航发专业英语翻译

飞动专业英语阅读（一）班级：1215062学号：121506206姓名：郭龙帮日期：2014年11月10日4: Combustion chambers燃烧室COMBUSTION PROCESS燃烧过程4.Air from the engine compressor enters the combustion chamber at a velocity up to 500 feet persecond, but because at this velocity the air speed isfar too high for combustion, the first thing that the chamber must do is to diffuse it, i.e. decelerate it andraise its static pressure. Since the speed of burning kerosine at normal mixture ratios is only a few feetper second, any fuel lit even in the diffused airstream, which now has a velocity of about 80 feet persecond, would be blown away. A region of low axial velocity has therefore to be created in the chamber,so that the flame will remain alight throughout the range of engine operating conditions。

空气从发动机通过压缩机以高达每秒500英尺的速度进入燃烧室,但由于在这种用来燃烧的空气速度太高,必须做的第一件事是扩散,即减速过程的静态压力并提高。

因为燃烧的煤油在正常的速度混合比率是只有很小的速度。

第二,任何燃料点燃即使在扩散气流,目前大约有每秒80英尺的速度,会被风吹走。

因此在轴向速度低的区域建立创建室,以便火焰仍将点燃整个范围的引擎操作条件。

5. In normal operation, the overall air/fuel ratio of acombustion chamber can vary between 45:1 and130:1, However, kerosine will only burn efficiently at,or close to, a ratio of 15:1, so the fuel must be burnedwith only part of the air entering the chamber, in whatis called a primary combustion zone. This is achieved by means of a flame tube (combustion liner) that hasvarious devices for metering the airflow distribution along the chamber。

在正常操作中,整体的空气/燃料比燃烧室在45:1和130:1之间。

然而,煤油只会更有效地燃烧,或接近的比例15:1,所以必须燃烧燃料只有一部分的空气进入室内,在什么被称为主要燃烧区。

这就是气流通过燃烧管(燃烧衬套)沿着燃烧室各种计量设备实现的。

6. Approximately 20 per cent of the air mass flow is taken in by the snout or entry section (fig. 4-2). Immediately downstream of the snout are swirl vanes and a perforated flare, through which air passes intothe primary combustion zone. The swirling air induces a flow upstream of the centre of the flame tube and promotes the desired recirculation. The air not picked up by the snout flows into the annular space between the flame tube and the air casing.大约20%的空气质量通过鼻子或进入区被吸入(图4 - 2)。

进入区下游的漩涡叶片和穿孔耀斑,通过空气传递向主燃烧区。

旋转的空气引起的上游流火焰的中心管和促进所需的再循环。

没有被进入区吸入的空气流入燃烧管之间的环形的空气套管中。

Fig. 4-2Apportioning the airflow图4 - 2分配气流7. Through the wall of the flame tube body, adjacent to the combustion zone, are a selected number of secondary holes through which a further 20 per cent of the main flow of air passes into the primary zone. The air from the swirl vanes and that from the secondary air holes interacts and creates a region of low velocity recirculation. This takes the form of a toroidal vortex, similar to a smoke ring, which has the effect of stabilizing and anchoring the flame (fig, 4-3). The recirculating gases hasten the burning of freshly injected fuel droplets by rapidly bringing them to ignition temperature 。

通过燃烧管体的墙壁,与燃烧区相邻,是一个选择的二级孔数量还有20%的主要流动空气进入主区。

来自涡流叶片和二次空气孔的空气进行交互并创建一个地区的低速度再循环。

这需要一个环形涡的形式,类似于烟戒指,稳定的影响和锚定火焰(图4 - 3)。

再循环气体加速新注入的燃料液滴的燃烧迅速将他们达到点火温度。

Fig. 4-3 Flame stabilizing and general airflow pattern图4 - 3火焰稳定和通用气流模式冷却 稀释8. It is arranged that the conical fuel spray from the nozzle intersects the recirculation vortex at its centre.This action, together with the general turbulence in the primary zone, greatly assists in breaking up the fuel and mixing it with the incoming air.这样布置锥形燃料喷嘴的喷雾贯穿再循环的漩涡中心。

这种方式,加上一般动荡的主要区域,大大有助于打破了燃料和混合的空气。

9. T he temperature of the gases released by combustion is about 1,800 to 2,000 deg. C., which is far too hot for entry to the nozzle guide vanes of the turbine. The air not used for combustion, which amounts to about 60 per cent of the total airflow, is therefore introduced progressively into the flame tube. Approximately a third of this is used to lower the gas temperature in the dilution zone before it enters the turbine and the remainder is used for cooling the walls of the flame tube. This is achieved by a film of cooling air flowing along the inside surface of the flame tube wall, insulating it from the hot combustion gases (fig. 4-4). A recent development allows cooling air to enter a network of passages within the flame tube wall before exiting to form an insulating film of air, this can reduce the required wall cooling airflow by up to 50 per cent. Combustion should be completed before the dilution air enters the flame tube, otherwise the incoming air will cool the flame and incomplete combustion will result.燃烧释放出来的气体的温度大约是1800到2000度。

,这样的对于喷嘴入口导流叶片的涡轮机来说温度太高。

空气不是用于燃烧,这相当于大约60%的总气流,因此将逐步引入火焰管。

大约三分之一的这是用来降低气体温度稀释区之前进入涡轮,其余用于冷却火焰管的墙壁。