ppt_Aero_3sem_EOA.ppt

U3AEA04
ELEMENTS OF AERONAUTICS
Mr. SYED ALAY HASHIM
Assistant Professor
Department of Aeronautical Engineering
VEL TECH Dr. RR & Dr. SR TECHNICAL UNIVERSITY
Chennai
INDIA

I to V
UNIT
POWER POINT PRESENTATION

TYPES OF WING
1. Monoplane
2. Biplane
3. Tandem wing
4. Triplane
5. Quadruplane
6. Multiplane
7. Canard wing

Leading edge extensions of various
kinds

Introduction
AEROSPACE ENGINES
• Comprehend the basic components of gas turbine
engines and their basic operations
• Comprehend the thermodynamic processes
occurring in a gas turbine engines
• Comprehend the support systems associated with
gas turbine engines

GAS TURBINE CYCLE
Single stage Ideal gas turbine cycle
Two stage turbine cycle
Gas Turbine Cycle

Gas Turbine Cycle
Two stage Compressor and Turbine cycle

Jet Propulsion Cycle
In practical or actual cycle Entropy is not constant

Compressor
• Supplies high pressure air for combustion process
• centrifugal flow and Axial flow
• Centrifugal Compressor
• Adv: simple design, good for low compression ratios (5:1), strong
• Disadvantage: Difficult to stage, less efficient, high frontal area

Compressor
Axial flow
• Good for high compression ratios (20:1)
• Most commonly used

Turbine
• Convert the kinetic energy into expansion work
• It is used to drive the compressor as well as
propeller shaft

Comparison of Gas Turbine and
Piston Engine

Classification of Engine
Jet Engines Reciprocating Engines
(Propulsive thrust is produced by jet)
Air Breathing Engine Non-Air Breathing Engine
(Using atm air to produced Power)
Engine
Gas Turbine Engine Non-Gas Turbine Engine
Turbojet Turboprop Turbofan Turbo-shaft
Ramjet Scramjet Pulsejet
(Presents of Fuel and absents of Air
instead of Air + Oxidizer. Hypersonic
vehicles, Operating Mach No : 15 to 20)
(Available moving parts like
Compressor and Turbine)
(No moving parts)
Rocket Engine
(No moving parts)

Turbojet
 Chemical energy is converted into mechanical energy
 100% Thrust produced by Nozzle
 Operating Mach No: 1 to 2
 Supersonic Aircraft (1 to 5)

Turbofan
 20 to 40% of Thrust produced by Nozzle
 60 to 80% of Thrust produced by Fan
 Operating Mach No: 0.4 to 0.8
 High Subsonic Aircraft (0.3 to 0.8)

Turboprop
 20 to 25% of Thrust produced by Nozzle
 75 to 80% of Thrust produced by Propeller
 Subsonic Aircraft (0.1 to 0.8)

Turbo Shaft
 High pressure turbine is used to
rotate HP & LP Compressor
 Low pressure turbine is used to
rotate output Shaft
 No Thrust produced in the exit
turbine gas

Turbo Shaft
 Kinetic energy is converted to Shaft power
 100% Thrust produced by Shaft
 High speed Subsonic helicopter (0.3 to 0.8)

Pulse Jet
 Made up of few moving parts
 Valved engines use a mechanical valve to control the flow of expanding exhaust,
forcing the hot gas to go out the back of the engine through the tailpipe
 Starting the engine usually requires forced air and an ignition method such as a
spark plug for the fuel-air mix.
 It can operate statically

Rocket Engines
 A rocket is a machine that develops thrust by the rapid expulsion of matter
 A rocket is called a launch vehicle when it is used to launch a satellite or other
payload into space
 Rocket engines are reaction engines
 The highest exhaust velocities
 It is used in missile

Passenger airplanes
Sl. No. Description Less Moderate High
1 Specific fuel consumption Turbofan Turboprop Turbojet
2 Noise Level Turbofan Turboprop Turbojet
3 Operating Mach No Turboprop Turbofan Turbojet
4 Take off Thrust Turbojet Turbofan Turboprop
5 Altitude Turboprop Turbofan Turbojet
6 Load Carrying capacity Turbojet Turboprop Turbofan
7 Specific Impulse Turbojet Turboprop Turbofan

Thrust Equation
Total Thrust = Momentum Thrust + Pressure Thrust
 mi=mj (mass flow rate)
 Inlet pressure = Exit pressure
 Thrust force is the forward motion of engine

Factors Affecting Thrust
 PRESSURE
 TEMPERATURE
 DENSITY
 HUMIDITY
 ALTITUDE
 FORWARD VELOCITY

Methods of Thrust Augmentation
 After burning
 High thrust for short duration
 It is used only in take-off (or) for high climbing rates
 Additional fuel is burning in the tail pipe between the turbine and exhaust
nozzle
 It is increased the jet velocity
 Oxidizer-Fuel Mixture
 Increase the mass flow rate
 Evaporative cooling which produces higher pressure and higher mass flow rate
 Increase the compressor pressure ratio due to reduced compressor air flow
 Water and menthol or alcohol Mixture

Oxidizer-Fuel Mixture
 Evaporative cooling which produces higher pressure and higher
mass flow rate

Advantages of Gas turbine Engines
• Weight reduction of 70%
• Simplicity
• Reduced manning requirements
• Quicker response time
• Faster Acceleration/deceleration
• Modular replacement
• Less vibrations
• More economical

Disadvantages of Gas Turbine Engines
• Many parts under high stress
• High pitched noise
• Needs large quantities of air
• Large quantities of hot exhaust (target)
• Cannot be repaired in place

ppt_Aero_3sem_EOA.ppt

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