1. Design of a Scramjet Engine
Adam J. Resler
ME 566 – Aerospace Propulsion
Wed 04/29/15

2. Overview
• Scramjet Introduction
• Current State of Scramjet Technology
• Design Considerations
• Methods
• Results and Conclusions
• Questions & Comments

3. Scramjet Introduction

5. Scramjet Benefits
• Air-Breathing Engine – No oxidizer required to
be carried onboard
• No moving parts
• Theoretical Specific Impulse between 1000 –
4000 seconds
• Escape velocity capable; Theoretical Range
between Mach 5 and Mach 26 flight velocity

6. Scramjet Disadvantages
• Special materials requirements
– High strength/weight – scramjet have high
payload mass fractions making weight a concern
– High thermal stress characteristics – heavy cooling
burden; also loss of cooling ability as fuel is
consumed
• Current designs typically start at Mach 5
• Poor thrust/weight ratio
• Low to very low lift/drag ratio

7. Scramjet Programs
• SCRAM: USA; Mach 4 – 10
• National Aerospace Plane (NASP): USA; Mach 17
Upper Limit; Mach 25 Possible; Current H2
Combustion Model (31 Reactions; 16 Species)
• HyShot: Australia; Flew at Mach 7.6 for 6
seconds; 10 vehicles; 40% Success Rate
• HyperX: USA; Mach 7 for 11 seconds (15 miles)
2004; Mach 10 in 2004;
• X-51 Waverider: USA; In 2013 flew for 240
seconds ~Mach 5.1 before running out of fuel

10. NASA X-43A HS Vehicle w/ Scramjet

12. Design Considerations
• Design Velocity: Mach 5
• Maximum Temperature: 2000 K
• Flight Altitude: 15 km
• Number of Inlet Shocks: 3

13. Design Method
• Solution of the simplified compressible,
inviscid, Navier-Stokes equations with semi-
perfect gas equations of state
• Generalized Quasi-1D Flow – takes into
account area change, friction, and heat
addition; however, no differential mass terms
• Complete combustion model (no dissociation,
complete combustion prior to nozzle)

20. Results of Analysis
• Thrust: 405.7 kN (91,210 lbf)
• Isp: 174.1 s
• Efficiency: 0.83pr/0.56t/.47o
• TSFC: 0.01757 kg/kN-s
• T/ma: 0.572 kN-s/kg
• Time in engine: 0.0021 s
• Specific burn time: 9.82 s/m3

21. Results of Analysis
Property Diffuser Combustor Nozzle
Pressure
Recovery
0.8355 0.5433 0.6724
Total
Recovery
0.3053
Adiabatic
Efficiency
0.9243 1.0 0.9127

22. Perspective
• Actual speed-over-land: ~0.9 to 1 mile/second
• New York to LA: 44.68 minutes
• Around Earth at Equator: 7.576 hours
• Destin, FL to New Orleans, LA: 5 minutes
• Compared to F-15 Eagle P&W F100-220
Turbofan Engine: ~3.8 times more thrust

23. Conclusions
• Low specific impulse - unexpected
• Engine not viable unless installed in a large
vehicle
• Better combustion model required to study
higher Mach numbers

24. Summary
• Scramjet Introduction
• Current State of Scramjet Technology
• Design Considerations
• Methods
• Results and Conclusions
• Questions & Comments

25. Q&C
• Scramjet CFD Model (1 min)
https://www.youtube.com/watch?v=kaVDDm222H8
• Scramjet Engine Wind Tunnel Test (no
apparent combustion): (40 sec)
https://www.youtube.com/watch?v=EfJp2luk_IY