 | Li Yi. Hot stage separation of rockets using coupled CFD and flight mechanics method: Diss. … Dr.-Ing. / Deutsches Zentrum für Luft- und Raumfahrt, Institut für Aerodynamik und Strömungstechnik, Braunschweig. - Köln: DLR, 2015. - xiii, 141 p.: ill. - (Forschungsbericht; 2015-19). - Res. also Germ. - Bibliogr.: p.134-141. - ISSN 1434-8454
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Abstract ........................................................ I
Kurzfassung .................................................... II
Acknowledgements .............................................. III
Nomenclature .................................................. VII
1 Introduction ................................................. 1
1.1 Background .............................................. 1
1.2 Stage Separation ........................................ 3
1.2.1 Cold Separation .................................. 3
1.2.2 Hot Separation (Fire-In-The-Hole) ................ 4
1.2.3 Separation Dynamics .............................. 6
1.3 Study Approaches for Staging Dynamics ................... 7
1.4 Objectives of this Study ................................ 9
2 Applied Numerical Methods ................................... 11
2.1 Governing Equations .................................... 11
2.1.1 Calorically Perfect Gas ......................... 14
2.1.2 Thermally Perfect Gas ........................... 15
2.1.3 Chemically Nonequilibrium Mixture of Perfect
Gases ........................................... 16
2.1.4 Equilibrium and Nonequilibrium Flows ............ 19
2.2 Flight Mechanics Equations ............................. 20
2.2.1 Coordinate Systems .............................. 20
2.2.2 The Equations of Motion ......................... 26
2.3 The Chimera Methodology ................................ 28
2.4 The Moving System ...................................... 30
2.5 Coupled Simulation of CFD and Flight Mechanics ......... 31
2.5.1 Sequential-static Simulation .................... 31
2.5.2 Fully-coupled, Time-accurate Simulation ......... 32
3 Aerodynamic Characterization of VLM-1 ....................... 35
3.1 Computational Geometry ................................. 36
3.2 Computational Mesh ..................................... 37
3.3 Computation and Analysis ............................... 42
4 Numerical Modeling of the Rocket Motor ...................... 46
4.1 Flow Patterns of Hot Staging ........................... 46
4.2 Gas Models for the Simulation of Rocket Plume .......... 50
4.3 Comparison of the Proposed Gas Models .................. 55
4.3.1 Computation of Flow Separations ................. 55
4.3.2 Computation of the Aerodynamic Forces on the
First Stage ..................................... 60
4.3.3 Evaluation of the gas models with Experiments
Data ............................................ 69
4.4 Summary ................................................ 81
5 Staging Simulation .......................................... 82
5.1 Staging Procedure ...................................... 82
5.1.1 Start-up Simulation ............................. 82
5.1.2 Results and Analysis ............................ 86
5.2 Meshing Strategy ....................................... 91
5.3 6-DoF Simulation ....................................... 94
5.3.1 Staging Dynamics ................................ 96
5.3.2 Time step size for the staging simulation ...... 113
5.3.3 Effects of the Center of Mass .................. 117
5.4 Study of the Computational Models for 6-DoF
Simulation ............................................ 120
5.5 Summary ............................................... 128
6 Conclusions ................................................ 129
6.1 Summary of the Work ................................... 129
6.2 Contributions of this Work ............................ 131
6.3 Shortages of this Work ................................ 132
6.4 Suggestions for Future Work ........................... 133
References .................................................... 134
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