modelPartialOneWayFlowElement
Partial model for flow resistance with one-way flow
Extends from AixLib.Fluid.Interfaces.PartialTwoPortInterface (Partial model with two ports and declaration of quantities that are used by many models), AixLib.Airflow.Multizone.BaseClasses.ErrorControl (Interface that defines parameters for error control).
Information
This partial model is used to model one way flow-elements. It holds the conservation equations and should be extended by definition of one of the following variables:
m_flow = mass flow rate trough the component
or
V_flow = volume flow rate through the component
The flow from A->B is the positive flow.
The resulting equation should be in the extends statement,
not in the equation section since this model sets both
m_flow = V_flow*rho and V_flow = m_flow/rho.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Assumptions | |||
| Boolean | allowFlowReversal (from PartialTwoPort) | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Nominal condition | |||
| Modelica.Units.SI.MassFlowRate | m_flow_nominal (from PartialTwoPortInterface) | Nominal mass flow rate | |
| Advanced | |||
| Modelica.Units.SI.MassFlowRate | m_flow_small (from PartialTwoPortInterface) | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow |
| Boolean | forceErrorControlOnFlow (from ErrorControl) | true | Flag to force error control on m_flow. Set to true if interested in flow rate |
| Boolean | homotopyInitialization | true | = true, use homotopy method |
| Boolean | useDefaultProperties | true | Set to false to use density and viscosity based on actual medium state, rather than using default values |
| Modelica.Units.SI.PressureDifference | dp_turbulent | 0.1 | Pressure difference where laminar and turbulent flow relation coincide. Recommended = 0.1 |
| Advanced › Diagnostics | |||
| Boolean | show_T (from PartialTwoPortInterface) | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_a (from PartialTwoPort) | Fluid connector a (positive design flow direction is from port_a to port_b) | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_b (from PartialTwoPort) | Fluid connector b (positive design flow direction is from port_a to port_b) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.MassFlowRate | m_flow (from PartialTwoPortInterface) | port_a.m_flow | Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) |
| Modelica.Units.SI.PressureDifference | dp (from PartialTwoPortInterface) | port_a.p - port_b.p | Pressure difference between port_a and port_b |
| Medium.ThermodynamicState | sta_a (from PartialTwoPortInterface) | if allowFlowReversal then Medium.setState_phX(port_a.p, noEvent(actualStream(port_a.h_outflow)), noEvent(actualStream(port_a.Xi_outflow))) else Medium.setState_phX(port_a.p, noEvent(inStream(port_a.h_outflow)), noEvent(inStream(port_a.Xi_outflow))) | Medium properties in port_a |
| Medium.ThermodynamicState | sta_b (from PartialTwoPortInterface) | if allowFlowReversal then Medium.setState_phX(port_b.p, noEvent(actualStream(port_b.h_outflow)), noEvent(actualStream(port_b.Xi_outflow))) else Medium.setState_phX(port_b.p, noEvent(port_b.h_outflow), noEvent(port_b.Xi_outflow)) | Medium properties in port_b |
| Modelica.Units.SI.VolumeFlowRate | V_flow | m_flow/rho | Volume flow rate through the component |
| Modelica.Units.SI.Density | rho | Fluid density at port_a |
Revisions
-
February 2, 2022, by Michael Wetter:
Revised implementation.
This is for IBPSA, #1436. -
Apr 06, 2021, by Klaas De Jonge:
First implementation.