THE BASIC THEORY AND PRINCIPLE OF THE GAS TURBINE ENGINES.
The jet engine was invented by Frank Whittle in 1937. It was not until
1939, however, when it was first used to power a working airplane, in
Germany.Flightpaths explains the course of jet engine advancement, from
the early small and inefficient piston engines, through each
revolutionary innovation, to the present day monsters that power the
jumbos and super jumbos like the Airbus A380.The latest jet engines are
over 17,000% more reliable than the first jet engines .
The gas turbine engines which most of the modern aircrafts are using are mainly of two classes.
a)The Turbo-jet engines.
b)The Turbo-prop engines.
c)The Turbo-fan engines.The
Basic difference between the turbo-jet, the turbo-prop ,and the
turbo-fan engines is that the turbo-prop will have a propeller in front
and the turbo fan will have a fan in front.The propeller helps in
accelerating a relatively large mass of air rearwards at comparatively
low speed.It is this reaction to the rate of change of momentum of the
mass of air that propels the aircraft in a piston engine.But in a
Turbo-prop it also helps in compressing the air mass which is entering
the jet inlet.With this already compressed air is entering the inlet
which will increase the performance of the turbo-prop engine.Now
let us know about the working of the Gas Turbine Engine.
This engine
operates in four stages which are almost similar to the stages of the
piston engine.The induction stage, compression stage, ignition stage,
and exhaust stage.Every jet engine has three main parts, the
Compressor, Combustion Chamber, and Turbines. Air from the intake is
fed through a rotating compressor stage, where a series of fan blades
reduces the air volume while increasing the pressure. The pressure may
increase by as much as 30 times. This compressed air flows into the
combustion chamber, where fuel is being continuously injected. The
resulting combustion creates a flow of hot, expanding gases. These
gases flow over a turbine with a set of fan blades. Since the turbine
is connected to the compressor by an axle, part of the power of the
exhaust gases is used to drive the compressor. The shaft may be used to
drive a machine or generate electricity. For some engines, there may be
a free wheeling turbine stage on its own coaxial shaft, driving a
front-mounted fan (turbofan) or propeller (turboprop) which are
mentioned above.