RAMJET is a type of jet engine in which the air drawn in for combustion is compressed solely by the forward motion of the aircraft. A ramjet uses this high pressure in front of the engine to force air through the tube, where it is heated by combusting some of it with fuel. It is then passed through a nozzle to accelerate it to supersonic speeds. This acceleration gives the ramjet forward thrust.

1. RAM JET
PROPULSIVE ENGINE
NAME: JAIMIN A. KEMKAR
EN. NO.: 160123119014
SEM. & BATCH: 7TH D1
SUBJECT: POWER PLANT ENGINEERING (217910)
GUIDED BY.: PROF. NIRAV JOSHI

2. CONTENTS
 INTRODUCTION OF JET PROPULSION AND CLASSIFICATION OF PROPULSIVE
ENGINE
 INTRODUCTION OF RAM JET ENGINE
 APPLICATION OF RAM JET ENGINES
 ADVANTAGES AND LIMITATIONS OF RAM JET ENGINES
 REFERANCES

3. INTRODUCTION OF JET PROPULSION AND
CLASSIFICATION OF PROPULSIVE ENGINE
 A jet propulsive
engine is a
reaction engine
that discharges a
fast moving jet of
fluid to generate
thrust in the
opposite direction
of the jet to
propel the
aircraft.
Propulsive
Engine
Air
breathing jet
engines
IC engine
driven
engines
Ram jet
engine
Intermittent
combustion
system
Pulse jet
engine
Gas turbine
propulsive
system
Turbojet
engine
Turbojet
with
afterburners
Turboprop Turbofan
Non air
breathing jet
engines
Solid
Propellant
rocket
Liquid
Propellant
Rocket

4. INTRODUCTION OF RAM JET ENGINE
 Ramjet is simplest of all the air
breathing engines and consists of
supersonic and subsonic diffusers, a
combustion chamber with fuel
injector and a discharge nozzle.
 As per the name all the compression
in the cycle is made to occur in the
intake diffuser, producing a
significant rise in static pressure.
 Fuel is burnt in this high pressure air
and the mixture is then expanded to
ambient static pressure through a
nozzle system.

5.  The ramjet engine produces power by increasing the momentum of the working
fluid with help of induction of energy by combustion of fuel, so that the
momentum of the exhaust jet exceeds that of the incoming air, on a continuous
basis.
 This high pressure gas is expanded through a nozzle, converting a low subsonic
flow in the combustion chamber -- to a supersonic jet.
 The mixture of air and burnt fuel is exhausted through a convergent-divergent (C-
D) nozzle.
 Exit pressure (Pe) is same as or nearly same as the ambient pressure. Thus, the
chocking pressure (Pc) at the throat is higher than the ambient pressure (Pa).
 However at low supersonic flights the exhaust may be sonic through a convergent
nozzle.
 At flight Mach 5 and above the unit becomes a Supersonic Combustion Ramjet
(SCRAMJET) in which the combustion is done in supersonic flow

6. APPLICATION OF RAM JET ENGINES
 Aircraft using ramjets:
 There are lots of aircrafts are powered
by ramjet engines some of them are
listed below.
 X-43A - The fastest unmanned aircraft was the
X-43A in which NASA installed a scramjet
engine.
 SR-71
 Nord 1500 Griffon
 Missiles powered by ramjet engines:
 Our own Brahmos missile is powerd by
scramjet engines
 Recently DRDO tested ASTRA missile
which is again powered by ramjet
engine.

7. ADVANTAGES RAM JET ENGINES
 Ramjet is very simple in construction and does not have any moving part such as
compressor and turbine
 It is very cheap and requires almost no maintenance
 Greater thrust per unit engine weight than any other propulsion engine at
supersonic speed except rocket
 At very high speed and high altitudes the specific fuel consumption is less than
turbojet engine
 It can be operated with any type of liquid fuels and even with solid nuclear fuels

8. LIMITATIONS OF RAM JET ENGINES
 At low and moderate speeds, the fuel consumption is very high
 It can not be started on its own. It has to be accelerated to a certain flight
velocity by some launching plateform
 Due to high air speed the combustion chamber requires flame holder to stabilize
the combustion.

9. REFERANCES
■ TEXTBOOK:
– POWER PLANT ENGINEERING BY BOOKSINDIA
■ NPTEL PDFs (http://nptel.ac.in/courses/101101002/downloads/Lect-37.pdf)
■ WIKIPEDIA (https://en.wikipedia.org/wiki/Ramjet#Aircraft_using_ramjets)