jet engine materials_reporter#5

8/13/2019 Jet Engine Materials_Reporter#5

1/28

F109 Model Mater ials Selection

Description: Elements of Materials ScienceYear/Course: III-BS Mechanical Engineering

Subject/Section: ES 67 Cc

Instructor: Prof. Earlinda O. Yape

Student: Eugene A. Micarandayo


2/28

Meet The Author

Daniel Kirk is an AssistantProfessor in the Mechanical andAerospace EngineeringDepartment at the FloridaInstitute of Technology.

Dr. Kirk and his students areinvolved in numerouscollaborative research endeavorswith NASA, the United States AirForce, the Advanced MagnetLaboratory, Space Florida and the

Department of Neuroscience atthe University of Florida.

His teaching interests focus onair-breathing and rocketpropulsion, fluid mechanics, andcombustion.

Dr. Daniel R. Kirk


3/28

What is a jet engine?

Ajet engineis a reaction enginethatdischarges a fast movingjetwhich generates

thrustbyjet propulsionin accordance withNewton'slaws of motion.
http://localhost/var/www/apps/conversion/tmp/scratch_4//wiki/Reaction_enginehttp://localhost/var/www/apps/conversion/tmp/scratch_4//wiki/Jet_(fluid)http://localhost/var/www/apps/conversion/tmp/scratch_4//wiki/Thrusthttp://localhost/var/www/apps/conversion/tmp/scratch_4//wiki/Jet_propulsionhttp://localhost/var/www/apps/conversion/tmp/scratch_4//wiki/Isaac_Newtonhttp://localhost/var/www/apps/conversion/tmp/scratch_4//wiki/Newton's_laws_of_motionhttp://localhost/var/www/apps/conversion/tmp/scratch_4//wiki/Newton's_laws_of_motionhttp://localhost/var/www/apps/conversion/tmp/scratch_4//wiki/Isaac_Newtonhttp://localhost/var/www/apps/conversion/tmp/scratch_4//wiki/Jet_propulsionhttp://localhost/var/www/apps/conversion/tmp/scratch_4//wiki/Thrusthttp://localhost/var/www/apps/conversion/tmp/scratch_4//wiki/Jet_(fluid)http://localhost/var/www/apps/conversion/tmp/scratch_4//wiki/Reaction_engine


4/28

works?

Jet engines movethe airplaneforward with agreat force that isproduced by atremendous thrustand causes the

plane to fly veryfast.


5/28

Force & Thrust


6/28

Location of Jet Engine

JSF

F119


7/28

INSIDE A JET F109 ENGINE

Bearing locations

Mechanism to vary

compressor stator angles


8/28

Jet EngineMaterials

A quick overview of thematerials requirements,

the materials being used,and the materials being developed


9/28

Motivation for Materials

Development Higher Operating

Temperatures

Higher Rotational Speeds Lower Weight Engine

Components

Longer Operating

Lifetime Decreased Failure

Occurrence

This all adds up to:

Better Performance

Lower Life Cycle

Costs


10/28

Materials Requirements

thousands of operating hours at temperatures up to 1,100C (2000 F)

high thermal stresses caused by rapid temperature changes and largetemperature gradients

high mechanical stresses due to high rotational speeds and largeaerodynamic forces

low- and high-frequency vibrational loading

oxidation

corrosion

time- , temperature- and stress-dependent effects such as creep, stressrupture, and high- and low-cycle fatigue.


11/28

Cold Section Materials

Requirements High Strength (static, fatigue)

High Stiffness

Low Weight Materials:

Titanium Alloys

Aluminum Alloys

Polymer Composites

Titanium intermetallics and composites


12/28

Flow Direction

Compressor Combustor Turbine

JSF

Regions of the Engine

Cold Sections

Inlet/Fan

Compressor

Casing

Hot Sections

Combustor

Turbine/Outlet


13/28

Titanium alloys used for critical

cold section components Fan disks/blade

Compressor

disks/blades

Typical Alloy:Ti-6Al-4V


14/28

Titanium Properties

High strength & stiffness to weight ratios> 150 ksi, E = 18 Msi

Specific gravity of 4.5 ( 58 % that of steel)

Titanium alloys can be used up to temperatures of~ 590 C (1100 F)

Good oxidation/corrosion resistance (also used inmedical implants)

High strength alloys hard to work - therefore manyengine components are cast


15/28

Aluminum alloys can reduceweight over titanium Conventional alloys have lower strength/weight

ratios than Ti but more advanced alloys approachthat of Ti.

Specific gravity: 2.8 ( 62 % that of Ti)

Lower cost than Ti

Max temp for advanced alloys: ~ 350 C (600 F)

Lower weight & rotating part inertia


16/28

Titanium Aluminide Ti3Al

An intermetallic alloy of Ti and Al

Extends the temperature range of Ti from 1100 Fto 1200-1300 F

Suffers from embrittlement due to exposure toatmosphere at high temperature - needs to becoated.


17/28

Titanium Composites (MMC)

Decreases weight while increases strength andcreep strength

TYPICAL Ti/SiC COMPOSITE

100X


18/28

Hot Section MaterialsRequirements

High Strength(static, fatigue,creep-rupture)

High temperatureresistance850 C - 1100 C(1600 F - 2000 F)

Corrosion/oxidation resistance

Low Weight


19/28

High Temperatures - 1100 C (2000F)

Creep becomes at factor for conventional metalswhen the operating temperature reachesapproximately 0.4 Tm(absolute melting temp.)

Conventionalengineering metals at 1100 C:

Steel ~0.9 Tm Aluminum ~1.4 Tm Titanium ~0.7 T

m Conclusion: We need something other than

conventional materials!


20/28

High Temperatures - 1100 C (2000F)

What Materials Can BeUsed?

Unconventional metal alloys - orsuperalloys

Ceramics


21/28

Superalloys

Nickel (or Cobalt) based materials

Can be used in load bearing applications up to

0.8Tm- this fraction is higher than for any otherclass of engineering alloys!

High strength /stiffness

Specific gravity ~8.8 (relatively heavy)

Over 50% weight of current engines


22/28

Non-metallics - Ceramics

Cobalt

Nickel

Chromium

Tungsten

Tantalum

Silicon Nitrogen

CarbonSUPERALLOY

CERAMIC


23/28

Ceramics - Advantages

Higher Temperatures

Lower Cost

Availability of Raw Materials

Lighter Weight

Materials:

Al2O3, Si3N4, SiC, MgO


24/28

Ceramics - Challenges

Superalloys

Ceramics

DUCTILITY

TOUGHNESS

IMPACT

CRITICAL FLAW SIZE


25/28

Ceramic Composites

Improve toughness

Improve defecttolerance

Fiber pre-formimpregnated withpowder and then hot-pressed to fuse matrix


26/28

ENGINE MATERIALS

Different materials used in F109 jet engine

Blue: titanium is ideal for strength and density, but not at high temperatures

Red: nickel-based superalloys

Orange: steel used for the static parts of the compressor

Green: Composite


27/28

Question & Answer Portion

Do you have any questions?

Ill do the best I can to answer your questions.

If I cant answer your question this time, maybe I

can answer it next meeting.


28/28

References

[1] United Technologies Pratt & Whitney, TheAircraft Gas Turbine Engine and Its Operation, P&WOper. Instr. 200, 1988.

[2] R.S. Shevell, Fundamentals of Flight, PrenticeHall, Englewood Cliffs,1989.

[3] Airbus Industrie, Getting to Grips with AircraftPerformance, Blagnac,2002.

[4] United Technologies Pratt & Whitney Canada,JT15D-4C Fact Sheet,

Longueuil, 1987.

jet engine materials_reporter#5

Documents