Optimization of the Propeller-Driven Propulsion System for a Small UAV Aerospace Engineering

124 Pages·2017·2.52 MB·English

by  Andre C. Marta

Optimization of the Propeller-Driven Propulsion System for
a Small UAV
Nuno de Sousa Mendes Moita
Thesis to obtain the Master of Science Degree in
Aerospace Engineering
Supervisor: Prof. André Calado Marta
Examination Committee
Chairperson: Prof. Fernando José Parracho Lau
Supervisor: Prof. André Calado Marta
Member of the Committee: Prof. Pedro da Graça Tavares Álvares Serrão
April 2018
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Dedicatedtomyfamilyforbelievinginme.
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Acknowledgments
I would like to thank to my supervisor Andre´ Calado Marta for his patience and guidance along this
MasterThesis. Itwasaprivilegetobeguidedbysomeonewithsomuchexperienceinthisfield.
Tomyhometownfriends,Joa˜oGonc¸alves,Joa˜oTavaresandRuiRamos,fortheirsupportandbeing
always available and present during the best and the worst moments of these last five years. Without
you,Iamsurethatallofthiswouldnotbepossible.
To my Te´cnico colleagues and friends, specially to Fa´bio Garcia, for all the support and motivation
duringthelastfiveyears. Alsotomyfriendsfromthetennistableclub,fortheirsupportandmotivation.
To my friend Maria Monteiro, for her support, motivation, proud and being always available during
the best and the worse moments during the last year. Without you, I am sure all of this would not be
possible.
To my maternal grandparents, for their love, support and motivation since always. Without you,
everythingwouldhavedoublethedifficulty.
To my father, for all his continuous support, love and patience over all the years. For considering
all my necessities as his priority, even in the hardest times. To my mother, for her love, concern and
for always encouraging me to be better and to fight for my objectives. To my sister, for all the support,
motivationandproud. Withoutyou,IwouldneverreachtheplacewhereIamtoday.
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Resumo
ComocrescimentododesenvolvimentodeUAVsdesdeofimda2a GuerraMundial,atualmente,exis-
temUAVscomasmaisdiversasfuncionalidadesemisso˜es.
Integrando no projeto do LEEUAV, um UAV desenvolvido pelo IDMEC, em conjunto com o AergoG
e o INEGI, o objetivo desta dissertac¸a˜o e´ otimizar o he´lice do sistema de propulsa˜o ja´ anteriormente
constru´ıdo. Apo´s uma revisa˜o da literatura e de pesquisa sobre os diferentes softwares existentes
para ana´lises de sistemas de propulsa˜o, foi escolhido o software QPROP para realizar as ana´lises.
Apo´s a escolha do software, foi realizada uma parametrizac¸a˜o do he´lice, incluindo paraˆmetros que
caracterizamageometriaexteriordohe´lice,taiscomoodiaˆmetroeadistribuic¸a˜odacordaedoaˆngulo
detorc¸a˜oemcadaumadaspa´sdohe´liceeparaˆmetrosquecaracterizamoperfilusadoemcadauma
daspa´sdohe´lice,nomeadamenteavariac¸a˜odocoeficientedesustentac¸a˜ocomoaˆngulodeataque,os
coeficientesdesustentac¸a˜oma´ximo,m´ınimoeparaumaˆngulodeataquenulodoperfil,ocoeficientede
resisteˆncia aerodinaˆmica resultante da forma do perfil e o correspondente coeficiente de sustentac¸a˜o
e o nu´mero de Reynolds usado como refereˆncia, assim como o expoente que e´ usado para ajustar
a curva para diferentes valores do nu´mero de Reynolds. Apo´s execuc¸a˜o do software QPROP, foram
consideradososparaˆmetrosusadosparaavaliarodesempenhodohe´licetaiscomoaforc¸apropulsiva,
oscoeficientesdepoteˆnciaedeforc¸apropulsiva,eaeficieˆnciadohe´lice.
Para realizar os ensaios experimentais, foram escolhidos treˆs he´lices diferentes, onde foi poss´ıvel
analisarcomovariaasuaperformanceparadiferentesdiaˆmetros,passosemotoresevalidarosoftware.
Tendoemcontaquena˜osesabiaaocertoqueperfilestavaaserusadoemcadahe´lice,foramconsid-
erados dois poss´ıveis perfis, cujos dados foram determinados com o software XFOIL. Os paraˆmetros
geome´tricosdohe´liceforamdeterminadosmanualmente.
Apo´s a realizac¸a˜o dos ensaios experimentais e validac¸a˜o do software QPROP, foi realizada uma
otimizac¸a˜o progressiva usando o software MATLAB(cid:13)R, tanto para a fase de voˆo cruzeiro como para a
fasedesubida. Inicialmenteapenasarotac¸a˜odomotorfoiconsideradacomoparaˆmetronaotimizac¸a˜o
eapenasmaistardefoiotimizadaageometria. Comestaotimizac¸a˜ofoiobtidoumsistemamotor+he´lice
comumaeficieˆnciasuperioraoinicialparaasduasfasesdevoˆo,talcomoeradesejado.
Palavras-chave:
He´lice,Otimizac¸a˜o,Eficieˆncia,Forc¸aPropulsiva,PoteˆnciaEle´trica
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Abstract
Sincetheendofthe2ndWorldWar,therehasbeenagrowthofthedevelopmentofUAVsand,nowadays,
thereareUAVsaimedtoavarietyoffunctionalitiesandmissions.
Integrated in the LEEUAV project, an UAV developed by IDMEC, together with AeroG and INEGI,
the objective of this dissertation is to optimize the propeller-driven propulsion system designed and
built previously. After some literature review and research about the different existing softwares for
propulsion systems analysis, the chosen software was the QPROP. After software selection, a pro-
peller parametrization was made, including the parameters that characterize the planform shape of the
propeller, such as the diameter and the chord and the pitch angle distributions of each blade and the
characteristicsoftheairfoilusedineachblade,namelythederivativeoftheliftcoefficientwiththeangle
of attack, the lift coefficient at zero angle of attack, the maximum and the minimum lift coefficient, the
profile drag coefficient and its corresponding lift coefficient, the Reynolds number used as a reference
and the exponent used to adjust the polar curve to different Reynold numbers. After running QPROP,
some functions were used to evaluate the performance of the propeller, such as the thrust, the power
andthrustcoefficientandthepropellerefficiency.
To perform the experimental tests, three different propellers were chosen to study how the perfor-
mance varies for different diameters, pitches and motors and to validate the software. Since it was not
knownaccuratelywhichairfoilwasusedineachpropeller,twodifferentairfoils,whosedatawasobtained
usingthesoftwareXFOIL,wereconsidered. Thegeometricparametersofthepropellerweremeasured
manually.
Following the experimental tests and the validation of the software QPROP, a progressive optimiza-
tionusingthesoftwareMATLAB(cid:13)R,forcruiseandclimb,wasperformed. Initially,onlythemotorrotation
speed was considered in the optimization and only later the geometry optimization was performed. At
theendofthisoptimization,asystemmotor+propellerwithanhigherefficiencyforbothflightconditions
wasobtained,asdesired.
Keywords:
Propeller,Optimization,Efficiency,Thrust,ElectricalPower
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