Aircraft Power Plants and Rocket Engines

Aircraft Power Plants and
Rocket Engines
U. Selvakumar, Lecturer, Dept of aero,
BIT, Sathy.
Unit V – 07A306 - Elements of Aeronautics
Unit V – 07A306 - Elements of Aeronautics
Syllabus
Principles of operation of rockets
Types of rockets
Typical applications
Exploration into space
Unit V – 07A306 - Elements of Aeronautics
Text and References
Gas Turbine Theory - H. Cohen , G.F.C. Rogers , H.I.H .
Saravanamutto – Third Edition - 1987
Principal Textbooks :
Rocket Propulsion Elements – George. P. Sutton – Third
Edition - 1967
Supplemental References :
The Jet Engine - Rolls – Royce Publication – 1986
Introduction to Space Sciences and Spacecraft Applications –
B.A. Campbell , S.W. McCandless JR - 1996
Unit V – 07A306 - Elements of Aeronautics
Helpful Resources
/> http:/www.eevl.ac.uk
/>Unit V – 07A306 - Elements of Aeronautics
Types of Rockets
Based on Gas acceleration mechanism
Thermal

Electrostatic

Electromagnetic

Based on Energy Source
Chemical ( always “thermal” )

Nuclear ( Thermal , Electric )

Solar ( Thermal , Electric)
> Solid
Liquid /Gas > Monopropellant
Hybrid Bipropellant
Based on Thrust Level
High thrust ( >= 1g )

Low thrust ( 10-5 – 10-2 g )

Unit V – 07A306 - Elements of Aeronautics
Solid-Propellant Rocket Motor
Mixed fuel and oxidizer

External ignition

Burn to completion

Unit V – 07A306 - Elements of Aeronautics
Thrust is proportional to burning area
Grain pattern affects the thrust profile

Propellant chamber must withstand high 'P' and 'T'

Environmentally unfriendly exhaust gases
Solid-Propellant Rocket Motor
Unit V – 07A306 - Elements of Aeronautics
Liquid / Gas-Propellant Rocket Motor
Catalytic ignition
Monopropellant :
Chemical decomposition
Bipropellant :
Separate fuel and oxidizer
Hypergolic ( spontaneous ) ignition
External ignition
Throttlable
Start and stop cycling
Unit V – 07A306 - Elements of Aeronautics
Liquid / Gas-Propellant Rocket Motor
Unit V – 07A306 - Elements of Aeronautics
Hybrid-Propellant Rocket Motor
Solid fuel and liquid oxidizer
Nitrous oxide (oxidizer)
Hydroxy Terminated Polybutadyene (fuel)
Separate fuel and oxidizer
Issues :
Hard start
Blow back
Complete mixing of oxidizer and fuel toward completion of burn
Unit V – 07A306 - Elements of Aeronautics
Hybrid-Propellant Rocket Motor
Unit V – 07A306 - Elements of Aeronautics
Thrust = m propellant V exhaust + A exit ( p exit -p ambient )
= m ceff

m = mass flow rate of on-board propellant
Rocket Thrust
I
sp
=Thrust /Weight flow rate of propellant 
Unit =m/ s/m/s
2
=s
Unit V – 07A306 - Elements of Aeronautics
Rocket Parameters
m
initial
/m
final


m
payload
/m
initial


m
structure
/m
initial



m

propellant
/m
initial

Mass ratio
Payload ratio
Structural ratio
Propellant ratio
m
initial
=m
payload
m
structura l /engine
m
propella nt
m
final
=m
payload
m
structural/engine
+ + = 1  