 (from PartialThreeWayResistance) | Second port, typically outlet | |
| Modelica.Fluid.Interfaces.FluidPort_a | port_3 (from PartialThreeWayResistance) | Third port, can be either inlet or outlet |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.Interfaces.PartialTwoPortInterface | res1 (from PartialThreeWayResistance) | ||
| Buildings.Fluid.Interfaces.PartialTwoPortInterface | res2 (from PartialThreeWayResistance) | ||
| Buildings.Fluid.Interfaces.PartialTwoPortInterface | res3 (from PartialThreeWayResistance) | ||
| Buildings.Fluid.Delays.DelayFirstOrder | vol (from PartialThreeWayResistance) | Fluid volume to break algebraic loop |