Today we will talk about what a jet engine is and what is its significance for modern aviation. From its very appearance on Earth, Man has been directing his gaze to heaven. How incredibly light the birds soar in the warm air! And not only small specimens, but even such large ones as pelicans, cranes and many others. Attempts to imitate them using primitive aircraft based on the muscular strength of the pilot himself, even if they led to a kind of “flight,” all the same, there couldn’t be any talk about mass implementation of the development - the designs were very unreliable, too many restrictions were imposed on the person, using them.
Then came the internal combustion engines and propeller motors. They were so successful that a modern jet engine and a screw-motor (propeller) still coexist in parallel. Of course, having undergone a number of modifications.
How did the jet engine appear?
Most of the technical solutions, the invention of which is attributed to Man, were actually spied on by nature. For example, the creation of a hang glider was preceded by observation of the flight of birds soaring in the sky. The streamlined forms of fish and birds were also brilliantly argued, but within the framework of technical means. A similar story was not spared and jet engine. This principle of movement is used by many marine inhabitants - octopuses, squids, jellyfish, etc. Tsiolkovsky spoke about such an engine. Even more - he theoretically substantiated the possibility of creating an airship for flights in interplanetary space.
Jet propulsion is at the core of rocket engines. And rockets were known in ancient China. We can say that the idea of creating a jet engine "was in the air", it was only necessary to see it and translate it into technology.
Engine structure and principle of operation
At the heart of any jet engine is a chamber with an outlet ending in a tube-bell. The fuel mixture is supplied inside the chamber, ignites there, turning into high-temperature gas. Since its pressure spreads uniformly in all directions, pushing against the walls, gas can leave the chamber only through a bell oriented in the opposite direction to the desired direction of movement. This creates a driving force. The foregoing is easier to understand by example: a man stands on ice, holding a heavy crowbar in his hands. But once he throws the crowbar aside, he will receive an impulse of acceleration and slip on the ice in the opposite direction. The difference in the flight range of the scrap and the displacement of a person is explained only by their mass, the forces themselves are equal, and the vectors are opposite. Drawing an analogy with a jet engine: a person is an aircraft, and scrap is superheated gas from a chamber bell.
For all its simplicity, this scheme has several significant drawbacks - high fuel consumption and huge pressure on the chamber walls. Various solutions are used to reduce consumption: liquefied gas and an oxidizing agent are used as fuel, which, changing their state of aggregation, are more preferable than liquid fuel; another option is an oxidizable powder instead of a liquid.
But the best solution is a ramjet engine. It is a through camera, with input and output (relatively speaking - a cylinder with a bell). When the apparatus moves, the air of the external environment enters the chamber under pressure, heats up and contracts. The supplied fuel mixture ignites and supplies additional temperature to the compressed air . Then it breaks out through the bell and creates an impulse, as in a conventional jet motor. In this scheme, fuel is an auxiliary element; therefore, its costs are significantly lower. This type of engine is used in airplanes, where you can see the blades of a turbine forcing air into the chamber.