GE Corporate Research and Developmentg

Melt Infiltrated (MI) SiC/SiC Composites for Gas Turbine Applications

Krishan L. LuthraGE Corporate Research & Development

Schenectady, NY 12301Talk Presented at DER Peer Review for Microturbine &

Industrial Gas Turbines Programs*on March 14, 2002

*Contract Monitor: Joe Mavec

GE Corporate Research and Developmentg 2

Outline

• Introduction– CMC Opportunities– Team Members

• Applications & Payoff

• Material System

• Pathway to Commercialization

• Current Status & Future Plans

• Summary

GE Corporate Research and Developmentg 3

CMC Opportunity

Tem

pera

ture

1970 1980 1990 2000

Material Temperature Capabilityat Product Introduction

SX

EquiaxedDS

2010

MI-CMC

SX+TBC+cooling

“Metals”

Base

+600

+1000

20 yrs ∆=550F

4 yrs ∆=400F(Static Parts)

• CMC’s represent a game changing technology• DOE had the vision to start the CFCC program in early nineties

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Collaboration

Prime Contractor: GE Global Research Center

Component Fabrication: GE Global Research Center

GE Power Systems Composites (GEPSC), formerly Honeywell Advanced Composites, Inc. (HACI)

Goodrich Aerospace

End User GE Power Systems

CMC Characterization: ORNL (Microstructural)Argonne National Lab (NDE)

Team Members

CMC Material Development HSCT (NASA); Air Force Programsat GEAE

Environmental Barrier Coating HSCT (NASA)Component testing CSGT (DOE) at Solar

Leverage from other programs

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Applications

CombustionLiner

Transition Piece

1st StageNozzle

1st StageShroud

1st StageBucket

Industrial Gas Turbine Engine

• Stationary components represent the best short-term opportunity

g

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Payoff & Selected Applications

• Higher temperature capability of CMCs allows reduction/eliminationof air needed for cooling metallic components– Improvement in fuel efficiency– Reduction in harmful emissions– Higher output of machines

• Applicable to all classes of gas turbines– GE gas turbines range 45 KW to 280,000 KW– F-class & H-class machines most advanced– Installed base for F-class machines ~36 GW(US) & ~64 GW (worldwide)

In 1999

• Initial focus on shrouds & combustor liners– Technology would flow to other stationary components, such as nozzles

DOE-CFCC And DOE – AMAIGT focused on CMCapplications in F-class machines

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Payoff For Stationary Components

• Up to 1.1% point increase in simple cycle efficiency

• Increase in 3% output

• Market growth of 6%/year and 20% market penetration by 2020– US annual savings of ~290 Billion BTU of energy, equivalent to ~0.29

Billion cubic ft. of natural gas at a cost of ~$960 Million (2001 dollars)

– Annual savings of ~4.3 Million MTCE of CO2 emissions

– Annual savings of ~51,000 MT of NOx emissions

– Extra power generation worth ~1.3 Billion dollars, further reducing the

cost of electricity to customers

Use of CMCs offers opportunity for enormous fuel savings, reductionin emissions and reduction in cost of electricity to customers

GE Corporate Research and Developmentg 8

MI-CMCs

Stress

Monolithic Ceramics(Si3N4)

Strain

MI-CMC

MI-CMC

Silicon layer

BSAS

Mullite + BSAS

SiC-SiMatrix

SiC Fiber(~15 µm)

FiberCoatings(~1 µm)

EBC

Fiber Reinforcement Increases Fracture Toughness (Damage Tolerance) 200 µm

Fracture Surface

GE Corporate Research and Developmentg 9

Strain (%)0.0 0.3 0.6 0.9 1.2 1.5 1.8

Stre

ss(M

Pa)

0

50

100

150

200

250

300

350

RT 871C 1093C 1204C

225GPa 191GPa

160MPa

300MPa

183MPa

240MPa

290MPa

216GPa

177MPa

254MPa

229GPa

170MPa

Hi Nicalon Reinforced M. I. Composites

CMCs offer high temperature strength along with damage tolerance

Entrance

Exit

NDE

GE Corporate Research and Developmentg 10

Ceramic Matrix Composites - The path into Gas Turbine Engines

Strain

Lab Tests

Rig Feasibility

Tests

Small EngineTesting

Large EngineValidation

Test

PGT2

7FA

Combustion Rig

Progressive testing provides riskReducing “stepping stones” to engine test

Rig Qualification

Tests

NewCombustion Rig

HS-188

MI-CFCCStg. 2 Shroud

Stg. 1 Shroud

200+ cycles & 200 hrs

80 cycles & 1070 hrs

50+ cycles & 300 total hours

4000 -8000 hrsat Customer

CMC Test Shroud

DOE-CFCC ProgramDOE-AMAIGT Program

Stre

ss

1996

1998-1999

2000

2001-2002

2002-2003

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Stainless GE MI CFCC

Shroud Rig Component Performance

Combustors

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Shroud Rig Testing at 1500°C Gas Temperature

HS-188

GE MI-CFCC

Failed after 50 cycles

Survived 200 cycles and 50 hours exposure

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GE2 S2S and S1S Testing at GE Oil & Gas

Engine Testing of Prepreg Processed Shrouds Has Been Very Successful to Date

PGT-2 Turbine Cross SectionOperated at Gas Temp of ~1875F

18.5” CMC Second Stage Shroud Ring

Blade Rub on SecondStage CMC Shroud

S1S and S2S Testing:- 1070 hrs- S1S had 46 starts, 24 trips, 1 blade rub- S2S had 61 starts, 27 trips, plus over 3 blade rubs

First Stage CMC Shroud

View aft looking forward

GE Corporate Research and Developmentg 14

Outline

• Introduction– CMC Opportunities– Team Members

• Applications & Payoff

• Material System

• Pathway to Commercialization

• Current Status & Future Plans

• Summary

GE Corporate Research and Developmentg 15

Status & Past Year Accomplishments

• Unique high pressure-high velocity rig designed and being used for long-term testing.– Needed to evaluate water vapor & velocity effects on CMC materials.

• Shroud system design completed.– Critical design features, such as attachment and blade rub tolerance,

were evaluated with sub-component tests.• Over 30 CMC inner shrouds fabricated for rig and engine testing.

– EBC deposition process scaled up and CMC shroud coating optimized.– Transient IR thermography demonstrated as useful NDE technique for

CMC shroud inspection.• A new combustion rig for testing of shroud system was designed,

assembled, and its operation verified.– Used as short-term validation of shroud system design before

proceeding to engine tests– ~200 hours of rig testing completed on two shroud system variations.

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Long-Term Rig Testing

Pressure Vessel

Combustor liner/Transition piece

Main tubeMain tube

Sample retaining rings

Test samples

Spacer tubes

Gas inlet

Fuel nozzle location

Exhaust pipe

Unique material testing facility being used for long-term life testing under turbine-

like conditions

• High pressure – high velocity rig– Evaluate effects of water

vapor and velocity• Capabilities

– Temperature up to 1200oC+

– Velocity of 450 ft/sec+

– 9 atmospheric pressure– 1 atmosphere of water vapor – Up to 28 tensile test

specimens• Status

– ~3000 hours of testing performed

– Another 2500 hours planned this year

– Facilities would also be used for microturbine program

GE Corporate Research and Developmentg 17

Blade Tip Rub Tolerance Validation

Rub tip

Rub specimen

Sample TC Specimen assembly

Apparatus

Uncoated Prepreg

RT

EBC coatedPrepreg

1200C

• Rub tests of prepreg and slurry cast samples, with and without EBC, were done at RT and 1200C– GTD-111 blades lost mass and

substrate gained mass in all tests - indicates wear of blade and deposition of metal onto CMC samples

– No spalling of EBC coating or substantial damage to CMC observed

CMC/EBC system very resistant to blade tip rubs

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EBC Process Scale-Up and Optimization

CMC shroud

• Process successfully scaled up to coat shroud components

• Quality and thickness control of EBC verified with shroud cut-ups

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NDE of CMC Shrouds Demonstrated

“Bad” Shroud

“Good” Shroud

NDE indications verified as defects by

microstructural characterization

NDE by Transient IR Thermography

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Shroud Test Rig

Primary Air

Diffusion Fuel

Premix Fuel

Cooling Air

Cooling Air

Cooling and“leakage” flows

Cooling Water

Fuel Nozzle

Combustor

TransitionPiece Shroud

TestSection

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Shroud Test Rig

Support FlangeSupport Flange

CombustorCombustorTransition PieceTransition Piece

Shroud Test SectionShroud Test Section

Surrogate metal shrouds

Cast ceramic lower wall

(replaced with CMC for

durability)

InstrumentationInstrumentation

Fuel NozzleFuel Nozzle

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Future Plans

• Shrouds– Engine test (4000 hours+) at a customer site starting from Fall ‘02

outage

• Combustor Liner– Combustor preliminary design completed CY 3Q02– Fabrication of MI-CMC combustor by CY 4Q02– Rig testing of combustor system starting CY 1Q03– Fabrication of final design and validation rig test by CY 1Q04

– Field engine test starting CY 4Q04

GE Corporate Research and Developmentg 23

Summary

• CMCs represent a game changing technology for industrial gas turbines– 400o F improvement over metals

• CMCs offer opportunities for enormous fuel savings, reduction inemissions, and reduction in cost of electricity to customers

• DOE’s CMC programs (CFCC & AMAIGT) have taken the lead in CMC material development for their applications in gas turbines

• GE’s efforts on CFCC & AMAIGT focused on shroud & combustor liners– Field test of first stage shroud in an F-class machine (~150 MW)

planned in 2002 at a customer site

– Combustor liner testing to follow at a customer site in 2004

GE working with DOE in a risk-reducing, step-wise approachfor developing CMCs for Industrial Gas Turbines