Hypersonic Air-Breathing Propulsion
Nishant Agarwal
Dept. of Aerospace Engineering
University of Colorado Boulder
Scramjet Engine:
• Brayton Cycle - Constant Pressure Cycle
• Components
- Inlet
- Isolator
- Combustor
- Nozzle
History
1st Gen
1963
Mach 4-7 in Test
2rd Gen
1969
Mach 6.7 in Flight
3rd Gen
2001
Mach 9.6 (World Record)
4th Gen – Present
2013
Mach 6 – 210 sec flight time
Combined Cycles
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Dual Mode Scramjets
Variable Geometry Scramjets
Hydrocarbon/Hydrogen based Scramjets
Rocket Based Combined Cycle Scramjets
Detonation/Pulse Detonation Scramjets
Rocket based combined cycle
V1 or the Buzz Bomb
Design Challenges
• Air Inlet
- Inlet Starting
• Combustor
- Fuel Injection
- Mixing
- Flameholding
• Structures and Materials
- Thermal Loads
- Thermal Expansion
- Thermal Management for aircraft body
• Fuel
- Endothermic property
- Thermal Stability
- Carbon deposit & coking
- Storage
Inlets
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External
Compression
External Compression
Internal Compression
Mixed Compression
Streamlines Compression
Operability
Internal
Compression
- Inlet Starting – Kantrowitz Limit
- Maximum Contraction ratio
- Shock Wave-BL Interaction
- Maximum Back-pressure
Mixed
Compression
Combustion
• Parallel, Normal and Transverse Injection
• Ramp Injectors
• Strut injector
Parallel Flow
• Plasma Ignitor
• Pylon Injection
• Upstream Injector
Ramp Injector
• Pulsed Injector
• Cavity Flame holders
Normal Injector
Pylon
Injector
Fuels
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Hydrocarbon
Hydrogen
Pyrophorics
Exotic high-energy-density fuels
Endothermic Hydrocarbon Fuels
Cubane
Materials
• Scramjet Structure
- Materials for dynamic compression ramp contour and variable flow path
- Actively cooled system: C fiber –SiC composite, Cb752, Ni alloys
- Strengthening of these materials: Vapor Phase Strengthening
- Low Thermal Expansion Lattices for Thermal Protection Systems
Thank You