Characteristics of Linear Alternator Performance Under Thermoacoustic-Power- Conversion Conditions
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THE AMERICAN UNIVERSITY IN CAIRO SCHOOL OF SCIENCES AND ENGINEERING CHARACTERISTICS OF LINEAR ALTERNATOR PERFORMANCE UNDER THERMOACOUSTIC-POWER- CONVERSION CONDITIONS BY AHMED YASSIN ABDELWAHED IBRAHIM A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering Under the supervision of: Prof. Ehab Abdel-Rahman Professor, Physics Department The American University in Cairo Prof. Mohamed Amr Serag Eldin Professor, Mechanical Engineering Department The American University in Cairo Dr. Abdelmaged Hafez Ibrahim Essawey Research Post-Doctoral Scholar The American University in Cairo November 2018 Acknowledgement The work that this thesis encompasses was made possible with the support of many individuals and organizations. First of all, I would like to thank my advisor Prof. Ehab Abdel- Rahman the head of the Thermoacoustics research team who provided me and the rest of the team with the needed scientific guidance and advanced facilities in the Thermoacoustic Research Lab throughout many years of research. Thanks also to my advisor Prof. Mohamed Amr Serag-Eldein who helped me a lot with his long and strong experience in the renewable energy field to produce this thesis work. For sure I would like to thank my advisor Dr. Abdelmaged H. Ibrahim Essawey whose experience, flexibility, technical guidance, and day-to-day follow up helped me produce the results of this work and made it easier to get over the many barriers in the field of the Thermoacoustics and linear alternators. I also have a great deal of gratitude for Prof. Steven Garrett (Penn State University) and Dr. Kai Wang (Imperial College) whom knowledge and experience in thermoacoustic engines and their applications are great. Their prompt replies on my questions enabled me to significantly enhance the analytical model. Additionally, for sure I would like to thank Prof. Gregory W. Swift (Los Alamos Labs) for his great help in the modeling of the load resistance and the power-factor- correcting capacitor in DELTAEC software. I am very thankful to John Corey, Phillip Spoor and Gordon Miller of Q-Drive (Rix Industries, Chart Industries in the past) for the technical support they provided on many aspects of linear alternators. For sure, I would like to thank Dr. Islam Ramadan who assisted on the numerical simulations using DELTAEC software, Eng. Moamen Bellah Abdelmawgoud who built the initial form of the experimental setup, and Eng. Khaled El Beltagey who assisted in the development of the experimental setup along the years. I am also thankful to every member in the thermoacoustic research team for the fruitful discussions, technical support, and the great time I had during this research period. The American University in Cairo provided access to numerous scientific resources, a research grant, and two conference grants that enabled me to greatly develop this work and assisted II in the building, continuous and smooth running of the experimental setup and presenting nine publications in international conferences and meetings. This work was possible with the financial assistance of the European Union. The contents of this document are the sole responsibility of the master student and can under no circumstances be regarded as reflecting the position of the European Union. I am very thankful for the Egyptian Academy of Scientific Research and Technology which partly funded the development of the initial form of the experimental setup used. This work is a new step of my research work in the space systems field that I have started under supervision of Dr.Mohammed Khalil Ibrahim, Prof. Atef Omar Sherif, Prof.Bahy-El Dein Argon and Dr.Ayman Kassem in Space Systems Technology Laboratory (SSTL), aerospace engineering department-Cairo University. I would like to thank all of these professors and the previous leader of this laboratory Eng.Samy Amin (Avelabs). Many thanks go to my parents (Dr.Yassin Ibrahim and Mrs.Hanim El Saadany) who give me all what they have of love and support. III Contents Acknowledgement .......................................................................................................................... II Contents ........................................................................................................................................ IV List of Figures .............................................................................................................................. VII List of Tables ................................................................................................................................ XI Nomenclature ............................................................................................................................... XII Abstract ........................................................................................................................................ XV 1. Introduction .............................................................................................................................. 1 1.1 Thermoacoustic Engines .................................................................................................. 1 1.1.1 Standing wave thermoacoustic engine ...................................................................... 1 1.1.1.1 Standing wave thermoacoustic engine components .............................................. 2 1.1.1.1.1 Heat source ............................................................................................................ 2 1.1.1.1.2 Heat exchanger ...................................................................................................... 3 1.1.1.1.3 Stack ...................................................................................................................... 3 1.1.1.1.4 Working Gas ......................................................................................................... 3 1.1.1.1.5 Resonator ............................................................................................................... 3 1.1.2 Travelling wave thermoacoustic engine ................................................................... 4 1.1.1.2 Travelling wave thermoacoustic engine components ........................................... 6 1.1.1.2.1 Main cold and hot heat exchangers ....................................................................... 6 1.1.1.2.2 Regenerator ........................................................................................................... 6 1.1.1.2.3 Thermal buffer tube (TBT) ................................................................................... 7 1.1.1.2.4 Secondary cold heat exchanger ............................................................................. 7 1.1.1.2.5 Feedback inertance tube ........................................................................................ 7 1.1.1.2.6 Compliance............................................................................................................ 7 1.1.1.2.7 Jet pump ................................................................................................................ 7 1.1.3 Advantages and limitations of thermoacoustic engines ............................................ 8 1.2 Linear Alternators ............................................................................................................ 9 1.2.1 Types of linear alternators ........................................................................................ 9 1.2.2 Advantages and limitations of moving magnet linear alternators .......................... 11 1.2.3 Linear alternators’ connections in thermoacoustic power converters ..................... 16 IV 1.2.4 Anti-drift network across the linear alternator’s piston .......................................... 17 1.3 Thesis Scope ................................................................................................................... 19 2. Literature Review .................................................................................................................. 21 3. Experimental Setup and DELTAEC Simulations .................................................................. 27 3.1 DELTAEC Simulations.................................................................................................. 35 4. Results: Analytical Model ..................................................................................................... 37 4.1 Analytical Model Derivation .......................................................................................... 37 4.1.1 Estimation of linear alternator performance indices ............................................... 41 4.1.2 Estimation of effective coil inductance................................................................... 46 4.2 Analytical Model Validation .......................................................................................... 49 4.3 Optimization of Piston Area and Load Resistance......................................................... 53 4.4 Summary of Analytical Model Results .......................................................................... 56 5. Results: Experimental Parametric Study ............................................................................... 59 5.1 Experimental Parametric Study under Linear Load Condition ...................................... 60 5.1.1 Effects of the operating frequency .......................................................................... 62 5.1.2 Effects of the