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A Method for Aircraft Afterburner Combustion

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A Method for Aircraft Afterburner Combustion A METHOD FOR AIRCRAFT AFTERBURNER COMBUSTION WITHOUT FLAMEHOLDERS A Dissertation Presented to The Academic Faculty By Shai Birmaher In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in Aerospace Engineering Georgia Institute of Technology May 2009 A METHOD FOR AIRCRAFT AFTERBURNER COMBUSTION WITHOUT FLAMEHOLDERS Approved by: Dr. Ben T. Zinn, Advisor Dr. Rick Gaeta School of Aerospace Engineering School of Aerospace Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Yedidia Neumeier Dr. Jeff Jagoda School of Aerospace Engineering School of Aerospace Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Thomas Fuller School of Chemical and Biomolecular Engineering Georgia Institute of Technology Date Approved: February 27, 2009 ACKNOWLEDGEMENTS I would like to first thank my advisor, Dr. Ben Zinn, for his valuable guidance and support throughout the course of this work . I wish to thank Dr. Yedidia Neumeier. This research would not have been possible without Yedidia, whose innovation and sense of humor enriched my experience at Georgia Tech. I would also like to thank the other members of my committee, Dr. Jeff Jagoda, Dr. Rick Gaeta, and Dr. Thomas Fuller, for their input and interest in this research. I would like to thank the research engineers and Georgia Tech staff who contributed to this work. Thanks to Sasha Bibik and Dimitriy Shcherbik for their technical expertise and willingness to help at a moment’s notice. Also, thanks to Scott Moseley and Scott Elliott for their friendly and skillful support at the machine shop. I wish to thank all the graduate students at the Ben Zinn Combustion Lab for their help and encouragement. In particular, I would like to thank Philipp Zeller, who started this research effort and set a high standard for efficiency and dedication. Also, I would like to thank Petter Wirfalt, who provided valuable assistance and great company. I am grateful to my family and friends for their encouragement throughout my graduate career. Above all, I am grateful to my fiancée, Claire, for her constant love, support and patience. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................... iii LIST OF TABLES ............................................................................................................. vi LIST OF FIGURES .......................................................................................................... vii NOMENCLATURE ........................................................................................................ xiv SUMMARY ..................................................................................................................... xxi INTRODUCTION .............................................................................................................. 1 1.1 Background and Motivation ............................................................................... 1 1.2 The Prime and Trigger Afterburner Concept ...................................................... 3 1.3 Research Objective and Overview ...................................................................... 5 PART 1 THE EXPERIMENTAL FACILITIES ............................................................... 9 CHAPTER 2 THE AFTERBURNER FACILITY ........................................................... 10 2.1 The Initial AF Design ....................................................................................... 10 2.2 Modifications to the AF .................................................................................... 16 CHAPTER 3 THE PROPANE AUTOIGNITION COMBUSTOR ................................. 18 PART 2 THE INVESTIGATION OF THE PRIME STAGE ......................................... 22 CHAPTER 4 THEORETICAL CONSIDERATIONS ..................................................... 23 4.1 Evaporation Sub-Model .................................................................................... 25 4.2 Mixing Sub-Model ............................................................................................ 30 4.3 Chemistry Sub-Model ....................................................................................... 31 4.4 Demonstration of the Developed Model ........................................................... 33 CHAPTER 5 EXPERIMENTAL RESULTS AND COMPARISON WITH THEORETICAL PREDICTIONS .................................................................................... 45 5.1 Temperature and Pressure Measurements ........................................................ 45 5.2 Chemiluminescence Measurements .................................................................. 52 5.3 Summary of AF Prime Stage Experiments ....................................................... 54 CHAPTER 6 FUEL PRIMING AND AUTOIGNITION AT HIGH OPERATING PRESSURE ............................................................................................................. 56 6.1 Pressure Dependence of the Evaporation Sub-Model ...................................... 56 6.2 Evaporation at Constant Pressure ..................................................................... 57 6.3 Evaporation with a Large, Rapid Drop in Pressure .......................................... 62 iv 6.4 Application of the Theoretical Model to High Pressure Operating Conditions 66 PART 3 THE INVESTIGATION OF THE TRIGGER STAGE .................................... 72 CHAPTER 7 CHEMKIN SIMULATIONS OF AUTOIGNITION WITH A TRIGGER 73 7.1 Chemkin Setup .................................................................................................. 74 7.2 Autoignition without a Trigger ......................................................................... 78 7.3 Autoignition with POx and Hydrogen Triggers................................................ 81 7.4 Trigger Gas Properties ...................................................................................... 92 CHAPTER 8 EXPERIMENTS IN THE PAC ................................................................ 104 8.1 Processing the Optical Spectrometer Measurements ...................................... 106 8.2 The Combustion Zone Characteristics ............................................................ 110 8.3 Analysis of Gas Composition and Combustion Efficiency ............................ 112 8.4 Experimental Results: Autoignition without a Trigger ................................... 115 8.5 Experimental Results: Combustion with the H 2 Trigger ................................. 121 8.6 Application of PAC Results to the AF Experiments ...................................... 130 CHAPTER 9 AF EXPERIMENTS ................................................................................. 132 9.1 Procedure for Processing the High-speed Camera Images ............................. 132 9.2 Expressions for the Analysis of Combustion Zone Fluctuations .................... 138 9.3 Results and Discussion ................................................................................... 139 PART 4 REVIEW, CONCLUSIONS AND FUTURE WORK.................................... 163 CHAPTER 10 REVIEW AND CONCLUSIONS .......................................................... 163 CHAPTER 11 FUTURE WORK ................................................................................... 171 APPENDIX A FUEL AND MIXTURE THERMOPHYSICAL PROPERTIES .......... 177 APPENDIX B REFERENCE FOR CHEMKIN ANALYSIS ....................................... 180 REFERENCES ............................................................................................................... 184 v LIST OF TABLES Table 1. Violi #3 surrogate fuel composition and the LHV for each constituent. The surrogate fuel molecular weight and LHV are 151g/mol and 43.87 MJ/kg, respectively. .................................... 76 Table 2. Trigger gas properties: species composition (%Vol), molecular weight (g/mol) and LHV (MJ/kmol). .......................................................................................................................................... 76 Table 3. Composition (%Vol) of the vitiated-air used in the Chemkin simulations .............................. 78 Table 4. Set 1 (Cases 1-4) operating points. ............................................................................................ 115 Table 5. Set 1 combustion zone characteristics based on total intensity profiles (430+/-5nm). The data upstream of the H 2 tube outlet (5.1cm) were excluded. ................................................................ 118 Table 6. Set 1 combustion zone characteristics based on CH* chemiluminescence profiles. .............. 119 Table 7. Set 1 gas composition predictions and measurements. ............................................................ 120 Table 8. Set 2 (Cases 5-8) operating points. ............................................................................................ 121 Table 9. Set 2 combustion zone characteristics based on total intensity profiles (430+/-5nm). The data upstream of the H 2 tube outlet (5.1cm) were excluded. ................................................................ 124 Table 10. Set 2 combustion zone characteristics based on CH* chemiluminescence profiles. ............ 125 Table 11. Set 2 (Cases 5-8) gas composition predictions and measurements ....................................... 125 Table 12. Set 3 (Cases 9-11) operating points. .......................................................................................
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