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HISTORY OF TECHNOLOGY, TECHNOLOGY, OBJECTS AROUND US
Jet engine. History of invention and production
Directory / The history of technology, technology, objects around us A jet engine is an engine that creates the traction force necessary for movement by converting the internal energy of the fuel into the kinetic energy of the jet stream of the working fluid. The working fluid flows out of the engine at high speed, and, in accordance with the law of conservation of momentum, a reactive force is formed that pushes the engine in the opposite direction. To accelerate the working fluid, both the expansion of a gas heated in one way or another to a high thermal temperature (the so-called thermal jet engines) and other physical principles, for example, the acceleration of charged particles in an electrostatic field (see ion engine), can be used. A jet engine combines the engine itself with a propeller, that is, it creates traction only through interaction with the working fluid, without support or contact with other bodies. For this reason, it is most commonly used to propel aircraft, rockets, and spacecraft.
In a jet engine, the thrust force necessary for movement is created by converting the initial energy into the kinetic energy of the working fluid. As a result of the expiration of the working fluid from the engine nozzle, a reactive force is formed in the form of recoil (jet). The recoil moves the engine and the device structurally connected with it in space. The movement occurs in the direction opposite to the outflow of the jet. Various types of energy can be converted into the kinetic energy of a jet stream: chemical, nuclear, electrical, solar. The jet engine provides its own movement without the participation of intermediate mechanisms. To create jet thrust, a source of initial energy is needed, which is converted into the kinetic energy of a jet stream, a working fluid ejected from the engine in the form of a jet stream, and the jet engine itself, which converts the first type of energy into the second. The main part of a jet engine is the combustion chamber, in which the working fluid is created. All jet engines are divided into two main classes, depending on whether they use the environment in their work or not. The first class is jet engines (WFD). All of them are thermal, in which the working fluid is formed during the oxidation reaction of a combustible substance with oxygen from the surrounding air. The main mass of the working fluid is atmospheric air. In a rocket engine, all components of the working fluid are on board the apparatus equipped with it. There are also combined engines that combine both of the above types. For the first time, jet propulsion was used in Heron's ball - the prototype of a steam turbine. Solid fuel jet engines appeared in China in the XNUMXth century. n. e. Such rockets were used in the East, and then in Europe for fireworks, signaling, and then as combat ones. An important stage in the development of the idea of jet propulsion was the idea of using a rocket as an engine for an aircraft. It was first formulated by the Russian revolutionary N. I. Kibalchich, who in March 1881, shortly before his execution, proposed a scheme for an aircraft (rocket plane) using jet thrust from explosive powder gases. N. E. Zhukovsky in his works "On the reaction of outflowing and inflowing fluid" (1880s) and "On the theory of ships set in motion by the reaction force of outflowing water" (1908) first developed the main issues of the theory of a jet engine. Interesting work on the study of rocket flight also belongs to the famous Russian scientist I. V. Meshchersky, in particular in the field of the general theory of the motion of bodies of variable mass. In 1903, K. E. Tsiolkovsky, in his work "Investigation of the World Spaces with Reactive Devices", gave a theoretical justification for the flight of a rocket, as well as a schematic diagram of a rocket engine, which anticipated many of the fundamental and design features of modern liquid-propellant rocket engines (LRE). So, Tsiolkovsky provided for the use of liquid fuel for a jet engine and its supply to the engine with special pumps. He proposed to control the flight of the rocket by means of gas rudders - special plates placed in a jet of gases emitted from the nozzle. A feature of a liquid-propellant engine is that, unlike other jet engines, it carries with it the entire supply of oxidizer along with the fuel, and does not take the oxygen-containing air necessary for burning fuel from the atmosphere. This is the only engine that can be used for ultra-high-altitude flight outside the earth's atmosphere. The world's first rocket with a liquid-propellant rocket engine was created and launched on March 16, 1926 by the American R. Goddard. It weighed about 5 kilograms, and its length reached 3 m. Goddard's rocket was fueled by gasoline and liquid oxygen. The flight of this rocket lasted 2,5 seconds, during which it flew 56 m. Systematic experimental work on these engines began in the 30s of the XX century. The first Soviet rocket engines were developed and created in 1930-1931. in the Leningrad Gas Dynamic Laboratory (GDL) under the guidance of the future academician V.P. Glushko. This series was called ORM - an experienced rocket motor. Glushko applied some novelties, for example, cooling the engine with one of the fuel components. In parallel, the development of rocket engines was carried out in Moscow by the Jet Propulsion Study Group (GIRD). Its ideological inspirer was F.A. Zander, and the organizer was the young S.P. Korolev. Korolev's goal was to build a new rocket apparatus - a rocket plane. In 1933, F.A. Zander built and successfully tested the OR1 rocket engine, which ran on gasoline and compressed air, and in 1932-1933. - engine OP2, on gasoline and liquid oxygen. This engine was designed to be installed on a glider that was supposed to fly as a rocket plane. In 1933, the first Soviet liquid-fuel rocket was created and tested at GIRD. Developing the work begun, Soviet engineers subsequently continued to work on the creation of liquid-propellant jet engines. In total, from 1932 to 1941, 118 designs of liquid-propellant jet engines were developed in the USSR. In Germany in 1931, rockets were tested by I. Winkler, Riedel, and others. The first flight on a rocket-propelled aircraft with a liquid-propellant engine was made in the Soviet Union in February 1940. An LRE was used as the power plant of the aircraft. In 1941, under the leadership of the Soviet designer VF Bolkhovitinov, the first jet fighter aircraft with a liquid-propellant engine was built. His tests were carried out in May 1942 by pilot G. Ya. Bakhchivadzhi. At the same time, the first flight of a German fighter with such an engine took place. In 1943, the United States tested the first American jet aircraft, on which a liquid-propellant engine was installed. In Germany, in 1944, several fighters with these Messerschmitt-designed engines were built and in the same year they were used in a combat situation on the Western Front. In addition, liquid propellant rocket engines were used on German V2 rockets, created under the direction of W. von Braun. In the 1950s, liquid rocket engines were installed on ballistic missiles, and then on artificial satellites of the Earth, the Sun, the Moon and Mars, automatic interplanetary stations. The rocket engine consists of a combustion chamber with a nozzle, a turbopump unit, a gas generator or a steam-gas generator, an automation system, control elements, an ignition system and auxiliary units (heat exchangers, mixers, drives). The idea of jet engines has been put forward more than once in different countries. The most important and original works in this respect are the studies carried out in 1908-1913. French scientist R. Loren, who, in particular, in 1911 proposed a number of schemes for ramjet engines. These engines use atmospheric air as an oxidizer, and the air in the combustion chamber is compressed by dynamic air pressure. In May 1939, the first test of a rocket with a ramjet engine designed by P. A. Merkulov took place in the USSR. It was a two-stage rocket (the first stage was a powder rocket) with a take-off weight of 7,07 kg, and the fuel weight for the second stage of the ramjet engine was only 2 kg. During the test, the rocket reached a height of 2 km. In 1939-1940. for the first time in the world in the Soviet Union, summer tests of jet engines installed as additional engines on an aircraft designed by N.P. Polikarpov were carried out. In 1942, ramjet engines designed by E. Senger were tested in Germany. The jet engine consists of a diffuser in which air is compressed due to the kinetic energy of the oncoming air flow. Fuel is injected into the combustion chamber through the nozzle and the mixture ignites. The jet stream exits through the nozzle. The operation of the WFD is continuous, so there is no starting thrust in them. In this regard, at flight speeds less than half the speed of sound, jet engines are not used. The use of WFD is most effective at supersonic speeds and high altitudes. The takeoff of an aircraft with a jet engine is carried out using solid or liquid propellant rocket engines. Another group of jet engines, turbocompressor engines, received more development. They are divided into turbojet, in which thrust is created by a jet of gases flowing from a jet nozzle, and turboprop, in which the main thrust is created by a propeller. In 1909, the design of a turbojet engine was developed by engineer N. Gerasimov. In 1914, Lieutenant of the Russian Navy M.N. Nikolskoy designed and built a model of a turboprop aircraft engine. The gaseous combustion products of a mixture of turpentine and nitric acid served as the working fluid for driving the three-stage turbine. The turbine worked not only on the propeller: the exhaust gaseous products of combustion, directed to the tail (jet) nozzle, created jet thrust in addition to the thrust force of the propeller. In 1924, V. I. Bazarov developed the design of an aircraft turbocompressor jet engine, which consisted of three elements: a combustion chamber, a gas turbine, and a compressor. For the first time, the compressed air flow here was divided into two branches: the smaller part went into the combustion chamber (to the burner), and the larger part was mixed with the working gases to lower their temperature in front of the turbine. This ensured the safety of the turbine blades. The power of the multistage turbine was used to drive the centrifugal compressor of the engine itself and partly to rotate the propeller. In addition to the propeller, thrust was created by the reaction of a jet of gases passed through the tail nozzle. In 1939, the construction of turbojet engines designed by A. M. Lyulka began at the Kirov Plant in Leningrad. His trials were interrupted by the war. In 1941, in England, the first flight was made on an experimental fighter aircraft equipped with a turbojet engine designed by F. Whittle. It was equipped with a gas turbine engine that drove a centrifugal compressor that supplied air to the combustion chamber. Combustion products were used to create jet thrust.
In a turbojet engine, air entering during flight is compressed first in the air intake and then in the turbocharger. Compressed air is fed into the combustion chamber, where liquid fuel (most often aviation kerosene) is injected. Partial expansion of the gases formed during combustion occurs in the turbine that rotates the compressor, and the final expansion occurs in the jet nozzle. An afterburner can be installed between the turbine and the jet engine, designed for additional combustion of fuel. Today, most military and civil aircraft, as well as some helicopters, are equipped with turbojet engines. In a turboprop engine, the main thrust is created by a propeller, and additional (about 10%) - by a jet of gases flowing from a jet nozzle. The principle of operation of a turboprop engine is similar to a turbojet engine, with the difference that the turbine rotates not only the compressor, but also the propeller. These engines are used in subsonic aircraft and helicopters, as well as for the movement of high-speed ships and cars. The earliest solid propellant jet engines were used in combat missiles. Their widespread use began in the XNUMXth century, when missile units appeared in many armies. At the end of the XIX century. the first smokeless powders were created, with more stable combustion and greater efficiency. In the 1920s-1930s, work was underway to create jet weapons. This led to the appearance of rocket launchers - "Katyusha" in the Soviet Union, six-barreled rocket mortars in Germany. Obtaining new types of gunpowder made it possible to use solid-propellant jet engines in combat missiles, including ballistic ones. In addition, they are used in aviation and astronautics as engines of the first stages of launch vehicles, starting engines for aircraft with ramjet engines and brake engines for spacecraft. A solid propellant jet engine consists of a body (combustion chamber) in which the entire supply of fuel and a jet nozzle are located. The body is made of steel or fiberglass. Nozzle - made of graphite, refractory alloys, graphite. The fuel is ignited by an igniter. Thrust is controlled by changing the combustion surface of the charge or the area of the critical section of the nozzle, as well as by injecting liquid into the combustion chamber. The direction of thrust can be changed by gas rudders, a deflecting nozzle (deflector), auxiliary control engines, etc. Jet solid propellant engines are very reliable, can be stored for a long time, and therefore, are constantly ready for launch. Author: Pristinsky V.L.
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