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•        Centrifugalflow 离心流

•        Axialflow 轴流

•        Coupled耦合的

•        Impeller叶轮

•        Diffuser扩压器

•        Alternate交替的、轮流的

•        Row 排

•        Rotor 转子

•        Blade 叶片、动叶

•        Stationary固定的

•        Stator静子

•        Vane 静叶

•        Diffuse扩散

•        Boost 促进、增长

•        Advantage优势

•        Disadvantage劣势

•        Robust健壮的、结实的

•        Consume消耗、耗费

•        Factor因子

•        Extra 额外的

•        Adoption采用

•        Ruggedness坚固性

•        Outweigh胜过

•        Occasionally偶然、偶尔

•        Ring 圆环

•        Rear 后方的、后部的

•        Plenum  增压、充实

•        Radially径向的

•        Tip 尖端

•        Swirl 旋转

•        Leakage泄漏

•        Ballbearing 滚珠轴承

•        Rollerbearing 滚柱轴承

•        Split 分裂、分段

•        Detachment脱离、分离

•        Forge 锻造

•        Disc 圆盘

•        Integral必须的、不可或缺的

•        Dispose处置、布置

•        Conjunction汇合点

•        Sweepback 后掠

•        Ease 放松、容易

•        Employed雇佣、采用

•        Curve 曲线

•        Accurate准确

•        Attach把……固定

•        Tangential切向的

•        Edge 边缘

•        Clearance间隙

•        Buffeting振动

•        Impulse脉冲

•        Unsteady不稳定

•        Vibration振动

•        Airfoil翼型

•        Incorporate合并

•        Series系列

•        Succeeding后继

•        Gradual平缓的、逐渐的

•        Annulus环形

•        Mountingflange 安装边

•        L.P.compressor 低压压气机

•        I.P.compressor 中压压气机

•        H.P.compressor 高压压气机

•        Convergence汇聚、收敛

•        Tapering逐渐变细的

•        Multi-spool多转子

•        Optimum最佳的

•        Flexibility灵活性

•        Obsolete淘汰的、过时的

•        Trend 趋势、趋向

•        Undergo经历、经受

•        Core 核心

•        Gasgenerator system 燃气发生器

•        Passenger旅客机

•        Transportaircraft 运输机

•        Adjacent相邻

•        Decelerate减速

•        Serve 提供

•        Straightener矫直器、整流器

•        Diagrammatically用图解法

•        Progressive进步的、先进的

•        Outgoing外向的

•        Deflection偏转

•        Breakaway分离

•        Subsequent后续

•        Stall 失速

•        Precede超前

•        Lb.磅

•        Minimize最小化

•        Fundamentally基本上

•        Range 范围

•        Incidence入射

•        Flowseparate 气流分离

•        Tolerate忍受

•        Alternative可供替代的

•        Interstagebleed 中间级放气

•        Dumpinto 倾入

•        Specific具体

•        Inner 内部

•        Diameter直径

•        Coaxial同轴

•        Utilize利用

•        Radius半径

•        Supercharge增压

•        Akin 类似的

•        Slight轻微的

•        Alignment对齐

•        Cylindrical圆柱形的

•        BoltedAxial joint 螺栓轴向连接

•        Centreline joint  中心线连接

•        Load 负荷

•        Weld 焊接

•        Periphery外围

•        Drum 鼓筒

•        Circumferential周向

•        Aim 目的

•        Maintainability维修性

•        Blisk 整体叶盘

•        Gradient梯度

•        Uniform一致的、均衡的

•        Twist 扭曲

•        Root 叶根

•        Stagnant停滞的

•        Wall 壁面

•        Compensate补偿

•        Boundarylayer 边界层

•        Localize局部

•        Camber（外）倾角

•        Extremity极端

•        End-bend端弯

•        Retaining保留

•        Segment部分、段

•        Shroud凸台

•        Staggerangle 安装角

•        Dissimilar不同的

•        Match 匹配

•        Impose推行、采用、迫使

•        Depart离开、离去

•        Intention意图、目的

•        Breakdown故障

•        Vibration振动

•        Phenomena现象

•        Destruction破坏、毁灭

•        Surge 喘振

•        Instantaneous瞬间

•        Adequate足够的

•        Margin差额、裕度

•        Provision提供

•        Wasteful浪费

•        Hydraulic水力的、液压的

•        Pneumatic气动的

•        Electronic电子的

•        Component组成部件、成分

•        Prevailing现行的、普遍的

•        Phial 小瓶

•        Reliefvalve 释压阀

•        Regulator调节器

•        Actuator执行机构、作动筒

•        Orifice孔口、节流孔

•        Servopressure 伺服压力

•        Sensing感知、传感

•        Rod 棒

•        Metering测量、计量

•        Diaphragm薄膜式、膜片

•        Rigid 刚性

•        Aluminum铝

•        Alloysteel 合金钢

•        Nickelbased alloy 镍基合金

•        Titanium钛

•        Rigidityto density ratio 刚度密度比

•        Inspite of 尽管、不管

•        Initial最初的、开始的

•        Fatiguestrength 疲劳强度

•        Notched有凹口的、缺刻

•        Ingestion摄入

•        Inferior较差的、次的

•        Decline衰落、下降

•        Rub 摩擦

•        Failure失效

•        Sufficient足够

•        Friction摩擦力

•        Ignite点燃

•        Airworthiness适航性

•        Hazard危害

•        Dominate支配、控制

•        Ratioof strength to density 强度密度比

•        Availability有效性、可用性、可利用、利用率

•        Chord 和弦、弦

•        Mid-spansupport 中部支撑

•        Snubber凸台

•        Clapper凸台

•        Situated位于

•        Widechord 宽弦

•        Fabricated编造

•        Skin 蒙皮

•        Honeycombcore 蜂窝芯

•        Mass 质量

读Sentence

•        1. Inthe gas turbine engine, compression of the air before expansion through theturbine is effected by one of two basic types of compressor, one givingcentrifugal flow and the other axial flow. Both types are driven by the engineturbine and are usually coupled direct to the turbine shaft.

•        2. Thecentrifugal flow compressor (fig. 3-1) is a single or two stage unit employingan impeller to accelerate the air and a diffuser to produce the requiredpressure rise. The axial flow compressor (fig. 3-7 and fig. 3-8) is amulti-stage unit employing alternate rows of rotating (rotor) blades andstationary (stator) vanes, to accelerate and diffuse the air until the requiredpressure rise is obtained. In some cases, particularly on small engines, anaxial compressor is used to boost the inlet pressure to the centrifugal.

•        5.Centrifugal flow compressors have a single or double-sided impeller andoccasionally a two-stage, single sided impeller is used, as on the Rolls-RoyceDart. The impeller is supported in a casing that also contains a ring ofdiffuser vanes. If a double-entry impeller is used, the airflow to the rearside is reversed in direction and a plenum chamber is required.

•        9. Tomaintain the efficiency of the compressor, it is necessary to prevent excessiveair leakage between the impeller and the casing; this is achieved by keepingtheir clearances as small as possible (fig. 3- 4).

•        10.The construction of the compressor centres around the impeller, diffuser andair intake system. The impeller shaft rotates in ball and roller bearings andis either common to the turbine shaft or split in the centre and connected by acoupling, which is usually designed for ease of detachment.

•        13. Anaxial flow compressor (fig. 3-7 and fig. 3-8) consists of one or more rotorassemblies that carry blades of airfoil section. These assemblies are mountedbetween bearings in the casings which incorporate the stator vanes. Thecompressor is a multi-stage unit as the amount of pressure increase by eachstage is small; a stage consists of a row of rotating blades followed by a rowof stator vanes. Where several stages of compression operate in series on oneshaft it becomes necessary to vary the stator vane angle to enable thecompressor to operate effectively at speeds below the design condition. As thepressure ratio is increased the incorporation of variable stator vanes ensuresthat the airflow is directed onto the succeeding stage of rotor blades at anacceptable angle, ref. para. 30, Airflow Control.

•        15. Asingle-spool compressor (fig. 3-7) consists of one rotor assembly and statorswith as many stages as necessary to achieve the desired pressure ratio and allthe airflow from the intake passes through the compressor.

•        16.The multi-spool compressor consists of two or more rotor assemblies, eachdriven by their own turbine at an optimum speed to achieve higher pressureratios and to give greater operating flexibility.

•        18.With the high by-pass ratio turbo-fan this trend is taken a stage further. Theintake air undergoes only one stage of compression in the fan before beingsplit between the core or gas generator system and the by-pass duct in theratio of approximately one to five (fig. 3-8). This results in the optimumarrangement for passenger and/or transport aircraft flying at just below thespeed of sound. The fan may be coupled to the front of a number of corecompression stages (two shaft engine) or a separate shaft driven by its ownturbine (three shaft engine).

•        19.During operation the rotor is turned at high speed by the turbine so that airis continuously induced into the compressor, which is then accelerated by therotating blades and swept rearwards onto the adjacent row of stator vanes. Thepressure rise results from the energy imparted to the air in the rotor whichincreases the air velocity. The air is then decelerated (diffused) in thefollowing stator passage and the kinetic energy translated into pressure.Stator vanes also serve to correct the deflection given to the air by the rotorblades and to present the air at the correct angle to the next stage of rotorblades. The last row of stator vanes usually act as air straighteners to removeswirl from the air prior to entry into the combustion system at a reasonablyuniform axial velocity. Changes in pressure and velocity that occur in theairflow through the compressor are shown diagrammatically in fig. 3-9. Thechanges are accompanied by a progressive increase in air temperature as thepressure increases.

•        24. Incompressor designs (fig. 3-10) the rotational speed is such that a disc isrequired to support the centrifugal blade load. Where a number of discs arefitted onto one shaft they may be coupled and secured together by a mechanicalfixing but generally the discs are assembled and welded together, close totheir periphery, thus forming an integral drum.

•        26.The rotor blades are of airfoil section (fig. 3-12) and usually designed togive a pressure gradient along their length to ensure that the air maintains areasonably uniform axial velocity. The higher pressure towards the tip balancesout the centrifugal action of the rotor on the airstream. To obtain theseconditions, it is necessary to 'twist' the blade from root to tip to give thecorrect angle of incidence at each point. Air flowing through a compressorcreates two boundary layers of slow to stagnant air on the inner and outerwalls. In order to compensate for the slow air in the boundary layer alocalized increase in blade camber both at the blade tip and root has been introduced.The blade extremities appear as if formed by bending over each corner, hencethe term 'end-bend'.

•        27.The stator vanes are again of airfoil section and are secured into thecompressor casing or into stator vane retaining rings, which are themselves securedto the casing (fig. 3-13). The vanes are often assembled in segments in thefront stages and may be shrouded at their inner ends to minimize thevibrational effect of flow variations on the longer vanes. It is also necessaryto lock the stator vanes in such a manner that they will not rotate around thecasing.

•        32.For casing designs the need is for a light but rigid construction enablingblade tip clearances to be accurately maintained ensuring the highest possibleefficiency. These needs are achieved by using aluminum at the front of thecompression system followed by alloy steel as compression temperatureincreases. Whilst for the final stages of the compression system, wheretemperature requirements possibly exceed the capability of the best steel,nickel based alloys may be required. The use of titanium in preference toaluminum and steel is now more common; particularly in military engines whereits high rigidity to density ratio can result in significant weight reduction.With the development of new manufacturing methods component costs can now bemaintained at a more acceptable level in spite of high initial material costs.

•        35.The high by-pass ratio fan blade (fig. 3-19) only became a design possibilitywith the availability of titanium, conventional designs being machined fromsolid forgings. A low weight fan blade is necessary because the front structureof the engine must be able to withstand the large out of balance forces thatwould result from a fan blade failure. To achieve a sufficiently light solidfan blade, even with titanium, requires a short axial length (or chord).However, with this design, the special feature of a mid-span support ('snubber'or 'clapper') is required to prevent aerodynamic instability. This designconcept has the disadvantage of the snubber being situated in the supersonicflow where pressure losses are greatest, resulting in inefficiency and areduction in airflow. This disadvantage has been overcome with the introductionof the Rolls-Royce designed wide chord fan blade; stability is provided by theincreased chord of the blade thus avoiding the need for snubbers. The weight ismaintained at a low level by fabricating the blade from skins of titaniumincorporating a honeycomb core.

读全文并回答以下问题：

•       Listthe advantages and disadvantages of axial flow compressor and centrifugalcompressor.

•       Whythe designers might install vanes in the engine’s intake duct?

•       Theclearance between impeller and the diffuser is an important factor, why?

•       Whatkind of structure is suitable for the by-pass type of engine?

•       Foraxial flow compressor, each stage’s pressure rise is small, why?

•       How tofix the flow separation in the compressor?

•       Whatkind of situation might happen, due to the operating conditions imposed uponthe compressor blade departs too far from the design intention?

•       Whytitanium is not suitable for stator vanes in the high pressure area?

收看收听以上资源的前12：50，并用英文回答以下问题，同时请将答案翻译成中文。