Kaveri engine is an afterburning turbofan project developed by the GTRE, lab under DRDO, India. GTRE is now running two separate successor engine programmes, the K9+ and the K10. Click here to know more about kaveri Engine : http://www.drdo.gov.in/drdo/English/index.jsp?pg=Kaveri.jsp

1. BULLETIN OF DEFENCE RESEARCH AND
DEVELOPMENT ORGANISATION
ISSN : 0971-4413
Technology
Vol. 17 No. 5 October 2009
Technology
GAS TURBINE RESEARCH
AS TURBINES have become essential power plants of
powerful military equipment like
aircraft, naval ships and tanks.GThe required precision manu-
facturing for components
and temperature-resistant
alloys necessary for high
efficiency often makes the
construction of a simple
turbine more complicated
t h a n p i s t o n e n g i n e s .
Defence Research and Develop-
ment Organisation (DRDO) is pioneering the
design and development of aero and marine gas
turbine engines for indigenous defence applications
besides research work in the areas of aero engine sub-
systems. DRDO has also established the requisite state-of-the-
art testing and prototype manufacturing facilities for components
andfull-scaleengines.
Gas Turbine Research Establishment (GTRE), Bengaluru, a constituent laboratory of DRDO, is entrusted with the
design and development of Kaveri engine which is an augmented low bypass twin spool turbofan engine of 80 kN thrust
class. The engine cycle is based on a detailed system analysis culminating into a potential power plant for the Indian Light
Combat Aircraft Tejas. The engine incorporates flat-rated characteristics to pre-empt and mitigate the thrust drop due to
high ambient intake temperature and/or high forward speed. Twin-lane full authority digital engine control with an
adequatemanualbackupisasalientdesignfeatureofKaveriengine.
Kaveri engines have been tested both in normally aspirated and with limited high pressure/temperature entry
conditionsformorethan1800h.Stringentstructural(safetyandlife)andaerodynamictestshavetakenupasapreludeto
officialaltitudetest,flyingtestbedtrialsandacceleratedmissiontestsleadingtoenginecertificationforairworthiness.

2. Technology
02
October09
KAVERI ENGINE COMPONENTS
Low Pressure and High Pressure Compressors
Annular Combustor
High Pressure and Low Pressure Turbines
Three-stage axial flow low
pressure (LP) compressor has
been designed with a mass
flow rate of 78 kg/s; pressure
ratio of 3.4; isentropic
efficiency of 85 per cent; and
surge margin in excess of
20 per cent. Design validation
of LP compressor has been
done for aerodynamic and
structural tests for life and
safety and the first rotor for bird
impactcharacterisation.
Six-stage axial flow high pressure (HP) compressor has been designed for a mass flow rate of 66 kg/s; pressure ratio
of6.4;isentropicefficiencyof85percent;andsurgemargininexcessof23percent.Designmethodologyisbasedon3-D
Navier Stokes code. Design validation of the HP compressor has been done for aerodynamic and structural tests for life
andsafety.
High intensity annular combustor has been designed for combustion
efficiency greater than 99 per cent, circumferential pattern factor of
0.35andradialpatternfactorof 0.14.Designanddevelopmentisbased
on computational fluid dynamics (CFD), empirical relations, water
analogy,andaero-thermaltestsathighpressure,hightemperatureand
altitudeconditionsbesidesextensivestructuralanalysis.
Single-stage cooled high pressure turbine has been designed for an
isentropic efficiency of 85 per cent and a maximum turbine entry
temperature (TET) of 1700 K. Navier Stokes codes such as TASC flow and
NUMECAhavebeenusedfordesignandanalysis.TheLPturbinerotorstage
isunshroudedwithanisentropicefficiencyof85percent.
HP compressor rotor assembly
Annular combustor
HP turbine rotor assembly
LP compressor rotor assembly

3. AfterburnerSystem
EngineGearbox
Electro-Hydro Mechanical Control Systems
The afterburner system (an additional component
added to some jet engines, primarily those on military
supersonic aircraft) provides a thrust boost of 60 per cent
over and above maximum dry thrust at an efficiency of
90 per cent, consistent light up from sea level to 11 km
altitude and stability besides buzz and screech free
operation. The burner has been designed using CFD tools
suchasFLUENTandStar-CD.
Engine gearbox (EGB) with a power rating of about
700 HP provides drive to 12 accessories of aircraft and
engineinthespeedrangeof5600-30000rpm.Castoutof
aluminium alloy, the EGB weighs less than 57 kg. It has
been tested for endurance and performance under
vibration, 'g' loads, attitude, and high and low
environmentaltemperatureconditions.
Integrated nozzle actuating system (INAS)
is used for actuation and control of the fully
variable convergent-divergent (CD) exhaust
nozzle to achieve optimum engine
performance (thrust and specific fuel
consumption) throughout the flight envelope.
INAS comprises four mechanically
synchronised hydraulic actuators (each
actuator with a load carrying capacity of 50 kN)
driven by engine gearbox-mounted integrated
hydraulicpowerpack.
October09
03
Afterburner system
Engine jet pipe with INAS and CD nozzle
Engine gearbox

4. Technology
Variable Geometry (VG)
Actuating System has been
used for varying the inlet guide
vanes (IGV) and the first two
stator blade angles, which
control the air flow direction
through the high pressure
compressor for optimising the
engine performance and
enhancingtheoperability.
Main engine control unit
and re-heat control unit supply
the fuel to the main and re-heat
combustion systems at the
desiredpressureandflowwhileensuringsmoothlightupandaccelerationof theengine.
All the electro-hydro mechanical control systems are interfaced with Kaveri digital engine control unit (KADECU) for
properclosedloopcontroloftheenginethroughouttheflightenvelope.
Kaveri Digital Engine Control Unit
(KADECU) is a microprocessor-based
real-time embedded full authority
digital control system to execute the
engine control to get optimum thrust
within safety limits. Two such units have
been mounted on the Kaveri with one
under control and the other in hot
standby mode. KADECU performs
extensive built-in test and sensor data
validation to detect failure and record
off-line analysis. Real-time monitoring
allows acquisition of data from the
control units and enables the study of
the control system performance vis-à-vis
theenginebehaviour.
GTRE has set up extensive structural test facilities for structural integrity and life evaluation of various components
and sub-systems such as fan/compressor/turbine rotor discs and blades, transmission shafts, casings, piping, engine
gearbox,etc.
KaveriDigitalEngineControlUnit
STRUCTURAL TEST FACILITIES
04
October09
Kaveri engine control unitdigital

5. Cyclicspintestfacilityisusedfor
low-cycle fatigue life evaluation of
engine rotor discs and incorporates
fully automated motor-driven
system capable of providing
variable speeds. This facility
simulates various combinations of
speedandtemperature.
Torsional test facility is used to
evaluate fatigue life of rotor shafts
under simulated torsion, axial, and temperature load conditions. The facility is capable of applying desired load profile
alongwithminorcyclessuperimposed.
Dynamic foreign body
impact test facility is used for
impact tests with simulated
bird models fired at various
speeds on rotor blades, disc
and casings. It comprises a
compressor air operated bird
g u n a n d h i g h - s p e e d
photography cameras for
monitoring the tests, both
under static and dynamic
conditions.
Full-scalepowerabsorptiontestfacilityisusedforperformanceandendurancetestingofengineaccessory gearbox
alongwithvarious LineReplaceableUnits(accessories)mountedanddulyloadedusingwaterbrakedynamometer.
Attitude testing is performed to
validate the design of Kaveri's
gearbox under attitude conditions
experienced during the flight,
including inverted flights also.
Gearbox internals experience both oil
starvation and oil flooding depend-
ing on attitudes. Performance
evaluation of the lubrication system
is the point of focus during the
subjecttest.
The casing structural test facility equipped with fatigue-rated actuators is used for structural integrity assessment of
engine frames, rotor-support structures, and engine-mount points. The system facilitates programming of desired load
spectrum,executionandmonitoringofthetestsinbothstaticanddynamicmodes.
October09
05
Dynamic foreign body impact test facility Full-scale power absorption test facility
Cyclic spin test facility Torsional test facility
Attitude test facility Casing structural test facility

6. Technology
06
October09
AERODYNAMIC TEST FACILITIES
GTRE has established in-house facilities for aero-thermodynamic performance evaluation of critical modules such
as fan, compressor, turbine, combustor, and afterburner. These facilities are equipped with extensive instrumentation
anddataacquisitionsystemsforonlinemonitoringaswellasanalysis.
Compressortestfacilityisusedtoevaluatetheperformanceoffanandcompressormodules,both underdesignand
off-designconditions.
Combustor test facility is used for evaluation of combustor system performance, both under design and off-design
conditionsofpressure,temperature andairflow.
Cold turbine test facility is used for evaluation of turbine module performance, both under design and off-design
conditions of pressure, temperature and air flow. It employs an electro-hydraulic dynamometer for power
absorption.
Afterburner test rig is used for test and evaluation of scaled-down model of engine afterburner, both under
simulatedscreechandbuzzconditionswithseveralpilotignitionsystemconfigurations.
Compressor test facility Combustor test facility
Cold turbine test facility Afterburner test facility

7. ENGINE TEST FACILITIES
SIMULATION AND ANALYSIS FACILITIES
GTRE has set up four engine
test cells for normally aspirated
condition and one test cell
capable of simulating inlet flight
conditions up to 0.4 Mach for
carryingoutperformancetests.
Test cells are designed for
normally aspirated testing
(thrust up to 20,000 kg) and
capable of carrying out engine
testing with afterburner system
(exhaust gas temperature of
>2000K).
SalientFeatures
Acoustically attenuated vertical intake and
exhaustsystems.
Roof-mounted thrust stand with off-line thrust
calibration.
Data Acquisition System (DAS) with provision of
1200channels.
Testcellsforenginebleedandpoweroff-take.
Customer bleed measuring facilities and
emergencyfuelsupply.
GTRE has also set up extensive simulation and analysis facilities to enable design evaluation, prototyping, digital
manufacturing, optimisation and assembly integration. These facilities consist of high-end hardware, and in-house and
commercialsoftwaretools.
GTRE has a computer-aided design and virtual reality laboratory for carrying out designing and validation tests. 3-D
CAD modelling of Kaveri for finite element analysis, mass property calculations, assembly integrity evaluations,
automated drafting, rapid prototyping and digital assembly manuals preparation, and enhanced visual feel of the
componentsandvirtualwalkthroughofassembliesweredoneatthislaboratory.
Computer-aidedDesignandVirtualRealityLaboratory
October09
07
Engine mounted in test cell
Engine test data acquisition system

8. Technology
08
October09
Computer-aidedEngineering
ComputationalFluidDynamics
Thecomputer-aidedengineeringfacilityisbeingusedforthefollowing:
Structural design analysis of gas
t u r b i n e c o m p o n e n t s u s i n g
NASTRAN, ANSYS, ABAQUS, LS-
DYNAandSAMCEFsoftware.
Kinematic design analysis of variable
CD nozzle and compressor variable
guide vane linkage mechanisms for
aero-engine.
Development of whole engine
model, engine static, dynamics and
blade-offsimulation.
L i f e p r e d i c t i o n o f e n g i n e
components employing in-house
practices and material characteri-
sation.
Methodology for life extension of
agingenginecomponents.
Damagetoleranceanalysisofthegasturbinecomponents.Designanddevelopmentofcompositestructures.
Computational fluid dynamics
(CFD) codes have been used
extensively for the design and
analysis of aero and marine
versions of Kaveri engine
modelling, CAD grid generation
and high performance compu-
ting form integral features of the
CFD and conjugate heat transfer
(CHT)analyses.
The parellel CFD software like
CFX TASC Flow, FLUENT, NUMECA
have been used for designing and
analysis of the engine compo-
nents.
Structural analysis of various components
Combustion flow analysis Turbine flow analysis

9. ThefollowingarethesalientfeaturesoftheCFDanalysis:
Estimationandimprovementofaerodynamicperformanceofallthemajormodulesandsub-systemsoftheengine,
viz.,fan,compressor,combustor,turbine,afterburnerwithCDnozzleandbypassduct.
Estimationofthelinermetaltemperaturesofhot-endcomponentsthroughCHTanalyses.
Estimation of the secondary air temperature rise while passing through the compressor and turbine annular disc
throughCHTanalyses.
GTRE has extensive manufacturing facilities consisting of CNC systems (machining centre, EDM wire cut and
vertical turn mill centre), investment casting, electron beam welding, vacuum heat treatment, jig boring, etc. Besides,
quality assurance and inspection facilities consisting of 3-D CMM, x-ray diffraction, ultrasonic testing, non-contact 3-D
scanning system, x-ray fluorescence spectrometer, and hard bearing balancing are also being used to maintain high
standardsoftheproducts.
MANUFACTURING, PROTOTYPING AND QUALITY CONTROL FACILITIES
October09
09
3-D CAD model Computational grid Tip clearance flows

10. Technology
10
October09
RAPID PROTOTYPING
This scaled engineering prototype of Kaveri engine has been prepared using rapid prototyping technologies of
stereolithography and fused deposition modelling using 3-D CAD model data. The entire sequence of prototyping
activitiesincludepre-processing,partbuilding,post-processing, assemblyandmounting.
KAVERI MARINE GAS TURBINE ENGINE
The Kaveri Marine Gas Turbine (KMGT) engine, a derivative of Kaveri aero engine, is also being developed as a power
plant for propelling Indian naval ships. The gas generator of KMGT is derived from Kaveri aero engine, and a two-stage
freepowerturbinehasbeendesignedtotranslatethegaspowerintomechanicaloutputtodrivetheshippropeller.

11. SalientFeatures
Output : 15MWatISA-SLS
Specificfuelconsumption : 0.27kg/kW-hatISA-SLS
Fuel : Lowsulphurhighspeeddiesel(LSHSD)
Powerturbinespeed : 5800rpm
TET : 1560K(max)
KMGT engine has successfully demonstrated output
power and SFC exceeding the specification. Spin test of
power turbine disc has been carried out using dummy
blades simulating the centrifugal load. Forty hours of test
has been successfully completed at maximum rated
speed of power turbine, thereby demonstrating the
mechanicalintegrityofpowerturbinediscassembly.
GTRE has implemented Product
Lifecycle Management (PLM) framework
for the design and development of Kaveri
and its derivatives. Team centre suite of
product was used for PLM implemen-
tation with customisation for product
design, configuration management,
change management, CAD management,
and programme management. High
performance computing facility (P 690)
and ESS800-based data centre from IBM
formsthecorehardwareinfrastructure.
PRODUCT LIFECYCLE MANAGEMENT
October09
11
High performance computing facility (P 690)
Spin test facility

12. Technology
Dr AL Moorthy, Director, DESIDOC, Metcalfe House, Delhi
Dr BR Gandhe, Director of Armaments, DRDO
Director of Materials, DRDO
Shri R Shankar, Director of CV&E, DRDO Bhavan, New Delhi
Director of Naval Research & Development
DRDO
Shri Ranjit Elias, SO to SA to RM, DRDO Bhavan, New Delhi
Coordinator
Members
Bhavan, New Delhi
Dr Sudarshan Kumar, Bhavan, New Delhi
Cmde PK Mishra,
Bhavan, New Delhi
lEikndh;eaMy Editorial Committee
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Editor-in-Chief Assoc. Editor-in-Chief Editors Editorial Assistant Printing Distribution
AL Moorthy Shashi Tyagi B Nityanand Dipti Arora SK Gupta RP Singh
Manoj Kumar Hans Kumar
Printed & published by Director, DESIDOC, on behalf of DRDO
Air mass flow : 78 kg/s
Kaveri Engine—Salient Features
By-pass ratio : 0.2-0.24
Overall pressure ratio : 21.5
Turbine entry temperature (flat-rated) : 1487-1700 K
Maximum thrust (dry)-IRA, SL : 52 kN
Maximum thrust with afterburner-IRA, SL : 81 kN
SFC (dry) : 0.78 kg/h/kg
Maximum SFC with afterburner : 2.03 kg/h/kg
Thrust/weight ratio : 7.8