Introduction Cum Need for a Scramjet Engine History Working More information about Scramjet Engines Hyper X Vehicle Applications of scramjet engines Challenges to scramjet engine technology Conclusion References For further explanation: https://www.youtube.com/watch?v=0Ux7mYSlAfg

1. Scramjet Engines
Submitted To Submitted by
Dr. K.B. Rana Chanderveer Singh
16/140

2. Contents
• Introduction Cum Need for a Scramjet Engine
• History
• Working
• More information about Scramjet Engines
• Hyper X Vehicle
• Applications of scramjet engines
• Challenges to scramjet engine technology
• Conclusion
• References

3. Introduction cum Need for Scramjet
Engines
• Nearly 70% of the propellant (fuel-oxidiser
combination) carried by today’s launch vehicles
consists of oxidiser.
• Launch vehicles (Rockets) designed for one time use
are expensive and their efficiency is low because they
can carry only 2-4% of their lift-off mass to orbit.
• That's the idea behind a different propulsion system
called "scramjet“.
• The oxygen needed by the engine to combust is taken
from the atmosphere passing through the vehicle,
instead of from a tank onboard. The craft becomes
smaller, lighter and faster.
• How fast? Researchers predict scramjet speeds could
reach 15 times the speed of sound. An 18-hour trip to
Tokyo from New York City becomes a 2-hour flight.

4. History
• In the 1950s and 1960s a variety of experimental
scramjet engines were built and ground tested in
the US and the UK.
• However, the first successful scramjet engine
flight test was done in 2002 by Australia. And
until today there are only 4 countries that have
demonstrated scramjet engine technology.
(Why did it take more than 40 years to realize this
technology?)

5. Working Principle
• For understanding the principle of scramjets,
we first need to understand the principle of
turbojets.

6. A turbojet engine is a gas turbine engine that works by
1) compressing air with an inlet and a compressor,
2) mixing fuel with the compressed air, burning the mixture in the combustor,
3) and then passing the hot, high pressure air through a turbine and a nozzle.
Note: Here, turbine is only used to run the compressor.

7. • Now, let’s move from turbojet engine to
ramjet engine.
• Ramjet engines have no moving parts unlike
turbojets or turbofans. It is an open duct
constituted of an inlet, a combustion chamber
and a nozzle.

8. If it doesn’t have a compressor then how is the air compressed before
the fuel ignition?
By Ram Effect
At flight numbers greater than 2, the incoming air, if captured and
decelerated properly, can be compressed to required pressure.
And hence if we do not need a compressor then we do not need a
turbine.Therfore, we do not have any moving part inside a Ramjet
Engine.
However, a ramjet engine only functions if it is moving at mach
number of greater than 2.Therefore it cannot take off and land by
itself.
(introduction of SR-71 blackbird)

9. Scramjet Engines
• At flight speeds of more than Mach 5, the
efficiency of a ramjet engine decreases.
Therefore, we use scramjet engines over Mach 5.
• Remember the only difference between a ramjet
engine and the scramjet engine is that the
combustion in ramjet engine is done subsonically.
But in scramjet engines, there is supersonic
combustion. Hence called “scramjet” or
supersonic ramjet.

10. Scramjet Engine

11. More information about Scramjet
Engines
• In scramjet engines, the engine is airframe
integrated as shown in figure below.
• Also, since the flow is supersonic, the flow
is accompanied with shocks.

12. Hyper –X Vehicle

13. Applications of scramjet engines
1)Space applications
• An alternative to rockets
• Rockets carry their own liquid oxygen with
them(for combustion)and therefore the payload
they can carry is only 2-4% of their lift-off mass.
• However, scramjets use atmospheric oxygen for
combustion which helps them to carry more
payload.
• Therefore, Scramjets can help reduce the cost of
satellite launching business to very large extent.

14. 2) Military applications
• Used in missiles
• Scramjet missiles are better than ballistic
missiles because of better maneuverability
and higher speed.

15. 3) Civil Applications
• Researchers predict scramjet speeds could
reach 15 times the speed of sound.
• An 18-hour trip to Tokyo from New York City
becomes a 2-hour flight.

16. Challenges to scramjet Engines
• It’s time to answer the question we put earlier.
• Why did it take more than 40 years to realize
scramjet engine technology?
• Scramjet engines are simple in the sense that it
doesn’t have any moving parts but applying
scramjet technology into reality is not that
simple.
We will address some of these challenges in this
section.

17. 1) Residence Time
Flow speed are very large in the combustion
chamber(Mach 2.2). Therefore the residence
time, the time for fuel-air mixing and
combustion in a combustion chamber of a
particular length becomes very
small(milliseconds).

18. 2) Engine-Airframe integration
• Boeing makes the airframe and Pratt& Whitney
makes the engine .So, the expertise of airframe
making and engine making are not in the same
place.(and that’s okay for a commercial aircraft)
• But you can’t do this separately for a scramjet
engine. The engine in a scramjet vehicle is a part
of the airframe. It is because there is a big
aerodynamic coupling between the two
things.And therefore, testing of scramjet engines
need the two areas to merge together.

19. 3) Drag
If you want a reasonable residence time, the
length of the vehicle has to be large. But if you
do that, the drag on the vehicle increases. As
the drag is not only on the airframe but also
on the inside of the engine. And the engine
length is comparable to vehicle length.

20. 4)Testing
• Building a wind tunnel for the scramjet
engines is very expensive.
• It is because to test any engine for supersonic
speeds the power required for testing even for
a very small time is very large.

21. 5) Scalability
• Now that testing is expensive. We go for small
scale testing. But the scalability becomes
another problem.
• Scalability is difficult for a circular intake. But,
it is good for a rectangular intake.

22. Conclusion
• Today, satellites are launched into orbit by multi-staged
satellite launch vehicles that can be used only once
(expendable)
• If those vehicles are made re-usable by scramjet engine
technology, the cost of launching satellites will further
come down significantly. Thus, the future re-usable
launch vehicle concept along with air-breathing
propulsion is an exciting candidate offering routine
access to space at far lower cost.
• There are a lot of challenges to the scramjet engine
technology. But it’s tonnes of applications make it
worth of more research.

23. REFERENCES
• ISRO’s Scramjet Engine Technology Demonstrator Successfully Flight Tested
https://www.isro.gov.in/launchers/isro%E2%80%99s-scramjet-engine-technology-demonstrator-successfully-
flight-tested
• What's a Scramjet?
https://www.nasa.gov/missions/research/f_scramjets.html
• Website: Scramjet
https://en.wikipedia.org/wiki/Scramjet
• X-51 Waverider Unmaned Scramjet Aircraft
https://www.airforce-technology.com/projects/x51-wave-rider/
• History of scramjet propulsion development
https://www.researchgate.net/publication/324946953_History_of_scramjet_propulsion_development
• Hyshot program secure place in flight history
https://www.uq.edu.au/news/article/2002/08/hyshot-program-secures-place-flight-history
• Corin Segal, The Scramjet Engine processes and characteristics, Cambridge publication press, 2009, ISBN-
13 978-0-511-65110-6

24. Thank You