modelTwoWayFlowElementBuoyancy
Flow resistance that uses the power law
Extends from Buildings.Airflow.Multizone.BaseClasses.TwoWayFlowElement (Flow resistance that uses the power law).
Information
This is a partial model for models that describe the bi-directional air flow through large openings.
Models that extend this model need to compute
mAB_flow and mBA_flow,
or alternatively VAB_flow and VBA_flow,
and the face area area.
The face area is a variable to allow this partial model to be used
for doors that can be open or closed as a function of an input signal.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Velocity | vZer (from TwoWayFlowElement) | 0.001 | Minimum velocity to prevent zero flow. Recommended: 0.001 |
| Assumptions | |||
| Boolean | allowFlowReversal1 (from PartialFourPort) | true | = false to simplify equations, assuming, but not enforcing, no flow reversal for medium 1 |
| Boolean | allowFlowReversal2 (from PartialFourPort) | true | = false to simplify equations, assuming, but not enforcing, no flow reversal for medium 2 |
| Nominal condition | |||
| Modelica.Units.SI.MassFlowRate | m1_flow_nominal (from PartialFourPortInterface) | Nominal mass flow rate | |
| Modelica.Units.SI.MassFlowRate | m2_flow_nominal (from PartialFourPortInterface) | Nominal mass flow rate | |
| Advanced | |||
| Medium1.MassFlowRate | m1_flow_small (from PartialFourPortInterface) | 1E-4*abs(m1_flow_nominal) | Small mass flow rate for regularization of zero flow |
| Medium2.MassFlowRate | m2_flow_small (from PartialFourPortInterface) | 1E-4*abs(m2_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 |
| Advanced › Diagnostics | |||
| Boolean | show_T (from PartialFourPortInterface) | false | = true, if actual temperature at port is computed |
| Geometry | |||
| Modelica.Units.SI.Length | wOpe | 0.9 | Width of opening |
| Modelica.Units.SI.Length | hOpe | 2.1 | Height of opening |
| Modelica.Units.SI.Length | hA | 2.7/2 | Height of reference pressure zone A |
| Modelica.Units.SI.Length | hB | 2.7/2 | Height of reference pressure zone B |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_a1 (from PartialFourPort) | Fluid connector a1 (positive design flow direction is from port_a1 to port_b1) | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_b1 (from PartialFourPort) | Fluid connector b1 (positive design flow direction is from port_a1 to port_b1) | |
| Modelica.Fluid.Interfaces.FluidPort_a | port_a2 (from PartialFourPort) | Fluid connector a2 (positive design flow direction is from port_a2 to port_b2) | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_b2 (from PartialFourPort) | Fluid connector b2 (positive design flow direction is from port_a2 to port_b2) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Medium1.MassFlowRate | m1_flow (from PartialFourPortInterface) | port_a1.m_flow | Mass flow rate from port_a1 to port_b1 (m1_flow > 0 is design flow direction) |
| Modelica.Units.SI.PressureDifference | dp1 (from PartialFourPortInterface) | port_a1.p - port_b1.p | Pressure difference between port_a1 and port_b1 |
| Medium2.MassFlowRate | m2_flow (from PartialFourPortInterface) | port_a2.m_flow | Mass flow rate from port_a2 to port_b2 (m2_flow > 0 is design flow direction) |
| Modelica.Units.SI.PressureDifference | dp2 (from PartialFourPortInterface) | port_a2.p - port_b2.p | Pressure difference between port_a2 and port_b2 |
| Medium1.ThermodynamicState | sta_a1 (from PartialFourPortInterface) | if allowFlowReversal1 then Medium1.setState_phX(port_a1.p, noEvent(actualStream(port_a1.h_outflow)), noEvent(actualStream(port_a1.Xi_outflow))) else Medium1.setState_phX(port_a1.p, inStream(port_a1.h_outflow), inStream(port_a1.Xi_outflow)) | Medium properties in port_a1 |
| Medium1.ThermodynamicState | sta_b1 (from PartialFourPortInterface) | if allowFlowReversal1 then Medium1.setState_phX(port_b1.p, noEvent(actualStream(port_b1.h_outflow)), noEvent(actualStream(port_b1.Xi_outflow))) else Medium1.setState_phX(port_b1.p, port_b1.h_outflow, port_b1.Xi_outflow) | Medium properties in port_b1 |
| Medium2.ThermodynamicState | sta_a2 (from PartialFourPortInterface) | if allowFlowReversal2 then Medium2.setState_phX(port_a2.p, noEvent(actualStream(port_a2.h_outflow)), noEvent(actualStream(port_a2.Xi_outflow))) else Medium2.setState_phX(port_a2.p, inStream(port_a2.h_outflow), inStream(port_a2.Xi_outflow)) | Medium properties in port_a2 |
| Medium2.ThermodynamicState | sta_b2 (from PartialFourPortInterface) | if allowFlowReversal2 then Medium2.setState_phX(port_b2.p, noEvent(actualStream(port_b2.h_outflow)), noEvent(actualStream(port_b2.Xi_outflow))) else Medium2.setState_phX(port_b2.p, port_b2.h_outflow, port_b2.Xi_outflow) | Medium properties in port_b2 |
| Modelica.Units.SI.VolumeFlowRate | VAB_flow (from TwoWayFlowElement) | Volume flow rate from A to B if positive | |
| Modelica.Units.SI.VolumeFlowRate | VBA_flow (from TwoWayFlowElement) | Volume flow rate from B to A if positive | |
| Modelica.Units.SI.MassFlowRate | mAB_flow (from TwoWayFlowElement) | Mass flow rate from A to B if positive | |
| Modelica.Units.SI.MassFlowRate | mBA_flow (from TwoWayFlowElement) | Mass flow rate from B to A if positive | |
| Modelica.Units.SI.Velocity | vAB (from TwoWayFlowElement) | Average velocity from A to B | |
| Modelica.Units.SI.Velocity | vBA (from TwoWayFlowElement) | Average velocity from B to A | |
| Modelica.Units.SI.Density | rho_a1_inflow (from TwoWayFlowElement) | Density of air flowing in from port_a1 | |
| Modelica.Units.SI.Density | rho_a2_inflow (from TwoWayFlowElement) | Density of air flowing in from port_a2 | |
| Modelica.Units.SI.Area | A (from TwoWayFlowElement) | Face area |
Revisions
-
June 27, 2018, by Michael Wetter:
Corrected old parameter annotation. -
July 20, 2010 by Michael Wetter:
Migrated model to Modelica 3.1 and integrated it into the Buildings library. -
February 4, 2005 by Michael Wetter:
Released first version.