Purdue University Purdue e-Pubs Open Access Dissertations Theses and Dissertations Fall 2014 Solid amine-boranes as high performance hypergolic hybrid rocket fuels Mark A. Pfeil Purdue University Follow this and additional works at: https://docs.lib.purdue.edu/open_access_dissertations Part of the Aerospace Engineering Commons Recommended Citation Pfeil, Mark A., "Solid amine-boranes as high performance hypergolic hybrid rocket fuels" (2014). Open Access Dissertations. 347. https://docs.lib.purdue.edu/open_access_dissertations/347 This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for additional information. PURDUE UNIVERSITY GRADUATE SCHOOL Thesis/Dissertation Acceptance . . To the best of my knowledge and as understood by the student in the Thesis/Dissertation Agreement, Publication Delay, and Certification/Disclaimer (Graduate School Form 32), this thesis/dissertation adheres to the provisions of Purdue University’s “Policy on Integrity in Research” and the use of copyrighted material. i SOLID AMINE-BORANES AS HIGH PERFORMANCE HYPERGOLIC HYBRID ROCKET FUELS A Dissertation Submitted to the Faculty of Purdue University by Mark A. Pfeil In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy i December 2014 Purdue University West Lafayette, Indiana ii To my dear children. ii iii ACKNOWLEDGEMENTS I would first like to thank my advisors Professor Stephen Heister and Professor Steven Son. I am forever thankful for their willingness to take me on and spend time and effort to help me develop professionally. I very much enjoy the rocket/energetics field, and because of their efforts, I will be able to enjoy a long and fruitful career in this area. I am also appreciative for their friendship along the way. I also want to thank all others who have spent time teaching me from other professors to fellow graduate students. Professor Timothée Pourpoint, Scott Meyer, Rob McGuire, Professor P. Veeraraghavan Ramachandran, and Bradley Templin were all very helpful in providing ideas and support for which I am very grateful. Brandon Terry deserves special thanks for all help performing tests and staying late into the night so I could perform research. I would like to thank the Department of Defense for financial support through the Science iii Mathematics and Research Transformation (SMART) scholarship so that I could complete my studies. I am grateful for the mentorship of Darren Thompson and the support of the Propulsion and Energetics Functions within Aviation and Missile Research, Development, and Engineering Center in Huntsville, AL. iv Finally, I would like to thank my family. My parents, for all the cheering and moral support. My dear wife, for the friendship, support, and companionship you have provided throughout this whole endeavor. iv v TABLE OF CONTENTS Page LIST OF TABLES ........................................................................................................... viii LIST OF FIGURES ............................................................................................................ x ABSTRACT ............................................................................................................ xvi CHAPTER 1. INTRODUCTION ................................................................................. 1 1.1 Introduction ............................................................................................... 1 1.2 Ignition Delay ............................................................................................ 6 1.3 Regression Rate ......................................................................................... 9 1.4 Motivation ............................................................................................... 11 1.4.1 Amine-boranes ..................................................................................12 1.4.2 Objectives ..........................................................................................13 CHAPTER 2. FUELS ................................................................................................. 15 2.1 Amine-boranes and Amines .................................................................... 15 2.1.1 Toxicity and Air Sensitivity ..............................................................18 2.2 Powder Characterization ......................................................................... 19 2.3 Fuel Matrices ........................................................................................... 24 2.4 Rocket Combustor Fuel Grain ................................................................ 30 CHAPTER 3. EXPERIMENTAL METHODS .......................................................... 35 v 3.1 Hypergolic Droplet Ignition Experiment ................................................ 35 3.2 Intrinsic Properties Experimental Methods ............................................. 36 3.3 Opposed Burner Experiment ................................................................... 39 3.4 Hybrid Rocket Combustor Experiment ................................................... 41 3.4.1 Combustor .........................................................................................43 3.4.2 Oxidizer Injectors ..............................................................................44 vi Page 3.4.3 Hybrid Combustor Operation ............................................................45 CHAPTER 4. SMALL SCALE EXPERIMENTAL RESULTS ................................ 46 4.1 Hypergolic Ignition ................................................................................. 46 4.1.1 Powder Materials ..............................................................................46 4.1.2 Amine-borane Ignition Mechanism ..................................................52 4.1.3 Fuel Pellets ........................................................................................53 4.2 Intrinsic Properties .................................................................................. 65 4.3 Theoretical Performance ......................................................................... 68 4.4 Comparison with Other Fuels ................................................................. 73 4.4.1 Solid Hybrid Hypergolic Fuels .........................................................73 4.4.2 Liquid Hypergolic Fuels ...................................................................74 4.4.3 Non-Hypergolic Fuels .......................................................................75 4.5 General Combustion Behavior – Opposed Burner .................................. 76 CHAPTER 5. ROCKET COMBUSTOR RESULTS ................................................. 85 5.1 Data Reduction ........................................................................................ 85 5.2 General Observations .............................................................................. 97 5.3 Characteristic Velocity Efficiency ........................................................ 107 5.4 Hypergolic Ignition Behavior................................................................ 109 5.5 Regression Rate ..................................................................................... 110 vi CHAPTER 6. MODELING COMBUSTION BEHAVIOR ..................................... 122 6.1 General Hybrid Rocket Combustion Theory ........................................ 122 6.2 Flame Kinetics....................................................................................... 123 6.3 Radiation Effects ................................................................................... 126 6.4 Pressure Dependent Hypergolic Reactions ........................................... 131 6.5 Partially Reacted Foam Layer ............................................................... 136 6.6 Summary ............................................................................................... 144 CHAPTER 7. CONCLUSIONS AND FUTURE WORK ........................................ 146 7.1 Amine-boranes ...................................................................................... 146 7.2 Combustion Behavior ............................................................................ 148 vii Page 7.3 Future Work .......................................................................................... 150 LIST OF REFERENCES ................................................................................................ 152 APPENDICES Appendix A Mixing Procedures Documents ............................................................. 161 Appendix B Combustor and Plumbing and Instrumentation Diagram ...................... 167 Appendix C Combustor Operation Procedures ......................................................... 169 Appendix D Liquid Oxidizer Transport ..................................................................... 179 VITA ........................................................................................................... 186 PUBLICATIONS ........................................................................................................... 188 vii viii LIST OF TABLES Table .............................................................................................................................. Page Table 1.1 Hypergolic hybrid rocket oxidizer and fuel combinations that have been used in experimental rocket combustors. .......................................................................................