工科课程设计汇本变速器.doc

Chapter 1 Overview of CFM56-5C1.1 PreviewIn this chapter, a general introduction to CFM56-5C engine will be given. Some basic information about CFM56-5C engine will be included. Before learning it, try to recognize the abbreviations. They will help you getting a better understanding of the text in the whole introduction.1.2 CFM InternationalIn 1974,GE of the U.S. and SNECMA (SAFRAN Group) of Francefounded the CFM International (CFMI), a 5050 joint pany that would be responsible for producing and marketing the 10-ton engine, the CFM56.The two primary roles for CFMI were to manage the program between GE and SNECMA, and to market, sell and service the engine at a single point of contact for the customer.The work split between the two panies gave GE responsibility for the high-pressure pressor (HPC), the bustor, and the high-pressure turbine (HPT); while SNECMA was responsible for the fan, the low-pressure pressor (LPC), and the low-pressure turbine (LPT). SNECMA was also responsible for the initial airframe integration engineering, mostly involving the nacelle design, and was initially responsible for the gearbox, but shifted that work to GE when it became apparent that it would be more efficient for GE to assemble that ponent along with their other parts.1.3 The CFM56-5CTurbofan Engine1.3.1 GeneralThe CFM56-5C series engine is an axial flow, dual spool, high bypass ratio, turbo-fan engine with fan and multistage pression systems driven by reaction turbines. The engine is designed for use with a long duct, forced mixed flow exhaust system. The single stage fan and 4 stage booster is driven by a 5 stage low pressure turbine. A 9 stage, variable geometry, high pressure pressor is driven by an air cooled single stage turbine. A full annular bustor with 20 duplex fuel nozzles distributes the fuel to provide the heat energy to drive the turbines with residual energy providing thrust. The accessory drive system extracts energy from the high pressure rotor to drive the engine and engine-mounted aircraft accessories. Reverse thrust for braking the aircraft after landing is supplied by an integrated system which acts on the fan discharge airflow.The principal operational differences between the CFM56-5C series engine models are summarized below: Table 1-1 Differences between the CFM56-5C series engine modelsENGINE MODELTAKEOFF THRUST RATINGMAX. EGT deg.CCFM56-5C2 31,200 lbs (13,878 daN) 950 CFM56-5C2/F 31,200 lbs (13,878 daN) 965 CFM56-5C2/G 31,200 lbs (13,878 daN) 975 CFM56-5C3/F 32,500 lbs (14,456 daN) 965 CFM56-5C3/G 32,500 lbs (14,456 daN) 975 CFM56-5C4 34,000 lbs (15,123 daN) 975 Fig.1-1 CFM56-5C Fig.1-2 View of the CFM56-5C front fan and fan case1.3.2 Main modulesThe main modules of the engine are: - the fan and booster - the high pressure pressor- the bustor chamber- the high pressure turbine- the low pressure turbine- the accessory drive gearbox.Fig.1-3 main modules of CFM56-5CFan and Booster1.Fan/Booster rotor The fan rotor consists of one full diameter single stage fan and a smaller 4 stage booster for the core engine flow.The fan and the booster are mounted on a mon internal concentric shaft driven by the 5 stage fan turbine. Two bearings support the fan assembly in the fan frame.2. Fan /Booster statorFixed stator vanes are provided for both the fan and the rotors. The fan casing, in which the fan stator is mounted, has provisions for blade containment forward of and in the plan of the fan rotor. The casing is supported by the fan frame and also supports the accessory drive gearbox.3. Fan frameThe fan frame is one of the major structural and aerodynamic ponents of the engine. Aerodynamically the fan frame forms the inner and outer flow passage of the fan and core airstreams.Structurally the fan frame functions are:- to carry inlet cowl loads- to support the fan casing, the two fan bearings and the core engine forward bearings- to contain the forward engine mount- to house the accessory drive power take off gearbox and radial drive shaft- to contain the variable bypass valve between the booster and high pressure pressor- to support the transfer and accessory gearboxes- to provide mounting surfaces for the fan-stream acoustic panelsThis frame also serves as the forward support for the high pressor.pressor1. pressor rotorThe pressor is a 9 stage axial flow assembly. The rotor consists of the stage 1 and 2 disks which form a spool, a separately attached stage 3 disks and a spool containing stage4-9 disks. Stages 1, 2 and 3 disks have axial dovetail slots and stages 4-9 blades are retained in circumferential slots. All blades are individually replaceable without spool disassembly.2. pressor statorAll 9 stages of the pressor stator are shrouded. The Inlet Guide Vanes (IGV) and the first 3 stages of the pressor are variable. The casing is posed of two semi-cylindrical halves, permitting a quick access to the core engine pressor.bustorA step diffuser is incorporated upstream of the bustor for reduction of the bustor sensitivity to the pressor velocity profile. The bustor can be replaced without disturbing the fuel nozzles. The bustor casing provides structural support for the bustor, the pressor Outlet Guide Vanes (OGV), the High Pressure (HP) stator and shrouds, and the seals for the pressor Discharge Pressure (CDP).Turbine1. High pressure turbineThe High Pressure Turbine (HPT) is an air-cooled single-stage high-energy turbine. Rotor blades are individually replaceable without the need for rotor disassembly or re-balancing.2. Low pressure turbineThe Low Pressure Turbine (LPT) consists of 5 stages of blades and vanes. The first stage nozzle vane is cooled and transfers cooling air for the high pressure and low pressure turbine disks. The LPT drives the fan rotor through the inner concentric shaft and is aerodynamically coupled to the high pressure system. The LPT casing is a 360 degree design to provide structural continuity. The front flange of the LPT casing supports the A8 flange extension and the partial axial flow bulkhead.Fig.1-4 Low pressure turbineTurbine frameThe turbine frame is located aft of the LPT. It contains the aft LPT bearing, and supports the mixer and center body. This frame contains the engine rear mount fitting.Accessories and accessory drivesThe engine and aircraft accessories are mounted on the accessory gearbox which is located on the lower portion of the fan casing and is driven by a shaft from the transfer gearbox. Power for the engine and the aircraft accessories is extracted from the HPC rotor shaft to the transfer gearbox. Quick Attach Detach (QAD) accessory mounting flanges are provided for all accessories.1.3.3The advantages of CFM56-5CQuick facts:· Lowest SFC of the CFM56 family · Quietest engine in its thrust class · High thrust-to-weight ratio to provide excellent takeoff performance for high-altitude and hot airfields · 36,000 pounds of thrust demonstrated during ground testing · Second-generation FADEC Long-duct, mixed-flow nacelle developed by CFM to provide significant noise attenuation, reduced fuel burn, and increased climb thrust Chapter 2 LPT Shaft of CFM56-5C2.1 PreviewAs we all know, the N1 Speed is the LP rotor assembly rotational speed. So in this chapter, we will introduce the LPT Shaft of CFM56-5C. And in the next chapter, we will introduce the fan and booster, for The Low Pressure Turbine (LPT) shaft module connects the fan shaft with the LPT rotor.2.2 System DescriptionThe LPT shaft module is posed of the LPT shaft and of the center vent tube.The aft end of the LPT shaft is supported by the NO.5 bearing, its forward end is coupled with the fan shaft. The LPT shaft has 2 functions: coupling the fan/booster rotor with the LPT rotor and providing for high pressure turbine rear support through the NO.4 bearing. In addition, the LPT shaft houses the center vent tube for venting forward and aft engine sumps.Fig.2-1 Low Pressure Turbine Shaft ModuleFig.2-2 Low Pressure Turbine Shaft Assembly2.3 ponent DescriptionThe LPT shaft module consists of the following major parts:- LPT shaft- Center Vent Tube (CVT)- NO.4 roller bearing- NO.5 roller bearing2.3.1 LPT Shaft The LPT shaft is made of steel alloy. It is located concentrically in the high pressure rotor system. Its forward end is provided with outer splines for coupling with the fan shaft. It is axially retained by a shoulder and a coupling nut. At the aft end of the shaft, the NO.4 and 5 bearings are located axially on both sides of an integral hub. On the rear face, the hub supports 2 rotating air/oil seals which control the air circulation through the LPT rotor and the sump pressurizing air. On the front face, the hub supports the turbine rotor support.2.3.2Center Vent TubeThe one-piece center vent tube (CVT) is made of titanium alloy. It is installed inside the LPT shaft. It forward end is inserted in the LPT shaft plug and its aft end is supported by the LPT shaft hub. The center vent tube is held radially in the LPT shaft through 2 expendable-type supports. At the front of the NO.5 roller bearing, 3 shoulder-pins engage the shaft hub and the center vent tube to prevent it to turn relative to the LP shaft. The 3 pins also supply for the correct location of the NO.5 bearing inner race. 2.3.3 NO.4 Bearing The NO.4 bearing, which takes the High Pressure Turbine (HPT) rotor radial loads, is a roller bearing installed between the HPT rear shaft and the LPT shaft. The bearing outer race is housed in the HPT rear shaft bore, and its inner race is bolted to the front face of the LPT shaft integral hub. The inner race has a shoulder which would act as an emergency bearing in case of roller failure. The inner race front end is provided with a sump air seal.2.3.4 NO.5 BearingThe NO.5 bearing supports the LPT rotor aft end inside the turbine frame and takes the radial loads. The bearing outer race is mounted in the turbine frame and its inner race is mounted at the rear of the LPT shaft integral hub.Chapter 3 Fan and Booster Assembly3.1 PreviewIn the last chapter, we have known The Low Pressure Turbine (LPT) shaft module connects the fan shaft with the LPT rotor. In order to known N1 Speed well, in this chapter, we are going to introduce the fan and booster assembly.3.2 General The fan and booster assembly consists of a single-stage fan rotor and a 4-stage axial booster, cantilever-mounted at the rear of the fan disk.3.3 ponent DescriptionThe fan and booster assembly consists of the following sections:- spinner rear and front cones- fan disk- fan blades- booster rotor - booster vane assemblies 3.3.1Spinner Front Cone The spinner front cone is made of posite material. Its design precludes the need for an engine nose anti-icing system. The front cone is bolted to the rear cone. 3.3.2 Spinner Rear ConeThe spinner rear cone is made of aluminum alloy. Its rear flange is bolted to the fan disk and is part of the fan blades axial retention system. The outer rim of rear flange is provided with tapped holes for trim balance screws. The front flange provides for attachment of the spinner front cone.3.3.3 Fan Disk The fan disk is a titanium alloy forging. Its inner rear flange provides attachment for the fan shaft and its outer rear flange is bolted to the booster rotor. The outer front flange provides attachment for the spinner rear cone. The disk outer rim has 36 recesses designed for fan blade retention. 3.3.4 Fan BladesThere are 36 titanium alloy, mid-span shrouded, fan blades approximately 25 inches (630 mm) long. Each blade has a dovetail base that engages in a dovetail recess on the disk rim. A spacer limits the radial movement of each blade. A retainer lug, machined in the rear end of blade root, engages the forward flange of the booster spool and limits the forward and rearward axial movements. 3.3.5 Booster Rotor The booster rotor consists of the booster spool and blades. The booster spool is forged and machined from titanium alloy and is cantilever-mounted on the rear of the fan disk. The inner front flange, bolted to the fan disk, acts as a stop for the fan blade spacers and the fan blades. The 4-stage spool has circumferential dovetail slots that retain the stages 2, 3, 4, and 5 booster rotor blades, locking lugs and balance weights. Stage 2 has 70 blades, stage 3 has 74 blades, stage 4 has 70 blades and stage 5 has 66 blades. Rotating air seal serrations are machined between each stage on the outer diameter of spool.A forward rotating air seal, integral with the front web of booster spool, provides partial sealing between the fan rotor stage and the inner shroud of booster stator stage 2 and (partial) pressurization of the engine forward sump.The booster blades are approximately 4.2 to 3.5 inches (105 to 90 mm) long and serve primarily to supercharge the HP pressor. Blades are held in the dovetail slots by locking lugs.3.3.6 Booster Stator The stacked vane assemblies of booster stator are cantilever-mounted on the fan frame front face. The entire assembly is posed of 5 vane stages of similar design. Each vane assembly consists of:- An outer shroud which, depending on its assembly location, is fitted with one or 2 mounting flanges at its ends. The outer shroud inner face of vanes assemblies, stages 1, 3, 4 and 5 is lined with an abradable material facing, respectively, the 1, 2, 3 and 4 rotor blades- An inner shroud, whose inner face is lined with abradable material facing the seal serrations machined on the booster spool - Stator vanes welded to the outer shroud and retained on the inner shroud by the abradable material. Stage one vane assembly has 106 vanes, stage 2 vane assembly has 124 vanes, stage 3 vane assembly has 124 vanes, stage 4 vane assembly has 116 vanes and stage 5 vane assembly has 90 vanes. The outer shroud rear flange of stage 5 vane assembly is bolted to the front face of the fan frame. The inner shroud rear flange is rabbeted to form an interference fit with a corresponding flange on the fan frame. The outer shroud of the booster stage 3 and stage 5 vane assemblies has an orifice, located approximately at 4.30 o'clock, to permit the borescope inspection of the booster mid and rear stages rotor blades (full view) and of the related vane assemblies (partial view only).Fig.3-1 Fan and Booster AssemblyFig.3-2 Fan and Booster Assembly-Section ViewChapter 4 Power and Speed Indicating4.1 PreviewIn order to solve the problem of N1 over-limit, we must know how do the Speed Indicating System work and how do the N1 Speed signal transfer. So in this chapter, we are going to introduce the Power and Speed Indicating of CFM56-5C engine. 4.2 Describe and Operation4.2.1 GeneralThe N1 speed