modelCompressorBase
Extends from ThermoPower.Icons.Gas.Compressor.
Information
This is the base model for a compressor, including the interface and all equations except the actual computation of the performance characteristics. Reverse flow conditions are not supported.
This model does not include any shaft inertia by itself; if that is needed, connect a Modelica.Mechanics.Rotational.Inertia model to one of the shaft connectors.
As a base-model, it can be used both for axial and centrifugal compressors.
Modelling options
The actual gas used in the component is determined by the replaceable Medium package. In the case of multiple component, variable composition gases, the start composition is given by Xstart, whose default value is Medium.reference_X.
The following options are available to calculate the enthalpy of the outgoing gas:
- explicitIsentropicEnthalpy = true: the isentropic enthalpy hout_iso is calculated by the Medium.isentropicEnthalpy function.
- explicitIsentropicEnthalpy = false: the isentropic enthalpy is obtained by equating the specific entropy of the inlet gas gas_in and of a fictitious gas state gas_iso, with the same pressure of the outgoing gas; both are computed with the function Medium.specificEntropy.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | explicitIsentropicEnthalpy | true | isentropicEnthalpy function used |
| SI.PerUnit | eta_mech | 0.98 | mechanical efficiency |
| Medium.Temperature | Tdes_in | inlet design temperature | |
| Boolean | allowFlowReversal | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction |
| Initialisation | |||
| Medium.AbsolutePressure | pstart_in | inlet start pressure | |
| Medium.AbsolutePressure | pstart_out | outlet start pressure | |
| Medium.Temperature | Tstart_in | Tdes_in | inlet start temperature |
| Medium.Temperature | Tstart_out | outlet start temperature | |
| Medium.MassFraction[Medium.nX] | Xstart | Medium.reference_X | start gas composition |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| FlangeA | inlet | ||
| FlangeB | outlet | ||
| Modelica.Mechanics.Rotational.Interfaces.Flange_a | shaft_a | ||
| Modelica.Mechanics.Rotational.Interfaces.Flange_b | shaft_b |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| ThermoPower.System | system | System wide properties | |
| Medium.BaseProperties | gas_in | ||
| Medium.BaseProperties | gas_iso | ||
| Medium.SpecificEnthalpy | hout_iso | Outlet isentropic enthalpy | |
| Medium.SpecificEnthalpy | hout | Outlet enthaply | |
| Medium.SpecificEntropy | s_in | Inlet specific entropy | |
| Medium.AbsolutePressure | pout | Outlet pressure | |
| Medium.MassFlowRate | w | Gas flow rate | |
| SI.Angle | phi | shaft rotation angle | |
| SI.AngularVelocity | omega | shaft angular velocity | |
| SI.Torque | tau | net torque acting on the compressor | |
| SI.PerUnit | eta | isentropic efficiency | |
| SI.PerUnit | PR | pressure ratio |
Contents
| Name | Description |
|---|---|
 Medium |
Revisions
- 13 Apr 2005
by Francesco Casella:
Medium.BaseProperties gas_outremoved. - 14 Jan 2005
by Francesco Casella:
Adapted to Modelica.Media. - 5 Mar 2004
by Francesco Casella:
First release.
Compressor model restructured using inheritance.