The document presents information about scramjet engines. It discusses the history of scramjet development from World War II to recent test flights reaching Mach 10 speeds. The key components of a scramjet engine are described as a converging inlet to compress incoming air, a combustor where fuel is burned, and a diverging nozzle to accelerate the heated air and produce thrust. Scramjets differ from other jet engines by not using rotating components for compression and relying on high flight speeds to compress air before combustion. Potential applications include hypersonic aircraft that could reduce intercontinental flight times to under 90 minutes.

1. A Seminar Presentation on :
SCRAMJET ENGINE
Presented By: Under The Guidance Of:
Saurav Ranjan Mishra Prof. S.K.Sahu
Regd no:1101292307
Mechanical- B

2. Contents
 Introduction
 History
 Progress of Scramjet Engine
 Designing Principle
 Working Principle
 Engine Efficiency
Advantage and Disadvantage
 Application
 References

3. Introduction
A Scramjet engine is a supersonic combusting ramjet
engine in which combustion takes place in a
supersonic airflow. Generally ramjet decelerates the air
to subsonic velocities before combustion, where as
airflow in a scramjet is supersonic throughout the entire
engine. This allows the scramjet to operate efficiently at
extremely high speeds.
Scramjet engines operate on the same principles as
ramjets, but do not decelerate the flow to subsonic
velocities. Rather, a scramjet combustor is supersonic
speed.

4. History
During World War II, a tremendous amount of time and
effort were put into researching high-speed jet engine
and rocket-powered aircraft, predominantly by the
Germans.
After the war, the US and UK took in several
German scientists and military technologies through
Operation to begin putting more emphasis on their own
weapons development, including jet engines.
In the 1950s and 1960s a variety of experimental
scramjet engines were built and ground tested in the US
and the UK.

5. Progress in 2000s
In 2000s, significant progress was made in the
development of hypersonic technology. In June 15, 2007,
the US Defense Advanced Research Project Agency
(DARPA), in cooperation with the Australian Defence
Science and Technology Organisation (DSTO),
announced a successful scramjet flight at Mach10 using
rocket engines to boost the test vehicle to hypersonic
speeds.
On 22 and 23 March 2010, Australian and American
defence scientists successfully tested a (HIFiRE)
hypersonic rocket. It reached an atmospheric velocity of
"more than 5,000 kilometres per hour.

6. Designing Principle
The scramjet is composed of three basic components
named as:
 A Converging inlet.
 A Combustor.
 A Diverging nozzle
The function of converging inlet is to compress the
incoming air. Where inside the combustor
chamber gaseous fuel is burned with atmospheric
oxygen to produce heat and in the diverging nozzle,
the heated air is accelerated to produce thrust.
.

7. Due to the nature of their design scramjets require the
high kinetic energy of a hypersonic flow to compress the
incoming air to operational conditions. Thus, a scramjet-
powered vehicle must be accelerated to the required
velocity by some other means of propulsion, such as
turbojet, railgun, or rocket engines.

8. Working Principle
Scramjet engines are a type of jet engine, and rely on the
combustion of fuel and an oxidizer to produce thrust.
Similar to conventional jet engines, scramjet-powered
aircraft carry the fuel on board, and obtain the oxidizer by
the ingestion of atmospheric oxygen.
To keep the combustion rate of the fuel constant,
the pressure and temperature in the engine must also be
constant. Because air density reduces at higher altitudes,
a scramjet must climb at a specific rate as it accelerates
to maintain a constant air pressure at the intake

10. Unlike a typical jet engine, such as a turbojet or turbofan
engine, a scramjet does not use rotating, fan-like
components to compress the air; rather, the achievable
speed of the aircraft moving through the atmosphere causes
the air to compress within the inlet. As such, no moving
parts are needed in a scramjet.
A scramjet relies on high vehicle speed to forcefully
compress and decelerate the incoming air before
combustion. But ramjet decelerates the air to subsonic
velocities before combustion and airflow in a scramjet is
supersonic throughout the entire engine. This allows the
scramjet to efficiently operate at extremely high speeds

11. Engine Efficiency
The overall engine efficiency can be represented (η₀), in
terms of the specific Impulse of the engine
η₀ = (g0 V0)/hPR* Isp
= (Thrust power/Chemical energy rate)
g0 is the acceleration due to gravity at ground level
V0 is the vehicle speed
Isp is the specific impulse
hPR is fuel heat of reaction

12. Advantages
No rotating fan like components.
Easy to manufacture.
 Less weight.
 High speed can be achieved upto mach 10.

13. Disadvantages
 Cost is high.
 Good insulation material is required.
 Special cooling is needed.
It doesn’t operate in atmospheric pressure.

14. Applications
An aircraft using this type of jet engine could
dramatically reduce the time which it takes to travel from
one place to another, potentially putting any place
on Earth within a 90-minute flight.
Scramjet vehicle has been proposed for
a single stage to tether vehicle, where a Mach 12
spinning orbital tether would pick up a payload from a
vehicle at around 100 km and carry it to orbit

15. References
Curran, E.T., “Scramjet Engines: The First Forty Years”,
Journal of Propulsion and Power, Vol. 17, No. 6, Nov-Dec
2001, pp. 1138-1148.
Epstein, M & Kutshenreuter, P 1994, ‘Fuel injection
system for scramjet engines’, United States Patent, Patent
number 5280705.
http://en.wikipedia.org/wiki/Scramjet.

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