13．排氣系統應當能夠承受很高的燃氣溫度，因此是用鎳或鈦合金制成。它還應當防止向周圍飛機結構有任何的熱量傳遞。這是通過在噴管周圍流過通風空氣，或通過在排氣系統的熱段套一個隔熱層(圖6-6)而實現的。每個隔熱層有一個由纖維隔熱材料制成的內層，外面由薄的不銹鋼外皮包裹，外層制
成波紋形以增加強度。另外，在排氣系統中有時還應用吸聲材料，以減小發動機的噪聲(第19章)。
14.當燃氣溫度非常高的時候(例如，采用加力燃燒室時)，整個噴管通常是雙壁結構(第16章)，兩壁之問有一個環腔。熱燃氣離開推進噴管時，通過引射作用，引射一股空氣流過發動機短艙的環形通道時，該空氣流冷卻噴管的內壁，通過減少自內壁向外界的傳熱，起著隔熱層的作用。
15．排氣系統的錐體及流線形整流罩承受排氣的壓力，因此，為了防止變形，要開通氣孔，保持壓力平衡。
16．低涵道比發動機所用的混合器裝置上有許多槽，使外涵空氣由斜槽流入排出的燃氣流中。在涵道比發動機的整體式噴管組件上采用了粘接的蜂窩結構，使這種大部件能夠得到輕重量、高強度。
17．由于排氣系統承受的溫度變化范圍很寬，它的安裝及其各段的連接方式應允許膨脹和收縮，而不致變形或損壞。
圖6-6 一種隔熱層
Fig. 6-6 An insulating blanket.
an outer skin of thin stainless steel, which is dimpled to increase its strength. In addition, acoustically absorbent materials are sometimes applied to the exhaust system to reduce engine noise (Part 19).
14.
When the gas temperature is very high (for example, when afterburning is employed), the complete jet pipe is usually of double-wall construc-tion (Part 16) with an annular space between the two walls. The hot gases leaving the propelling nozzle induce, by ejector action, a flow of air through the annular space of the engine nacelle. This flow of air cools the inner wall of the jet pipe and acts as an insulating blanket by reducing the transfer of heat from the inner to the outer wall.
15.
The cone and streamline fairings in the exhaust unit are subjected to the pressure of the exhaust gases; therefore, to prevent any distortion, vent holes are provided to obtain a pressure balance.
16.
The mixer unit used in low by-pass ratio engines consists of a number of chutes through which the bypass air flows into the exhaust gases. A bonded honeycomb structure is used for the integrated nozzle assembly of high by-pass ratio engines to give lightweight strength to this large component.
17.
Due to the wide variations of temperature to which the exhaust system is subjected, it must be mounted and have its sections joined together in such a manner as to allow for expansion and contraction without distortion or damage.
Rolls-Royce Gnome
羅爾斯-羅伊斯公司“諾姆”(Gnome)發動機
De Havilland H2 Ghost
“幽靈”(Ghost)發動機是作為“妖魔”(Goblin)的尺寸和功率加大型而設計的。在1945年9月2日首次運轉之后,它獲準裝在阿弗羅“蘭開斯特”(Avro Lancastrian)飛機的外側發動機短艙中，推力4000磅。后來，“幽靈”發動機投產，推力達5000磅，裝用于德 哈維蘭(de Havilland)公司的“彗星”（Comet）I客機和“毒辣”(Venom)殲山機上。
The Ghost was designed as a larger and more powerful version of the Goblin. After running for the first time on 2 September 1945 the engine was cleared for flight in the outer nacelles of an Avro Lancastrian at 4000 lb thrust. The Ghost later went into production at 5000 lb thrust to power the de Havilland Comet 1 airliner and Venom fighter.
德 哈維蘭公司
H2“幽靈”發動機
2．通常，附件裝置是由發動機的旋轉軸，經過內部齒輪箱傳向外部齒輪箱來驅動。外部齒輪箱用作附件的安裝座，并向各個附件裝置分配相應的齒輪傳動機構。其上還可能裝一個起動機，為發動機提供輸入扭矩。在高涵道比發動機上，一套附件傳動系統從發動機吸取的功率在400到500馬力之間
緒言
1．附件裝置為飛機液壓、氣壓和電氣系統提供動力，而且為發動機有效工作提供各種泵和控制系統的動力。由于這些裝置存在很高的依賴性，所以要求傳動系統具有極高的可靠性。
第七章 附件傳動裝置
7: Accessory drives
目 錄
Contents Page
Introduction 65
緒言
齒輪箱及傳動裝置
Gearboxes and drives 65
Internal gearbox
Radial driveshaft
Direct drive
Gear train drive
Intermediate gearbox
內部齒輪箱
徑向傳動軸
直接傳動
齒輪鏈條傳動
中間齒輪箱
外部齒輪箱
輔助齒輪箱
External gearbox
Auxiliary gearbox Construction and materials 69
Gears
Gearbox sealing
結構和材料
齒輪
齒輪箱封嚴
材料
Materials
INTRODUCTION
1.
Accessory units provide the power for aircraft hydraulic, pneumatic and electrical systems in addition to providing various pumps and control systems for efficient engine operation. The high level of dependence upon these units requires an extremely reliable drive system.
2.
The drive for the accessory units is typically taken from a rotating engine shaft, via an internal gearbox, to an external gearbox which provides a mount for the accessories and distributes the appropriate geared drive to each accessory unit. A starter may also be fitted to provide an input torque to the engine. An accessory drive system on a high by-pass engine takes between 400 and 500 horsepower from the engine.
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