Reactive means movement in which one of its parts is separated from the body at a certain speed. The force resulting from such a process acts on its own. In other words, she does not even have the slightest contact with external bodies.
Jet movement in nature
During a summer vacation in the south, almost each of us, swimming in the sea, met with jellyfish. But few people thought that these animals move in the same way as a jet engine. The principle of operation in nature of such an aggregate can be observed when moving some types of marine plankton and dragonfly larvae. Moreover, the efficiency of these invertebrates is often higher than that of technical means.
Who else can clearly demonstrate what a jet engine has in principle? Squid, octopus and cuttlefish. A similar movement is made by many other marine mollusks. Take, for example, cuttlefish. She draws water into her gill cavity and vigorously throws it through a funnel, which directs back or sideways. At the same time, the mollusk is capable of making movements in the right direction.
The principle of operation of a jet engine can be observed when moving the seals. This marine animal takes water into a wide cavity. After that, the muscles of his body contract, pushing the fluid through the hole located at the back. The reaction of the jet thus obtained allows the salsa to move forward.
Sea rockets
But squid did achieve the greatest perfection in jet navigation. Even the form of the rocket itself seems to be copied from this marine inhabitant. When moving at low speed, the squid periodically bends its diamond-shaped fin. But for a quick throw he has to use his own "jet engine". The principle of operation of all his muscles and body is worth considering in more detail.
Squids have a kind of mantle. This is the muscle tissue that surrounds his body on all sides. During movement, the animal sucks a large volume of water into this mantle, abruptly throwing a stream through a special narrow nozzle. Such actions allow squids to jerk back at speeds up to seventy kilometers per hour. During the movement, the animal collects all its ten tentacles into a bundle, which gives the body a streamlined shape. The nozzle has a special valve. The animal turns it with the help of muscle contraction. This allows the marine life to change direction. The role of the helm during the movements of the squid is played by its tentacles. He directs them left or right, up or down, easily dodging collisions with various obstacles.
There is a type of squid (stenotevtis), which belongs to the title of the best pilot among mollusks. Describe the principle of the jet engine - and you will understand why, chasing fish, this animal sometimes jumps out of the water, even on the decks of ships traveling across the ocean. How does this happen? The squid pilot, being in the water element, develops maximum reactive thrust for him. This allows him to fly over the waves at a distance of up to fifty meters.
If we consider a jet engine, the principle of operation of which animal can be mentioned yet? These are, at first glance, baggy octopuses. Swimmers from them are not as fast as squids, but in case of danger of their speed even the best sprinters can envy. Biologists who studied the migration of octopuses have found that they move like the principle of a jet engine.
The animal with each stream of water thrown out of the funnel makes a spurt of two or even two and a half meters. At the same time, the octopus swims in a peculiar way - back to front.
Other examples of jet propulsion
There are rockets in the plant world. The principle of a jet engine can be observed when even with a very light touch, the "mad cucumber" bounces off the stem at high speed, while tearing away the sticky liquid with seeds. In this case, the fetus itself flies a considerable distance (up to 12 m) in the opposite direction.
The principle of the jet engine can also be observed while in the boat. If heavy stones are thrown from it into the water in a certain direction, then the movement will begin in the opposite direction. The rocket engine has the same operating principle. Only there, instead of stones, gases are used. They create a reactive force that provides movement in the air and in the discharged space.
Fantastic travel
Mankind has long dreamed of flying into space. This is evidenced by the works of science fiction writers, who proposed a wide variety of means to achieve this goal. For example, the hero of the story of the French writer Hercule Savignen Cyrano de Bergerac reached the Moon on an iron wagon, over which a strong magnet was constantly thrown. The famous Munchausen reached the same planet. A giant bean stalk helped him travel.
The jet movement was used in China in the first millennium BC. At the same time, bamboo tubes that started with gunpowder served as original rockets for fun. By the way, the project of the first car on our planet, created by Newton, was also with a jet engine.
History of RD
Only in the 19th century. mankind's dream of space began to take on specific features. Indeed, it was in this century that the Russian revolutionary N.I. Kibalchich created the world's first jet-powered aircraft project. All the papers were compiled by the Volunteer in prison, where he ended up after the assassination attempt on Alexander. But, unfortunately, on 03.04.1881, Kibalchich was executed, and his idea did not find practical implementation.
At the beginning of the 20th century. The idea of using rockets for space flights was put forward by the Russian scientist K. E. Tsiolkovsky. For the first time his work, containing a description of the motion of a body of variable mass in the form of a mathematical equation, was published in 1903. Later, the scientist developed the very scheme of a jet engine driven by liquid fuel.
Tsiolkovsky also invented a multi-stage rocket and expressed the idea of creating real space cities in near-Earth orbit. Tsiolkovsky convincingly proved that the only means for space flight is a rocket. That is, a device equipped with a jet engine, fueled with fuel and oxidizer. Only such a rocket can overcome gravity and fly outside the Earth’s atmosphere.
Space exploration
An article by Tsiolkovsky, published in the periodical publication Scientific Review, confirmed the reputation of a dreamer for the scientist. Nobody took his arguments seriously.
The idea of Tsiolkovsky was realized by Soviet scientists. Led by Sergei Pavlovich Korolev, they launched the first artificial Earth satellite. On October 4, 1957, this vehicle delivered a rocket with a jet engine into orbit. The work of RD was based on the conversion of chemical energy, which is transferred by the fuel to a gas stream, turning into kinetic energy. In this case, the rocket makes a movement in the opposite direction.
A jet engine, the principle of operation of which has been used for many years, finds its application not only in space, but also in aviation. But most of all it is used to launch missiles. After all, only a taxiway is capable of moving the device in a space in which any medium is absent.
Liquid jet engine
Anyone who shot from a firearm or simply watched this process from the side knows that there is a force that will certainly push the barrel back. Moreover, with a larger amount of charge, the return will certainly increase. A jet engine also works. Its principle of operation is similar to how the barrel is pushed back under the influence of a stream of hot gases.
As for the rocket, in it the process during which the mixture ignites is gradual and continuous. This is the simplest, solid fuel engine. He is well known to all rocket-modellers.
In a liquid propellant engine (LRE), a mixture of fuel and an oxidizing agent is used to create a working fluid or a pushing jet. The last, as a rule, is nitric acid or liquid oxygen. The fuel in the rocket engine is kerosene.
The principle of operation of the jet engine, which was in the first samples, has been preserved to this day. Only now it uses liquid hydrogen. When this substance is oxidized, the specific impulse increases immediately by 30% compared with the first LRE. It is worth saying that the idea of using hydrogen was proposed by Tsiolkovsky himself. However, the difficulties of working with this extremely explosive substance at that time were simply insurmountable.
What is the operating principle of a jet engine? Fuel and oxidizing agent enter the working chamber from separate tanks. Next, the components are converted into a mixture. It burns out, emitting a colossal amount of heat under pressure of tens of atmospheres.
Components in the working chamber of a jet engine fall in different ways. The oxidizing agent is introduced directly here. But the fuel goes a longer way between the walls of the chamber and the nozzle. Here it warms up and, already having a high temperature, is thrown into the combustion zone through numerous nozzles. Further, the jet formed by the nozzle breaks out and provides the aircraft with a pushing moment. So you can tell what the jet engine has the principle of work (briefly). In this description, many components are not mentioned, without which the operation of the rocket engine would be impossible. Among them are the compressors necessary to create the pressure necessary for the injection, valves, feed turbines, etc.
Modern use
Despite the fact that the operation of a jet engine requires a large amount of fuel, LRE continue to serve people today. They are used as the main marching engines in launch vehicles, as well as shunting for various spacecraft and orbital stations. In aviation, other types of taxiways are used, which have slightly different performance characteristics and design.
Aviation development
From the beginning of the 20th century, until the time when the Second World War broke out, people flew only on propeller-driven aircraft. These devices were equipped with internal combustion engines. However, progress did not stand still. With its development, there was a need for more powerful and faster aircraft. However, here aviation designers faced a seemingly insoluble problem. The fact is that even with a slight increase in engine power , the mass of the aircraft increased significantly. However, the way out of this situation was found by the Englishman Frank Will. He created a fundamentally new engine called the jet. This invention gave a powerful impetus to the development of aviation.
The principle of operation of an aircraft jet engine is similar to that of a fire hose. Its hose has a tapered end. Leaking through a narrow hole, water significantly increases its speed. The back pressure force created by this is so strong that the firefighter hardly holds the hose in his hands. This behavior of water can also explain what the principle of the jet engine of an airplane is.
Direct-flow taxiways
This type of jet engine is the simplest. You can imagine it in the form of a pipe with open ends, which is mounted on a moving airplane. At the front, its cross section expands. Thanks to this design, the incoming air reduces its speed, and its pressure increases. The widest place of such a pipe is a combustion chamber. Here, fuel is injected and burned further. This process contributes to the heating of the resulting gases and their strong expansion. In this case, thrust of the jet engine occurs. All the same gases produce it when they forcefully break out from the narrow end of the pipe. It is this thrust that makes the plane fly.
Use problems
Ram engines have some drawbacks. They are able to work only on the plane that is in motion. The aircraft, which is at rest, direct-flow taxiways cannot be powered. In order to take such an aircraft into the air, any other starting engine is needed.
Solution
The principle of operation of a jet engine of a turbojet type aircraft, which is devoid of the disadvantages of a direct-flow taxiway, allowed aviation designers to create the most advanced aircraft. How does this invention work?
The main element located in a turbojet engine is a gas turbine. With its help, an air compressor is driven, passing through which, compressed air is sent to a special chamber. The products resulting from the combustion of fuel (usually kerosene) fall on the turbine blades, thereby driving it. Further, the air-gas flow passes into the nozzle, where it accelerates to high speeds and creates a huge reactive thrust.
Power increase
Reactive traction can increase significantly in a short period of time. Afterburning is used for this. It is the injection of an additional amount of fuel into a gas stream escaping from a turbine. Oxygen not used in the turbine contributes to the combustion of kerosene, which increases the thrust of the engine. At high speeds, the increase in its value reaches 70%, and at low - 25-30%.