燃气轮机发动机与回报发动机(活塞发动机)
Like all the other machinery, aircraft needs a power source to operate, especially to generate thrust which is required to move the aircraft forward. From the earliest attempts reciprocating engines working on petrol were used for powered flight.
世界上的第一个比空气动力飞行更重,是由赖特传单公司(Wright Flyer I)制造的,它用单个4缸水冷活塞发动机提供动力,该发动机最大程度地产生了12匹马动力。在第二次世界大战之前,每架飞机都用往复式 /活塞发动机供电。
在第二次世界大战的后期阶段,德国人使用喷气发动机进行动力飞机,其他国家很快随之而来。即使自1930年代以来就已经开发了概念和设计,但仅在第二次世界大战结束后才成功实施这款喷气发动机。
从那时起,由于它们比往复式发动机的优势多样,因此喷气发动机及其变体已成为飞机发电厂的主要形式。
More about Reciprocating Engine (Piston Engine)
A reciprocating engine, also known as a piston engine is a machine with reciprocating pistons, which converts the thermal energy from a combustion process into mechanical work, such as shaft work. The main engine type used in the aircrafts are based on fossil fuel combustion and called internal combustion engines.
发动机的力学是通过在气缸内部产生巨大的压力来移动连接到活塞缸机制的轴。取决于圆柱体在轴周围排列的方式,它们分为直(垂直),旋转,径向,V型和水平相反的类别。
The engine types mentioned above operate on Otto cycle, and they were used in most of the aircraft in the early 20Thcentury. Usually they are used to drive a propeller, which generate the thrust. Any aircraft operating on piston engines has relatively low maximum speeds, and the power produced by the engines is comparatively less than jet engines. The reason is that the powers to weight ratio of the piston engines are very low and, if more power is required, the engine size has to be increased and that increases the overall weight of the aircraft, which is not desirable for aircrafts. The design and production of the piston engines are less complex and requires lesser maintenance and the cost f the piston engines are also low.
More about Gas Turbine Engine
Gas turbine engine or simply a gas turbine is an internal combustion engine, using gases such as air as the working fluid. Thermodynamic aspect of the operation of the gas turbine is ideally modelled by the Brayton cycle. Gas turbine engines work based on rotary components and, therefore, has a working fluid flowing continuously through the engine in either radial or axial directions. They are the underlying principal component of the jet engine.
The main components of the gas turbine engine are the compressor, combustion chamber, and the turbine, and sometimes, a nozzle. They operate by bringing the working fluid into different thermodynamic states and extracting shaft work or thrust at the exhaust. If the thrust generated from the exhaust is used, it is known as a turbo jet engine; if the turbine extracts some portion of the work and drives a fan, it is known as a turbofan engine. The engine type that extracts almost all the work as the shaft work of the turbine is known as a turboshaft engine; if a propeller is driven by the shaft, it is known as a turbo prop engine.
Many variants of the gas turbines exist, designed for specific tasks. They are preferred over other engines (mainly reciprocating engines) due to their high power to weight ratio, less vibration, high operation speeds and reliability.
什么是维ifference between Gas Turbine and Reciprocating Engine (Piston Engine)?
• Piston engines have reciprocating mechanisms (to and from motion) while gas turbine engines have rotary mechanisms.
•两者都将空气用作工作流体,但是燃气轮机的流量是连续的,而往复式发动机的流量则是间歇性的。
• Power to weight ratio of the gas turbine engines is much higher than that of reciprocating engines.
• Gas turbines are sophisticated in design and manufacture, while reciprocating engines are simpler in design and easier to manufacture.
• Maintenance of the reciprocating engines are simpler and has to be performed frequently, while maintenance of the gas turbine engines is complex, but the inspection and maintenance occurs at longer intervals.
• Gas turbine engines or its variants are expensive, while reciprocating engines are relatively inexpensive.
• Gas turbine engines power large and powerful aircrafts such as military jet fighters or commercial airliner, but piston engine are being used in smaller and short ranged aircraft.
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