The turbofan engine is a propulsive mechanism to combine the high thrust of a turbojet with the high efficiency of a propeller. Basically, a turbojet engine forms the core of the turbofan; the core contains the diffuser, compressor, burner, turbine, and nozzle. However, in the turbofan engine, the turbine drives not only the compressor, but also a large fan external to the core. The fan itself is contained in a shroud that is wrapped around the core.

1. PRESENTED BY
SHAMBU S
ROLL NO. 55
MECH
SNIT

2. INTRODUCTION
TURBOFAN
TURBOFAN HISTORY
PARTS OF TURBOFAN
TURBOFAN ENGINE WORKING
ADVANTAGES
DISADVANTAGES
CONCLUSION
REFERENCE

3.  The turbofan or fanjet is a type of air breathing
jet engine that is widely used for aircraft
propulsion.
 The ‘turbo’ portion refers to a gas turbine
engine which takes mechanical energy from
combustion
 The ‘fan’ uses the mechanical energy from the
gas turbine to accelerate air rearwards

4. •Powered by gas turbine
•The combination of thrust
produced from the fan &
the exhaust from the core
is more efficient
•Efficient at subsonic speeds
•Used in commercial jet
aircraft

5.  In early jet engines, high velocity jet exhaust
mixing with surrounding air is major source of
noise
 In 1960’s, low-bypass-ratio turbofans
introduced
 In 1967, NASA initiates acoustically treated
nacelle program
 Engine ducts and inlets are lined with acoustic
treatments

6.  Flight tested on Boeing 707 and DC-8
 Acoustic treatment proven effective and feasible
 Even greater jet noise reduction is achieved
 With further reduction of jet noise, fan noise
becomes major noise source
 German Daimler-Benz, the very first turbofan
tested on April 1,1943
 Improved materials and twin compressors in the
Pratt & Whitney JT3C engine

7. German Daimler-Benz DB605

8. A. LOW PRESSURE SPOOL
B. HIGH PRESSURE SPOOL
C. STATIONARY COMPONENTS
1. NACELLE
2. FAN
3. LOW PRESSURE COMPRESSOR
4. HIGH PRESSURE COMPRESSOR
5. COMBUSTION CHAMBER
6. HIGH PRESSURE TURBINE
7. LOW PRESSURE TURBINE
8. CORE NOZZLE
9. FAN NOZZLE

9. The incoming air is captured by the inlet
 The incoming air is compressed by the
compressor
 In the combustion chamber, the
Compressed air is mixed with fuel and
then ignited

11.  The hot exhaust gases passes through the Core,
fan turbines & then out of the
nozzle
 A turbofan gets thrust from both fan & the core
 The ratio of air that goes around the engine & To
the air that goes through the core is called
BYPASS RATIO

13.  Since a fan is used, more amount of air is
sucked into the engine providing more thrust.
 The fan is enclosed by the cowling and is thus
protected and its aerodynamics can be easily
controlled.
 Due to presence of fan, the fuel consumption
is increased only a little , the turbofan produces
more thrust for same amount of fuel and is thus
fuel efficient.

14.  It is the most efficient at subsonic speeds only.
 It has a greater complexity due to addition of
ducts and multiple shafts.
 The engine diameter is increased.

15.  Considering the future applications of turbofan
engine,the most outstanding one is ‘The Geared
Turbofan Concept’
 In a geared turbofan, a (planetary) reduction
gearbox between the fan and the LP shaft allows
the latter to run at a higher rotational speed thus
enabling fewer stages to be used in both the LP
turbine increasing efficiency and reducing weight.

16.  A higher bypass ratio gives a low (actual) exhaust
speed. As a result, the thrust specific fuel
consumption is reduced. A lower bypass ratio
gives high exhaust speed, which is used to sustain
supersonic speeds. Thus, one can conclude that a
high bypass turbofan engine gives lower thrust
specific fuel consumption.
 A high bypass turbofan engine is used at subsonic
speeds because of low exhaust speed it produces.
 Turbofan engines gain better performance
capabilities and better fuel efficiency

17.  Aderson Jr., John D., 1995. McGraw Hill,
nInc.,“Computational Fluid Dynamics: The Basics
with Applications” , New York, USA.
 Ganesan, V., 2010. Ajay Shukla, Tata McGraw
Hill Education Private
 Advanced Control of Turbofan Engines - Hanz
Richter
 Gas Turbines: A Handbook of Air, Land and Sea
Application - Claire Soares