Gas Turbine Engine - How It Works!!


Gas Turbine Engine - How It Works!!



In this blog we will understand the working principles behind a gas turbine engine. Gas turbines are used mainly for two purposes - first for power production and second for generating thrust force in an aircraft even though functions are different working principle behind each case is the same let us understand how gas turbine engine is used for generating thrust force in an aircraft here is a close look of gas turbine engine of an aircraft in order to make the flight move forward this engine should produce a force and forward direction.


Gas turbine engine image

This force is produced by jet effect of this exit fluid when a high velocity fluid is ejected by the engine it will produce a reaction force which will power the aircraft this force is known as jet force. By applying newton's second law of motion to jet engine controlled volume one can easily find that magnitude of this jet force it is momentum at minus momentum in so if jet velocity is high it means high jet force this is why exit portion of a jet engine has got decreasing area if the flow is subsonic or the exit pushing that slight nozzle which increases jet velocity. 

                                    The million dollar question how to produce such a high velocity jet continuously?? we will produce it by a combustion process by injecting fuel into it which will produce flames with very high velocity but for a sustainable combustion process we need the inlet air to the combustion chamber to be at high temperature and pressure this is achieved with help of diffuser plus compressor arrangement air gets into the engine by forward motion of engine and sucking effective compressor diffuser increases pressure of this fluid to some extent by converting some part of kinetic energy to pressure energy after that compressor comes where both pressure and temperature of the air is raised by energy addition from compressor, so it outlet the compressor we will have air at high pressure and high temperature but compressor requires some power input to do that this power is given by a turbine which is situated right after the combustion chamber the turbine absorbs some amount of energy from the high energy fluid and transmits it to the compressor. There are different Types of gas turbine engines.


jet engines image

Thus, the process of producing high velocity jet at outlet has become self-sustainable we will get continuous supply of high-velocity jet and thrust force to this aircraft thanks to synchronized working of all these components that is the diffuser compressor combustion chamber turbine and nozzles let's see how energy level of fluid changes from inlet gas turbine engine to exit assume this is the inlet point in a temperature entropy diagram which is same as state of surrounding air due to diffuser effect pressure and temperature of the fluid increases slightly entropy remains same assuming this is an adiabatic reversible process next in compresses our stage also same process continues and temperature and pressure rise to a level where combustion process is sustainable now heat addition to the fluid this process happens almost at constant pressure and temperature of the stream raises to very high level right after that turbine will absorb some amount of energy which is required by the compressor so here temperature and pressure of the fluid come down the last section which produces high velocity jet nozzle this is again a constant entropy process where internal energy of the fluid gets converted into kinetic energy.  Gas Turbine Engine - How it Works


single shaft gas turbine

Here pressure of stream expands to the surrounding pressure, it should be noted here that the exit stream never goes back to the inlet condition and inlet it sucks fresh steam of airing so this is an open cycle process, but since both these points are having same pressure we can assume a pseudo constant pressure process like this in order to complete the cycle this cycle is called as bragging cycle. That is all about working of a gas turbine engine.  If You like to understand it in details through video do check out this video below :-


                              Thank you for reading this blog . I hope it increases your knowledge and you are benefited from my article. Thank You!!.

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