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 哈維蘭公司的“妖魔”(Goblin)發動機于1941年開始和設計推力3000磅的“哈爾福德”H1(Halford H1)一起發展。該發動機于1942年9月通過了25小時的特種等級試車，并獲準以2000磅推力飛行。1943年3月5日在格洛斯特公司的“流星”(Gloster Meteor)飛機上進行了飛行，這也是這種飛機的首次飛行。1943年9月，德哈維蘭公司的DH100“吸血鬼”(DH100 Vampire)裝用2300磅推力的一臺“妖魔”發動機進行了首次飛行。
Rolls-Royce RB211-22B
羅爾斯-羅伊斯公司 RB211-228 發動機
德·哈維蘭公司H1“妖魔”發動機
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 壓氣機
工作狀態
空氣流量控制
材料
平衡
緒言
離心式壓氣機
工作原理
結構
葉輪
擴壓器
Contents Page
Introduction 19 The centrifugal flow compressor 21
Principles of operation
Construction
Impellers
Diffusers
The axial flow compressor 22 Principles of operation 軸流式壓氣機
工作原理
結構
轉子
轉子葉片
靜子葉片
Construction
目錄 頁碼
Rotors
Rotor blades
Stator vanes
Operating conditions Airflow control Materials Balancing 28 29 29 33
緒言
1．在燃氣渦輪發動機中，空氣在通過渦輪膨脹以前，它的壓縮可由兩種壓氣機中的一種進行的，一種產生離心氣流，另一種產生軸向氣流。這兩種壓氣機均由發動機渦輪驅動，通常直接與渦輪軸相連。
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．就這兩種壓氣機的優缺點而言，離心壓氣機通常比軸流壓氣機更結實，也比較容易發展和制造。
2.離心式壓氣機(圖3-1)是一個單級或二級裝置，用葉輪加速空氣，用擴壓器產生要求的壓力升高。軸流壓氣機(圖3-7和圖3-8)是一多級裝置，用交替布置的排排旋轉的(轉子)葉片和靜止的(靜于)葉片來加速空氣并使之擴壓，直到達到要求的壓力提高。在某些情況下，尤其是小發動機上，用一個軸流壓氣機來給離心壓氣機的進口氣流增壓。
Compressors
3．就這兩種壓氣機的優缺點而言，離心壓氣機通常比軸流壓氣機更結實，也比較容易發展和制造。然而，軸流壓氣機比同樣迎風面積的離心壓氣機吸入的空氣多得多，并能從設計上得到高得多的增壓比。因為空氣流量是決定推力大小的一項重要因素，這就意味著，在同樣的迎風面積條件下，軸流壓氣機發動機將產生更大的推力。再加上通過額外增加級數就能增加壓比的這種能力，使得大多數發動機設計采用軸流壓氣機。然而，離心壓氣機仍然為較小型發動機所喜愛采用，因為在這種情況下，離心壓氣機的簡單和結實壓倒了它的所有缺點。
后進氣機匣
漩渦葉片
壓氣機
進氣槽
葉輪的軸直接和渦輪連接
葉輪
旋轉的導向葉片
前進氣機匣
壓氣機空氣出口機匣
圖3-1 典型的離心氣流壓氣機
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 中國航空網 www.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：勞斯萊斯噴氣引擎－中英(10)
