Air Force Institute of Technology AFIT Scholar Theses and Dissertations Student Graduate Works 9-18-2014 Design and Evaluation of Dual-Expander Aerospike Nozzle Upper Stage Engine Joseph R. Simmons Follow this and additional works at: https://scholar.afit.edu/etd Recommended Citation Simmons, Joseph R., "Design and Evaluation of Dual-Expander Aerospike Nozzle Upper Stage Engine" (2014). Theses and Dissertations. 561. https://scholar.afit.edu/etd/561 This Dissertation is brought to you for free and open access by the Student Graduate Works at AFIT Scholar. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of AFIT Scholar. For more information, please contact [email protected]. DESIGN AND EVALUATION OF DUAL-EXPANDER AEROSPIKE NOZZLE UPPER STAGE ENGINE DISSERTATION Joseph R. Simmons, III, AFIT-ENY-DS-14-S-06 DEPARTMENT OF THE AIR FORCE AIR UNIVERSITY AIR FORCE INSTITUTE OF TECHNOLOGY Wright-Patterson Air Force Base, Ohio DISTRIBUTION STATEMENT A: APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED The views expressed in this dissertation are those of the author and do not reflect the official policy or position of the United States Air Force, the Department of Defense, or the United States Government. This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States. AFIT-ENY-DS-14-S-06 DESIGN AND EVALUATION OF DUAL-EXPANDER AEROSPIKE NOZZLE UPPER STAGE ENGINE DISSERTATION Presented to the Faculty Dean, Graduate School of Engineering and Management Air Force Institute of Technology Air University Air Education and Training Command in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Joseph R. Simmons, III, BFA, MS September 2014 DISTRIBUTION STATEMENT A: APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED AFIT-ENY-DS-14-S-06 DESIGN AND EVALUATION OF DUAL-EXPANDER AEROSPIKE NOZZLE UPPER STAGE ENGINE DISSERTATION Joseph R. Simmons, III, BFA, MS Approved: //signed// 15 Jul 2014 Jonathan Black, PhD (Chairman) Date //signed// 15 Jul 2014 LtCol Ronald Simmons, PhD (Member) Date //signed// 15 Jul 2014 LtCol Richard Branam, PhD (Member) Date //signed// 15 Jul 2014 Carl Hartsfield, PhD (Member) Date //signed// 15 Jul 2014 David Jacques, PhD (Member) Date Accepted: //signed// 30 Jul 2014 Adedeji B. Badiru Date Dean, Graduate School of Engineering and Management AFIT-ENY-DS-14-S-06 Abstract The goal of the Dual-Expander Aerospike Nozzle, a modification to traditional engine architectures, is to find those missions and designs for which it has a competitive advantage over traditional upper stage engines such as the RL10. Previous work focused on developing an initial design to demonstrate the feasibility of the Dual-Expander Aerospike Nozzle. This research expanded the original cycle model in preparation for optimizing the engine’s specific impulse and thrust-to-weight ratio. The changes to the model allowed automated parametric and optimization studies. Preliminary parametric studies varying oxidizer-to-fuel ratio, total mass flow, and chamber length showed significant improvements. Drawing on modeling lessons from previous research, this research devloped a new engine simulation capable of achieving a specific impulse comparable to the RL10. Parametric studies using the new model verified the Dual-Expander Aerospike Nozzle architecture conforms to rocket engine theory while exceeding the RL10’s performance. Finally, this research concluded by optimizing the Dual-Expander Aerospike Nozzle engine for three US government missions: the Next Generation Engine program, the X-37 mission, and the Space Launch System. The optimized Next Generation Engine design delivers 35,000 lbf of vacuum thrust at 469.4 seconds of vacuum specific impulse with a thrust-to-weight ratio of 127.2 in an engine that is one quarter the size of a comparable RL10. For the X-37 mission, the optimized design operates at 6,600 lbf of vacuum thrust and has a vacuum specific impulse of 457.2 seconds with a thrust-to- weight ratio of 107.5. The Space Launch System design produces a vacuum thrust of 100,000 lbf with a vacuum specific impulse of 465.9 seconds and a thrust-to-weight ratio of 110.2. When configured in a cluster of three engines, the Dual-Expander Aerospike Nozzle matches the J2-X vacuum thrust with a 4% increase in specific impulse while more than doubling the J2-X’s thrust-to-weight ratio. iv Dedicated to the men and women of Mach 30: past, present, and future. ad astra per civitatem — to the stars through community v Acknowledgments I would like to begin by thanking my committee for their support and mentorship. I am especially thankful to my advisor, Dr. Black, who encouraged me to continue my academic career beyond my masters work. I had not really considered pursuing a PhD until he first asked me about it. I would also like to thank all of the other students who have contributed to the DEAN research efforts. Each and every paper, thesis, and model contributed to this research. The following companies and organizations provided software used in this research: National Aeronautics and Space Administration provided the Numerical Propulsion System Simulation package, Phoenix Integration provided ModelCenter, and SpaceWorks Software provided REDTOP-Lite. Extra thanks goes out to Phoenix Integration and its staff for being so flexible and supportive. I cannot imagine a better place to work or better people to work with. Special thanks go out to my friends and family who have been so supportive of my academic career. You have all at one time or another been flexible, generous, or understanding as I have worked my way from technical theatre to space systems engineering. Thank you. Oh, and Capt. Bellows, don’t forget “you did good work today...” – Well, you know the rest. Finally, I would like to conclude my acknowledgments by recognizing the organiza- tions which helped fund my research. This research was supported in part by a PhD fellowship from the Dayton Area Graduate Studies Institute. This research was supported in part by an appointment to the Postgraduate Research Participation Program at U.S. Air Force Research Laboratory, Air Force Institute of vi Technology, administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and USAFRL. This research was supported in part by the US Air Force Research Lab, Edwards AFB. Joseph R. Simmons, III vii Table of Contents Page Abstract......................................... iv Dedication........................................v Acknowledgments.................................... vi Table of Contents.................................... viii List of Figures...................................... xii List of Tables...................................... xviii List of Symbols..................................... xxii List of Source Code................................... xxxii I. Introduction.....................................1 1.1 Research Motivation.............................1 1.2 Problem Statement..............................5 1.3 Research Objective..............................6 1.4 Method Overview...............................6 1.5 Research Contributions............................7 1.6 Dissertation Overview............................8 II. Background..................................... 11 2.1 Rocket Propulsion............................... 11 2.1.1 Rocket Fundamentals......................... 11 2.1.2 Liquid Rocket Engines........................ 16 2.1.3 Liquid Rocket Engine Design.................... 21 2.1.4 Modeling Liquid Rocket Engines.................. 26 2.1.4.1 REDTOP.......................... 27 2.1.4.2 Rocket Propulsion Analysis................ 28 2.1.4.3 Numerical Propulsion System Simulation......... 29 2.1.4.4 Rocket Engine Transient Simulator............ 30 2.2 Government Demand for Improved Rocket Engines............. 30 2.2.1 Current Launch Vehicles....................... 31 viii Page 2.2.2 US Air Force Next Generation Launch Programs.......... 32 2.2.3 NASA’s Space Launch System.................... 34 2.2.4 US Air Force Space Plane Program................. 37 2.3 The Dual-Expander Aerospike Nozzle Upper Stage Engine......... 40 2.3.1 DEAN Architecture......................... 40 2.3.2 Research History of Core Technologies............... 42 2.3.2.1 Dual-Expander Cycles................... 42 2.3.2.2 Aerospike Nozzles..................... 43 2.3.3 DEAN Research History....................... 46 2.3.3.1 First Generation DEAN.................. 47 2.3.3.2 Second Generation DEAN................ 49 2.3.3.3 Third Generation DEAN................. 50 2.3.3.4 Methane DEAN...................... 52 2.4 Engineering Optimization........................... 53 2.4.1 Optimization Terminology...................... 53 2.4.2 Defining Optimization Problems................... 54 2.4.2.1 Unconstrained Single Objective Problem......... 55 2.4.2.2 Unconstrained Multi-Objective Problem......... 56 2.4.2.3 Constrained Single Objective Problem.......... 57 2.4.2.4 Constrained Multi-Objective Problem........... 58 2.4.3 Optimization Algorithms....................... 59 2.5 Concluding Remarks............................. 60 III. Parametric Study of Dual-Expander Aerospike Nozzle Upper Stage Rocket Engine 61 3.1 Introduction.................................. 61 3.2 Existing NPSS DEAN Model......................... 62 3.2.1 Existing DEAN Architecture..................... 63 3.2.2 NPSS Model Details......................... 65 3.3 Parameteric