22．将空气喷雾燃油喷嘴(第l0章)引入这种类型
的燃烧室大大改善了燃油为燃烧所做的准备，因空气会进入靠近喷嘴处的燃油汽泡中，而这些泡都是过度富油的。这大大减轻了初始碳粒的形成。
环管形燃烧室
18．环管形燃烧室填补了从多个单管燃烧室过渡到环形燃烧室的空档。多个火焰筒装在一个共同的空气机匣里(图4-8)。气流与已描述的情形相似。这种布局兼有多个单管燃烧室易于翻修和试验以及环形系统的紧凑性的优点。
图4-7 多个单管燃烧窒
Fig. 4-7 Multiple combustion chambers.
Tubo-annular combustion chamber
18. The tubo-annular combustion chamber bridges the evolutionary gap between the multiple and annular types. A number of flame tubes are fitted inside a common air casing (fig. 4-8). The airflow is similar to that already described. This arrangement combines the ease of overhaul and testing of the multiple system with the compactness of the annular system.
Annular combustion chamber
19. This type of combustion chamber consists of a single flame tube, completely annular in form, which is contained in an inner and outer casing (fig. 4-9). The airflow through the flame tube is similar to that already described, the chamber being open at the front to the compressor and at the rear to the turbine nozzles.
Combustion chambers
20.
The main advantage of the annular chamber is that, for the same power output, the length of the chamber is only 75 per cent of that of a tubo-annular system of the same diameter, resulting in consider-able saving of weight and production cost. Another advantage is the elimination of combustion propagation problems from chamber to chamber.
21.
In comparison with a tubo-annular combustion system, the wall area of a comparable annular chamber is much less; consequently the amount of cooling air required to prevent the burning of the flame tube wall is less, by approximately 15 per cent, This reduction in cooling air raises the combustion efficiency (para. 27) to virtually eliminate unburnt fuel, and oxidizes the carbon monoxide to non-toxic carbon dioxide, thus reducing air pollution.
22.
The introduction of the air spray type fuel spray nozzle (Part 10) to this type of combustion chamber
燃烧室性能
23.燃烧室必须能够允许燃油在范围广泛的工作状态有效地燃烧而不致产生巨大的压力损失。此外，如果火焰熄灭了。它必须能够重新点燃。在完成这些功能时，火焰筒和喷嘴雾化器部件必须在机械上是可靠的。
Combustion chambers
also greatly improves the preparation of fuel for combustion by aerating the over-rich pockets of fuel vapours close to the spray nozzle; this results in a large reduction in initial carbon formation.
COMBUSTION CHAMBER PERFORMANCE
23. A combustion chamber must be capable of allowing fuel to burn efficiently over a wide range of operating conditions without incurring a large pressure loss. In addition, if flame extinction occurs, then it must be possible to relight. In performing these functions, the flame tube and spray nozzle atomizer components must be mechanically reliable.
主空气戽斗
24．燃气涡轮发动机按等压循环工作，因而，燃烧过程的压力损失必须保持在最低水平。在提供足够的紊流和掺混时，总压损失在燃烧室进口空气压力的3～8％之间变化。
燃烧强度
25．由燃烧室或任何别的热量发生装置放出的热量取决于燃烧区的容积。因而，为了获得要求的高功率输出，一个相当小而紧凑的燃气涡轮燃烧室必须以极高的放热率放热。
稀释空气孔
涡轮安装边
24. The gas turbine engine operates on a constant pressure cycle, therefore any loss of pressure during the process of combustion must be kept to a minimum. In providing adequate turbulence and mixing, a total pressure loss varying from about 3 to 8 per cent of the air pressure at entry to the chamber is incurred.
Combustion intensity
25. The heat released by a combustion chamber or any other heat generating unit is dependent on the volume of the combustion area. Thus, to obtain the required high power output, a comparatively small
图4-8 环管形燃烧室
26．例如，在起飞状态，一台罗尔斯-罗伊斯公司的RB211-524发动机每小时消耗20635磅燃油。这种燃油具有大约18550英国热量单位／磅的热值。因此，该燃烧室每秒释放将近106300英国热量单位的热量。换言之，这种潜在的热量消耗率相当于大
约150000马力。
图4-9 环形燃烧室
Fig. 4-9 Annular combustion chamber.
and compact gas turbine combustion chamber must release heat at exceptionally high rates.
26. For example, at take-off conditions a Rolls-Royce RB211-524 engine will consume 20,635 lb. of fuel per hour. The fuel has a calorific value of approx-imately 18,550 British thermal units per lb., therefore the combustion chamber releases nearly 106,300 British thermal units per second. Expressed in
涡轮导向器叶片
燃烧室外机匣
Combustion chambers
another way this is an expenditure of potential heat
at a rate equivalent to approximately 150,000 horse-power.
Combustion efficiency
27. The combustion efficiency of most gas turbine
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(21)
