Working of Jet-engines
Parts of the jet engine
A Jet engine moves a plane by Jet Force. And this Jet Force is proportional to the velocity of hot combusted gas blasted out from the back of the engine. A simple jet engine has four main parts. These are low-pressure compressor, high-pressure compressor, combustion chamber, and turbine.
Working principle of a jet engine
First of all, the jet engine works with the synchronization of all its parts and mechanism. At first, the low-pressure compressor blade soaks the air from the front of the engine and compress it a little bit. Certainly it increase the air pressure and temperature, now the high-pressure compressor compresses the air even more which increase further pressure and temperature. Thus the incoming air gets the optimum pressure and temperature. That is required for the perfect combustion of kerosene.
At first Combustion
Another requirement is necessary to the air before it enters into the combustion chamber. It has a high velocity which is not suitable for the combustion of fuel. This will extinguish the fuel so an angle shaped pipe or a diffuser is used to slow down the air. Only 20% of this year goes inside the combustion chamber to help the combustion of fuel and remaining 80% air goes by the outer layer of the combustion chamber because its purpose is to cool down the combustion chamber.
Inside a combustion chamber, electrical igniter lights up and nozzle spreads the fuel and the continuous combustion process began. Therefore the temperature touches up to over 1200 degree Celsius, that would be able to melt down the metal. These combustion chambers have many tiny holes. And the 80% air that goes by the outer wall of the chamber get inside through these holes and make a cushion of cold air to prevent it from meltdown.
At last Ejection of Pressurised super Hot Gas
After an efficient combustion of the fuel and air the hot gas mixture expanded at a high level and blasted out through the back of an engine. But before ejection from jet engine the expanded air and gas mixture goes through a set of blades called turbine for giving some force to the turbine to rotate. These turbines are also connected with the compressor blades at the front of the engine with a shaft. Thus when the turbines rotate it also make compressor to revolve. These are the basis of a jet engine and this types of jet engines are called Turbojet.
The turbojet is not fuel efficient and very noisy. The turbojet is mainly used in the military for high speed, some Turbojet has also after-burner. In a turbo-jet with after-burner, some more fuel is injected into the exhaust gases back through the jet engine for more power so it is much more fuel consumptive.
The type of jet engine which is revolutionizing commercial plane is the turbo-fan engine. In this type of engine, a big fan is added in front of the compressor and less than 1/5 th of air goes through the engine core for combustion and 4/5 th of air just bypass to backwards. Turbofan engine generates most of its thrust from the bypass air, so this type of engine is highly efficient. Therefore, most of the modern day passenger aircraft use this type of engine.
The next is a turboprop engine, it is likely a turbo-fan engine, the difference is that instead of a fan in front of engine it uses a propeller and most of the power comes by the propeller, not through exhaust gases.
Now we have Ramjet, it has no moving parts in it. It is just like hollow can, designed with inlet diffuser and have flame holder where atomize fuel spreads for combustion. And this is the way of combustion in a Ramjet. It works only at very high speed over 2.5 Mach. Consequently, it is also very inefficient in fuel consumption.
At last, we have a Scramjet. This type engine called scramjet because it produces a loud noise like screaming. Also it is very similar to ram-jet, but instead of inlet diffuser it is designed to make compression on supersonic incoming air and the remaining process is likewise ramjet, this also works over 2.5 Mach speed and due to this is also very inefficient in fuel consumption.
Another thing to say if you like this article, please comment below.
How Jet Engine Works Video
Also Read > How big is our Universe.