SUBSYSTEM ARCHITECTURE SIZING AND ANALYSIS FOR AIRCRAFT CONCEPTUAL DESIGN A Thesis Presented to The Academic Faculty by Imon Chakraborty In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Daniel Guggenheim School of Aerospace Engineering Georgia Institute of Technology December 2015 Copyright c 2015 by Imon Chakraborty SUBSYSTEM ARCHITECTURE SIZING AND ANALYSIS FOR AIRCRAFT CONCEPTUAL DESIGN Approved by: Professor Dimitri N. Mavris, Advisor Professor Daniel P. Schrage Daniel Guggenheim School of Daniel Guggenheim School of Aerospace Engineering Aerospace Engineering Georgia Institute of Technology Georgia Institute of Technology Professor Brian J. German Dr. Ruben Del Rosario Daniel Guggenheim School of Glenn Research Center Aerospace Engineering National Aeronautics and Georgia Institute of Technology Space Administration Dr. Elena Garcia Date Approved: Nov 13, 2015 Daniel Guggenheim School of Aerospace Engineering Georgia Institute of Technology To my parents iii ACKNOWLEDGEMENTS It would seem that yet another graduate student’s Ph.D. journey has come to a completion through several challenging, laborious, and/or time-consuming activities: A research proposal was formulated, pitched, and approved, a research plan was painstakingly executed, a doctoral dissertation was compiled, and finally a defense was successfully mounted. At the end of it all, I gladly and gratefully acknowledge those who guided, assisted, and encouraged me along the way. First and foremost, I would like to express my profound appreciation for the members of my defense committee. I must thank whole-heartedly my advisor Professor Dimitri Mavris for multiple things, among them the opportunity to be a part of the Aerospace Systems Design Laboratory (ASDL) and the freedom to explore a number of research areas and projects en route to identifying my dissertation focus. Along the way, he provided unwavering mentoring and encouragement, displayed admirably imperturbable patience, and shared many an enlightening insight into the inner workings of academia and industry. I must also thank Professor Brian German for finding time from his schedule on numerous occasions to review, critique, and provide advice on various intricate technical details of my analysis approach. It is difficult for me to express in words how grateful I am to Dr. Elena Garcia for her sustained patience, her ever-present willingness to review and critique my work, and her constant reminders that I should remain mindful of the larger picture when the engineer in me tended to dive at and strafe a pixel. Last but not least, I would like to thank Professor Daniel Schrage and Dr. Ruben Del Rosario, who despite joining the committee quite far along in the process, took time from their busy schedules to review my work and provide me valuable technical feedback. iv The graduate school experience is not merely about one’s research but also about one’s interactions with colleagues, friends, and compatriots. I cannot possibly name everyone, but let me at least name a few in no particular order: Kalyana Gottiparthi, Daniel Garmendia and Burak Bagdatli (each of whom I’ve known since I started graduate school!), Matthew LeVine (synchronized promotions, proposal, and defense!), David Trawick (a fair bit of cross-country piloting together!), Michael Miller, Metin Ozcan, Charlie Potter, Mohammed Hassan, and of course Gokcin Cinar and Fatma Karagoz (continuous source of amusement!). To the few I mentioned and to many others as well, I have this to say: my graduate school experience was made all the richer through my interactions with all of you. I shall never forget the camaraderie and I wish all of you the very best in your professional careers and personal lives. Last but most certainly not least, I would like to thank my parents for the continuous support, guidance, and encouragement that they provided throughout my life. This work is dedicated to both of you. My father, the most well-rounded and technically sound engineer that I have ever met, inspired me from a young age to pursue a career in aerospace engineering. My mother, despite the lack of an engineering or technical background, did (and continues to do) everything in her power to ensure that I am steadfast in that pursuit. Collectively, they taught me that there is no substitute for perseverance and no easy route to success, which in turn cannot endure unless established upon a solid foundation of honesty and integrity. Imon Chakraborty Atlanta, GA November, 2015 v TABLE OF CONTENTS DEDICATION .................................. iii ACKNOWLEDGEMENTS .......................... iv LIST OF TABLES ............................... xii LIST OF FIGURES .............................. xiv LIST OF ACRONYMS ............................ xviii SUMMARY .................................... xxii I BACKGROUND AND MOTIVATION ................ 1 1.1 Aircraft Subsystems and Their Functions . 1 1.2 Non-propulsive / Secondary Power for Subsystems . 2 1.3 Gravitation Towards Conventional Subsystem Architectures . .... 4 1.4 The Drive for More Electric Subsystem Architectures . 5 1.5 Subsystem Considerations during Conceptual Design . 10 1.6 Previous AEA/MEA Feasibility Studies and Programs . 13 1.7 Relevant Prior Theses/Dissertations . 22 1.8 Observations from Previous Studies and Characteristics of the Present Approach................................. 26 1.9 ChapterSummary............................ 32 II RESEARCH OBJECTIVE, QUESTIONS, AND HYPOTHESES 33 2.1 ResearchObjective ........................... 34 2.2 StatementofResearchQuestions . 35 2.3 Comparing Competing Subsystem Solutions and Competing Subsystem Architectures (Research Question 1) .......... 36 2.4 Evaluating Subsystem Architecture Space and the Effect of Aircraft Size (Research Question 2) ..................... 42 2.5 Investigating Subsystem Architecture Sensitivities to Modeling and Technological Uncertainty (Research Question 3) ......... 50 2.6 ChapterSummary............................ 53 vi III TECHNICAL APPROACH ....................... 54 3.1 System, Subsystems, and Subsystem Architectures . ... 54 3.1.1 SubsystemArchitectures . 55 3.1.2 Degree of Subsystem Electrification (DSE) . 59 3.1.3 Total Fuel Impact and Total Weight Impact of Subsystems . 60 3.2 IntegratedSizingandAnalysisApproach . 61 3.2.1 Definition of Design Requirements . 63 3.2.2 Traditional Aircraft and Engine Sizing Process . 64 3.2.3 Generation of Subsystem Architecture Combinations . 67 3.2.4 Subsystem Architecture Sizing and Evaluation . 76 3.2.5 Evaluation and Decomposition of Subsystem Impacts . 79 3.2.6 Re-sizingofAircraftandSubsystems . 86 3.2.7 Post-processingAnalyses . 90 3.3 ChapterSummary............................ 90 IV MODELING OF POWER CONSUMING SUBSYSTEMS .... 92 4.1 FlightControlsActuationSystem(FCAS) . 93 4.1.1 ControlSurfaceDescriptionsandLayouts . 94 4.1.2 Actuation Loads for Ailerons, Elevators, and Rudders . 98 4.1.3 ActuationLoadsforSpoilers . 100 4.1.4 Actuation Loads for High-lift Devices . 102 4.1.5 Actuation Loads for Trimmable Horizontal Stabilizer . 103 4.1.6 ActuatorMassEstimation . 105 4.1.7 Hydraulic Actuation Power Consumption . 107 4.1.8 Electric Actuation Power Consumption . 108 4.1.9 Power Requirements for Prescribed Sinusoidal Motion . 110 4.2 LandingGearActuationSystem(LGAS) . 112 4.2.1 Landing Gear Actuation Requirements and System Sizing . 112 4.2.2 PowerRequirements. 116 vii 4.2.3 MassEstimation......................... 116 4.3 Nose-wheel Steering System (NWSS) . 117 4.3.1 Determination of Sizing Steering Moment . 117 4.3.2 PowerRequirements. 120 4.3.3 MassEstimation......................... 121 4.4 WheelBrakingSystem(WBS) . 121 4.4.1 Physical Modeling and Relationships . 122 4.4.2 SystemSizing .......................... 124 4.4.3 MassEstimation......................... 127 4.4.4 PowerRequirements. 129 4.5 Thrust Reverser Actuation System (TRAS) . 129 4.5.1 PowerRequirements. 130 4.5.2 MassEstimation......................... 131 4.6 ElectricTaxiingSystem(ETS) . 131 4.6.1 Estimation of System Power Requirement . 132 4.6.2 EstimationofSystemMass . 135 4.6.3 Estimation of Fuel Burn during Taxiing . 136 4.7 EnvironmentalControlSystem(ECS) . 138 4.7.1 Cabin Temperature, Pressure, and Airflow Requirements . 138 4.7.2 Cabin Thermal Loads Analysis . 140 4.7.3 ECSPackModel......................... 143 4.7.4 PowerRequirements. 146 4.7.5 DragGeneration......................... 148 4.7.6 MassEstimation......................... 148 4.8 WingIceProtectionSystems(WIPS) . 149 4.8.1 DeterminationofProtectedSurfaceArea . 150 4.8.2 Modeling Assumptions and Technology Assumptions . 155 4.8.3 Estimation of water impingement . 157 4.8.4 Estimation of Required Heat Flux . 158 viii 4.8.5 Determination of WIPS Sizing Flight Condition . 159 4.8.6 PowerRequirements. 161 4.8.7 MassEstimation......................... 163 4.8.8 Drag Penalty Estimation . 164 4.9 CowlIceProtectionSystem(CIPS) . 164 4.9.1 DeterminationofProtectedSurfaceArea . 165 4.9.2 Estimation of Required Heat Flux . 166 4.9.3 Determination of CIPS Sizing Flight Condition . 166 4.9.4 PowerRequirements. 166 4.9.5 MassEstimation......................... 167 4.9.6 Drag Penalty Estimation . 167 4.10ChapterSummary............................ 167 V MODELING OF POWER GENERATION AND DISTRIBUTION SUBSYSTEMS ............................... 168 5.1 Heuristic Determination of Connectivity Among Subsystem ArchitectureElements. 170 5.1.1 Actuation Architecture (Hydraulic and/or Electric) . 170 5.1.2 ElectricSystemArchitecture . 175 5.1.3 HydraulicSystemArchitecture