HAL

PROJECT ON CONSTRUCTION AND MECHANISM OF AL31FP ENGINE

HINDUSTAN AERONAUTICS LIMITED, KORAPUT DIVISION, ODISHA

SUBMITTED BY: SUBHASIS NAYAK  V.T. NO: 8377

Acknowledgement We take immense pleasure in thanking , Training and Development Institute, HAL for having

permitted us to to carry out the vocational training at

Hindustan Aeronautics Limited, Engine Division, Koraput. We wish to express our deep sense of gratitude to our internal guide, for his able guidance and useful suggestions, which helped us in completing the project work in time. Words are inadequate in the offering thanks to the project assistants, HAL for their encouragement and cooperation in carrying out the project work. SUBHASIS NAYAK

NATIONAL INSTITUTE OF TECHNOLOGY, ROURKELA

CERTIFICATE This is to certify that SUBHASIS NAYAK  pursuing B.TECH (MECHANICAL ENGINEERING) from NATIONAL INSTITUTE OF TECHNOLOGY,ROURKELA has successfully undergone one month vocational training at HAL, ENGINE DIVISION, KORAPUT from 2 MAY to 01 JUNE 2014. He has taken keen interest in absorbing the aerospace technologies and completing the project on “ CONSTRUCTION AND MECHANISM OF  AL31FP ENGINE during his training period at HAL. During their training  period they have been familiarized with assembly and application of various machining and manufacturing processes used in production of different SUKHOI variant engines. ”

We found him sincere, hardworking and his performance was excellent during the training period. His character and conduct was also found very good. We wish him good luck in his future endeavour.

MR. S.K.BISHOYI

MR. S.D.SATISH CHANDRA

MANAGER

MANAGER

(GEARBOX CASING SHOP)

(HR-TRG)

PROJECT GUIDE

Hindustan Aircraft Limited was found by Late Shree Walchand and Hirachand at Bangalore in Karnataka on 23rd December 1940, in association with the Government of Mysore which was first started for overhauling of aero-engines that were handed over by England to the United States Air Force. There after an overhauling branch opened at Bangalore. In June 1942, Government of India purchased the interest of the company and took over its management. HAL was first started for overhauling of aero-engines for HARLOW TRAINER AND CURTIS HAWK FIGHTER AIRCRAFT LIMITED. The company was started between Second World War. After 1945, the company came under the administrative control of the Ministry of Industry and Supply. Since then, there has been continuous expansion of HAL Company.

Presently there are 19 production divisions and 10 R& D centres of HAL all over the country:-

•

Bangalore

(Karnataka) : Head office

•

Barrackpore (West Bengal)

•

Koraput

(Odisha)

•

Hyderabad

(Andhra Pradesh)

•

Korwa

(Uttar Pradesh)

•

Lucknow

(Uttar Pradesh)

•

Kanpur

(Uttar Pradesh)

•

Nasik

(Maharashtra)

•

Kasargarh

(Kerala)

There are 5 main complexes of HAL for the design,manufacturing , and overhauling of the fighter aircrafts, engines and helicopters and its accessories :•

Bangalore complex

•

MIG complex

•

Accessories complex

•

Design complex

•

Helicopter complex

•

Air craft division and Overhaul division, Nasik: Manufacturing and overhaul of MiG series & Su30 MKI air Frames.



Engine division, and SUKHOI Engine division, Koraput : Manufacturing and overhaul of MiG series engines engines for Su 30 MKI aircrafts.

and AL31FP

The indigenous names of the HAL products:-

SL NO.

AIRCRAFT

ENGINE

INDIGENOUS NAME

1.

MiG-21FL

R11-F20

BADAL

2.

MiG-21BIS

R-25

VIKRAM

3.

MiG-29

RD-33

VAJ

4.

GNAT

ORPHEUS-701

AJEET

5.

HT-2

ORPHEUS-703

MARUT

6.

HJT-36

VIPER-11

KIRAN

7.

JAGUAR

ADOUR MK-803

SAMSHER

8.

MIRAGE-2000

M-53

VAJRA

9.

AN-32

HS-748(AVRO)

SATLUJ

10.

LCA

KAVERI

TEJAS

This division which comes under MiG complex of HAL , specializes in MiG series engine design and AL 31FP engines. The name MiG was given after two Russian designers Mikoyan and Gurevich. The floor area of Koraput division is 109212sq.m. Plant and machinery have been provisioned for the manufacture of 120 engines of F2 series and overhaul of 144 engines per annum, on two initially. Subsequently, plant and machinery for overhaul engines was increased to 160 in the calendar year 1981-82 and to 256 during 1990-91.This division is presently engaged in the manufacture of RD33 engines fitted to MiG-29 aircraft. Annual task envisages overhaul of R25, R29B and RD33 engines fitted on MiG-21, Mig 27M and MiG 29 aircrafts respectively. The new SE division also deals with the overhaul of and the manufacture of AL31FP engine fitted on Su- 30 MKI aircrafts.

• FULL FLEDGED QUALITY ASSURANCE DEPARTMENT WITH • DEDICATED FACILITIES, QUALIFIED, EXPERIENCED AND TRAINED MANPOWER. • CENTRAL LABORATORY WITH DEDICATED FACILITIES OF NDT, MATERIAL TESTING, FATIGUE AND CREEP ANALYSIS. • GAS TURBINE R&D CENTRE TO CATER TO DESIGN AND DEVELOPMENT ACTIVITIES AND LIFE EXTENSION STUDIES. • INDIGENISATION DEPARTMENT TO ESTABLISH ALTERNATE SOURCES FOR METALLIC / NON-METALLIC MATERIALS AND COMPONENTS. • PRODUCTION ENGINEERING DEPARTMENT TO COORDINATE MATERIAL PROVISIONING, PLANNING AND CONTROL ACTIVITIES. • CUSTOMER SUPPORT SERVICES TO PROVIDE TOTAL INTERACTION WITH CUSTOMER ON LOGISTICS, TECHNICAL  AND TRAINING REQUIREMENTS.

SOME DEFINATION RELATED TO JET ENGINE 1.  Engine: Engine is a machine which converts chemical energy of fuel into heat energy to do work. 2. Aero engine:  Aero engine is a machine which transforms potential energy contained in the fuel and air into kinetic and / or mechanical energy. 3. Gas Turbine Engine:  A type of engine which transforms energy by means of a compressor, combustion chamber and turbine. 4.  Turbine: Turbine is a wheel which derives its power from the motion of a fluid. 5.  Propulsion: Imparting acceleration to a certain mass. 6. Thrust:  A gas jet exhausting at high velocity from a nozzle generating a force in the opposite direction is termed as thrust. 7. Turbo jet: All air flow goes through a gas generator i.e. compressor, combustion chamber and turbine. 8. Bypass Turbo jet:  It admits more air than necessary for Gas Generator, additional flow by-passing the Gas Generator. 9. Twin spool bypass Turbo jet:  A generator incorporates two independent rotating assemblies. A low pressure turbine and high pressure turbine shaft runs coaxially e.g. AL-31FP, RD-33 engine.

Aim of jet engine  Aim of jet engine is to generate hot gases at a pressur e much higher than ambient pressure for expansion in a nozzle to produce thrust. Central element of jet engine is gas generator which comprises of compressor, combustion chamber and turbine. By adding an inlet and a nozzle, a turbojet results.

Working principle of a jet engine / gas turbine engine The aviation gas turbine engine is categorized as a heat engine. It uses gas as its working fluid and produces (mechanical) shaft power and thrust. Generating thrust, in particular, is possible only if the exhaust velocity of gas is higher than the velocity at which air enters the engine. In order to accelerate the gas, energy must be added to the airflow within the engine which can then be converted into kinetic energy. In a gas turbine engine, the increase of energy is accomplished in two consecutive steps, and by two different, though adjacent, engine components. First, pressure of the airflow is raised by action of mechanical shaft power. This is done in the compressor section. After its discharge from the compressor, the pressurized air enters in the combustion chamber, where the fuel and pressurized air burns, thereby temperature of the gas is steeply raised (due to chemical reaction of air and fuel mixture). The gas is now sufficiently processed to provide physical work for the turbine, the first station within the engine where work extracted from the hot gas is turbine. As the gas expands and accelerates, it rotates the turbine which in turn rotates the compressor as turbine is directly coupled to the compressor by a shaft (spool). After discharging from the turbine, the gas is further accelerated in the exhaust nozzle, where all remaining usable heat energy is converted into kinetic energy which produces thrust for moving the aircraft forward (Newton Third Law). Explanation of working principle ( Fig 2.1) A. The air from atmosphere is taken in through a simple or complex air intake depending on the flight speed and geometry ofthe aircraft air intake.

B. Air is compressed in a centrifugal or axial flow compressor to increase the pressure and temperature of air .

C. Compressed air enters in combustion chamber where fuel is injected and burned, thus adding more energy to airflow. Temperature of gas increases where as pressure remains constant.

D. Part of the energy generated is used to run a turbine Which provides power for running the compressor and also Some accessories necessary for engine operation.

E. The remaining energy of gas stream is converted into Kinetic energy by exhaust nozzle to produce thrust. High exhaust velocity is prerequisite to generation of thrust.

The main function of any aero plane propulsion system is to provide a force to overcome the aircraft drag, this force is called thrust. Both propeller driven aircraft and jet engines derive their thrust from accelerating a stream of air the main difference between the two is the amount of air accelerated. A propeller accelerates a large volume of air by a small amount, whereas a jet engine accelerates a small volume of air by a large amount. This can be understood by Newton's 2nd law of motion which is summarized by the equation F=ma (force = mass x acceleration). Basically the force or thrust (F) is created by accelerating the mass of air (m) by the acceleration (a).

A propeller accelerates a large volume A jet engine accelerates a small volume of air by a small amount

of air by a large amount

Given that thrust is proportional to airflow rate and that engines must be designed to give large thrust per unit engine size, it follows that the jet engine designer will generally attempt to maximize the airflow per unit size of the engine. This means maximizing the speed at which the air can enter the engine, and the fraction of the inlet area that can be devoted to airflow. Gas turbine engines are generally far superior to piston engines in these respects; therefore piston-type jet engines have not been developed.

The gas turbine engine is essentially a heat engine using air as a working

fluid to provide thrust. To achieve this, the air passing through the engine has to be accelerated; this means that the velocity or kinetic energy of the air must be increased. First, the pressure The operation cycle of a gas turbine

energy is raised, followed by the addition of heat energy, before final

conversion back to kinetic energy in the form of a high velocity jet. The basic mechanical arrangement of a gas turbine is relatively simple. It consists of only four parts 1.The compressor, which is used to increase the pressure (and temperature) of the inlet air. 2. One or a number of  combustion chambers in which fuel is injected into the high-pressure air as a fine spray, and burned, thereby heating the air. The pressure remains (nearly) constant during combustion, but as the temperature rises, each kilogram of hot air needs to occupy a larger volume than it did when cold and therefore expands through the turbine. 3. The turbine which converts some of this temperature rise to rotational energy. This energy is used to drive the compressor. 4. The exhaust nozzle which accelerates the air using the remainder of the energy added in the combustor, producing a high velocity jet exhaust.

A schematic of a gas-turbine engine (turbojet)

AL31-FP ENGINE  1. Sukhoi SU-30 MKI, (Russian:   Modernizirovannyi Kommercheskiy Indiski; Modernized Commercial India), is the variant of the Sukhoi SU-30.   The SU30 MKI a highly specialized aircraft developed for the   Indian Air Force.   It is a heavy class, long-range, multi-role, air superiority fighter and  strike fighter. The variant also consists of French, Israeli and Indian subsystems. The MKI variant is a much more advanced fighter jet than the basic K and MK variants and is considered a 4.5 generation aircraft. The MKI variant is considered to be the most advanced fighter aircraft of Russian origin in service. 2. Aircraft SU-30MKI is a multipurpose twin seated supersonic fighter designed to destroy air targets in free space and against the earth background both by day and at night under visual and adverse weather conditions and to engage ground and surface targets within tactical and operational depths under heavy noise conditions as well. 3. To destroy aerial targets, a provision is made for employment of all angle medium-range missiles (active, semi-active radar and infra-red guid ed missiles) and short-range missiles (infra- red guided missiles) capable of high target hit probability. 4. To destroy ground targets, use is made of unguided bombs, guided bombs and missiles. The aircraft is also equipped with a rapid fire gun mount with caliber of 30 mm. 5. The aircraft is also intended for training, acquisition (perfection) of skills in flying techniques, air navigation and combat employment in cluding participation in group combat actions.

TECHNICAL INFORMATION 6. The SU-30MKI is powered by the two AL-31FP turb ofans (P for Povorotnoye meaning "Movable"), Each AL-31FP is rated at 12,500 Kgf (27,550 lbf)   of full afterburning thrust with the capability to vector in 2 planes. The TVC nozzle of the MKI deflects 32 degrees in the horizontal plane and 15 degrees in the vertical plane. This is done by angling them inwards by 15 degrees, which produces a cork-screw effect and thus enhancing the turning capability of the aircraft. The TVC nozzle is made of Titanium to reduce the nozzle's weight. The two nozzles can be vectored asymmetrically, i.e. each nozzle can point at different directions independent from the other nozzle and thus multiplying the effect. Two AL-31FP by-pass thrust-vectoring turbojet reheated engines (25,000 Kgf full afterburning thrust) ensure a 2Mach horizontal flight speed (a 1350 km/h ground-level speed) and a rate of climb of 230 m/s.

7. The mean time between overhaul for the AL-31FP is given at 1,000 hours with a full-life span of 2,000 hours. The Titanium nozzle (TVC) has a mean time between overhaul of 500 hours. The pilot controls the aircraft with help of a standard control stick. On the pilot's left, there is a switch which is turned on for performing difficult maneuvers. After the switch-over, t he

computer determines the level of use of aerodynamic surfaces and swiveling nozzles and their required deflection angles

Full form of AL-31FP

AL 31FP-

Arxip Lyolka Series Farsa Povorotnoye

(Name of designer) (Name of designer) (Reheat/After Burner) (Movable/TVC)

Special features of the engine : -

(a)

It is a by-pass engine with a by-pass ratio of 0.57: 1. Mass flow of

exhaust gases is increased by addition of by-pass air at the exit, thereby increasing propulsive efficiency. (b)

Inlet guide vanes of LP compressor, inlet guide vanes of HP

compressor and 1st & 2nd  stage stator blades of HP compressor are variable. They regulate the airflow to LP compressor and HP compressor depending on engine rating. (c)

The engine has convergent –divergent swivelling exhaust nozzle,

which enables efficient expansion of exhaust gases for improved engine performance and high manoeuvrability for tactical advantage in combat operation. (d)

The engine parameters are automatically controlled by Electronic

Engine Controller (KRD – 99B). (e)

The engine has a “Special” mode of operation with certain

limitations (BP Mode) to have additional thrust in combat operations. In this mode, the thrust increases by 6 to 8% (750  – 1000 kgs) above max. Reheat thrust. (f)

Anti-surge system incorporated in this engine ensures suitable

corrective action in case of surge. (g) Effective and efficient cooling of engine turbine. (h)

A very high thrust to weight ratio i.e. 8: 1.

AL31FP

Dry Weight (Kg)

1570

Length (mm)

4950

inlet Dia. (mm)

910

External Dia(mm)

1280

LP Rotor RPM N1 (100%)

10,200

HP Rotor RPM N2 (100%)

13,300

LP Compression Stage

4

HP Compressor Stage

9

LPC Compression Ratio

3.5:1

HPC Compression Ratio

6.6:1

Total Compression Ratio

23:1

Combustion Chamber

Annular

TET (T3) Deg. C Max.

1392

JPT (T4) Deg. C Max.

765

Thrust at Max. Dry(Kgf)

7670

Thrust at Max. AB(Kgf)

12500

S.F.C (Kg/Kg/Hr)

0.67-1.96

Air Mass Flow (Kg/Sec)

112

By Pass Ratio

0.571

TBO/TTL (Hrs.)

1000/2000

CONSTRUCTIONAL DETAILS OF AL-31FP AERO ENGINE

1.

The AL – 31 FP engine consists of the following main assemblies (a)

Inlet guide vane assembly.

(b)

LP compressor assembly.

(c)

Intermediate Casing.

(d)

High Pressure Compressor.

(e)

Main combustion chamber.

(f)

Turbine and Nozzle Guide Vanes Assembly.

(g)

After Burner Assembly.

(h)

Thrust Vectoring Nozzle Assembly

(i)

External Housing

(j)

Accessory Drives Gear Box.

Engine Internal view

1. Inlet Guide Vane Assembly ; The purpose of IGV assembly is to vary the inlet cross-section area of LP compressor. It is made of Titanium alloy. It is a load-carrying member of the engine. It consists of external and internal rings connected by 23 movable inlet guide vanes. The circular cavity on the external ring forms a channel to convey hot air tapped from HP compressor seventh stage for engine anti- icing system. The IGVs are hollow and they are in two sections. Their leading edge is stationery and trailing edge is movable, having a deflection from -30 to 0° and controlled by LP IGV control system by arms through drive ring with ten retainers located around its circumference. The stationary vanes are attached to the external ring with the help of threaded studs and nuts, end faces which are smooth and flushed with skin. 2. Low Pressure Compressor: The purpose of low-pressure compressor is to compress the air and supply to engine by-pass duct and main duct. It consists of rotor and stator assembly. (a) LP Compressor Rotor: It is of cylinder type construction. It has two supports- Front roller bearing and Rear ball bearing. Main elements of rotor are Blades and Discs. There are slots between the rotors for accommodating the stator rings and thus separating rotor from stator. The rotor comprises of three sections: (i) The first section cannot be dismantled. It consists of front journal, first stage disc and second stage disc, which are connected to each other by electron beam welding. (ii) Second section includes the disc of 3rd stage and the inclined back  journal. (iii) The third section includes the disc of 4th stage and is also interconnected with second section by flange, nut and bolt. (b) LP Compressor Stator Blade Assembly : The casings of stator blades 1, 2, 3 stages are connected to the flanges with the help of special bolts (self locking nuts). It has outer and inner shrouds. The outer shrouds have grooves in casings. The semicircular rings of inner shrouds are fixed geometrically with root of blade. Special soft cover is placed on inner surface of semicircular ring. The design of 4th  stage is similar to 2nd  and 3rd  stage, but they are in two rows. The blades are welded to the inner and outer ring. Space ‘Γ’ above the blades communicates with compressor air flow duct through slots ‘Б’ and form slot type blow off to expand the range of the compressor stable operation modes. The casings are provided with inspection holes ‘E’ for

visual inspection by endoscope. The front flange connected to IGV assembly, rear flange connected with intermediate casing. 3. Compressor Intermediate Casing: It is the primary loadcarrying member of the engine. The air delivered from LP compressor is divided into by-pass and main duct airflows. Thrust from the engine is transferred to aircraft through this casing. It consists of outer ring, inner ring and splitter nose ring. 12 hollow struts connect all three rings with each other. The struts are numbered clock wise viewed from rear. It is a welded construction. The following assemblies are mounted in the intermediate casing: (a) (b) (c) (d)

LP compressor outlet guide vane assembly (4th  stage stator casing of LPC). LP compressor rotor rear bearing support. HP compressor rotor front bearing support. Central bevel gear assembly.

The purpose of High-pressure 4. High Pressure Compressor: compressor is to compress the air delivered to the engine main duct. It consists of stator and rotor assembly. .

(a)

HPC Stator Assembly : It comprises of: -

(i) First casing which accommodate IGV and first stage stator blades. (ii) Second casing which accommodates second and third stage stator blades. (iii) Rear casing accommodate fourth to eighth stage stator blades. (iv) Ninth stage stator blades are installed on combustion chamber casing.

5. HP Compressor Rotor Assembly ; construction consisting of:-

It

is

drum

disc

type

(a) Section I: It cannot be dismantled. All the discs are electron beam welded. This section includes the disc of 1, 2, 3 stages rotor blades. (b) Section II : The second section comprises of the discs of 4, 5 and 6 stages of rotor blades. It has cone type flanges for load bearing. 1st and 2nd sections are attached to each other by means of bolts at the

specified place of flange. The front trunion is also fixed to these sections with same bolts. (c) Section III: It includes the discs of 7, 8 and 9 stages of rotor blades and another disc with labyrinth sealing. These discs are connected to cone type rear flange of section by bolts. There are three spacer rings installed between the casings to maintain the requisite clearance. The special bolt passes through these rings, discs and is finally attached to the turbine shaft. It transmits torque from HP turbine rotor

6. Combustion Chamber : The combustion chamber is of annular type, consisting of outer casing, inner casing and flame tube. The fuel manifold supplies fuel to the combustion chamber through 28 dual orifice burners. Fuel is ignited by two igniters (3 & 9’O clock position)

7. Turbines and Nozzle Guide Vane Assembly; The turbine section incorporates HP and LP single stage axial turbines arranged in series and the bearing support as well. The High Pressure Turbine rotates the HP compressor and the units installed on the aircraft accessory gearbox (AAGB) and on engine accessory gearbox (EAGB).The Low Pressure Turbine rotates the LP compressor.Each turbine consists of a rotor and nozzle guide vane assembly. The bearing support of the turbine section is a load-carrying member of the engine. The radial loads are transmitted from the HP and LP turbine rotors to the bearing support via the inter rotor bearing. LP turbine shaft and LP turbine rotor bearing located in the bearing support. The turbine section comprises the bearing support casing and bearing casing. 8.

After burner Assembly ;

After burner consists of the following:

(a) Exhaust Mixer. It is intended to mix main duct gas stream with by-pass air flow before transition section. (b) Transition Section. It is designed to provide for the steady burning of fuel in the A/B.

(c) After burner casing. It consists of casing and shield. Some portion of the by-pass air is supplied into the space which is formed by shields and walls of transition section casing and after burner casing to cool the jet nozzle and casings. (d) Exhaust Fairing. It is designed to decrease the exhaust gas energy losses. The exhaust fairing perforations are intended to decrease the after burner intermittent burning.

(10) Thrust Vectoring Control Nozzle Assembly

The thrust vectoring variable area jet nozzle is an all mode super sonic convergent and divergent nozzle. It comprises of:(a) Tilting Device: The tilting device consists of fixed casing and movable casing. Fixed casing is hinged to movable casing by means of two pivots. The movable casing is turned with respect to the fixed casing by a maximum angle of ±14° by means of two pairs of hydraulic cylinders located on both sides of the horizontal axis of the tilting device. The hinge pin of the tilting device is turned relative to the horizontal plane by an angle of 32° counter clock wise for LH engine and clockwise for RH engine viewed from rear. (b) Sub-sonic jet nozzle It is convergent nozzle (Subsonic section) with synchronization drive and control mechanism to control the nozzle throat area 16 convergent nozzle shutters with 16 sealing spacers forms the convergent sub sonic jet nozzle. The shutters are controlled by 16 hydraulic cylinders. The hydraulic cylinders are fuel operated to actuate the jacks. A high pressure pump (NP-160D) delivers fuel under pressure to the jacks. The control is carried out by Engine Nozzle and After burner Controller (RSF 31BTI). (c) Supersonic Jet nozzle. It is a divergent nozzle (Supersonic section) with synchronization drives and control mechanism to control the jet nozzle exit area by outer shutters. 16 divergent nozzle shutters with 16 sealing spacers forms the divergent supersonic section of jet nozzle. These shutters are controlled by the hydraulic cylinders. There

are 16 Pneumatic cylinders to limit the maximum exit area within the operating limits.

Engine Main Bearings (Total No. 6) (A)

LP ROTOR RESTS ON FOUR BEARING SUPPORTS.

(i) Front support bearing (roller), located in IGVcasing. (ii) Rear support bearing (ball bearing), located in the intermediate casing. (iii)LP turbine rotor front support bearing (roller bearing)located in the intermediate casing (arranged in the drive gear shaft of central bevel gear). (iv) Tail support bearing (roller bearing) located in the turbine bearing housing. (B) HP ROTOR RESTS ON TWO BEARING SUPPORTS. (i) Front bearing support (ball bearing), located in the intermediate casing. (ii) Rear bearing support (roller bearing), located on the LP turbine shaft. Intermediate casing is the primary load carrying member.

1.

Roller bearing of LP compressor rotor front bearing support.

2.

LP rotor.

3.

Ball bearing of LP Compressor rotor rear bearing support.

4.

Roller bearing of LP turbine rotor front bearing support.

5.

Ball bearing of HP rotor front bearing support.

6.

HP rotor.

7.

Roller bearing of HP rotor rear bearing support.

8.

Roller bearing of LP turbine rotor tail bearing support.

AIRCRAFT ACCESSORY GEAR BOX (AAGB) 1. Purpose. The purpose of aircraft accessory gear box (AAGB) is to transmit rotary motion from the engine accessory gear box (EAGB) to the aircraft accessories, when the engine is running. During engine starting, the drive is transmitted from the Turbo Starter to the high pressure rotor (HPR) via AAGB, flexible drive shaft, EAGB and vertical torsion shaft. After engine start up the drive load is taken up by HPR. There are two AAGB on the aircraft. 2.

Components and Accessories mounted on AAGB ;

The following components are mounted on AAGB:(a)

Turbo starter GTDE-117-1.

(b)

Two oil scavenge pumps for scavenging oil from AAGB only.

(c)

One hydraulic pump (NP-128).

(d)

N2 RPM TachoGenerator (D-3M).

(e)

N2 RPM transmitter (Dchv-2500).

(f)

One centrifugal fuel booster pump (DTsN -80).

(g)

AC Generator with constant speed drive (GP-25-2).

3. Coupling of AAGB with EAGB. The AAGB is coupled with EAGB by means of the flexible shaft (Fig 5.2). The construction of the flexible shaft makes it possible to compensate for misalignment of axis of the AAGB and EAGB shafts being coupled.

Flexible Drive Shaft

ENGINE ACCESSORY GEAR BOX(EAGB)

1. Components and Accessories mounted on EAGB :  following components are mounted on EAGB:(a)

Centrifugal breather

(b)

High pressure fuel pump (NP-160D)

(c)

Mechanical fuel booster pump (DTsN-82)

(d)

Oil pump block

(e)

Main fuel pump (NR-31)

(f)

After burner fuel pump (FN-31AT1)

The

TURBO STARTER (GTDE-117-1MO) Purpose . The purpose of the GTDE is: (a) To rotate the engines up to self sustaining RPM (53%) during engine starting. (b) To rotate the engines up to cranking RPM (18+3%) during cold/wet cranking and preservation/ depreservation. Description. The turbo-starter is essentially a gas turbine engine with a free turbine, which transmits power through reduction gear to an output shaft which drives the AAGB. The turbo starter consists of a single stage centrifugal compressor, combustion chamber, turbine and an accessory gear box .There is a free turbine, coupled to the output shaft through the reduction gear. Operation. Air is drawn into compressor through the air-intake. In the combustion chamber, compressed air is mixed with the atomized fuel supplied by fuel nozzle. The resultant fuel-air mixture is ignited by the igniter. This mixture is assisted with the supply of oxygen into the primary igniter for reliable light-up. The hot gases are delivered to the turbine which converts a part of the energy into mechanical energy. The torque developed by the free turbine is transmitted via reduction gear to

 AAGB. The exhaust gases are expelled into atmosphere through an exhaust pipe on board. AAGB Oil System. Oil is supplied to the AAGB and turbo starter from the engine oil system. AAGB has its own scavenge pumps and breathing system. A thermal chip detector is installed in the scavenge line of AAGB to ascertain the mechanical condition of AAGB. In the event of oil temperature exceeding 210±6°C or presence of metal chips in the AAGB oil system, “DECELERATE L(R) ENG” caption will appear on MFWS.

Accessory Gear Box & Torque Transmission GTDE FLEX. SHAFT

KDA

BKA

LPCR 

 A detailed study of the Construction and mechanism AL31FP Engine was completed. It is certainly true that engine is the heart of any aircraft.

HPCR 

HPT LPT

CONCLUSION It is therefore concluded that in a jet engine like those in AL31FP caters to the following basic functions at all engine-operating conditions, • Quick and trouble-free starting, • Smooth accelerations,

• Stable operations. Further the construction and mechanism of engine system should incorporate safety features to limit turbine entry temperature, compressor delivery pressure and engine rotor rpm within permissible limits. Quite often, the system is also called upon to perform auxiliary functions.