1. UNIVERSITÀ DEGLI STUDI DI
NAPOLI
“FEDERICO II”
SCUOLA POLITECNICA E DELLE SCIENZE DI BASE
DIPARTIMENTO DI INGEGNERIA CHIMICA, DEI MATERIALI
E DELLA PRODUZIONE INDUSTRIALE
CORSO DI LAUREA IN INGEGNERIA MECCANICA PER LA
PROGETTAZIONE E LA PRODUZIONE
TESI DI LAUREA
Comparative analysis of manufacturing technologies for
liquid rocket regenerative thrust chambers
Relatore Candidato
Ch.mo Prof. Ing. Antonino Squillace Alfonso Sciano
Matr. M64/280
Correlatori
Ing. Manrico Fragiacomo
Ing. Fabio Scherillo
ANNO ACCADEMICO 2014/2015
2. INDEX
Page
Acknowledgements………….…………………………...…………...i
Abstract………………………………………………………………ii
List of Figures……………………………………………………….iii
List of Tables………………………………………...…………….viii
CHAPTER 1. Introduction…...……………………………………...1
1.1 Background and motivation….…………………………...……………………..1
1.2 The Hyprob-Bread project………………………………………………………3
1.3 Thesis objective………………………………...…………………………………7
1.4 Outline of the work……………………………………………………………….8
CHAPTER 2. Liquid rocket engine: Design and main
parameters…………………………………………………………..10
2.1 Liquid rocket thrust chamber basic performance parameters and main
technological issues………...…………………………………………………..10
2.1.1 Specific Impulse Is...............................................................11
2.1.2 Characteristic Velocity c*……………………………….……12
2.1.3 Thrust Coefficient Cf…………………………………………..13
2.2 Injector head……………………………………………………………………..14
2.3 Combustion chamber……………………………………………………………23
2.4 Cooling system…………………………………………………………………..27
2.4.1 Regenerative cooling………………………………………….27
2.4.2 Dump cooling…………………………………………………..28
2.4.3 Film cooling…………………………………………………….30
2.4.4 Transpiration cooling…………………………………………30
2.4.5 Ablative cooling………………………………………………..31
2.4.6 Radiation cooling……………………………………………...33
2.4.7 Heat-Sink Cooling……………………………………………..33
2.5 Nozzle……………………………………………………………………………..35
2.5.1 Conical nozzle………………………………………………….37
2.5.2 Bell nozzle………………………………………………………37
2.6 Ignition system…….……………………………………………………………..40
2.6.1 Pyrotechnic igniters………….………………………………..40
2.6.2 Spark plugs……………………………………………………..41
4. 4.6.2 Electroless Plating…………………………………………...101
4.6.3 Electroforming…..…………………….……………………..101
4.6.4 Electroplating for thrust chambers………………………...103
4.7 Composite materials………...………………………………….……………..105
4.7.1 Reinforced plastics…………………………………………...106
4.7.2 Metal-matrix Composites……………………………………107
4.7.3 Ceramic-matrix Composites………………………………..108
4.7.4 Composites materials for thrust chamber…………………110
4.8 Centrifugal casting…………………………………………………………….113
4.8.1 True Centrifugal Casting……………………………………114
4.8.2 Semi-Centrifugal Casting…………………………………...114
4.8.3 Centrifuge or Pressure Casting…………………………….115
4.8.4 Centrifugal casting for thrust chamber……………………118
4.9 Thermal spray………………………………………………………………….119
4.9.1 High Velocity Oxy/Fuel Spraying HVOF…………………123
4.9.2 Vacuum Plasma Spraying VPS……………………………..124
4.9.3 RF Plasma Spraying…………………………………………126
4.9.4 Thermal spray for thrust chamber…………………………127
CHAPTER 5. Selected technology………………………………...131
5.1 Assessment criteria..………...……………………………………….131
5.2 Evolution of brazing procedure………………………………...…..132
5.2.1 The materials’ choice………………….……………………………..132
5.2.2 Activities of CIRA in cooperation with ATM: synthesis of main
results…........................................................................................135
5.2.3 Activities of CIRA in cooperation with AVIO: synthesis of main
results………………………………………………..…………………141
5.2.4 Activities of CIRA in cooperation with CSM: synthesis of main
results..……………………………………………………..…………..151
CHAPTER 6. Butt joints analysis…………………………………163
6.1 Preparation of the specimens..……………………………………..165
6.2 SEM and EDS analysis……………………..………………………..167
6.3 Tensile tests………………………………………….........................174
CHAPTER 7. Conclusions…………………………………….…179
7.1 Final considerations…………………………………………...179
7.2 Future developments of the chosen process and alternative
approaches…………..………………….………………………..180
Bibliography………………………………………………………182
5. ACKNOWLEDGEMENTS
The author gratefully thanks Prof. Antonino Squillace and Prof. Luigi
Carrino, Dr. Francesco Battista, Michele Ferraiuolo, Daniele Ricci,
Guido Saccone and the co-rapporteurs Dr. Fabio Scherillo and
Manrico Fragiacomo for their very precious support and useful
contribution to the work reported here.
6. ABSTRACT
This study was performed within the framework of the HYPROB BREAD program,
aimed to design and develop new promising configuration of rocket engine
regenerative thrust chambers, fuelled by methane and oxygen. This choice was
motivated by safety, handling and operation easiness and environmentally friendly
considerations.
Regenerative thrust chamber manufacturing is still a bottleneck in the design and
development process of rocket engines and several manufacturing methods were
proposed worldwide e.g., vacuum brazing, diffusion bonding, laser beam welding,
ultrasonic welding, electroplating, additive manufacturing, thermal spray,
centrifugal casting etc.
After a comprehensive literature survey brazing was chosen by CIRA in order to
obtain a technological on-ground demonstrator of a thrust chamber, based on
CuCrZr alloy inner liner and Inconel 718 outer shell.
The selected manufacturing process was investigated and developed in
collaboration with CIRA’s partners e.g., ATM, AVIO and CSM.
An alternative more efficient vacuum brazing method consisting in a preliminary
copper electroplating of Inconel 718 joint surfaces aimed to use a brazing alloy for
homogeneous component edges was conceived, experimentally studied and
realized.
Specimens produced by CSM were tested in the laboratories of the Department of
Chemical Engineering, Materials and Industrial Manufacturing at the University of
Naples Federico II.
Preliminary results of mechanical characterization and SEM and EDS analysis
show promising feasibility of this method to regenerative rocket engine thrust
chamber manufacturing. In any case, a future optimization and industrialization
should be carried out for a complete achievement of the final objective.
