modelRecircFlap
Information
This model describes an idealized model for a recirculation flap. Depending on the flap position the outdoor air is mixed with the exhaust air.
The flap position can be set by the input parameter
flapPosition where 0 means the flap is fully closed and
1 means fully open.
The mixture of the streams is calculated using the Richmann's mixing rule.
TOdaOut=(ṁOdaIn · cp,OdaIn · TOdaIn+ ṁEtaRecirc · cp,EtaIn · TEtaIn) ⁄ (ṁOdaIn · cp,OdaIn + ṁEtaRecirc · cp,EtaIn)
XOdaOut=(ṁOdaIn · XOdaIn+ ṁEtaRecirc · XEtaIn) ⁄ (ṁOdaIn + ṁEtaRecirc)
The recirculating mass flow rate of the exhaust air is calculated
using a parameter splitFactor. The
splitFactor is calculated by the
flapPosition depending on the calculation mode. By
default the relation between these is linear.
ṁEtaRecirc=ṁEtaIn · splitFactor
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Advanced | |||
| Modelica.Units.SI.SpecificHeatCapacity | cpAir | 1005 | specific heat capacity of dry air |
| Modelica.Units.SI.SpecificHeatCapacity | cpSteam | 1860 | specific heat capacity of steam |
| Modelica.Units.SI.Density | rhoAir | 1.2 | Density of air |
| Nominal conditions | |||
| Modelica.Units.SI.MassFlowRate | m_flow_nominal | nominal mass flow rate | |
| Modelica.Units.SI.PressureDifference | dp_nominal | pressure drop at nominal mass flow rate | |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput | flapPos | position of recirculating flap | |
| Modelica.Blocks.Interfaces.RealInput | mAirInEta_flow | mass flow rate of incoming exhaust air | |
| Modelica.Blocks.Interfaces.RealInput | TAirInEta | mass flow rate of incoming exhaust air | |
| Modelica.Blocks.Interfaces.RealInput | XAirInEta | mass flow rate of incoming exhaust air | |
| Modelica.Blocks.Interfaces.RealOutput | mAirOutEta_flow | mass flow rate of outgoing exhaust air | |
| Modelica.Blocks.Interfaces.RealOutput | TAirOutEta | temperature of outgoing exhaust air | |
| Modelica.Blocks.Interfaces.RealOutput | XAirOutEta | absolute humidity of outgoing exhaust air | |
| Modelica.Blocks.Interfaces.RealInput | mAirInOda_flow | mass flow rate of incoming outdoor air | |
| Modelica.Blocks.Interfaces.RealInput | TAirInOda | Temperature of incoming outdoor air | |
| Modelica.Blocks.Interfaces.RealInput | XAirInOda | absolute humidity of incoming outdoor air | |
| Modelica.Blocks.Interfaces.RealOutput | mAirOutOda_flow | mass flow rate of outgoing mixed air | |
| Modelica.Blocks.Interfaces.RealOutput | TAirOutOda | temperature of outgoing mixed air | |
| Modelica.Blocks.Interfaces.RealOutput | XAirOutOda | absolute humidity of outgoing mixed air | |
| Modelica.Blocks.Interfaces.RealOutput | dp | pressure difference |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| PartialPressureDrop | partialPressureDrop | ||
| PartialPressureDrop | partialPressureDrop2 |
Contents
| Name | Description |
|---|---|
| PartialPressureDrop |
Revisions
- May 2019, by Ervin Lejlic:
First implementation. - May 2019, by Martin Kremer:
Changing variable names. Adding possibility for other relation between flap position and volume flow through flap than linear.