 | Webster S.Ch.L. Analysis of pressure dynamics, forced excitation and damping in a high pressure LOX/H2 combustor = Untersuchung von dynamischen Druckschwankungen, Anregung und Dämpfung in einer LOX/2 - Hochdruckbrennkammer: Diss … Dr.-Ing. / Deutsches Zentrum für Luft- und Raumfahrt. - Köln: DLR, 2016. - xxv, 216 p.: ill. - (Forschungsbericht; 2016-17). - Res. also Germ. - Bibliogr.: p.193-206. - ISSN 1434-8454
Шифр: (Pr 1120/2016-17) 02
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List of Figures .............................................. xiii
List of Tables ................................................ xix
Acronyms ...................................................... xxi
Nomenclature ................................................ xxiii
1 Introduction and scope ....................................... 1
2 Background ................................................... 3
2.1 Motivation ................................................ 3
2.2 Chemical Rocket Propulsion ................................. 4
2.2.1 Introduction to rocket propulsion ................... 4
2.2.2 Liquid rocket propulsion ............................ 5
2.2.3 Combustion chamber processes ....................... 10
2.3 Combustion Instability .................................... 15
2.3.1 Introduction to combustion instabilities ........... 16
2.3.2 Combustion chamber acoustics ....................... 17
2.3.3 Rayleigh criterion ................................ 22
2.3.4 Driving mechanisms ................................. 23
2.3.5 Dissipation mechanisms ............................. 29
2.4 Summary ................................................... 32
3 Experimental Apparatus .................................... 33
3.1 Test facility and operations .............................. 33
3.1.1 Test facility ...................................... 33
3.1.2 Test operation procedure ........................... 35
3.2 Test specimen ............................................. 36
3.2.1 Combustion chamber design & heritage ............... 36
3.2.2 Combustor H (BKH) .................................. 39
3.2.3 Injector system .................................... 42
3.3 Diagnostics ............................................... 46
3.3.1 Physical property measurements ..................... 46
3.3.2 Optical measurements ............................... 48
3.4 Subsystems ................................................ 52
3.4.1 Excitation system ................................. 52
3.4.2 Optical Imaging ................................... 54
3.5 Operation of test specimen ............................... 56
3.5.1 No forcing configuration ........................... 56
3.5.2 Externally forced configuration .................... 58
3.6 Summary ................................................... 59
4 Acoustic response ......................................... 61
4.1 Introduction .............................................. 61
4.1.1 Motivation ........................................ 61
4.1.2 Review of acoustic response to injection
conditions ......................................... 61
4.2 Methodology ............................................... 69
4.2.1 Experimental technique ............................. 69
4.2.2 Analysis procedure ................................. 69
4.3 Parametric study of unforced injection conditions ......... 76
4.3.1 Combustion and jet noise ........................... 76
4.3.2 Influence of injection parameters .................. 79
4.3.3 Examination of underlying physical properties ..... 80
4.3.4 Discussion ......................................... 84
4.4 Parametric study of injection with forced acoustic field .. 85
4.4.1 First transverse mode .............................. 85
4.4.2 Discussion ......................................... 87
4.5 Summary ................................................... 88
5 Acoustic dissipation under representative conditions ...... 93
5.1 Motivation ............................................... 93
5.2 State of the Art .......................................... 94
5.2.1 Acoustic dissipation theory ........................ 94
5.2.2 Measurement of damping in a combustion chamber ..... 98
5.3 Experimental methodology ................................ 100
5.4 Numerical model .......................................... 101
5.4.1 Damped driven harmonic oscillator ................. 101
5.4.2 Numerical oscillator with continuous excitation ... 102
5.4.3 Numerical oscillator with periodic excitation .... 103
5.5 Analytical methodology ................................... 108
5.5.1 Exponential decay method ......................... 108
5.5.2 Amplitude response method ......................... 110
5.5.3 Uncertainty analysis .............................. 113
5.5.4 Summary of analysis methodology qualification ..... 114
5.6 Comparison of results and methodologies ................. 115
5.6.1 Influence of sector wheel design on decay rate .... 115
5.6.2 Influence of asymmetry on decay rate .............. 116
5.6.3 Influence of method on decay rate ................. 118
5.6.4. Summary of analysis method comparison ............ 118
5.7 lL-mode dissipation ...................................... 119
5.7.1 Spatial dependence of amplitude and damping ....... 119
5.7.2 Influence of operating conditions ................. 120
5.7.3 Discussion of 1L mode damping rate ................ 123
5.8 IT mode dissipation ...................................... 126
5.8.1 Spatial dependence of amplitude and damping ....... 126
5.8.2 Influence of operating conditions ................. 127
5.8.3 Discussion of 1T mode damping rate ................ 132
5.9 Quantitative comparison of 1L and 1T mode dissipation .... 136
5.9.1 Comparison between absolute values ................ 136
5.9.2 Comparison of 1L- and 1T mode responses to
injection conditions .............................. 137
5.10 Summary .................................................. 138
6 Visible imaging of oxygen-hydrogen combustion ............ 141
6.1 Motivation .............................................. 141
6.2 State of the art ......................................... 141
6.2.1 Flame emission imaging in oxygen hydrogen
combustion ........................................ 142
6.2.2 Shadowgraph imaging ............................... 146
6.2.3 Visible imaging ................................... 148
6.3 Methodology .............................................. 149
6.3.1 Experimental methodology .......................... 149
6.3.2 Analytical methodology ............................ 149
6.4 Comparison of OH* and visible imaging .................... 151
6.4.1 Line-of-sight measurements ........................ 151
6.4.2 Flame length ...................................... 153
6.5 Flame response to periodic excitation ................... 155
6.5.1 Mean intensity fluctuations ....................... 155
6.5.2 Comparison of imaging and acoustic spectra ........ 157
6.5.3 Comparison with photomultiplier signals ........... 157
6.5.4 Response of flame phenomenology to periodic
excitation ........................................ 158
6.6 Flame response to continuous excitation .................. 159
6.6.1 Jet transverse displacement ....................... 159
6.6.2 Localised frequency response to continuous
excitation ........................................ 164
6.7 Summary .................................................. 166
7 Response of Transverse eigenmode frequency to dynamic
pressure amplitude ....................................... l69
7.1 Motivation .............................................. 169
7.2 Introduction ............................................. 169
7.3 Methodology .............................................. 171
7.3.1 Physical basis for frequency shift model .......... 171
7.3.2 Frequency shift model ............................. 177
7.4 Results .................................................. 180
7.4.1 Examination of model response ..................... 180
7.4.2 Comparison of model with experimental data ........ 182
7.4.3 Discussion ........................................ 183
7.5. Summary ................................................. 186
8 Conclusions and outlook .................................. 189
Bibliography .................................................. 193
Appendices .................................................... 207
A List of publications resulting from this work ............ 209
......................................................... 209
B Influence of additional operating conditions on damping
rate ..................................................... 210
B.1 lL-mode .................................................. 210
B.2 1T-Mode .................................................. 213
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