modelJunction
Flow splitter with fixed resistance at each port
Extends from Buildings.Fluid.FixedResistances.Junction (Flow splitter with fixed resistance at each port).
Information
This is a model of a flow junction with an optional fixed resistance in each flow leg and an optional mixing volume at the junction. This model is identical to Buildings.Fluid.FixedResistances.Junction except for the icon which has been changed for better integration into the templates.
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 |
| Graphics | |||
| Buildings.Templates.Components.Types.IntegrationPoint | icon_pipe1 | Buildings.Templates.Components.Types.IntegrationPoint.Supply | Pipe symbol - Branch 1 |
| Buildings.Templates.Components.Types.IntegrationPoint | icon_pipe2 | icon_pipe1 | Pipe symbol - Branch 2 |
| Buildings.Templates.Components.Types.IntegrationPoint | icon_pipe3 | icon_pipe1 | Pipe symbol - Branch 3 |
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 |
Revisions
-
March 29, 2024, by Antoine Gautier:
First implementation.