Propeller Design for Conceptual Turboprop Aircraft

123 Pages·2017·4.9 MB·English

Propeller Design for Con-
ceptual Turboprop Aircraft
Y.A.P. Teeuwen
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Coverimage:Guittet,A.http://mycockpitview.com/
Propeller Design for
Conceptual Turboprop
Aircraft
by
Y.A.P. Teeuwen
inpartialfulfilmentoftherequirementsforthedegreeof
MasterofScienceinAerospaceEngineeringattheDelftUniversityofTechnology,
tobedefendedpubliclyonThursdayOctober12,2017at01:00PM.
Studentnr.: 4026152
Thesisregistrationnr.: 164#17#MT#FPP
Supervisor: Dr.ir.R.Vos
Thesiscommittee: Prof.dr.ir.L.L.M.Veldhuis, TUDelft
Dr.ir.R.Vos, TUDelft
Dr.ir.C.J.SimãoFerreira, TUDelft
Anelectronicversionofthisthesisisavailableathttp://repository.tudelft.nl/.

Preface
ThisreportmarkstheconclusionofmyMasterofScienceprogramatthefacultyofAerospaceEngineering.
Itconcernspropellerdesignintheconceptualdesignphaseofturbopropairliners. Propellersremainanin-
terestingchoiceforaircraftpropulsion,duetotheirhighpropulsiveefficiencywhencomparedtoalternative
formsofpropulsion. Thefindingsofthisresearchshowtheimplicationsofpropellerdesignchoicesonair-
craftmaximumtake-offmass.
Thisreportcametofruitionwiththesupportofothers,towhomIwishtoextendmygratitude. Iwould
liketothankRoelofVosforhisguidanceandsupportduringthisresearchprojectandthefurthercommittee
membersLeoVeldhuisandCarlosSimãoFerreirafortheirtimeandeffortinassessingthisreport. Afurther
acknowledgementofTomStokkermansandPeterKleinfortheirinsightsinpropellertheoryaswellasMal-
colmBrownandJelleBoersmafortheircontributionstomyprogrammingskillsandcomprehensionofthe
Initiatordesignsoftware. Finally, tothefriendsandlovedoneswithaspecialmentionofmyparentsand
girlfriend.Ihaveadeepappreciationofyourloveandsupportwhichallowedmetoreachthishighlightinmy
accomplishmentssofar.
YorickTeeuwen
Delft,October2017
iii

Abstract
Intheconceptualdesignphaseofaturbopropaircraft,theconfigurationisdeterminedandprimarycom-
ponentslikethewing,fuselageandpropulsionaresized. Exactsubsystemperformanceremainsunknown.
Propellerperformanceisestimatedtosizetheaircraftpropulsion.
Thisthesisexplorestheconsequencesontheaircraft’smaximumtake-offmassifthepropellerestimation
isremovedinfavorofahigherfidelitydesignapproach. Theinfluenceisdeterminedbyimplementingan
optimizationroutinewhichminimizesaircraftmaximumtake-offmassbyadjustingthepropellerdesign.
Arapidconceptualdesigntoolisusedtoestablishtheinterdependencebetweenpropellerandaircraft:
‘TheAircraftDesignInitiator’. Thistoolisabletoquicklyconceiverealisticaircraftdesignstoinvestigatethe
effectofnewtechnologiesandaircraftconfigurations.TheInitiatorisemployedtocreateadesignobjective.
Thisobjectivecontainstheinformationneededtoachieveanoptimumbetweenpropelleraerodynamiceffi-
ciencyanditsimplicationonthemassofthepropulsionunit.Thesetwofactorsdeterminethefuelrequired
forthemission,aswellasthemassofthepropellerenginecombination. Inturn,thesemassesimpactthe
maximumtake-offmassoftheaircraft.
Toestablishapropellerdesign,asetoftoolsisdeveloped. Aerodynamicperformanceiscalculatedfrom
blade element momentum theory. Mass estimation is performed by a class II sizing approach. A limited
structuraltoolisusedtosizethepropellerbladeroot.Propelleroptimizationisperformedwithtwostrategies:
a gradient descent optimization and a genetic algorithm. It is concluded that the propeller design space
features a lot of local minima and is poorly suited for gradient based optimization. Genetic optimization
isbettersuitedforpropellerdesign. Thisstrategyresultsincertainconclusionsregardingpropellerdesign
influencesontheaircraft’smaximumtake-offmass.
Theinfluenceofthepropelleronthemaximumtake-offmassisdeterminedtobelessthan1%compared
toinitialperformanceestimations. Theapplicabilitytoconceptualaircraftdesignisthereforelimited. How-
ever,theresultsdoclearlyshowtheinfluenceofthepropellerdesignparametersontheaircraft’smaximum
take-offmass.
v

Contents
ListofFigures xi
ListofTables xiii
Nomenclature xv
1 Introduction 1
2 Methodology 3
2.1 ConceptualdesignofanaircraftwiththeInitiatorwithemphasisonthepropulsiveunit. . . . . 3
2.1.1 Calculationofmissionfuelweight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1.2 Calculationofthethrustrequirement,enginesizeandpropulsivemass. . . . . . . . . . 4
2.1.3 Formingthedesignobjective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Optimizationroutine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.1 Optimizationstrategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.2 Optimizationvariablesandconstraintsforthedifferentstrategies. . . . . . . . . . . . . 9
I Tools 13
3 Aerodynamicmodule 15
3.1 Propellertheoryselection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1.1 Descriptionofbladeelementmomentumtheory . . . . . . . . . . . . . . . . . . . . . 16
3.1.2 BEMequations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.1.3 Tiplossmodel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.2 BEMmethodsolverselection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.2.1 Solverdescription . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.2.2 Solverselection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.3 ImplementationofBEMtheoryintotheaeroanalysismoduleandfinalnotes . . . . . . . . . . 20
4 AirfoilSectionData 23
4.1 Airfoilgeometryparameterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1.1 Propellerairfoildesignsensitivities . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1.2 Designcriteriaairfoilfamily . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.1.3 Sectionconclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.2 Discussiononthebehaviorofrotorairfoilsections. . . . . . . . . . . . . . . . . . . . . . . . 25
4.2.1 Stalldelayofrotorairfoilsandpoststalldevelopmentofliftanddrag . . . . . . . . . . . 25
4.2.2 Representingairfoildatanumerically . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.2.3 Comparisonofairfoilsolvers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.3 DevelopmentoftheaerodynamicairfoildatabaseforuseintheBEMcode. . . . . . . . . . . . 29
4.4 ImplementationoftheaerodynamicdatabaseintotheBEMcode . . . . . . . . . . . . . . . . 32
5 Take-offsimulationmodule 33
5.1 Aircraftdata. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.2 Take-offspeeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.3 Dragbreakdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.4 ThrustCalculationmethods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.4.1 Actuatordiscmethod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.4.2 BEMmethod. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.4.3 Thrustlapsecomparison. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
5.5 Implementationofthetake-offmodule. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
vii
viii Contents
6 Structuremodule 39
6.1 Bladeforces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
6.2 Structuralelementdiscretization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
6.3 Calculationofnormalstressatthebladeroot. . . . . . . . . . . . . . . . . . . . . . . . . . . 40
6.3.1 Calculationofsectionproperties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
6.3.2 Calculationofthebladestressduetobending. . . . . . . . . . . . . . . . . . . . . . . 41
6.4 Analysisofthestructuremoduleresultsandassumptionforthestructureconstraint. . . . . . . 42
6.4.1 Assumptionforpropellerstructuralconstraint. . . . . . . . . . . . . . . . . . . . . . . 42
6.4.2 Consequenceoflimitedstructuretool. . . . . . . . . . . . . . . . . . . . . . . . . . . 42
7 Massestimationmodule 45
7.1 Enginemassestimation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
7.2 Gearboxmassestimation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
7.3 Gasturbinemassestimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
7.4 Propellermassestimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
7.5 Massofpropulsionsystems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
8 Verification 51
8.1 Verificationofthepropulsivemass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
8.2 Verificationofthestructuremodule. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
8.2.1 Secondmomentofareaverification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
8.2.2 Verificationofrootsectionnormalstresses . . . . . . . . . . . . . . . . . . . . . . . . 52
8.3 Influenceofthenumberofaerodynamicbladesections . . . . . . . . . . . . . . . . . . . . . 53
II Results 57
9 Resultsofoptimizationstrategies 59
9.1 Referenceaircraft. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
9.2 Resultsofgradientbasedoptimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
9.2.1 Influenceofthestartingpointondesign. . . . . . . . . . . . . . . . . . . . . . . . . . 60
9.2.2 Optimizationwithdetailedaerodynamicmodel. . . . . . . . . . . . . . . . . . . . . . 61
9.2.3 Optimizingfordifferentdesignobjectives . . . . . . . . . . . . . . . . . . . . . . . . . 62
9.3 Resultsofgeneticoptimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
9.3.1 Optimizationwithlargediameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
9.3.2 Optimizationwithadiameterconstraint. . . . . . . . . . . . . . . . . . . . . . . . . . 65
9.4 Discussiononoptimizationtechniques. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
9.4.1 Comparisonofoptimizationresults . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
9.4.2 Explorationofpropellerdesignspace . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
10 Dependenceofvariables 71
10.1 Dependenceofpropellerparameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
10.1.1 Bladeactivityfactor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
10.1.2 Numberofblades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
10.1.3 Propellerdiameter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
10.2 Take-offfieldlengthsensitivitystudy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
11 Discussionontheresults,accuracyofthetoolsandapplicabilityoftheresearch 79
11.1 Accuracyofthetools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
11.2 Relevanceofthisthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
12 Conclusionsandrecommendations 83
12.1 Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
12.2 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
A Propellerspeedgoverning 91
A.1 ATR42-500propellergoverning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
A.2 Pitchgoverningmechanismmodel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92