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The Design and Experimental Optimization of a Wingtip Vortex Turbine for General Aviation Use Theses - Daytona Beach Dissertations and Theses 4-1997 The Design and Experimental Optimization of a Wingtip Vortex Turbine for General Aviation Use Andrew Roberts Embry-Riddle Aeronautical University - Daytona Beach Follow this and additional works at: https://commons.erau.edu/db-theses Part of the Aerospace Engineering Commons, and the Aviation Commons Scholarly Commons Citation Roberts, Andrew, "The Design and Experimental Optimization of a Wingtip Vortex Turbine for General Aviation Use" (1997). Theses - Daytona Beach. 234. https://commons.erau.edu/db-theses/234 This thesis is brought to you for free and open access by Embry-Riddle Aeronautical University – Daytona Beach at ERAU Scholarly Commons. It has been accepted for inclusion in the Theses - Daytona Beach collection by an authorized administrator of ERAU Scholarly Commons. For more information, please contact [email protected]. THE DESIGN AND EXPERIMENTAL OPTIMIZATION OF A WINGTIP VORTEX TURBINE FOR GENERAL AVIATION USE by Andrew Roberts A Thesis Submitted to the Office of Graduate Programs in Partial Fulfillment of the Requirements for the Degree of Master of Science in Aerospace Engineering Embry-Riddle Aeronautical University Daytona Beach, Florida April 1997 UMI Number: EP31827 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. UMI Microform EP31827 Copyright 2011 by ProQuest LLC All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, MI 48106-1346 THE DESIGN AND EXPERIMENTAL OPTIMIZATION OF A WINGTIP VORTEX TURBINE FOR GENERAL AVIATION USE by Andrew Roberts This thesis was prepared under the direction of the candidate's thesis committee advisor, Prof. Charles N. Eastlake, P.E., Department of Aerospace Engineering, and has been approved by the members of his thesis committee. It was submitted to the Office of Graduate Studies and was accepted in partial fulfillment of the requirements for the degree of Master of Science in Aerospace Engineering. THESIS COMMITTEE: (UUJM,2»dfcQ,. Prof. Charles N. Eastlake, P.E. Advisor Dr. David Kim Member Dr. Vicki John Member Dr. David Kim MSAE Graduate Program Chair MJL~ Dr. Allen Ormsbee Department Chair, Aerospace Engineering ii ACKNOWLEDGEMENTS I would like to express special thanks to my thesis advisor, Prof. Charles Eastlake for his unwavering guidance and advice, good-natured experiential storytelling, and his Piper Cherokee as the subject basis in the preparation and research for this thesis. Appreciation and thanks go out as well to Committee Members Dr. David Kim and Dr. Vicki Johnson, Shop Technician Don Bouvier, Electronics Wizard Mike Potash, and KOMO CNC Milling Machine Operator Extraordinaire Alfred Stanley for their superior technical support and assistance. A special thank-you is also expressed to the late Dr. Ernest Jones, my initial thesis advisor, for without his initial support and enthusiasm this project would never have gotten off the ground. I would especially like to thank my family for putting up with my moodiness this semester and always being there to give me words of encouragement at all hours of the day and night. Finally, I want to thank my friends David, Eric, Richard, and Michelle, and all of my fellow students for their e-mail, jokes, late-night mayhem, sound files of questionable content, kindness, and constant support and interest in my work. I couldn't have done it without you. in ABSTRACT Author: Andrew Roberts Title: The Design and Experimental Optimization of a Wingtip Vortex Turbine for General Aviation Use Institution: Embry-Riddle Aeronautical University Degree: Master of Science in Aerospace Engineering Year: 1997 A wingtip vortex turbine (WVT) is an induced drag reduction device that straightens the vortex flow (reducing induced drag and wake turbulence) and also produces a thrust force component. The WVT also has the advantage of extracting the rotational energy of the vortex to turn a generator, which could be used to power onboard applications during normal or emergency flight operations. A 1/4-scale model of a thrust- producing WVT has been designed and tested in a wind tunnel for optimal drag reduction and power generation for general aviation aircraft — specifically, a Piper Cherokee — in both a stationary and a rotating mode. In addition, 2, 3, 4, 5, and 6-bladed configurations were tested, over a pitch angle range of-35° to 0°. The 6-bladed configuration proved to be the most efficient at both reducing drag and generating maximum power. At cruise, this model was shown to increase the overall drag slightly by 40 to 60 counts. However, at lift coefficients greater than 0.8, the overall drag was reduced by 20 to 40 counts, depending on whether it was stationary or rotating. At cruise, it generated a power coefficient of 0.004, and a maximum of 0.0059 at a CL=0.85. These coefficients corresponded to full-scale power outputs of 4.5 hp and 6.7 hp, respectively. iv TABLE OF CONTENTS Page Signature Page ii Acknowledgements iii Abstract iv Table of Contents v List of Tables vii List of Figures viii CHAPTER 1 INTRODUCTION 1 1.1 Overview 1 1.2 Previous Research 4 1.2.1 Wind Tunnel Testing of the WVT 5 1.2.2 Flight Testing of the WVT * 7 1.3 Current Research 9 CHAPTER2 BACKGROUND THEORY 12 2.1 Vortex Theory 12 2.1.1 Wingtip Vortex Generation 12 2.1.2 Wingtip Vortex Structure 14 2.2 Experimental Vortex Flow Measurements 18 CHAPTER 3 WVT DESIGN METHODOLOGY AND PREDICTION 25 3.1 WVTNacelle .: 25 3.1.1 Design Criteria 25 3.1.2 Effect of the Nacelle on the Flowfield 27 3.2 WVT Blades 30 3.2.1 Design Parameters 30 3.2.1.1 Turbine Diameter 30 3.2.1.2 Blade Airfoil 31 3.2.1.3 Blade Number 33 3.2.1.4 Blade Planform 34 3.2.1.5 Blade Twist 37 3.2.1.6 Blade Pitch Angle 38 CHAPTER4 TEST APPARATUS AND PROCEDURE 39 4.1 WVT Model Construction 39 4.1.1 Nacelle Construction 39 4.1.2 Blade Construction 40 4.2 Support Equipment and Test Instrumentation 41 4.2.1 Low-Speed Wind Tunnel 41 4.2.2 Force Balance and Data Acquisition System 42 4.2.3 WVT Power Measurement Instrumentation 43 v 4.3 Test Procedure 46 4.3.1 General 46 4.3.2 Static WVT Tests 48 4.3.3 Rotating WVT Tests 48 4.3.4 Static WVT Alpha Sweeps 49 4.3.5 Rotating WVT Alpha Sweeps 49 CHAPTER 5 WIND TUNNEL TEST RESULTS 52 5.1 Correction of Drag Coefficient For Reynolds Number 52 5.2 Stationary WVT Results 53 5.2.1 Pitch Angle and Blade Number Optimization 53 5.2.2 Alpha Sweep Test Results 55 5.3 Rotating WVT Results 56 5.3.1 Pitch Angle and Blade Number Optimization 56 5.3.2 Alpha Sweep Test Results 59 5.3.3 Power Output Results 59 CHAPTER 6 CONCLUSIONS AND RECOMMENDATIONS 63 6.1 Conclusions 63 6.1.1 Drag Reduction 63 6.1.2 Comparison of Actual to Predicted Drag Reduction 64 6.1.3 Power Generation 65 6.1.4 Applications 65 6.2 Recommendations 67 REFERENCES 69 APPENDICES A. Five-Hole Probe Calibration Data 70 B. WVT Performance Prediction Program and Sample Output 74 C. Hard Copy Wind Tunnel Test Data 85 VI LIST OF TABLES Page Table 4.1 Force Balance Load Limits and Accuracy 43 Table 5.1 Torque and Rotational Speed Measurements For WVT Configurations . 62 Table C.l Clean Wing, Run 1 86 Table C.2 Clean Wing, Run 2 88 Table C.3 Clean Wing, Run 3 90 Table C.4 Stationary WVT, 2 Blades 92 Table C.5 Stationary WVT, 3 Blades 94 Table C.6 Stationary WVT, 4 Blades 96 Table C.7 Stationary WVT, 5 Blades 98 Table C.8 Stationary WVT, 6 Blades 100 Table C.9 Rotating WVT, 2 Blades 102 Table CIO Rotating WVT, 3 Blades 104 Table C.ll Rotating WVT, 4 Blades 106 Table C.12 Rotating WVT, 5 Blades 108 Table C.13 Rotating WVT, 6 Blades 110 Table C.l4 Stationary WVT Alpha Sweep, 6 Blades (One Run Only) 112 Table C.15 Rotating WVT Alpha Sweep, 6 Blades, Run 1 114 Table C.16 Rotating WVT Alpha Sweep, 6 Blades, Run 2 116 Table C.17 Rotating WVT Alpha Sweep, 6 Blades, Run 3 118 vii LIST OF FIGURES Page Figure 1.1 General Configuration of a Wingtip Vortex Turbine ..4 Figure 1.2 NASA Langley Wind Tunnel Test of a WVT ..5 Figure 1.3 Flight Test of WVT's on a Piper Turbo Arrow IV ..7 Figure 1.4 Lift Coefficient vs. Angle of Attack for Model Cherokee Wing . 11 Figure 2.1 System of Bound and Trailing Vortices . 13 Figure 2.2 Vortex Flowfield Around a Cylindrical Core Rotating as a Rigid Body . 15 Figure 2.3 Experimental Data and Theoretical Vortex Models Compared .16 Figure 2.4 Velocity and Pressure Distributions in a Viscous Vortex .17 Figure 2.5 Vortex Centerline Location .19 Figure 2.6 United Sensor DC-125-12-CD Five-Hole Probe .20 Figure 2.7 Vortex Flow Measurement Apparatus in Wind Tunnel Test Section .
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