View this article in RussianThe heat engine is a device that performs work by converting internal energy into mechanical energy. According to the method for supplying heat to the working fluid heat engines share: 1) external combustion engines, such class of engines in which the working fluid is separated from the combustion process; 2) internal combustion engines, this engine class, in which the supply of heat to the working fluid is carried out by combustion of fuel inside the engine.
Engine is a mechanism which converts energy of combustion into mechanical work. The engines may use different types of energy sources, such as electric, electrostatic, chemical, nuclear, gravity, pneumatic, hydraulic, laser.
An internal combustion engine include: the piston engine, gas turbine, rotary piston engine, a liquid-jet engine, jet engine. The piston engine includes a housing, two mechanisms (crank and gas distribution), through which the heat energy is transformed into mechanical energy, as well as several systems: the intake, fuel, ignition, lubrication, cooling, exhaust and control system. Powered piston engine on diesel fuel and gasoline.
The disadvantages of this engine include: the exhaust gases are very toxic, low life of the engine, a low coefficient of performance (COP), a high level of noise. The advantage is its widespread use and versatility, low cost, low weight, compact size, the ability to run the engine as soon as possible.
Gas turbine: the turbine engine component that converts the potential energy of the heated working fluid under pressure into mechanical work. The gas turbine consists of basic elements such as the rotor and stator.The turbine engine has significant drawbacks: a very high level of noise at high temperatures has a short service life, the cost is much higher than that of similar size piston engines. The advantages of the engine are: quick set power after starting the turbine, ease of maintenance, cooling requires a small amount of water.
The rotary-piston engine was developed in 1957 as an engineer company NSU Walter Freude, co-authored with Felix Wankel, was working on another engine design. The rotary-piston engine conversion of energy is due to the rotation of the rotor special profile working gases.
The disadvantages of the rotary-piston engine are: low environmental friendliness, high fuel consumption, complexity, maintenance, high consumption of engine oil, high tendency to overheat (compared to a piston engine), complex manufacturing, high geometrical requirements due to the manufacturing accuracy of parts. The advantage of the rotary-piston engine (before the piston engine) is: a higher coefficient of performance (COP), very low vibration, due to the fact that the motor is fully mechanically balanced, smaller dimensions, fewer parts, higher power at low volume combustion chamber.
Liquid-jet engine is a chemical rocket engine, which uses liquid fuel, as well as liquefied gases. Depending on the elements used distinguish one-, two- and three-component liquid-jet engine.The disadvantage of liquid-jet engine is a low coefficient of performance (COP). As the high cost of the use and complexity of the missile on the basis of the engine, the difficulty of transporting fuel, labor-intensive technology training missiles for launch, uncontrolled movement of the components of the liquid fuel in the weightlessness (requires additional measures, in the form of inclusion of auxiliary engines, working on the basis of solid fuel or gas ). Advantages of the liquid-jet engine – this is the highest level of specific impulse in a class of chemical rocket engines. The ability to adjust the fuel flow, the ability to work in a vacuum, and as there is no need for a special oxidizer that is part of the on-board fuel capacity. When using a liquid-jet engine, compared with the solid propellant in large rockets is possible to achieve weight advantages.
Jet engine – a thermal jet engine, which heated by a mixture of air and combustion products of fuel with oxygen is used as the working fluid. The acceleration due to an increase of pressure due to the heating of the fuel oxidation by oxygen.The disadvantages of the use of the engine is a height restriction of use. The advantage is that you can significantly increase the speed of flight, for each type of jet engine has its own speed limit of the flight, there is no need for a special oxidizer that is part of the on-board fuel supply, as well advantage is its simplicity and high reliability.
As a result of the analysis applications of internal combustion engines, the following conclusions:
The piston engine is widely distributed and used in machine building, aviation, shipbuilding, as has the main essential for these industries, the benefits as relatively low weight and compact size, the ability to run the engine as soon as possible.
Gas turbines have become widespread in transport, are used in stationary gas turbines, combined cycle power plants and gas turbine engines, due to the fact that the engine should be easy to maintain, and also that there is a rapid set of power immediately after starting the engine.
The rotary-piston engine in demand in the industry, because it has a high coefficient of performance (COP), very low vibration.
Liquid-jet engine used in launch vehicles, propulsion of spacecraft, as it has the highest level of the specific impulse in a class of chemical rocket engines, as an important feature is that the engine has the ability to work in a vacuum.
Jet engines used in aircraft designed to fly in the atmosphere (surface-to-air missile, unmanned reconnaissance flying targets) because the engine is simple and inexpensive, as well as sufficiently reliable.
Thus, the heat engine is a device that performs work by converting internal energy into mechanical energy, separated two types of engines: internal combustion engines and external combustion engines. For internal combustion engines are: piston engine, gas turbine, rotary piston engine, a liquid-jet engine, jet engine.
Summing up the analysis of the application of internal combustion engines has been revealed that the engines have been applied in various industries due to its characteristic features. The piston engine is widely distributed and used in mechanical engineering, aircraft construction. Gas turbines have become widespread in transport, are used in stationary gas turbines , combined cycle gas turbines , and gas turbine engines. The rotary-piston engine in demand in the aviation industry. Liquid-jet engine used in launch vehicles, spacecraft propulsion. Jet engines used in aircraft designed to fly in the atmosphere.
References
- Герасимов В.Г., Орлов И.Н., Филиппов Л.И. От знаний — к творчеству. М.: Изд-во МЭИ, 1995.
- http://www.ai08.org/
- Двигатели внутреннего сгорания: Устройство и работа поршневых и комбинированных двигателей./ Учебник для студентов вузов/ под ред. А. С. Орлина, М. Г. Круглова.3-е изд., перераб. и доп. М.: Машиностроение, 1980.
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