氧
液体燃油
燃烧室
燃油喷嘴
14.
The application of the gas turbine to jet
propulsion has avoided the inherent weakness of the
rocket and the athodyd, for by the introduction of a
turbine-driven compressor a means of producing
thrust at low speeds is provided. The turbo-jet engine
operates on the 'working cycle' as described in Part
推进喷管
2. It draws air from the atmosphere and after
compressing and heating it, a process that occurs in
all heat engines, the energy and momentum given to
the air forces It out of the propelling nozzle at a
velocity of up to 2,000 feet per second or about 1,400
miles per hour. On its way through the engine, the air
gives up some of its energy and momentum to drive
the turbine that powers the compressor. Fig. 1-8 A rocket engine.
图1-8火箭发动机
14.应用燃气轮机于喷气推进避免了火箭和冲压喷气发动机固有的弱点，因为通过采用涡轮驱动的压气机提供了低速时产生推力的一种手段。涡轮喷气发动机按照第2章叙述的“工作循环”工作。它从大气中吸进空气，经压缩和加热这一所有热力发动机中的过程之后，得到能量和动量的空气以高达2000英尺/秒或大约1400英里/小时的速度从推进喷管中排出。在空气通过发动机的过程中，它释放一些能量和动量驱动给压气机提供动力的涡轮。
Basic mechanics
图1-9-1几种燃气涡轮发动机的机械布局
Fig. 1-9-1 Mechanical arrangement of gas turbine engines.
Basic mechanics
双轴内外涵涡轮-喷气发动机(低涵道比)
图1-9-2 几种燃气涡轮发动机的机械布局
Fig. 1-9-2 Mechanical arrangement of gas turbine engines.
and turbine blades, and the design of the exhaust system through which the gases are ejected to form the propulsive jet.
16. At aircraft speeds below approximately 450 miles per hour, the pure jet engine is less efficient than a propeller-type engine, since its propulsive efficiency depends largely on its forward speed; the pure turbo-jet engine is, therefore, most suitable for high forward speeds. The propeller efficiency does, however, decrease rapidly above 350 miles per hour due to the disturbance of the airflow caused by the high blade-tip speeds of the propeller. These charac-
16．飞机速度低于大约450英里／小时时,纯喷气发
动机的效率低于螺旋桨型发动机的效率，因为它的
推进效率在很大程度上取决于它的飞行速度；因而，纯涡轮喷气发动机最适合高的飞行速度。然而，由于螺旋桨的高叶尖速度造成的气流扰动，在350英里／小时以上时螺旋桨效率迅速降低。这些特性使得中等速度飞行的飞机不用纯涡轮喷气推进装置而采用螺旋桨和燃气涡轮发动机的组合。
17．螺旋桨/涡轮组合的优越性在一定程度上被内
外涵发动机、涵道风扇发动机和浆扇发动机的引八
所抵消。这些发动机比纯喷气发动机流量大而喷气
速度低。因而，其推进效率(第21章)与涡轮螺旋桨
的相当，超过了纯喷气发动机的推进效率(图1-lO)。
Basic mechanics
teristics have led to some departure from the use of pure turbo-jet propulsion where aircraft operate at medium speeds by the introduction of a combination of propeller and gas turbine engine.
17. The advantages of the propeller/turbine combination have to some extent been offset by the introduction of the by-pass, ducted fan and propfan engines. These engines deal with larger comparative airflows and lower jet velocities than the pure jet engine, thus giving a propulsive efficiency (Part 21) which is comparable to that of the turbo-prop and exceeds that of the pure jet engine (fig. 1-10).
图1-1O 推进效率的比较
Fig. 1-10 Comparative propulsive efficiencies.
18．涡轮／冲压喷气发动机(图1-11)将涡轮喷气发
动机(它用于马赫数高达3的各种速度)与冲压喷气
发动机结合起来，在高马赫数时具有良好的性能。
可调喷口(大面积)
可调进气道(小面积)
可调喷口(小面积)
高马赫数
进口导流叶片 (关闭)
低马赫数
可调进气道(大面积)
进口导流叶片 (打开)
Basic mechanics
图1-11 一种涡轮／冲压喷气发动机
Fig. 1-11 A turbo/ram jet engine.
18. The turbo/ram jet engine (fig. 1-11) combines ventional turbo-jet with the afterburner lit; at other the turbo-jet engine (which is used for speeds up to flight conditions up to Mach 3, the afterburner is
Mach 3) with the ram jet engine, which has good inoperative. As the aircraft accelerates through Mach performance at high Mach numbers.
3, the turbo-jet is shut down and the intake air is diverted from the compressor, by guide vanes, and
19. The engine is surrounded by a duct that has a variable intake at the front and an afterburning jet ducted straight into the afterburning jet pipe, which
pipe with a variable nozzle at the rear. During take-becomes a ram jet combustion chamber. This engine 燃烧室
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：劳斯莱斯喷气引擎－中英(5)
