Ganesan amp Mukul Atri Final Year BTechMTech Dual Degree Students mentored by Dr Abhijit Kushari Department of Aerospace Engineering Indian Institute of Technology Kanpur ID: 275680
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Slide1
Sriram
Ganesan & Mukul Atri Final Year B.Tech-M.Tech Dual Degree Studentsmentored byDr. Abhijit KushariDepartment of Aerospace EngineeringIndian Institute of Technology Kanpur
NASA Environmentally Responsible Aviation Slide2
Presentation Outline
Baseline aircraft -Hybrid Wing Body ConceptBaseline Engine-GE90After DilationGeared TurbofanStator Noise ReductionLean Direct Injection CombustorsSpiroid wingletsGolf-ball wingsWeights estimateSlide3
Hybrid Wing Body Concept
Supercritical outer wing profileShorter landing gear via better tail clearancePropulsive efficiency via Boundary Layer Ingestion (BLI) 30% reduction in structural weight Drooped leading edge deviceFaired undercarriage for reduction in noiseSource : N+3 Aircraft Concept Designs and Trade Studies, Final ReportSlide4
Variable Area Nozzle
Reduced jet noise during takeoff, landingLow fan speed operationCruise: Pitch trim- minimizes profile dragApproach : increased drag using thrust vectoring combined with elevonsSlide5
GE 90 Engine Data
sdCruiseTake-offHeight (Km)10.6680Mach No.0.8500RAMPR1.5901FPR1.6501.580LPCPR1.140
1.100HPCPR21.5
23OPR40.4439.97
BPR
8.1
8.4
Cruise
Takeoff
T
a
218.820
288.16
P
a
0.239
1.014TIT (K)1380.01592.0ma(kg/s)576.01350.0Thrust (kN)69.2375.3mf(kg/s)1.0792.968SFC (mg/N-s)15.67.91
Intake
Fan
Compressor
Turbine
Nozzle
Combustion
Polytrophic Efficiency
0.980
0.930
0.910
0.930
0.950
0.99Slide6
Trade -Off PlotsSlide7
Mixed Exhaust
State of Art Augmenters- Low bypass Turbofan Engines- Takeoff, climb and combatAtomized fuel ignites the mixtureAnnular Mixers- Shearing effect at stream interface- Low mixing efficiencyForced Mixers- Intertwined chutes force mixing- High pressure losses
Source :
http://shirshosengupta.blogspot.com/ 2011/04/ jet-engines-101.html
Courtesy of Pratt & WhitneySlide8
After Dilation
1) Diffuser2) Mixing Zone3) Nozzle 6) Iris Nozzle5) Bleed Valve
4) Bypass Duct
High pressure differential between core and
bypass
Bleed Valve- controls bypass bleed factor
κ
Iris nozzle-allows various modes of
operation
1
2
3
4
5
6Slide9
Modes of Operation
κ=0κ=0.4κ=0.8Slide10
Boundary conditions
Inlet conditions:Bypass: Core :P08=62689 Pa P05=38143 PaT08=291.97 K T05=576.69 KP8=52848 Pa P5=37467 PaExit:Pa=23900Pa Ta=218 KSlide11
Temperature Profile
2-d simulations conducted using ANSYS fluentMixing converts thermal energy to kinetic energyQuick dissipation due to efficient turbulent mixingSlide12
Velocity Profile
Mixing at the interfaceBleed valve optimization Uniformity of profile across exitSlide13
Pressure Profile
Propagation of Pressure frontsCore expands to ambient pressureBypass flow exits in under-expanded stateSlide14
Results
EngineGE90 in cruiseGE90 with κ=0.6GE90 with κ=0.7GE90 with κ=.9Thrust(N)69219
7043970767
71432
SFC(mg/N/s)
15.588
15.318
15.247
15.105
Exit Velocity of Core/Mixer (m/s)
368
293.3
292.8
295.1
Exit Velocity of Bypass (m/s)
248
283.0289.6290.9Exit Pressure of Core/Mixer (Pa)24094336063389734110Exit Pressure of Bypass4164936146
35421
35223
Exit area of Core/Mixer(m^2)
1.011
3.22
3.569
4.260
Exit area of Bypass(m^2)
3.593
1.384
1.035
0.344
Net Gain in Thrust
-
1.76%
2.24%
3.2%Slide15
Summary
Significant reduction in jet noise. - proportional to 8th power of velocity gradient - 64% reduction in velocity gradient3.2% decrease in SFC for κ=0.9Noise due to internal mixingDynamic InstabilitiesMaterials & ActuatorsSlide16
Geared Turbofan
High BPR desired due to increase in SFCIncrease in fan diameterLower RPM operation required for preventing shock lossesEfficiency of LPC decreases at lower RPMPlanetary reduction gear box usedSlide17
Benefits
Low FPR and bypass exit velocityLow fan RPM, low fan noise and jet noiseHigh propulsive efficiencyLength reduction of low-pressure spool components like LPC, LPT and thus a reduction in engine weightRelatively higher LPC and LPT efficiency than the normal turbofan enginesSlide18
Stator Noise Reduction
Source: E. Envia, M. Nallasamy, ‘Design Selection and Analysis of a Swept and Leaned Stator Concept’,Journal of Sound and Vibration (1999) 228(4), 793-836, Article No. jsvi.1999.2441Slide19
Stator Configurations
Leaned stator: tangential rotation about the baseline radial positionSwept Stator: axial rotation about the baseline radial positionAft-position radial stator (APRF): stator position displaced by a distance equal to the distance between the leading edge of the rotor and the swept statorResults of high-sweep angles(300) are marginally better than those of APRFAPRF requires only small changes to the engineSlide20
Results
Noise reduction due to modification in bladeLocationSwept only(300) (dB)Sweep(300) + lean(-300) (dB)Aft-position radial stator (dB)Take-off151813Approach787Cutback
131715
Total3543
35
*-Values are averaged over upstream and downstream for 2 X BPF toneSlide21
Lean Direct Injection Combustors
Injects fuel into multiple zonesReduces local temperatureAllows lean combustionLDI combustors reduce LTO NOx emissions by 15-20%Slide22
Golf-ball wings
Golf-ball wings + smart structures => flap-less wingsActuation can produce “dimples”Larger Cl max Differentiated operation of actuators can eliminate the need for ailerons as wellApplication is similar to that of vortex generators on wingsSource: http://www.aerospaceweb.org/question/aerodynamics/q0215.shtmlSlide23
Spiroid Winglets
Reduction of Induced drag10%
reduction in fuel burn for short journeys
Testing on-going for long flights
Source: Aviation Partners,
http://www.aviationpartners.com/future.htmlSlide24
Weights Estimate
ComponentWeight (in kgs)Fan Weight (Single Gear Drive Fan)1296Nacelle Weight760Compressor (3 LPC+12 HPC)1564Combustor325
Turbine(4 LPT+3 HPC)
2506Accessories & Others
500
Total Weight
6951Slide25
The desire to fly is an idea handed down to us by our ancestors who... looked enviously on the birds soaring freely through space... on the infinite highway of the air.
-Wilbur WrightAs we embark on the challenge of greener aviation, the envy remains and the quest continues……Slide26
Many thanks to
Dr. Abhijit Kushari, our project mentor who contributed his time and knowledge for this designVivek and Anandh for their invaluable help in conducting the computational simulationsDr. Elizabeth Ward for prompt responses to all the queries and concerns through out the projectDean Resource Planning and Generation Office (DRPG) and Department of Aerospace Engineering, IIT Kanpur for travel support to attend the forumSlide27
References
N+3 Aircraft Concept Designs and Trade Studies, Final Reporthttp://www.pw.utc.com/products/commercial/purepower-pw1000g.asp Vivek Sanghi and B. K. Lakshmanan 2002 “Optimum Mixing of Core and Bypass Streams in High-Bypass Civil Turbofan”, Journal of Propulsion and Power Vol 18, No.4, July-August 2002Pearson, H., “Mixing of Exhaust and Bypass Flow in a Bypass Engine,” Journal of Royal Aeronautical Society, Vol. 66, Aug. 1962, pp. 528–530 Frost, T. H., “Practical BypassMixing Systems for Fan Jet Aero Engine,”The Aeronautical Quarterly, May 1966, pp. 141–160.
http://www.grc.nasa.gov/WWW/RT/RT1997/5000/5860harrington.htmhttp://en.wikipedia.org/wiki/Propelling_nozzle#Iris_nozzles
http://en.wikipedia.org/wiki/Geared_turbofan (continued..)Slide28
C.
Riegler, C. Bichlmaier ‘The Geared Turbofan Technology-Opportunities, Challenges and Readiness Status’, http://www.mtu.de/en/technologies/engineering_news/others/Riegler_Geared_turbofan_technology.pdfPhilip G. Hill, Carl R. Peterson , Mechanics and Thermodynamics of PropulsionIlan Kroo ,‘Drag due to Lift: Concepts for Prediction and Reduction’, , Annu. Rev. Fluid Mech. 2001. 33:587–617http://www.flightglobal.com/blogs/flightblogger/2008/06/spiroid-wingtip-technology-the.htmlhttp://www.jet-engine.net/civtfspec.htmlE. Envia, M. Nallasamy, ‘Design Selection and Analysis of a Swept and Leaned Stator Concept’, Journal of Sound and Vibration (1999) 228(4), 793-836, Article No. jsvi.1999.2441Richard P. Woodward, David M. Elliott, Christopher E. Hughes and Jeffrey J. Berton
‘Benefits of Swept-and-Leaned Stators for Fan Noise Reduction’, www.stanford.edu/~cantwell/AA283.../GE90_Engine_Data.pdf