56.只有在需要時(shí)，警告、注意事項(xiàng)及建議信息才顯示出來，并以顏色編碼，向飛行機(jī)組人員提示故障的緊迫程度。系統(tǒng)中有這樣的設(shè)備，用來將任何事件或參數(shù)超差記錄在長(zhǎng)期性內(nèi)存中，以供地面維護(hù)人員以后評(píng)估。
57.電子指示系統(tǒng)由于減輕了駕駛員的工作負(fù)擔(dān)，從而改善了飛行操作條件，這一切是通過發(fā)動(dòng)機(jī)工作的自動(dòng)監(jiān)視，和一個(gè)集中化的提示和警告系統(tǒng)來實(shí)現(xiàn)的。整頓好飛行駕駛艙的雜亂無章是其中一個(gè)特點(diǎn)，因?yàn)閭鹘y(tǒng)出現(xiàn)的大量?jī)x表被陰極射線管取代了。
同步和同相
58.有時(shí)在渦輪螺槳發(fā)動(dòng)機(jī)飛機(jī)上準(zhǔn)備同步和同相系統(tǒng)，用于減少飛行中的噪聲。
propeller engine. On multi-spool engines, only one spool is synchronized. Manual trimming of engine or shaft speed can be done with the assistance of a synchroscope. This visually indicates, in comparison with a master engine, if the other engines are running at exactly the same speed; the normal engine speed indicator is, of course, not sufficiently sensitive to use for synchronizing.
Rolls-Royce advanced turbo-propeller
When a change in government fighter require-ments halted development of the 20,000 lb thrust H4 Gyron in 1955, de Havilland decided to build a 0.45 scale version known as the H6 Gyron Junior. First run in August 1955 it was later used to power the Blackburn Buccaneer S1 at 7100 lb thrust and the stainless steel
De Havilland H6 Gyron Junior
Bristol 188 at 14,000 lb with afterburner.
13: Ice protection
Contents
Page
Introduction
147
Hot air system
149
緒言
1．當(dāng)飛機(jī)穿越含有過冷水珠的云層或在有凍霧的地面工作時(shí)，發(fā)動(dòng)機(jī)和進(jìn)氣道前緣處會(huì)結(jié)冰。防止結(jié)冰是必要的，因?yàn)樵谶@些地方結(jié)冰會(huì)大大限制通過發(fā)動(dòng)機(jī)的空氣流量，從而引起發(fā)動(dòng)機(jī)性能損失并可能會(huì)使發(fā)動(dòng)機(jī)發(fā)生故障。此外，脫落下來的冰塊被吸入發(fā)動(dòng)機(jī)或撞擊進(jìn)氣道吸音材料襯層時(shí)可能造成損壞。
2.防冰系統(tǒng)必須在該飛機(jī)的使用要求內(nèi)有效地防止冰的生成。防冰系統(tǒng)必須可靠，易于維護(hù)，不會(huì)過分增加重量，且在工作中不會(huì)引起發(fā)動(dòng)機(jī)嚴(yán)重的性能損失。
3．有必要進(jìn)行一些分析以確定是否需要防冰。如果需要，則要確定使冰的集結(jié)限制在可允許的范圍之內(nèi)所要求輸入的熱量。圖13-1說明一種渦輪風(fēng)扇發(fā)動(dòng)機(jī)通常需要防冰的地方。
目錄
緒言
熱空氣系統(tǒng)
電加溫系統(tǒng)
Electrical system
150
第十三章 防冰
INTRODUCTION
1. Icing of the engine and the leading edges of the intake duct can occur during flight through clouds containing supercooled water droplets or during ground operation in freezing fog. Protection against ice formation may be required since icing of these regions can considerably restrict the airflow through the engine, causing a loss in performance and possible malfunction of the engine. Additionally, damage may result from ice breaking away and being ingested into the engine or hitting the acoustic material lining the intake duct.
2.
An ice protection system must effectively prevent ice formation within the operational requirements of the particular aircraft. The system must be reliable, easy to maintain, present no excessive weight penalty and cause no serious loss in engine performance when in operation.
3.
Analyses are carried out to determine whether ice protection is required and, if so, the heat input required to limit ice build up to acceptable levels. Fig. 13-1 illustrates the areas of a turbo-fan engine typically considered for ice protection.
4.
There are two basic systems of ice protection; turbo-jet engines generally use a hot air supply (fig. 13-2), and turbo-propeller engines use electrical power or a combination of electrical power and hot
Ice protection
至前整流罩的引氣口
空氣進(jìn)口總管
調(diào)壓活門
鼻錐
前整流罩
進(jìn)口導(dǎo)向葉片
Fig. 13-1 Areas typically considered for ice protection.
圖13-2 熱空氣防冰
148
圖13-1 通常需要防冰的地方
確定結(jié)冰的可接受程度
確定結(jié)冰的可接受程度
確定用于防冰的熱量或無加熱時(shí)結(jié)冰的允許程度
確定防冰的熱量并保證滿足防冰的要求
確保能充分地
防冰(儀表測(cè)試)
確保防冰是否滿足要求
確保結(jié)冰將
不會(huì)影響性能
4.有二種基本的防冰系統(tǒng)。渦輪噴氣發(fā)動(dòng)機(jī)一般采用熱空氣供應(yīng)(圖13-2)，渦輪螺槳發(fā)動(dòng)機(jī)采用電加溫或熱空氣與電加溫混合型。防冰可通過熱滑油沿進(jìn)氣道周圍循環(huán)來補(bǔ)充熱量，如圖13-3所示。熱空氣系統(tǒng)一般用來防止冰的生成，稱為防冰系統(tǒng)。電加溫系統(tǒng)用來破碎已在各表面上形成的冰，稱為除冰系統(tǒng)。
Ice protection
熱空氣系統(tǒng)
5.熱空氣系統(tǒng)在可能會(huì)結(jié)冰的地方為發(fā)動(dòng)機(jī)或動(dòng)
力裝置提供表面加溫。轉(zhuǎn)子葉片幾乎沒有必要進(jìn)行保護(hù)，因?yàn)槿魏畏e冰都會(huì)被離心作用驅(qū)散。如果靜子裝在壓氣機(jī)第一級(jí)轉(zhuǎn)子的上游，則可能需要進(jìn)行防冰保護(hù)。如果鼻錐是旋轉(zhuǎn)的，也可不必采取防冰措施，只要其形狀、結(jié)構(gòu)和旋轉(zhuǎn)特性能使結(jié)冰限制在允許的程度以內(nèi)的話。
6．防冰系統(tǒng)的熱空氣通常取自高壓壓氣機(jī)級(jí)，通過調(diào)壓活門用導(dǎo)管輸送至需要防冰的零件。前整流罩防冰系統(tǒng)用過的空氣可排入壓氣機(jī)進(jìn)口或排出機(jī)外。
7．如果鼻錐是防冰的，其熱空氣源可以是獨(dú)立的也可以是將它與前整流罩及壓氣機(jī)靜子的熱空氣供應(yīng)組合在一起。對(duì)一獨(dú)立系統(tǒng)而言，鼻錐的防冰一般是從壓氣機(jī)引出，經(jīng)內(nèi)部管道提供連續(xù)不調(diào)節(jié)的熱空氣。
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