Cfm56 3-core majormodule

CFM56-3 Familiarization Training Manual MTU Maintenance Zhuhai Co. Ltd.

Jiang Weixing, George Gravelle, Training Department/Human Resources Revision Date: Feb.20,2004

Core Major ModulePurpose:

Provide the energy to drive the LPT

Components:

The core major module consists of eight maintenance modules as follows: HPC rotor, HPC front stator, HPC rear stator, combustion case, combustion chamber, HPT nozzle, HPT rotor, HPT shroud and first stage LPT nozzle.

Description:

HPC rotor is a nine stage, high speed, unitized spool-disk structure. The rotor consists of five major parts: the front shaft, the 1st and 2nd stage spool, the third stage disk, the 4th through 9th stage spool and the compressor rear (CDP) seal.

HPC front stator, consists of: front casing halves, extension casing halves (configuration 1), IGV’s and first 5 stages of stator vanes. The IGV’s and the 1st through 3rd stage vanes are variable, the 4th and 5th stage vanes are fixed. The

HPC rear stator consists of: rear casing halves, liners (Configuration 1), three stages of fixed vanes, and vane shrouds. The rear stator is located inside the front stator extension and is cantilever-mounted to the rear stator support. The rear stator support outer flange is mounted between the compressor front stator extension and the combustion case.

Combustion case is a fabricated structural weldment located between the HPC and the LPT. It provides structural interface, transmits engine axial loads, and provides gas flow path between the compressor and the LPT.

Combustion chamber contained in the combustion case, consists of outer and inner cowls, 20 primary and 20 secondary swirl nozzles, dome, and outer and inner liners.



Core Major Module (Cont.)

HPT nozzle is a single stage, air-cooled assembly that mounts in the combustion case and directs the gas flow from the combustion chamber onto the blades of the HPT at the optimal angle.

HPT rotor is a single stage, air-cooled turbine. Structurally, the rotor consists of the front shaft, the forward air seal, the disk, and the rear shaft. The HPT rotor drives the HPC rotor and is directly connected to it by a bolted flange to form what is essentially a single core rotor.

HPT shroud and 1st stage LPT nozzle is located in the aft section of the combustion case. It forms the interface between the core section and the LPT module of the engine. The forward flange of the assembly is rabbeted and bolted to the inner surfaces of the combustion casing. The aft flange is bolted between the combustion casing aft flange and the LPT stator forward flange.


Core Major Module – High Pressure Compressor

Compressor Section

The compressor section provides compressed air for combustion and bleed air from stages 5 and 9 for engine and aircraft use.

5th stage air

Is extracted through bleed manifold segments just aft of the stage 5 stator and is directed into forward and aft air extraction manifolds. The forward manifold provides air for turbine clearance control and stage 1 LPT nozzle cooling. The aft manifold provides a bleed source for aircraft use.

9th stage air

Is extracted through a gap between the rear stator case and combustion case (just aft of stage 9 rotor). Stage 9 manifold provides the aircraft with the high pressure source of bleed air.



HPC Rotor

HPC Rotor Description:

The HPC rotor is a 9 stage, high speed, unitized s pool-disk structure. The rotor consists of five major components:- Front shaft, Stage 1-2 spool, Stage 3 disk, Stage 4-9 spool- HPC rear rotating (CDP) air seal

HPC Rotor Components:

Front shaftThe front shaft is bolted between the stage 1 and 2 spool and the stage 3 disk, and is the forward support for the rotor. The shaft is splined to and secured to the IGB horizontal bevel gear by a coupling nut. The IGB contains the thrust bearing (No. 3 ball bearing) for the core engine. The front shaft is made of a titanium alloy.

Disk and SpoolsThe stage 1 and 2 spool and the stage 3 disk are made of titanium alloy forgings and retain the stages 1-3 blades in axial slots. The stages 4-9 spool is made of a nickel alloy and retains stages 4-9 blades in circumferential grooves. The disk and stages 4-9 spool are internally cooled by LPC booster discharge air which enters the rotor through holes in the front shaft. There are abrasive coated seals between the rotor blade stages for improved compressor performance.

Blades:The stages 1-3 blades are made of a titanium alloy. The stage 4-9 blades are made of a nickel alloy. The first three stages of blades are secured in the disk and spool axial slots by retaining rings; the blades in the stages 4-9 are secured in the circumferential grooves by locking lugs. All blades are replaceable without disassembling the rotor.





HPC Rotor (cont.)

Number of rotor blades per Stage

Stage 1 – 38 bladesStage 2 – 53 bladesStage 3 – 60 bladesStage 4 – 68 bladesStage 5 – 75 bladesStage 6 – 82 bladesStage 7 – 82 bladesStage 8 – 80 bladesStage 9 – 76 blades


HPC Rotor (cont.)Rear SealThe compressor rotor rear rotating (CDP) air seal is a one-piece nickel alloy forging with abrasive, protective-coated sealing teeth. The seal is mounted to the aft flange of the stages 4-9 spool by a tight fitting rabbet diameter and is axially clamped by the bolts and nuts securing the forward flange of the HPT rotor to the compressor.

HPC Rotor Airflow

An air duct through the inside diameter of the rotor forms a flow path for pressurizing and cooling air. Pressurizing air from the forward sump flows between the air duct and LPT shaft. This air enters the aft sump through holes in the HPT aft shaft and pressurizes the aft sump seals. Cooling air from the No. 3 bearing aft stationary seal flows through holes in the compressor rotor front shaft through the compressor and HPT rotors and enters into the LPT rotor through holes in the aft shaft of the HPT. This airflow is referred to as bore rotor cavity cooling.



HPC Front Stator Assembly

Description

Configuration one (Titanium Stator Case)

The front casing halves are a matched set machined from a titanium forging. The extension casing halves are also a matched set and are machined from an Inco 718 steel forging. The extension case attaches to the front case with bolts and nuts which must not removed. Segmented liners make-up the stage 1-5 flow path. The front stator forms the load carrying structure between the fan frame and the combustion case. Bleed air is extracted from pads on the front case and extension for customer use, and for the HPT and LPT cooling. The stage 5 bleed manifolds have a controlled inside diameter that interfaces with the forward end of the rear stator.



HPC Front Stator Assembly Components (cont.)

Configuration two (steel stator case) (S/B 72-383)

The configuration two front case halves are made from an M152 steel forging. This forging replaces the titanium front case / Inco 718 extension case forgings. The stage 1-5 flow path is a machined, integral part of the case, instead of liners.



HPC Front Stator Assembly Components

Stator contains IGV’s and five stator stages:

IGV’s 42 IGV’sStage 1 - 82 VSV’sStage 2 - 84 VSV’sStage 3 - 72 VSV’sStage 4 - 10 sectors of seven fixed vanes eachStage 5 - 12 sectors of seven fixed vanes each

Stator vanes

The IGV and stages 1-3 vanes are variable; the stages 4 and 5 vanes are fixed. All stages of variable vanes are shrouded. The IGV shrouds are made of an epoxy resin, and are in two 180 degree sections. Shrouds for stages 1, 2 and 3 are made of aluminum and are in 12 segments. IGV inner shroud mates with No. 3 bearing aft stationary air/oil seal.




The fixed vanes, in stage 4 and 5, are fabricated into segments consisting of several vanes each. The fixed vanes have removable interstage honeycomb shroud segments attached to their inner bands that interface with the labyrinth rib seals on the rotor spool diameter.

Sector wear guides protect the vanes, liners (configuration 1) and casing from wear.



HPC Front Stator Assembly Components

Variable Vane Actuation

Actuation of the variable vanes is accomplished with hydraulically actuated bell crank assemblies mounted on the front compressor stator at the 2 and 8 o’clock positions. Adjustable linkages connects the bell cranks toactuation rings. Lever arms attached to the variable vanes connect to the actuation rings. Fuel from MEC is used to operate the hydraulic actuators.




Variable stator vane attachment assembly

Typical for stages 1 through 3 Typical for IGV’s except inner trunnion bushing

Bushings are installed from the outer side of the stator case VSV hole and on the inside of each VSV hole an inner washer provides sealing for the compressor air path. The interstage seal retains the shroud pins in addition to sealing the area between the vane inner diameter and compressor rotor. In the actuation rings, at stages 1-3, bushings are installed to interface with the lever arm of the VSV assembly.

For the IGV variable stage, the attachment assembly is the same at the case, lever arm and actuation ring as for stages 1-3, but each IGV and inner trunnion bushing is assembled to the shroud segments and held in place with a retainer, or on some later designs, bolted to the forward shroud segment.




Stage 5 bleed manifold, fourteen segments bolted to the inner flange of the forward aft compressor case, provides a flow path for the air extraction at the three large holes for customer 5th stage bleed (two in the upper half extension case at 12 and 2:30 o’clock positions/ALF and one in the lower half extension case at the 8:30 o’clock position/ALF). A new configuration has replaced the fourteen segments with segments machined as an integral part of the case. The forward flange of the HPC rear case rests on these brackets.

Extension case encloses rear stator case and contains threaded bosses at the 5 o’clock position/ALF for the outer portion of stage 6-8 borescope plugs.

Borescope ports at all five stages plus IGV’s at approximately 5 0’clock position/ALF.

Core engine major module dimensional data plate (5 o’clock ALF, attached to flange N)



Fourteen (14) bracket segments

Core Major Module – Rear Stator Case

Description:

The rear stator assembly is located inside of the front stator assembly extension and is cantilever mounted to the rear stator support. The rear stator support outer flange is mounted between the compressor front stator extension and the combustion case.



Cantilever support

Rear case rests on brackets

Core Major Module – Rear Stator Case (cont.)

Components:

Casing:

Casing halves (configuration one) Pre S/B 72-015

The rear casing halves are a matched set machined from an inconel forging. The casings have internally machined circumferential slots that retain stage 6,7 and 8 stator vane segments and stages 6, 7, 8 and 9 liners.

Liners

Configuration one has replaceable liners between each stage of vanes. Liners provide a rubbing surface for the rotor blades. Configuration two is linerless. The rub coating is applied directly to the casing lands.



Liners


Description:

Post S/B 72-015

The rear casing quarters are a matched set machined from inconel castings. The upper and lower halves are permanently bolted together at 12 o’clock and 6 o’clock. The configuration two casings have internally machined circumferential slots that retain stages 6,7 and 8 stator vane segments and stages 6,7,8 and 9 Metco 450 coated rub lands.



Split Line


Vanes

The stage 6,7 and 8 stages vanes are manufacture in replaceable vane segments. They have removable honeycomb seals that meet with the knife edge seals on the compressor rotor.




Core Major Module – combustion section

Purpose

The combustion section is a place to effectively blend and burn the fuel/air mixture at the proper ratio for top performance /efficiency of the engine.

Components:

The combustion case encloses the combustion chamber and high pressure turbine (HPT) components. The combustion chamber, compressor rear stationary (CDP) seal, HPT nozzle assembly, HPT Rotor and HPT shroud/stage 1 LPT nozzle assembly are mounted in and structurally supported by the combustion case. The case mounts and positions the 20 fuel nozzles, two igniter plugs, and fuel manifold.




High Pressure Turbine (HPT) HPT Shroud Support and Stage 1 LPT Nozzle

Core Major Module – Combustion Case

Description:

The combustion case is a fabricated structural weldment located between the high pressure compressor (HPC) and the low pressure turbine (LPT). It provides the structural interface, transmits the engine axial load, and provides gas flow path between the compressor and LPT. The case incorporates the HPC outlet guide vanes (OGV) and a diffuser for the reduction of combustion chamber sensitivity to the compressor air velocity profile.

There are six borescope ports: four for inspection of the combustion chamber and HPT nozzles, and two for inspection of the HPT blades, HPT shrouds and the 1st stage LPT blades. The case has four ports for extraction of compressor discharge air for aircraft systems use, four ports for introduction of 5th stage compressor air for Stage 1 LPT cooling, and three ports for HPT shroud support cooling air for HPT Clearance Control . There is also one port for the CDP (PS3C) sensing tube which connects to the main engine control (MEC), two ports for spark igniters (4 and 8 o’clock positions) and 20 ports for fuel nozzles.



Core Major Module – Combustion ChamberDescription:

The combustion chamber is a short, annular structure. The design of the combustion chamber, along with the swirler nozzles, and high pressure/temperature air, produces fuel-air mixing to provide a uniform combustion pattern and low thermal stresses. The combustion chamber, contained in the combustion case, consists of outer and inner cowls, 20 primary swirl nozzles, dome, and outer and inner liners. The outer liner and inner cowl are either bolted or welded to the dome. The inner liner and inner cowl are bolted to the dome at a common joint.

Components:

Dome

The dome consists of both cast and machined components. 20 primary s wirl nozzles and 20 secondary swirl nozzles with venturi’s and sleeves are used to provide mixing of air and fuel. The entire surface of the dome is cooled by a film of air.

Cowls

The inner and outer cowls are designed to provide uniform and stable airflow profiles to the combustion chamber.

Liners

The outer and inner liners are of an integral design with panel overhangs which contain closely spaced holes for film cooling. Dilution holes are employed in the liners to provide additional mixing and cooling air which lowers the gas temperature at the turbine inlet. The outer liner contains two ferrules for the igniters. The Inner liner is bolted between the HPT nozzle and the HPT nozzle support. The out liner mates with the inner surface of the combustion case and is aligned by tabs. The aft end of the liners interface with the HPT through leaf seals.



Core Major Module – High Pressure Turbine NozzlePurpose:

Direct the combustion gasses onto the HPTR.

Description:

The high pressure turbine (HPT) nozzle is a single-stage air cooled assembly that is mounted in the combustion case and directs the gas flow from the combustion chamber onto the blades of the HPT rotor at the optimal angle. The major parts of the nozzle are 23 nozzles segments, outer support, and inner support. The aft support and seal assembly and the aft stator seals, while not integral components of the HPT nozzle module are included since they attach to the HPT stator parts.



Core Major Module – High Pressure Turbine Nozzle (cont.)

Components:

Nozzle segments

The HPT nozzle segments are assemblies of 2 vanes brazed into inner and outer platforms. Each vane is a cast shell divided into forward and aft compartments by an inner rib. The vanes and platforms are cooled by compressor discharge air (CDP) entering the vane compartments through inserts in the inner and outer ends of vanes and exiting through the vane leading and trailing edges. The vanes and platforms are made of a high strength cobalt base alloy with a protective coating on the vane airfoils and on the platform flow path surfaces.


Trailing


HPT Nozzle Segment

Core Major Module – High Pressure Turbine Nozzle (cont.)

Inner and Outer supports

The nozzle inner and outer supports are both one-piece nickel base alloy rings. The major portion of the nozzle axial load is carried by the inner support through the bolted flanges of the support and nozzle inner platforms. The outer support carries a minor portion of the load.

Aft outer support and seal

The aft outer support is a one-piece nickel base alloy ring that provides support for the four-step honeycomb seal that mates with the HPT rotor inducer seal to help maintain the proper amount of cooling air flow and rotor thrust.

Aft stator seals

The aft stator seal segments form a seal ring which controls the amount of cooling air leakage that passed between the seal and the HPT blades.



Core Major Module – High Pressure Turbine Rotor

Description:

The high pressure turbine (HPT) rotor is a single-stage, air-cooled, high efficiency turbine. The rotor consists of the front shaft, the front rotating air seal, the bladed disk, and the rear shaft. The HPT rotor drives the compressor rotor and is directly connected to it by a bolted flange to form what is essentially a single core rotor. The rotor is internally cooled by low pressure compressor (booster) discharge air. It has interference rabbeted flanges for rigidity and stability. The four main structural parts are made of high strength nickel alloys.



Core Major Module –High Pressure Turbine rotor (cont.)Front shaft

The front shaft forms the structural connection between the compressor rotor and the HPT rotor, and supports the aft end of the compressor rotor.

Disk

The HPT disk is a forged and machined part that retains the turbine blades in axial dovetail slots. The inner part of the disk is cooled by booster discharge air. The outer part of the disk is cooled by compressor discharge air.

Rear shaft

The rear shaft is bolted to the aft side of the disk at a rabbeted flange and forms the aft support for the HPT rotor. The shaft is supported by the NO. 4 roller bearing which rides on the low pressure shaft. Repairable abrasive-coated seals are machined as an integral part of the rear shaft.

Front rotating air seal

The front rotating air seal is bolted between the disk and the front shaft of the rotor. It forms a cavi ty between itself and the disk to direct compressor discharge air against the disk web and out through the turbine blades. The seal is a labyrinth inclined tooth form that reduces leakage past the seals. The seal teeth are abrasive coated and repairable.

Blades

The blades are made of a high temperature nickel alloy with a high strength to weight ratio. They are a single-shank design and are individually replaceable. The single-stage design allows for better air cooling and lower metal temperature. The blades are internally cooled by compressor discharge air entering through the blade root and exiting through holes in the leading edge tip, and trailing edge.



Core Major Module – High Pressure Turbine Shroud and Stage 1 LPT NozzleDescription:

The high pressure turbine (HPT) shroud and stage 1 low pressure turbine (LPT) nozzle assembly is located inside the aft end of the combustion case. It forms the interface between the core section and the LPT module. The forward flange of the assembly is bolted to the inner surface of the combustion case. The aft flange is bolted between the combustion case aft flange and the LPT stator forward flange. The shroud/nozzle support assembly has a thermal response (turbine clearance control) matched to the rotor to provide optimum tip clearance control and structural stability. An air cavi ty between the shroud/nozzle support assembly and the combustion case directs 5th and 9th stage compressor bleed air onto the support. This cooling air maintains a closer clearance between the shrouds and the rotor blades.

The stage 1 LPT nozzles direct the core engine exhaust gas onto the stage 1 LPT blades. An air cavity between the stage 1 nozzle support and the combustion case directs 5th compressor stage bleed air through the nozzle vanes for cooling. After passing through the vanes, the air pressurizes and cools the cavity between the aft side of the HPT rotor and the forward side of the LPT rotor.

The assembly is bolted between the LPT case forward flange and the combustion case aft flange. Borescope ports at 5:30 and 8:30 o’clock are provided in the support to allow ins pection of the nozzle area.

Components:

Shroud/nozzle support assembly

The shroud/nozzle support assembly forms the outer shell of the assembly and provides an air space or manifold area between the outer shell and the combustion case. High pressure compressor bleed air is introduced into the manifold area to provide cooling for the HPT shrouds and the LPT nozzles.



HPT Shroud and Stage 1 LPT Nozzle Support Assembly

Core Major Module – High Pressure Turbine Shroud and Stage 1 LPT Nozzle (cont.)

HPT Shrouds

The HPT shrouds have a smooth abrasive rub surface that is tolerant to localized blade tip rubs and has good resistance to erosion from hot exhaust gasses. The shrouds are held in place on the support by retainers and are individually replaceable.



Core Major Module – High Pressure Turbine Shroud and Stage 1 LPT Nozzle (cont.)

Stage 1 LPT Nozzle Segments

The assembly has 28 LPT nozzle segments, each having 3 vanes. The nozzle segments are installed in the shroud /nozzle support assembly and are held in place on the nozzle inner air seal by the stationary air seal which is bolted on the aft face of the inner air seal.



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Cfm56 3-core majormodule