This document provides an overview of jet engines, including: - Jet engines work by expelling a fast moving jet of air out the back, which generates thrust according to Newton's third law of motion. - The first jet engine was invented in ancient Egypt in 100 BC, while modern jet engines were developed starting in the early 20th century. - The key parts of a jet engine are the air intake, compressor, combustion chamber, turbine, and nozzle. - Jet engines work by compressing air, adding fuel and igniting it to increase air velocity, and expelling it through a nozzle for propulsion. - Main types include turbojets, turbofans, turboprops, ramjets

1. PRESENTED BY
SUNIL KUMAR MAHANTA
REGD.NO.-2001109507
SECTION-B
BRANCH-MECHANICAL ENGINEERING
SEMINAR ON JET ENGINE

2. INTRODUCTION
• A jet engine is a reaction engine that discharges a fast moving jet
which generates thrust by jet propulsion in accordance with Newton’s
laws of motion. This broad definition of jet engines includes turbojets,
turbofans, rockets, ramjets, and pulse jets. jet engine is nothing but a
Gas Turbine.

3. HISTORY OF JET ENGINE
• The first jet engine was built by Egyptian scientists during 100 B.C.
• This device was known as Aeolipile.
• Jet propulsion only took off with the invention of the gunpowder-
powered rocket by the Chinese in the 13th century.

4. Heinkel He 178, the world's first aircraft to fly purely on turbojet power

5. HOW DOES AN AEROPLANE FLY

6. PRINCIPLE OF JET ENGINE
• Principle of jet engine is based on Newton's second and third law of
motion.
• Second law states that the rate of change of momentum in any direction is
proportional to the force acting in that direction.
• Third law states that for every action there is an equal and opposite reaction.

7. WORKING OF JET ENGINE

8. WORKING OF JET ENGINE
• Sucks in air from front with fan
• A compressor raises the pressure of the air
• Then the compressed air is ignited
• Gas expends and comes out nozzle
• Engine/Aircraft thrusts forward

9. PARTS OF JET ENGINE
• Air intake (Fan)
• Compressor
• Combustion chamber
• Turbine
• Nozzle

10. BRAYTON CYCLE
Ideal thermodynamic cycle divided into following
process:
• Isentropic compression process
• Isobaric heat addition process
• Isentropic expansion process
• Isobaric heat rejection process

11. TYPES OF JET ENGINE
• TURBOJET ENGINE
The turbojet is an airbreathing jet engine, usually used in aircraft. It
consists of a gas turbine with a propelling nozzle. The gas turbine has
an air inlet, a compressor, a combustion chamber, and a turbine (that
drives the compressor).

12. • TURBOFAN
The word "turbofan" is combination of "turbine" and "fan": the turbo
portion refers to a gas turbine engine which takes mechanical energy
from combustion, and the fan, a ducted fan that uses the mechanical
energy from the gas turbine to accelerate air rearwards.

13. • TURBOPROP
A turboprop engine is a turbine engine that drives an aircraft propeller.
In contrast to a turbojet, the engine's exhaust gases do not contain
enough energy to create significant thrust, since almost all of the
engine's power is used to drive the propeller.

14. • RAMSET
Ramjets cannot produce thrust at zero airspeed; they cannot move an
aircraft from a standstill. A ramjet-powered vehicle, therefore, requires
an assisted take-off like a rocket assist to accelerate it to a speed where
it begins to produce thrust. Ramjets work most efficiently at supersonic
speeds around Mach 3

15. It is a form of airbreathing jet engine that uses the
engine's forward motion to compress incoming air
without an axial compressor

16. TURBOSHAFT
A turboshaft engine is a form of gas turbine which is optimized to
produce shaft power rather than jet thrust. They are even more similar
to turboprops, with only minor differences, and a single engine is often
sold in both forms.

17. MERITS & DEMERITS
Merits of Jet engine over IC engine
• Mechanical efficiency of jet engine is high as compared to IC engine.
• Speed of jet engine per HP developed is higher than IC engine.
• Ignition and lubricating systems are much simpler in jet engine than
IC engine.

18. Demerits Of Jet Engines Over IC engine
• Thermal efficiency of Jet engine is low compared to IC engine.
• Difficult to start.
• Turbine blades need a special cooling system due high temperature.

19. APPLICATION OF JET ENGINE
• The industry they're most prominent in is in the transport industry,
where they are used to propel aircraft, boats, and in some one of
creations such as a turbojet powered truck.
• The first use of the jet engine was to power military aircraft.
• Normal type of jet engine is used for domestic purpose i.e. Traveling,
carrying goods etc.
• As industrial gas turbine for power generation, natural gas, oil
pumps etc.

20. LATEST AND FASTEST JET ENGINE
North American X-15
This aircraft has the
current world record for
the fastest manned
aircraft. Its maximum
speed was mach 6.70
(about 7,200 km/h)
which it attained on the
3rd of October 1967

21. THANK YOU