19.
On some front fan engines, the by-pass airstream is ducted overboard either directly behind the fan through short ducts or at the rear of the engine through longer ducts; hence the term 'ducted fan'. Another, though seldom used, variation is that of the aft fan.
德 哈维兰公司的“妖魔”(Goblin)发动机于1941年开始和设计推力3000磅的“哈尔福德”H1(Halford H1)一起发展。该发动机于1942年9月通过了25小时的特种等级试车，并获准以2000磅推力飞行。1943年3月5日在格洛斯特公司的“流星”(Gloster Meteor)飞机上进行了飞行，这也是这种飞机的首次飞行。1943年9月，德哈维兰公司的DH100“吸血鬼”(DH100 Vampire)装用2300磅推力的一台“妖魔”发动机进行了首次飞行。
Rolls-Royce RB211-22B
罗尔斯-罗伊斯公司 RB211-228 发动机
德·哈维兰公司H1“妖魔”发动机
De Havilland H1 Goblin
Development of the de Havilland Goblin began in 1941 with the Halford H1 with a design thrust of 3000 lb. The engine passed a 25 hr special category test in September 1942 and was cleared for flight at 2000 lb thrust. This took place in a Gloster Meteor on 5 March 1943 and was also the first flight of that aircraft type. In September 1943 the first flight of a de Havilland DH100 Vampire was made with a Goblin of 2300 lb thrust.
3: Compressors
第三章 压气机
工作状态
空气流量控制
材料
平衡
绪言
离心式压气机
工作原理
结构
叶轮
扩压器
Contents Page
Introduction 19 The centrifugal flow compressor 21
Principles of operation
Construction
Impellers
Diffusers
The axial flow compressor 22 Principles of operation 轴流式压气机
工作原理
结构
转子
转子叶片
静子叶片
Construction
目录 页码
Rotors
Rotor blades
Stator vanes
Operating conditions Airflow control Materials Balancing 28 29 29 33
绪言
1．在燃气涡轮发动机中，空气在通过涡轮膨胀以前，它的压缩可由两种压气机中的一种进行的，一种产生离心气流，另一种产生轴向气流。这两种压气机均由发动机涡轮驱动，通常直接与涡轮轴相连。
INTRODUCTION
1.
In the gas turbine engine, compression of the air before expansion through the turbine is effected by one of two basic types of compressor, one giving centrifugal flow and the other axial flow. Both types are driven by the engine turbine and are usually coupled direct to the turbine shaft.
2.
The centrifugal flow compressor (fig. 3-1) is a single or two stage unit employing an impeller to
accelerate the air and a diffuser to produce the required pressure rise. The axial flow compressor (fig. 3-7 and fig. 3-8) is a multi-stage unit employing alternate .rows of rotating (rotor) blades and stationary (stator) vanes, to accelerate and diffuse the air until the required pressure rise is obtained. In some cases, particularly on small engines, an axial compressor is used to boost the inlet pressure to the centrifugal.
3. With regard to the advantages and disadvan-tages of the two types, the centrifugal compressor is usually more robust than the axial compressor and is also easier to develop and manufacture. The axial compressor however consumes far more air than a
3．就这两种压气机的优缺点而言，离心压气机通常比轴流压气机更结实，也比较容易发展和制造。
2.离心式压气机(图3-1)是一个单级或二级装置，用叶轮加速空气，用扩压器产生要求的压力升高。轴流压气机(图3-7和图3-8)是一多级装置，用交替布置的排排旋转的(转子)叶片和静止的(静于)叶片来加速空气并使之扩压，直到达到要求的压力提高。在某些情况下，尤其是小发动机上，用一个轴流压气机来给离心压气机的进口气流增压。
Compressors
3．就这两种压气机的优缺点而言，离心压气机通常比轴流压气机更结实，也比较容易发展和制造。然而，轴流压气机比同样迎风面积的离心压气机吸入的空气多得多，并能从设计上得到高得多的增压比。因为空气流量是决定推力大小的一项重要因素，这就意味着，在同样的迎风面积条件下，轴流压气机发动机将产生更大的推力。再加上通过额外增加级数就能增加压比的这种能力，使得大多数发动机设计采用轴流压气机。然而，离心压气机仍然为较小型发动机所喜爱采用，因为在这种情况下，离心压气机的简单和结实压倒了它的所有缺点。
后进气机匣
漩涡叶片
压气机
进气槽
叶轮的轴直接和涡轮连接
叶轮
旋转的导向叶片
前进气机匣
压气机空气出口机匣
图3-1 典型的离心气流压气机
Fig. 3-1 A typical centrifugal flow compressor.
centrifugal compressor of the same frontal area and which in turn leads to improved specific fuel can be designed to attain much higher pressure consumption for a given thrust, ref. fig. 3-2. ratios. Since the air flow is an important factor in determining the amount of thrust, this means the axial compressor engine will also give more thrust for the same frontal area. This, plus the ability to increase the pressure ratio by addition of extra 耗油率 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(10)
