modelPartialCompressor
Partial model for compressor that contains basic definitions used in
various compressor models
Information
This is a base model for simple compressor models that are used, for example, in close-loop systems like heat pumps or chillers.
Definitions needed for completion
Three definitions need to be added by an extending class using this component:
- Redecleration of the model
parCom. - Connection of
parCom.heatPortwithheatPort. - Connection of
port_aandport_bwithparCom.port_aandparCom.port_b.
The latter provides the possibility to add further components (e.g. pressure losses or heat transfers) located at the compressor's inlet and outlet.
Modeling approaches
This base model mainly consists of one sub-models and, therefore, please checkout this model for further information of underlying modeling approaches:
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| General › Geometry | |||
| Modelica.Units.SI.Volume | VDis | 13e-6 | Displacement volume of the compressor |
| Modelica.Units.SI.Efficiency | epsRef | 0.04 | Ratio of the real and the ideal displacement volume |
| Modelica.Units.SI.Diameter | diameterInl | 12e-3 | Diameter of the pipe at compressor's inlet |
| Modelica.Units.SI.Diameter | diameterOut | 8e-3 | Diameter of the pipe at compressor's outlet |
| General › Compressor's characterisitcs | |||
| Modelica.Units.SI.Frequency | rotSpeMax | 120 | Maximal rotational speed executable by the compressor |
| Real | piPreMax | 15 | Maximal pressure ratio executable by the compressor |
| Transient behaviour | |||
| Boolean | useInpFil | true | = true, if transient behaviour of rotational speed is computed |
| Modelica.Units.SI.Time | risTim | 0.5 | Time until rotational speed reaches 99.6 % of its set value |
| Pressure losses › General | |||
| Real | zetInl | ((1/0.59 - 1)^2 + (1 - (diameterInl/0.066)^2))*(1 - (diameterInl/0.066)^2) | Pressure loss factor at compressor's inlet for flow of port_a -> port_b |
| Real | zetOut | ((1/0.59 - 1)^2 + (1 - (diameterOut/0.1122)^2))*(1 - (diameterOut/0.1122)^2) | Pressure loss factor at compressor's outlet for flow of port_a -> port_b |
| Pressure losses › Advanced | |||
| Boolean | from_dp | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Boolean | homotopyInitialization | true | = true, use homotopy method for initialisation |
| Boolean | linearized | false | = true, use linear relation between m_flow and dp for any flow rate |
| Heat losses › General | |||
| Utilities.Types.HeatTransferModels | heaTraMod | Utilities.Types.HeatTransferModels.Simplified | Choose heat transfer model for heat losses at compressor's inlet and outlet |
| Heat losses › Geometry | |||
| Modelica.Units.SI.Mass | mWal | 2.5 | Mass of the fictitious wall |
| Modelica.Units.SI.SpecificHeatCapacity | cpWal | 450 | Specific heat capacity of the fictitious wall |
| Heat losses › Thermal conductances | |||
| Modelica.Units.SI.ThermalConductance | kAMeaInl | 25 | Effective mean thermal conductance between medium and fictitious wall at inlet |
| Modelica.Units.SI.ThermalConductance | kAMeaOut | 35 | Effective mean thermal conductance between medium and fictitious wall at outlet |
| Modelica.Units.SI.ThermalConductance | kAMeaAmb | 5 | Effective mean thermal conductance coefficient between fictitious wall and ambient |
| Heat losses › Initialisation | |||
| Boolean | iniTWal0 | true | = true, if wall is initialised at fixed temperature; Otherwise, steady state initialisation |
| Modelica.Units.SI.Temperature | TWal0 | 293.15 | Temperature of wall at initialisation |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Utilities.Types.SimpleCompressor | simCom | Utilities.Types.SimpleCompressor.Default | Parameter used to activate or deactivate menue choices |
| Advanced › General | |||
| Modelica.Units.SI.PressureDifference | dp_start | -20e5 | Guess value of compressor's dp = port_a.p - port_b.p |
| Medium.MassFlowRate | m_flow_start | 0.5*m_flow_nominal | Guess value of compressor's m_flow = port_a.m_flowr |
| Medium.MassFlowRate | m_flow_small | 1e-6*m_flow_nominal | Small mass flow rate for regularization of compressor's zero flow |
| Modelica.Units.SI.MassFlowRate | m_flow_nominal | 0.1 | Nominal mass flow rate |
| Advanced › Diagnostics | |||
| Boolean | show_T | false | = true, if compressor's temperatures at port_a and port_b are computed |
| Boolean | show_V_flow | false | = true, if compressor's volume flow rate at inflowing port is computed |
| Boolean | show_staEff | false | = true, if thermodynamic states and efficiencies are computed |
| Boolean | show_qua | false | = true, if vapour qualities are computed |
| Advanced › Initialisation | |||
| Modelica.Units.SI.Frequency | rotSpe0 | 60 | Compressor's rotational spped at initialisation |
| Modelica.Units.SI.AbsolutePressure | pInl0 | 3e5 | Pressure at compressor's inlet at initialisation |
| Modelica.Units.SI.Temperature | TInl0 | 283.15 | Temperature at compressor's inlet at initialisation |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_b | ||
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_b | heatPort | Heat port connector to calculate heat losses to ambient | |
| Modelica.Blocks.Interfaces.RealInput | manVarCom | Prescribed compressor's rotational speed | |
| Modelica.Blocks.Interfaces.RealOutput | curManVarCom | Current compressor's rotational speed |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| CompressionProcess | comPro | Model describing compression process |
Contents
| Name | Description |
|---|---|
 Medium | |
 EngineEfficiency | |
| VolumetricEfficiency | |
| IsentropicEfficiency | |
 CompressionProcess |
Revisions
- October 20, 2017, by Mirko Engelpracht:
First implementation (see issue 467).