Thermodynamic operation and air systems

Engine operation
The turbojet engine belongs to the heat-engine group. Its energy source is fuel which ,mixed with a combustive (air oxygen) and by means of combustion gives under thermal form the energy which is contained in it under chemical form.
In piston engines ,thermal energy given to certain air amount is taken on mechanical form to a shaft. In a turbojet engine, this energy serves to increase the speed of the air passing through it .
The air leaves the engine at a grater velocity than that at the intake and develops a thrust which moves the aircraft forward.
So that the engine may operate efficiently, combustion must take place under a given compression ratio. Compression is provided by a compressor which can operate under varying relative engine conditions (different altitudes and airspeed) and is driven by a turbine absorbing the necessary energy from the gases leaving the combustion chamber.
The remaining energy is transformed into kinetic energy in the nozzle.
Operationally the propulsion unit of a turbojet engine comprises:
- an air intake duct
an turbojet engine.-
technically the components of the engine are :
1) intake casing
2) compressor
3) central casing
4)combustion chamber
5) turbine
6) afterburner jet pipe
7) nozzle
the first six components constitute a compressed-air generator.
The nozzle accelerates the flow of compressed and heated gases at the velocity of which determines the thrust of the turbojet engine.