Compressor¶

Represents a compressor unit operation that raises the pressure of a gas or vapor stream using adiabatic or polytropic compression. Supports multiple calculation modes including outlet pressure, pressure ratio, power required, and performance curves.

DWSIM.UnitOperations.UnitOperations.Compressor
Assembly DWSIM.UnitOperations.dll · Object ← BaseClass ← UnitOpBaseClass ← Compressor

At a glance¶

Compressor in the example flowsheet

Port	Index	Connected in the example
Inlet, material	`0`	Gas-in
Inlet, energy	`1`	K-1 power
Outlet, material	`0`	Gas-out

Example¶

This code runs on every build of this site, and the output below is what it printed.

Python

fs = (Flowsheet.Create("CompressorExample")
      .WithCompounds("Methane", "Ethane", "Propane")
      .WithPropertyPackage(PropertyPackages.PengRobinson))

gas_in = (fs.AddMaterialStream("Gas-in")
          .At(Q.Celsius(30.0), Q.Bar(20.0))
          .SetCompoundMolarFlow("Methane", 90.0)     # mol/s
          .SetCompoundMolarFlow("Ethane", 7.0)
          .SetCompoundMolarFlow("Propane", 3.0))
gas_out = fs.AddMaterialStream("Gas-out")
power = fs.AddEnergyStream("K-1 power")

compressor = (fs.AddCompressor("K-1")
              .WithOutletPressure(Q.Bar(60.0))
              .WithAdiabaticEfficiencyPercent(75.0)
              .ConnectFeed(gas_in)
              .ConnectProduct(gas_out)
              .ConnectEnergyFeed(power, 1))      # energy inlet is port 1

fs.AutoLayout()
fs.Solve()

k1 = compressor.Object
print(f"Power required  = {k1.DeltaQ:.1f} kW")
print(f"Outlet T        = {gas_out.TemperatureK - 273.15:.1f} C")
print(f"Adiabatic head  = {k1.AdiabaticHead:.0f} m")
print(f"Adiabatic coeff = {k1.AdiabaticCoefficient:.3f}")
print(f"Mass flow       = {gas_in.Object.GetMassFlow():.3f} kg/s")

Output

Power required  = 395.1 kW
Outlet T        = 133.4 C
Adiabatic head  = 17613 m
Adiabatic coeff = 1.282
Mass flow       = 1.787 kg/s

DWSIM 10.2.11.0, generated 2026-10-08.

Calculation modes¶

Set with CalcMode (CalculationMode). The mode decides which properties are inputs; every other one is a result and is overwritten by the calculation.

Mode	Value	What it does	Inputs
`OutletPressure`	0	Outlet conditions calculated from a specified outlet pressure.	`PROP_CO_1`, `PROP_CO_4`
`Delta_P`	1	Outlet conditions calculated from a specified pressure increase (Pa).	`PROP_CO_0`, `PROP_CO_1`
`EnergyStream`	2	Power input read from the connected energy stream.	`PROP_CO_1`
`PowerRequired`	3	Outlet pressure calculated to consume the specified power.	`PROP_CO_1`, `PROP_CO_3`
`Head`	4	Outlet pressure calculated from a specified polytropic or adiabatic head.	`PROP_CO_1`, `AdiabaticHead`
`Curves`	5	Outlet conditions determined from pump performance curves.	`PROP_CO_1`, `RotationSpeed`
`PressureRatio`	6	Outlet conditions calculated from a specified pressure ratio.	`PROP_CO_1`, `PressureRatio`

Properties¶

IDs accepted by GetPropertyValue, SetPropertyValue, the sensitivity analysis, the optimizer, the Adjust block and dynamic events. Units are SI; pass another unit system to GetPropertyValue to get them converted.

ID	Name	Unit (SI)	Input in
`PROP_CO_0`	Pressure Increase	Pa	`Delta_P`
`PROP_CO_1`	Adiabatic Efficiency	%	all modes
`PROP_CO_2`	Temperature Difference	K (difference)	result
`PROP_CO_3`	Power Required	kW	`PowerRequired`
`PROP_CO_4`	Pressure	Pa	`OutletPressure`
`PolytropicEfficiency`	Polytropic Efficiency	%	result
`AdiabaticCoefficient`	Adiabatic Coefficient		result
`PolytropicCoefficient`	Polytropic Coefficient		result
`AdiabaticHead`	Adiabatic Head	m	`Head`
`PolytropicHead`	Polytropic Head	m	result
`RotationSpeed`	Rotation Speed	rpm	`Curves`
`PressureRatio`			`PressureRatio`

Dynamic mode¶

Extra properties used when the flowsheet runs in dynamic mode.

Name	Unit
Flow Conductance	[kg/s]/[Pa^0.5]
Volume	m3
Minimum Pressure	Pa
Initialize using Inlet Stream
Reset Content
Rotational Inertia
Current Speed
Target Speed
Motor Torque
Surge Flow Fraction
Surge Alarm
Design Inlet Volumetric Flow	m3/s
Integrate Casing Holdup
Rated Speed

Learn more¶

User guide
- Compressor/Expander
Tutorials
FluentAPI
- CompressorBuilder
- 10 — Pump + Compressor Train

API members¶

Public members declared by this class. Inherited members are documented on the base classes.

Constructors¶

Compressor(): Initializes a new default instance of the Compressor class.

Initializes a new default instance of the Compressor class.

C#VB.NET

public Compressor()

Public Sub New()

Compressor(string, string): Initializes a new instance of the Compressor class with a name and description.

Initializes a new instance of the Compressor class with a name and description.

Parameter	Type	Description
`name`	`String`	The display name of the compressor.
`description`	`String`	A brief description of the compressor.

C#VB.NET

public Compressor(string name, string description)

Public Sub New(name As String, description As String)

Properties¶

AdiabaticCoefficient: Gets or sets the calculated adiabatic head coefficient.

Gets or sets the calculated adiabatic head coefficient.

C#VB.NET

public double AdiabaticCoefficient { get; set; }

Public Property AdiabaticCoefficient As Double

AdiabaticEfficiency: Gets or sets the adiabatic (isentropic) efficiency (%).

Gets or sets the adiabatic (isentropic) efficiency (%).

C#VB.NET

public double AdiabaticEfficiency { get; set; }

Public Property AdiabaticEfficiency As Double

AdiabaticHead: Gets or sets the calculated adiabatic head (J/kg).

Gets or sets the calculated adiabatic head (J/kg).

C#VB.NET

public double AdiabaticHead { get; set; }

Public Property AdiabaticHead As Double

CalcMode: Gets or sets the active calculation mode.

Gets or sets the active calculation mode.

C#VB.NET

public Compressor.CalculationMode CalcMode { get; set; }

Public Property CalcMode As Compressor.CalculationMode

CurveEff: Gets or sets the efficiency read from the performance curve (%).

Gets or sets the efficiency read from the performance curve (%).

C#VB.NET

public double CurveEff { get; set; }

Public Property CurveEff As Double

CurveFlow: Gets or sets the volumetric flow rate read from the performance curve (m³/s).

Gets or sets the volumetric flow rate read from the performance curve (m³/s).

C#VB.NET

public double CurveFlow { get; set; }

Public Property CurveFlow As Double

CurveHead: Gets or sets the head read from the performance curve (m).

Gets or sets the head read from the performance curve (m).

C#VB.NET

public double CurveHead { get; set; }

Public Property CurveHead As Double

CurvePower: Gets or sets the power read from the performance curve (kW).

Gets or sets the power read from the performance curve (kW).

C#VB.NET

public double CurvePower { get; set; }

Public Property CurvePower As Double

Curves: Gets or sets the dictionary of performance curves keyed by rotation speed (RPM).

Gets or sets the dictionary of performance curves keyed by rotation speed (RPM).

C#VB.NET

public Dictionary<int, Dictionary<string, Curve>> Curves { get; set; }

Public Property Curves As Dictionary(Of Integer, Dictionary(Of String, Curve))

CurvesDB: Gets or sets the serialized performance curves database string.

Gets or sets the serialized performance curves database string.

C#VB.NET

public string CurvesDB { get; set; }

Public Property CurvesDB As String

DeltaP: Gets or sets the pressure increase across the compressor (Pa).

Gets or sets the pressure increase across the compressor (Pa).

C#VB.NET

public double DeltaP { get; set; }

Public Property DeltaP As Double

DeltaQ: Gets or sets the shaft power required (kW).

Gets or sets the shaft power required (kW).

C#VB.NET

public double DeltaQ { get; set; }

Public Property DeltaQ As Double

DeltaT: Gets or sets the calculated temperature change across the compressor (K).

Gets or sets the calculated temperature change across the compressor (K).

C#VB.NET

public double DeltaT { get; set; }

Public Property DeltaT As Double

DesignInletVolumetricFlow: Inlet volumetric flow (m3/s) recorded by the last steady-state calculation.

Inlet volumetric flow (m3/s) recorded by the last steady-state calculation. The dynamic surge alarm compares the running inlet flow against a fraction of this value.

C#VB.NET

public double DesignInletVolumetricFlow { get; set; }

Public Property DesignInletVolumetricFlow As Double

EquipmentTypes: Gets the list of equipment sub-types available for this compressor.

Gets the list of equipment sub-types available for this compressor.

C#VB.NET

public override List<string> EquipmentTypes { get; }

Public Overrides ReadOnly Property EquipmentTypes As List(Of String)

EquipType: Gets or sets the equipment sub-type identifier string.

Gets or sets the equipment sub-type identifier string.

C#VB.NET

public string EquipType { get; set; }

Public Property EquipType As String

HasPropertiesForDynamicMode: Gets a value indicating whether this unit operation exposes properties for dynamic mode.

Gets a value indicating whether this unit operation exposes properties for dynamic mode.

C#VB.NET

public override bool HasPropertiesForDynamicMode { get; }

Public Overrides ReadOnly Property HasPropertiesForDynamicMode As Boolean

HeatDuty: Gets or sets the shaft power (kW) as a proxy for DeltaQ.

Gets or sets the shaft power (kW) as a proxy for DeltaQ.

C#VB.NET

public double HeatDuty { get; set; }

Public Property HeatDuty As Double

IgnorePhase: Gets or sets whether the phase check is bypassed during calculation.

Gets or sets whether the phase check is bypassed during calculation.

C#VB.NET

public bool IgnorePhase { get; set; }

Public Property IgnorePhase As Boolean

MobileCompatible: Gets a value indicating whether this unit operation is compatible with the DWSIM mobile interface.

Gets a value indicating whether this unit operation is compatible with the DWSIM mobile interface.

C#VB.NET

public override bool MobileCompatible { get; }

Public Overrides ReadOnly Property MobileCompatible As Boolean

ObjectClass: Gets or sets the simulation object class category (PressureChangers).

Gets or sets the simulation object class category (PressureChangers).

C#VB.NET

public override SimulationObjectClass ObjectClass { get; set; }

Public Overrides Property ObjectClass As SimulationObjectClass

OutletTemperature: Gets or sets the calculated outlet temperature (K).

Gets or sets the calculated outlet temperature (K).

C#VB.NET

public double OutletTemperature { get; set; }

Public Property OutletTemperature As Double

PolytropicCoefficient: Gets or sets the calculated polytropic head coefficient.

Gets or sets the calculated polytropic head coefficient.

C#VB.NET

public double PolytropicCoefficient { get; set; }

Public Property PolytropicCoefficient As Double

PolytropicEfficiency: Gets or sets the polytropic efficiency (%).

Gets or sets the polytropic efficiency (%).

C#VB.NET

public double PolytropicEfficiency { get; set; }

Public Property PolytropicEfficiency As Double

PolytropicHead: Gets or sets the calculated polytropic head (J/kg).

Gets or sets the calculated polytropic head (J/kg).

C#VB.NET

public double PolytropicHead { get; set; }

Public Property PolytropicHead As Double

POut: Gets or sets the specified outlet pressure (Pa).

Gets or sets the specified outlet pressure (Pa).

C#VB.NET

public double POut { get; set; }

Public Property POut As Double

PressureIncrease: Gets or sets the pressure increase (Pa) as a proxy for DeltaP.

Gets or sets the pressure increase (Pa) as a proxy for DeltaP.

C#VB.NET

public double PressureIncrease { get; set; }

Public Property PressureIncrease As Double

PressureRatio: Gets or sets the specified pressure ratio (outlet/inlet).

Gets or sets the specified pressure ratio (outlet/inlet).

C#VB.NET

public double PressureRatio { get; set; }

Public Property PressureRatio As Double

ProcessPath: Gets or sets the thermodynamic process path (adiabatic or polytropic).

Gets or sets the thermodynamic process path (adiabatic or polytropic).

C#VB.NET

public Compressor.ProcessPathType ProcessPath { get; set; }

Public Property ProcessPath As Compressor.ProcessPathType

Speed: Gets or sets the operating rotation speed (RPM) used for curve interpolation.

Gets or sets the operating rotation speed (RPM) used for curve interpolation.

C#VB.NET

public int Speed { get; set; }

Public Property Speed As Integer

SupportsDynamicMode: Gets a value indicating whether this unit operation supports dynamic simulation mode.

Gets a value indicating whether this unit operation supports dynamic simulation mode.

C#VB.NET

public override bool SupportsDynamicMode { get; }

Public Overrides ReadOnly Property SupportsDynamicMode As Boolean

TemperatureChange: Gets or sets the temperature change (K) as a proxy for DeltaT.

Gets or sets the temperature change (K) as a proxy for DeltaT.

C#VB.NET

public double TemperatureChange { get; set; }

Public Property TemperatureChange As Double

Methods¶

Calculate(object): Performs the compressor calculation: determines outlet pressure, temperature, and power consumption using the...

Performs the compressor calculation: determines outlet pressure, temperature, and power consumption using the selected CalcMode and ProcessPath.

Parameter	Type	Description
`args`	`Object`	Optional calculation arguments (not used).

C#VB.NET

public override void Calculate(object args = null)

Public Overrides Sub Calculate(args As Object = Nothing)

CloneXML(): Creates a deep copy of this compressor via XML serialization.

Creates a deep copy of this compressor via XML serialization.

C#VB.NET

public override object CloneXML()

Public Overrides Function CloneXML() As Object

CloseEditForm(): Closes and disposes the editing form for this compressor if it is open.

Closes and disposes the editing form for this compressor if it is open.

C#VB.NET

public override void CloseEditForm()

Public Overrides Sub CloseEditForm()

CreateCurves(): Creates an empty set of performance curves for one rotational speed: head ('HEAD'), efficiency ('EFF') and power...

Creates an empty set of performance curves for one rotational speed: head ("HEAD"), efficiency ("EFF") and power ("POWER").

C#VB.NET

public Dictionary<string, Curve> CreateCurves()

Public Function CreateCurves() As Dictionary(Of String, Curve)

CreateDimensionsList(): Creates the dimensions list (Flow, Pressure, PressureDiff, Efficiency, Power).

Creates the dimensions list (Flow, Pressure, PressureDiff, Efficiency, Power).

C#VB.NET

public override void CreateDimensionsList()

Public Overrides Sub CreateDimensionsList()

CreateDynamicProperties(): Registers the dynamic properties for dynamic simulation mode: flow conductance, casing volume and holdup options...

Registers the dynamic properties for dynamic simulation mode: flow conductance, casing volume and holdup options, minimum pressure, rotor inertia, current, target and rated speeds (RPM), motor torque, and the surge limit and alarm.

C#VB.NET

public override void CreateDynamicProperties()

Public Overrides Sub CreateDynamicProperties()

DeCalculate(): Resets the outlet material and energy streams to an uncalculated state.

Resets the outlet material and energy streams to an uncalculated state.

C#VB.NET

public override void DeCalculate()

Public Overrides Sub DeCalculate()

DisplayEditForm(): Opens or activates the editing form for this compressor.

Opens or activates the editing form for this compressor.

C#VB.NET

public override void DisplayEditForm()

Public Overrides Sub DisplayEditForm()

GetCalculationModes(): Returns the list of available calculation mode names and IDs.

Returns the list of available calculation mode names and IDs.

C#VB.NET

public override string[] GetCalculationModes()

Public Overrides Function GetCalculationModes() As String()

GetChartModel(string): Builds an OxyPlot model of one map kind in the units of the first enabled curve, with the operating point marked...

Builds an OxyPlot model of one map kind in the units of the first enabled curve, with the operating point marked when the flow axis is an actual volumetric flow.

Parameter	Type	Description
`name`	`String`

C#VB.NET

public override object GetChartModel(string name)

Public Overrides Function GetChartModel(name As String) As Object

GetChartModelNames(): Chart names the PFD chart object can embed: the performance map, one series per measured speed, with the operating...

Chart names the PFD chart object can embed: the performance map, one series per measured speed, with the operating point.

C#VB.NET

public override List<string> GetChartModelNames()

Public Overrides Function GetChartModelNames() As List(Of String)

GetDisplayDescription(): Returns the localized display description for the compressor type.

Returns the localized display description for the compressor type.

C#VB.NET

public override string GetDisplayDescription()

Public Overrides Function GetDisplayDescription() As String

GetDisplayName(): Returns the localized display name for the compressor type.

Returns the localized display name for the compressor type.

C#VB.NET

public override string GetDisplayName()

Public Overrides Function GetDisplayName() As String

GetIconBitmapBytes(): Returns the raw bytes of the compressor icon image resource.

Returns the raw bytes of the compressor icon image resource.

C#VB.NET

public override byte[] GetIconBitmapBytes()

Public Overrides Function GetIconBitmapBytes() As Byte()

GetProperties(PropertyType): Returns the list of property identifiers available for this compressor.

Returns the list of property identifiers available for this compressor.

Parameter	Type	Description
`proptype`	`PropertyType`	The type of properties to retrieve.

C#VB.NET

public override string[] GetProperties(PropertyType proptype)

Public Overrides Function GetProperties(proptype As PropertyType) As String()

GetPropertyDescription(string): Returns a human-readable description for the specified property name, used in the property grid.

Returns a human-readable description for the specified property name, used in the property grid.

Parameter	Type	Description
`p`	`String`	The property display name.

C#VB.NET

public override string GetPropertyDescription(string p)

Public Overrides Function GetPropertyDescription(p As String) As String

GetPropertyUnit(string, IUnitsOfMeasure): Returns the unit string for the specified property.

Returns the unit string for the specified property.

Parameter	Type	Description
`prop`	`String`	The property identifier string.
`su`	`IUnitsOfMeasure`	The unit system to use; defaults to SI if not provided.

C#VB.NET

public override string GetPropertyUnit(string prop, IUnitsOfMeasure su = null)

Public Overrides Function GetPropertyUnit(prop As String, su As IUnitsOfMeasure = Nothing) As String

GetPropertyValue(string, IUnitsOfMeasure): Returns the value of the specified property converted to the given unit system.

Returns the value of the specified property converted to the given unit system.

Parameter	Type	Description
`prop`	`String`	The property identifier string (e.g., "PROP_CO_0").
`su`	`IUnitsOfMeasure`	The unit system to use; defaults to SI if not provided.

C#VB.NET

public override object GetPropertyValue(string prop, IUnitsOfMeasure su = null)

Public Overrides Function GetPropertyValue(prop As String, su As IUnitsOfMeasure = Nothing) As Object

GetReport(IUnitsOfMeasure, CultureInfo, string): Generates a text report summarizing the compressor's inlet, outlet, and calculation parameters.

Generates a text report summarizing the compressor's inlet, outlet, and calculation parameters.

Parameter	Type	Description
`su`	`IUnitsOfMeasure`	The unit system for reported values.
`ci`	`CultureInfo`	The culture info used for number formatting.
`numberformat`	`String`	The numeric format string.

C#VB.NET

public override string GetReport(IUnitsOfMeasure su, CultureInfo ci, string numberformat)

Public Overrides Function GetReport(su As IUnitsOfMeasure, ci As CultureInfo, numberformat As String) As String

GetStructuredReport(): Generates a structured (tabular) results report for display in the UI.

Generates a structured (tabular) results report for display in the UI.

C#VB.NET

public override List<Tuple<ReportItemType, string[]>> GetStructuredReport()

Public Overrides Function GetStructuredReport() As List(Of Tuple(Of ReportItemType, String()))

LoadData(List<XElement>): Restores the compressor state from a list of XML elements, including performance curves.

Restores the compressor state from a list of XML elements, including performance curves.

Parameter	Type	Description
`data`	`List<XElement>`	The list of `XElement` objects containing the serialized state.

C#VB.NET

public override bool LoadData(List<XElement> data)

Public Overrides Function LoadData(data As List(Of XElement)) As Boolean

ReadCurveMap(double, double, double, ref double, ref double, ref double): Reads the performance map at a flow and a speed.

Reads the performance map at a flow and a speed. The curves of every measured speed are interpolated along their own flow axis (actual volumetric flow when the unit of that axis carries the @ P,T suffix, molar flow otherwise), and the readings are then interpolated across the measured speeds. Head, power and efficiency come back in SI (m, kW, fraction), and NaN where the machine has no enabled curve of that kind.

Parameter	Type	Description
`qactual`	`Double`
`qmolar`	`Double`
`atspeed`	`Double`
`head`	`Double`
`power`	`Double`
`efficiency`	`Double`

C#VB.NET

public void ReadCurveMap(double qactual, double qmolar, double atspeed, ref double head, ref double power, ref double efficiency)

Public Sub ReadCurveMap(qactual As Double, qmolar As Double, atspeed As Double, head As Double, power As Double, efficiency As Double)

RunDynamicModel(): Runs one dynamic-mode integration step.

Runs one dynamic-mode integration step. The rotor speed moves towards the target speed at a rate set by the motor torque and inertia. By default the compressor acts as a pressure-flow element and sets the outlet to the inlet pressure plus the pressure rise at the current flow and speed; with "Integrate Casing Holdup" enabled it integrates the casing volume as a capacity. The pressure rise comes from the curve map in Curves mode, or from the flow conductance scaled by the square of the speed ratio. The surge alarm is updated at the end.

C#VB.NET

public override void RunDynamicModel()

Public Overrides Sub RunDynamicModel()

SaveData(): Serializes the compressor state, including performance curve data, into a list of XML elements.

Serializes the compressor state, including performance curve data, into a list of XML elements.

C#VB.NET

public override List<XElement> SaveData()

Public Overrides Function SaveData() As List(Of XElement)

SetCalculationMode(int): Sets the calculation mode by numeric ID and returns the mode name.

Sets the calculation mode by numeric ID and returns the mode name.

Parameter	Type	Description
`modeID`	`Int32`	The integer ID of the desired calculation mode.

C#VB.NET

public override object SetCalculationMode(int modeID)

Public Overrides Function SetCalculationMode(modeID As Integer) As Object

SetPropertyValue(string, object, IUnitsOfMeasure): Sets the value of the specified property from the given unit system.

Sets the value of the specified property from the given unit system.

Parameter	Type	Description
`prop`	`String`	The property identifier string.
`propval`	`Object`	The new value to assign.
`su`	`IUnitsOfMeasure`	The unit system of the supplied value; defaults to SI if not provided.

C#VB.NET

public override bool SetPropertyValue(string prop, object propval, IUnitsOfMeasure su = null)

Public Overrides Function SetPropertyValue(prop As String, propval As Object, su As IUnitsOfMeasure = Nothing) As Boolean

UpdateDimensionsList(): Updates all dimension values from the current calculated results.

Updates all dimension values from the current calculated results.

C#VB.NET

public override void UpdateDimensionsList()

Public Overrides Sub UpdateDimensionsList()

UpdateEditForm(): Refreshes the displayed data in the editing form if it is currently open.

Refreshes the displayed data in the editing form if it is currently open.

C#VB.NET

public override void UpdateEditForm()

Public Overrides Sub UpdateEditForm()

Fields¶

f: The classic (WinForms) editor window open for this unit operation, if any.

The classic (WinForms) editor window open for this unit operation, if any. Not saved with the flowsheet.

C#VB.NET

public object f

Public f As Object