This document discusses scramjet engines and their history and operation. It provides background on jet propulsion and defines key terms like ramjet and scramjet. Scramjets work like ramjets but can operate at supersonic speeds without pre-compression of incoming air. They take oxygen from the atmosphere and use hydrogen fuel. India successfully tested a scramjet engine in 2016. Scramjets offer advantages over other jet engines like fewer moving parts but come with challenges like needing an additional boost to reach efficient speeds.

2.  Introduction To Jet Propulsion
 Basic Terminology Used In Jet Propulsion
 Why We need a SCRAM JET ENGINE?
 History and progress Of SCRAM JET
 Designing Principle
 Working Of SCRAM Jet
 Advantages & Disadvantages

3.  Jet propulsion is thrust produced by passing
a jet of matter (typically air or water) in the
opposite direction to the direction of motion.
By Newton's third law, the moving body is
propelled in the opposite direction to the jet. It
is most commonly used in the jet engine, but is
also the most common means of spacecraft
propulsion.
A jet engine is a reaction engine that
discharges a fast moving jet of fluid to generate
thrust by jet propulsion and in accordance
with Newton's laws of motion. This broad
definition of jet engines includes Turbo
jets,Turbo Fans, Rockets, Ramjets ,SCRAM Jets
etc.

4. Propulsion System
Air Breathing
Engines
Turbo-
Prop
Turbo
Jet
Ram
Jet
SCRAM
jet
Non Air Breathing
Engines
(Rocket Engines)
Solid
Propellent
Liquid
Propellent

5.  Bernoulli’s Theorem :
Above equation shows that Pressure P is inversely proportional to
velocity ‘v’ (If z=constant)
If P increases v decreases
If velocity decreases pressure is increased.
 Mach Number :
It is the ratio of the speed of a body to the speed of sound
in the surrounding medium.

6. If Mach Number is denoted by Ma Then,
 Convergent
And
Divergent Nozzle:
Convergent part Divergent Part

7.  To reduce the cost and for increasing the high speed
of mach 6 next generation launch vehicle must use a
propulsion system which can utilise the atmospheric
oxygen during their flight through the atmosphere.
 India is the fifth country who successfully launched
and tested scram jet technology.On August 28, 2016,
ISRO successfully tested its scramjet engine.
 Nearly 70 % of the propellant ( fuel – oxidiser
combination )carried by today’s launch vechicle
consists of oxidiser.

8.  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 1960 a variety of experimental scramjet engine
were built and ground tested in the US and the UK.
.

9. 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.

10. The scramjet is composed of three basic components :
 A Converging Inlet, where incoming air is compressed
and decelerated.
 A Combustor, where gaseous fuel is burned with
atmospheric oxygen to produce heat.
 A Diverging Nozzle, where the heated air is accelerated to
produce thrust.

11. • In scramjets, the engine inlet is designed so it
doesn’t create as much compression as in
ramjet, allowing the air to zip through the engine
at supersonic speeds.
• The simplest type of air breathing engine is the
scramjet engine and simplified sketch of engine
is given in figure.

12. Scramjets works on the same principle of ramjet.
Based on air breathing propulsion system.
The engine caries hydrogen as a fuel & takes
oxygen from the atmospheric air.
Basically in order to achieve the initial speed, a
second engine is integrated in the Scramjet model,
it may be rocket or turbojet engine.

13. Hot air flows in the combustion chamber and at
this moment the propellant
i.e. hydrogen (having a very low ignition temperature)
are injected by the injector in the combustor,
where it gets self ignited within a millisecond and
the combustion process is carried out at supersonic
speed.

15. Does not have to carry oxygen.
No rotating parts, makes it easier to manufacture.
Less weight and simple design.
As the hydrogen is used as a propellant combustion
is carried out at supersonic velocity with the help of
oxygen from the atmosphere.
As a result of that, steam is being exhaust gas which
is eco-friendly in nature.

16. A scramjet cannot produce efficient thrust unless
boosted to high speed, around Mach 5.
As a result an additional propulsion systems are
required.
Lack of stealth.
Testing difficulties.

17.  Wikipedia : https://en.wikipedia.org/wiki/Scramjet
 ISRO : http://www.isro.gov.in/update/28-aug-2016/
successful-flight-testing-of-isros-scramjet-engine-technology-demonstrator
 Weber, Richard J.; Mackay, John S
"An Analysis of Ramjet Engines Using Supersonic Combustion".
 Varvill, Richard; Bond, Alan (2003)."A Comparison of Propulsion
Concepts for SSTO Reusable Launchers"