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Design and Analysis of a Single Stage, Traveling Wave, Thermoacoustic Engine for Bi-Directional Turbine Generator Integration Mitchell Mcgaughy Clemson University

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Design and Analysis of a Single Stage, Traveling Wave, Thermoacoustic Engine for Bi-Directional Turbine Generator Integration Mitchell Mcgaughy Clemson University Clemson University TigerPrints All Theses Theses 12-2018 Design and Analysis of a Single Stage, Traveling Wave, Thermoacoustic Engine for Bi-Directional Turbine Generator Integration Mitchell McGaughy Clemson University Follow this and additional works at: https://tigerprints.clemson.edu/all_theses Part of the Mechanical Engineering Commons Recommended Citation McGaughy, Mitchell, "Design and Analysis of a Single Stage, Traveling Wave, Thermoacoustic Engine for Bi-Directional Turbine Generator Integration" (2018). All Theses. 2962. https://tigerprints.clemson.edu/all_theses/2962 This Thesis is brought to you for free and open access by the Theses at TigerPrints. It has been accepted for inclusion in All Theses by an authorized administrator of TigerPrints. For more information, please contact [email protected]. DESIGN AND ANALYSIS OF A SINGLE STAGE, TRAVELING WAVE, THERMOACOUSTIC ENGINE FOR BI-DIRECTIONAL TURBINE GENERATOR INTEGRATION A Thesis Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Master of Science Mechanical Engineering by Mitchell McGaughy December 2018 Accepted by: Dr. John R. Wagner, Committee Co-Chair Dr. Thomas Salem, Committee Co-Chair Dr. Todd Schweisinger, Committee Member ABSTRACT The demand for clean, sustainable, and cost-effective energy continues to increase due to global population growth and corresponding use of consumer products. Thermoacoustic technology potentially offers a sustainable and reliable solution to help address the continuing demand for electric power. A thermoacoustic device, operating on the principle of standing or traveling acoustic waves, can be designed as a heat pump or a prime mover system. The provision of heat to a thermoacoustic prime mover results in the generation of an acoustic wave that can be converted into electrical power. Thermoacoustic devices offer highly reliable and transportable power generation with low environmental impact using a variety of fuel sources. Heating and cooling sources are necessary to create the required thermal gradient. This technical strategy is environmentally friendly as it utilizes noble gases, or air, as the working fluid and does not directly produce harmful emissions. Due to the inherent simplicity and limitation of moving components, thermoacoustic devices require little maintenance and have a forecasted long operational lifespan. This research study will present the design considerations necessary to construct a traveling wave thermoacoustic heat engine. The modeling, analysis, fabrication, and testing with integrated sensors will be discussed to offer insight into the capabilities and subtleties. Performance testing and system analysis have been completed for a variety of heat input profiles. For a 300 W heat source, the thermoacoustic engine generates a 54 Hz acoustic wave with a thermal efficiency of 7.8%. The acoustic power output of the thermoacoustic ii engine may be increased by 81.5% through improved heat exchanger design. Potential future research efforts to improve system performance are also presented. iii DEDICATION I would like to dedicate this thesis to everyone that has supported me through my arduous journey. Without the support of my friends and family, I could not have sustained the drive and focus required to complete my Master’s of Science in Mechanical Engineering degree. iv ACKNOWLEDGMENT This research project represents a significant personal achievement and it is the final objective to complete one of the most difficult goals I have ever pursued. Through this research, I have gained valuable skills and deepened my knowledge in areas that I find both interesting and important. I would like to thank Dr. John Wagner and other Clemson University faculty for their commitment to my success and encouragement in times of doubt. Additionally, the completion of this degree could not have been achieved without the support of my friends and family. I will always be grateful for the opportunities and blessings that have been granted to me. This research effort was sponsored by the Office of Naval Research grant N00014- 14-1-0227. The support and involvement of Dr. Thomas Salem and Eric Boessneck of the SCE&G Energy Innovation Center were essential to the success of the project. External support from Dr. Greg Swift of Los Alamos National Laboratory was vital to accomplishing successful DeltaEC modeling of the system. Mr. Kees de Blok of Aster thermoacoustic provided a tremendous amount of assistance regarding the practical application, build, and design of the thermoacoustic system. Selfless contributions from a diverse range of individuals were paramount to the success of this project. v TABLE OF CONTENTS Page Abstract ............................................................................................................................ ii Dedication ....................................................................................................................... iv Acknowledgment ............................................................................................................. v List of Tables ................................................................................................................ viii List of Figures ................................................................................................................. ix Nomenclature List .......................................................................................................... xii Chapter One Introduction ................................................................................................ 1 1.1 Literature Review .................................................................................................. 4 1.2 Thesis Layout ......................................................................................................... 8 Chapter Two Technical Background ............................................................................... 9 2.1 Acoustics ................................................................................................................ 9 2.2 Thermoacoustics .................................................................................................. 11 Chapter Three Mathematical Concepts .......................................................................... 16 Chapter Four Thermoacoustic Design Considerations .................................................. 22 4.1 Operational Characteristics .................................................................................. 22 4.2 Core Assembly ..................................................................................................... 24 4.3 Acoustic Network ................................................................................................ 27 Chapter Five Experimental System ............................................................................... 30 5.1 Component Design .............................................................................................. 32 5.2 Measurement and Electrical System .................................................................... 42 Chapter Six Performance Indicators .............................................................................. 46 6.1 Instrumentation .................................................................................................... 46 6.2 Variable Acoustic Load ....................................................................................... 49 Chapter Seven Computer Simulations ........................................................................... 52 Chapter Eight Experimental Findings ............................................................................ 60 vi Table of Contents (Continued) Page Chapter Nine Conclusions and Future Work ................................................................. 67 Appendices..................................................................................................................... 69 Appendix A: DeltaEC Simulation Model .................................................................. 70 Appendix B: LabVIEW Block Diagram .................................................................... 80 Appendix C: LabVIEW Front Panel .......................................................................... 85 Appendix D: Electrical Instrumentation Calibration ................................................. 88 Appendix E: Relevant MATLAB Codes ................................................................... 89 Appendix F: Experimental System Component Dimensions .................................... 95 References ...................................................................................................................... 96 vii LIST OF TABLES Page Table 8.1: Measured thermoacoustic engine efficiencies .............................................. 66 Table F-1: Dimensions of experimental components .................................................... 95 viii LIST OF FIGURES Page Figure 1.1: Global energy consumption by source [1] .................................................... 1 Figure 1.2: Projected energy demand by source [2] ........................................................ 2 Figure 1.3: Thermoacoustic conversion process - (a) prime mover, and (b) heat pump ...................................................................................................... 3 Figure 1.4: Early thermoacoustic devices - (a) Higgins singing flame, (b) Rijke tube, and
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