Class CompressorChartKhader2015

java.lang.Object

neqsim.process.equipment.compressor.CompressorChart

neqsim.process.equipment.compressor.CompressorChartAlternativeMapLookup

neqsim.process.equipment.compressor.CompressorChartAlternativeMapLookupExtrapolate

neqsim.process.equipment.compressor.CompressorChartKhader2015

All Implemented Interfaces:

Serializable, Cloneable, CompressorChartInterface

public class CompressorChartKhader2015
extends CompressorChartAlternativeMapLookupExtrapolate

CompressorChartKhader2015 is a class that implements the compressor chart calculations based on the Kader 2015 method. It extends the CompressorChartAlternativeMapLookupExtrapolate class and provides methods to set compressor curves based on speed, flow, head, and efficiency values. See: https://github.com/EvenSol/NeqSim-Colab/discussions/12

Author:

esol

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	CompressorChartKhader2015.CorrectedCurve	Simple POJO to hold corrected (dimensionless) compressor curve data for a given speed.
static class	CompressorChartKhader2015.RealCurve	Simple POJO to hold real (physical units) compressor curve data for a given speed.

Field Summary

Fields

Modifier and Type	Field	Description
(package private) SystemInterface	fluid
private double	impellerOuterDiameter
(package private) static org.apache.logging.log4j.Logger	logger	Logger object for class.
(package private) List<CompressorChartKhader2015.RealCurve>	realCurves
(package private) SystemInterface	ref_fluid
private static final long	serialVersionUID	Serialization version UID.
(package private) StreamInterface	stream

Fields inherited from class CompressorChartAlternativeMapLookup

chartConditions, fanLawCorrectionFunc, gearRatio, isStoneWall, isSurge, reducedHeadFitterFunc, reducedPolytropicEfficiencyFunc, referenceSpeed, refMW, refPressure, refTemperature, refZ

Fields inherited from class CompressorChart

chartSpeeds, chartValues, fanLawCorrectionFitter, flow, flowPolytropicEfficiency, head, maxSpeedCurve, minSpeedCurve, polytropicEfficiency, redflow, redflowPolytropicEfficiency, redhead, redpolytropicEfficiency, reducedFlowFitter, reducedHeadFitter, reducedPolytropicEfficiencyFitter, speed, stoneWallCurve, surgeCurve

Constructor Summary

Constructors

Constructor	Description
CompressorChartKhader2015(StreamInterface stream, double impellerdiam)	Constructs a CompressorChartKhader2015 object with the specified stream and impeller diameter.
CompressorChartKhader2015(SystemInterface fluid, double impellerdiam)	Constructs a CompressorChartKhader2015 object with the specified fluid and impeller diameter.
CompressorChartKhader2015(SystemInterface fluid, SystemInterface referenceFluid, double impellerdiam)	Constructs a CompressorChartKhader2015 object with the specified fluid and impeller diameter.

Method Summary

Modifier and Type	Method	Description
private SystemInterface	createDefaultFluid(double[] chartConditions)	Creates and initializes a default fluid for compressor chart calculations.
void	generateRealCurvesForFluid()	Converts a list of dimensionless (corrected) compressor curves to real (physical units) curves for a given fluid and speeds.
void	generateStoneWallCurve()	generateStoneWallCurve.
void	generateSurgeCurve()	Generates the surge curve by taking the head value at the lowest flow for each speed from the compressor chart values.
List<CompressorChartKhader2015.CorrectedCurve>	getCorrectedCurves(double[] chartConditions, double[] speed, double[][] flow, double[][] head, double[][] flowPolyEff, double[][] polyEff)	Returns a list of corrected compressor curves (dimensionless) based on the provided chart conditions and map data.
double	getImpellerOuterDiameter()	Returns the outer diameter of the impeller.
double	getPolytropicEfficiency(double flow, double speed)	Get method for polytropic efficiency from reference curves.
double	getPolytropicHead(double flow, double speed)	Get method for polytropic head from reference curves.
List<CompressorChartKhader2015.RealCurve>	getRealCurves()	Getter for the field realCurves.
SystemInterface	getReferenceFluid()	getReferenceFluid.
double	getStoneWallFlowAtSpeed(double speed)	Get the stone wall flow (maximum flow) at a specific speed.
double	getStoneWallHeadAtSpeed(double speed)	Get the stone wall head (polytropic head at maximum flow) at a specific speed.
double	getSurgeFlowAtSpeed(double speed)	Get the surge flow (minimum flow) at a specific speed.
double	getSurgeHeadAtSpeed(double speed)	Get the surge head (polytropic head at minimum flow) at a specific speed.
void	prettyPrintRealCurvesForFluid()	Pretty print all RealCurve objects for the current fluid.
void	setCurves(double[] chartConditions, double[] speed, double[][] flow, double[][] head, double[][] flowPolyEff, double[][] polyEff)	Sets the compressor curves based on the provided chart conditions, speed, flow, head, flowPolytrpicEfficiency and polytropic efficiency values.
void	setImpellerOuterDiameter(double impellerOuterDiameter)	Sets the outer diameter of the impeller.
void	setReferenceFluid(SystemInterface ref_fluid)	setReferenceFluid.

Methods inherited from class CompressorChartAlternativeMapLookupExtrapolate

getClosestRefSpeeds

Methods inherited from class CompressorChartAlternativeMapLookup

addCurve, addCurve, addSurgeCurve, bisect_left, bisect_left, checkStoneWall, checkSurge1, checkSurge2, getChartConditions, getChartValues, getCurveAtRefSpeed, getFlow, getFlows, getGearRatio, getHeads, getHeadUnit, getMaxSpeedCurve, getMinSpeedCurve, getPolytropicEfficiencies, getSpeed, getSpeeds, getSpeedValue, getStoneWallCurve, getSurgeCurve, isUseCompressorChart, main, plot, polytropicEfficiency, prettyPrintChartValues, setCurves, setGearRatio, setHeadUnit, setReferenceConditions, setStoneWallCurve, setSurgeCurve, setUseCompressorChart, setUseRealKappa, useRealKappa

Methods inherited from class CompressorChart

equals, fitReducedCurve, getDischargeTemperatures, getGamma, getInletPressure, getInletTemperature, getPolytropicExponent, getPowers, getPressureRatios, getReferenceDensity, hashCode, setGamma, setInletPressure, setInletTemperature, setMaxSpeedCurve, setMinSpeedCurve, setPolytropicExponent, setReferenceDensity

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface CompressorChartInterface

equals, getDischargeTemperatures, getGamma, getInletPressure, getInletStream, getInletTemperature, getOperatingMW, getPolytropicExponent, getPowers, getPressureRatios, getRatioToMaxSpeed, getRatioToMinSpeed, getReferenceDensity, hashCode, isHigherThanMaxSpeed, isLowerThanMinSpeed, isSpeedWithinRange, setGamma, setInletPressure, setInletStream, setInletTemperature, setOperatingMW, setPolytropicExponent, setReferenceDensity

Field Details

serialVersionUID

private static final long serialVersionUID

Serialization version UID.

See Also:

• Constant Field Values

logger

static org.apache.logging.log4j.Logger logger

Logger object for class.

fluid

SystemInterface fluid

ref_fluid

SystemInterface ref_fluid

stream

StreamInterface stream

impellerOuterDiameter

private double impellerOuterDiameter

realCurves

List<CompressorChartKhader2015.RealCurve> realCurves

Constructor Details

CompressorChartKhader2015

public CompressorChartKhader2015(SystemInterface fluid,
 double impellerdiam)

Constructs a CompressorChartKhader2015 object with the specified fluid and impeller diameter.

Parameters:

fluid - the working fluid for the compressor

impellerdiam - the outer diameter of the impeller

CompressorChartKhader2015

public CompressorChartKhader2015(SystemInterface fluid,
 SystemInterface referenceFluid,
 double impellerdiam)

Constructs a CompressorChartKhader2015 object with the specified fluid and impeller diameter.

Parameters:

fluid - the working fluid for the compressor

referenceFluid - the referenceFluid for the compressorcurve

impellerdiam - the outer diameter of the impeller

CompressorChartKhader2015

public CompressorChartKhader2015(StreamInterface stream,
 double impellerdiam)

Constructs a CompressorChartKhader2015 object with the specified stream and impeller diameter.

Parameters:

stream - the stream for the compressor

impellerdiam - the outer diameter of the impeller

Method Details

setCurves

public void setCurves(double[] chartConditions,
 double[] speed,
 double[][] flow,
 double[][] head,
 double[][] flowPolyEff,
 double[][] polyEff)

Sets the compressor curves based on the provided chart conditions, speed, flow, head, flowPolytrpicEfficiency and polytropic efficiency values. Mathematical background (see Kader 2015):
The method normalizes compressor map data using the following relations:

• Corrected Head Factor: H_corr = H / c_s²
• Corrected Flow Factor: Q_corr = Q / (c_s D²)
• Corrected Flow Factor for Efficiency: Q_corr,eff = Q_eff / (c_s D²)
• Polytropic Efficiency: η_p = η_p
• Machine Mach Number: Ma = N D / c_s

where:

• H = head
• Q = flow
• Q_eff = flow for efficiency
• N = speed
• D = impeller outer diameter
• c_s = sound speed of the fluid

These dimensionless numbers allow for comparison and extrapolation of compressor performance across different conditions, as described in Kader (2015) and the referenced NeqSim discussion.

Specified by:

setCurves in interface CompressorChartInterface

Overrides:

setCurves in class CompressorChartAlternativeMapLookup

Parameters:

chartConditions - array with temperature, pressure, (optionally density, molecular weight)

speed - array of speeds

flow - 2D array of flows

head - 2D array of heads

flowPolyEff - 2D array of flows for efficiency

polyEff - 2D array of polytropic efficiencies

getCorrectedCurves

public List<CompressorChartKhader2015.CorrectedCurve> getCorrectedCurves(double[] chartConditions,
 double[] speed,
 double[][] flow,
 double[][] head,
 double[][] flowPolyEff,
 double[][] polyEff)

Returns a list of corrected compressor curves (dimensionless) based on the provided chart conditions and map data. Each CorrectedCurve contains the machine Mach number, corrected flow factor, corrected head factor, corrected flow factor for efficiency, and polytropic efficiency arrays for each speed.

Parameters:

chartConditions - array with temperature, pressure, (optionally density, molecular weight)

speed - array of speeds

flow - 2D array of flows

head - 2D array of heads

flowPolyEff - 2D array of flows for efficiency

polyEff - 2D array of polytropic efficiencies

Returns:

List of CorrectedCurve objects containing dimensionless map data

generateRealCurvesForFluid

public void generateRealCurvesForFluid()

Converts a list of dimensionless (corrected) compressor curves to real (physical units) curves for a given fluid and speeds.

prettyPrintRealCurvesForFluid

public void prettyPrintRealCurvesForFluid()

Pretty print all RealCurve objects for the current fluid.

createDefaultFluid

private SystemInterface createDefaultFluid(double[] chartConditions)

Creates and initializes a default fluid for compressor chart calculations.

Parameters:

chartConditions - array with temperature, pressure, (optionally density, molecular weight)

Returns:

the sound speed of the fluid

getPolytropicHead

public double getPolytropicHead(double flow,
 double speed)

Get method for polytropic head from reference curves.

This method interpolates the polytropic head values from reference speeds closest to the given speed and averages them to estimate the polytropic head at the specified flow and speed.

Calculates the polytropic head for a given flow and speed by interpolating or extrapolating between reference compressor curves.

The method first converts the input flow and speed to dimensionless numbers using the sound speed and impeller diameter:

• Corrected Flow Factor: Q_corr = Q / (c_s D²)
• Machine Mach Number: Ma = N D / c_s

It then interpolates/extrapolates the polytropic head from the reference compressor curves in this dimensionless space, and finally converts the result back to physical units by multiplying with c_s².

Specified by:

getPolytropicHead in interface CompressorChartInterface

Overrides:

getPolytropicHead in class CompressorChartAlternativeMapLookupExtrapolate

Parameters:

flow - [m3/h], speed in [rpm].

speed - a double

Returns:

polytropic head in unit [getHeadUnit]

getPolytropicEfficiency

public double getPolytropicEfficiency(double flow,
 double speed)

Get method for polytropic efficiency from reference curves.

Calculates the polytropic efficiency of the compressor for a given flow and speed. The method interpolates the efficiency values from reference speed curves and averages them to estimate the efficiency at the specified conditions.

Calculates the polytropic efficiency for a given flow and speed by interpolating or extrapolating between reference compressor curves.

The method first converts the input flow and speed to dimensionless numbers using the sound speed and impeller diameter:

• Corrected Flow Factor: Q_corr = Q / (c_s D²)
• Machine Mach Number: Ma = N D / c_s

It then interpolates/extrapolates the polytropic efficiency from the reference compressor curves in this dimensionless space.

Specified by:

getPolytropicEfficiency in interface CompressorChartInterface

Overrides:

getPolytropicEfficiency in class CompressorChartAlternativeMapLookupExtrapolate

Parameters:

flow - [m3/h], speed in [rpm].

speed - a double

Returns:

polytropic efficiency [%].

getImpellerOuterDiameter

public double getImpellerOuterDiameter()

Returns the outer diameter of the impeller.

Returns:

the impeller outer diameter

setImpellerOuterDiameter

public void setImpellerOuterDiameter(double impellerOuterDiameter)

Sets the outer diameter of the impeller.

Parameters:

impellerOuterDiameter - the new outer diameter of the impeller unit meters

getReferenceFluid

public SystemInterface getReferenceFluid()

getReferenceFluid.

Returns:

a SystemInterface object

setReferenceFluid

public void setReferenceFluid(SystemInterface ref_fluid)

setReferenceFluid.

Parameters:

ref_fluid - a SystemInterface object

generateSurgeCurve

public void generateSurgeCurve()

Generates the surge curve by taking the head value at the lowest flow for each speed from the compressor chart values.

Generates and prints the surge curve based on RealCurve data. The surge curve is typically the minimum stable flow for each speed.

Specified by:

generateSurgeCurve in interface CompressorChartInterface

Overrides:

generateSurgeCurve in class CompressorChart

generateStoneWallCurve

public void generateStoneWallCurve()

generateStoneWallCurve.

Generates the stone wall curve by taking the head value at the highest flow for each speed from the compressor chart values.

Generates and sets the stone wall curve based on RealCurve data. The stone wall curve is typically the maximum flow for each speed.

Specified by:

generateStoneWallCurve in interface CompressorChartInterface

Overrides:

generateStoneWallCurve in class CompressorChart

getRealCurves

public List<CompressorChartKhader2015.RealCurve> getRealCurves()

Getter for the field realCurves.

Returns:

a List object

getSurgeFlowAtSpeed

public double getSurgeFlowAtSpeed(double speed)

Get the surge flow (minimum flow) at a specific speed.

This method finds the compressor curve closest to the specified speed and returns the minimum flow on that curve. This is useful for single speed compressors where the surge curve is not active, as well as for multi-speed compressors to get the surge point at a specific speed.

Override to use RealCurve data which contains the corrected flow and head values for the actual fluid.

Specified by:

getSurgeFlowAtSpeed in interface CompressorChartInterface

Overrides:

getSurgeFlowAtSpeed in class CompressorChart

Parameters:

speed - The compressor speed in RPM

Returns:

The surge flow (minimum flow) at the specified speed in m3/hr, or Double.NaN if no curves exist

getSurgeHeadAtSpeed

public double getSurgeHeadAtSpeed(double speed)

Get the surge head (polytropic head at minimum flow) at a specific speed.

This method finds the compressor curve closest to the specified speed and returns the polytropic head at the minimum flow point (surge point) on that curve.

Override to use RealCurve data which contains the corrected flow and head values for the actual fluid.

Specified by:

getSurgeHeadAtSpeed in interface CompressorChartInterface

Overrides:

getSurgeHeadAtSpeed in class CompressorChart

Parameters:

speed - The compressor speed in RPM

Returns:

The surge head at the specified speed in kJ/kg or meter (depending on headUnit), or Double.NaN if no curves exist

getStoneWallFlowAtSpeed

public double getStoneWallFlowAtSpeed(double speed)

Get the stone wall flow (maximum flow) at a specific speed.

This method finds the compressor curve closest to the specified speed and returns the maximum flow on that curve (choke limit). This is useful for single speed compressors where the stone wall curve is not active.

Override to use RealCurve data which contains the corrected flow and head values for the actual fluid.

Specified by:

getStoneWallFlowAtSpeed in interface CompressorChartInterface

Overrides:

getStoneWallFlowAtSpeed in class CompressorChart

Parameters:

speed - The compressor speed in RPM

Returns:

The stone wall flow (maximum flow) at the specified speed in m3/hr, or Double.NaN if no curves exist

getStoneWallHeadAtSpeed

public double getStoneWallHeadAtSpeed(double speed)

Get the stone wall head (polytropic head at maximum flow) at a specific speed.

This method finds the compressor curve closest to the specified speed and returns the polytropic head at the maximum flow point (choke limit) on that curve.

Override to use RealCurve data which contains the corrected flow and head values for the actual fluid.

Specified by:

getStoneWallHeadAtSpeed in interface CompressorChartInterface

Overrides:

getStoneWallHeadAtSpeed in class CompressorChart

Parameters:

speed - The compressor speed in RPM

Returns:

The stone wall head at the specified speed in kJ/kg or meter (depending on headUnit), or Double.NaN if no curves exist