Jet Engine - Scientific Principle, Rockets, Ramjets, Turbojets, Turbofan Jets, Afterburners, Turboprop Engines
air breathing gases hot
A jet engine is a heat engine that is propelled in a forward direction as the result of the escape of hot gases from the rear of the engine. Two general types of jet engines exist: the air-breathing jet engine and the rocket. In an air-breathing jet engine, air entering the front of the engine is used to burn a fuel within the engine, producing the hot gases needed for propulsion. In a rocket, air is not needed for propulsion. Instead, some type of chemical, nuclear, or electrical reaction takes place within the rocket engine. Hot gases formed as a result of that reaction exit the engine from the rear, providing the engine with its thrust, or forward momentum. Some authorities reserve the term jet engine for the first of these two types, the air-breathing jet engine. Air-breathing jet engines are used for the fastest commercial and military aircraft now available.
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Rockets can be broadly classified into one of two categories: those that use a chemical reaction as their energy source, and those that use some other kind of energy source. An example of the former are rockets that are powered by the chemical reaction between liquid oxygen and liquid hydrogen. When these two chemicals react with each other, they produce very hot steam (water vapor). The escape of…
The simplest of all jet engines is the ramjet. The ramjet consists of a long cylindrical tube made of metal, open at both ends. The tube bulges in the middle and tapers off at both ends. This shape causes air entering the front of the engine to expand and develop a higher pressure in the center of the engine. Within the engine, the compressed air is used to burn a fuel, usually a kerosene-like mat…
One might guess that one way to improve the efficiency of a jet engine would be to increase the speed at which exhaust gases are expelled from the engine. In fact, that turns out not to be the case. Aeronautical engineers have discovered that a larger mass of gas moving at a lower velocity produces greater thrust in the engine. The modification that was developed to produce this effect is called a…
A jet engine can be made more efficient by the addition of a large fan surrounded by a metal cowling at the front of the engine. The fan is somewhat similar to a propeller except that it has many more blades than a simple propeller. The fan is attached to a shaft that is also powered by the turbine at the rear of the engine. When exhaust gases from the compression chamber cause the turbine to spin…
When jet engines were first introduced in the 1940s, they were not very efficient. In fact, the cost of operating a jet airplane was so great that only military uses could be justified. At the time, commercial airline companies decided to compromise between the well-tested piston engines they were then using and the more powerful, but more expensive, jet engines. The result was the turboprop engin…
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