ir comparitive materials evaluation for gas turbine kesseli et al

COMPARATIVE MATERIALS EVALUTIONFOR A GAS TURBINE ROTOR

27th Annual Conference on Composites, Materials andStructures

January 27-30, 2003

Jim Kesseli, Shaun Sullivan, and Michael Swarden; Ingersoll-Rand Energy SystemsS.F. Duffy, Cleveland State University, E.H. Baker, Connecticut Research Technologies,

Matt Ferber, Oak Ridge National Laboratory,Jill Jounkouski, DoE OIT,Kyocera Research Center

Keywords: microturbine, silicon nitride, turbine, CARES, recuperator, ceramic, gas turbine, life analysis

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR Kesseli et. al

Ingersoll-Rand’s Ceramic Microturbine (CMT) Plan

Following a low riskdevelopment path that willyield significant performanceincrease for PowerWorks™products in 2003

Introduce ceramic turbine rotorto operate within proven limits oftoday’s technology

Size and manufacturing limitsTemperatureStress

Use metallic alloy for turbinehousing and down-stream section,including recuperator. 70 kWe PowerWorks™

Microturbine Cogen System


Trade Study Final Conclusions:

Formula for Success:Define cycle to utilize IR’s highly durable, low-cost stainlesssteel recuperator

Gas inlet temperature below 700 CModerate turbine inlet temperature (TIT) (1000 to 1020 C) - toavoid unacceptable recession and coating cost/complexity Resulting rise in pressure ratio to 4.8 to 5.2

Low ceramic rotor tip speed - (Expansion ratio ~ 2 to 2.2) show large margin based on stress predictions, leading to lowstatistical failure predictions

Build from Kyocera’s proven manufacturing baseAdopt experience form high volume turbochargermanufacturingKeep rotor diameters below about 100-mm


PowerWorks™ - Frame 3

Air Inlet

GasifierCompressor

GasifierTurbine

PowerTurbine

Exhaust

Combustor

Generator

Gearbox

UtilityPower

ElectricPower To

User

Heat ToUser

400 ° F

WasteHeat

Recovery

CounterflowRecuperator

Unchangedbalance of plant

Ceramic rotor

Unchanged

All new and improved aero-components (compressor + 2 turbines)

Metallicpowerturbine(IN713LC)


Cycle selection - Defining recuperator stainless alloy, sets optionsfor PRc and TIT

0.32

0.34

0.36

0.38

0.40

0.42

0.44

0.46

2 3 4 5 6 7 8 9 10 11 12 13 14

Cycle Pressure Ratio

LHV

Elec

tric

al E

ffici

ency

TIT=1000oC Tamb=15oC, pamb=14.7psia ηc=83%, ηt=81.5% (polytropic) εHX=91%, ηgen=95% ∆p/p: 0.5% inlet, 1.0% exhaust 3.0% comb, 1.3% recup air 2.7% recup gas mech losses: 2% gasifier spool, 2% output shaft

LOCUS OF RECUPERATORINLET TEMP = 700oC(Max for Alloy-347)

LOCUS OF RECUPERATORINLET TEMP = 800oC

TIT=900oC

TIT=1200oC

TIT=1100oC

TIT=1300oC

TIT=1400oC Simple Recuperated CycleCMT design target


Performance optimization within proven andconservative limits of monolithic Silicon Nitride

Gasifier Turbine Aerodynamic and ThermodynamicSpecifications

TIT = 1000 CExpansion ratio = 2.1Physical Speed = 97,500 RPMRotor tip speed = 485 m/sRunning clearance, inducer tip = 0.46 mm (0.018 in.)Running clearance, exducer tip = 0.30 mm (0.012 in.)Minimum blade thickness at inducer tip = 2 mm (0.080 in)Minimum blade thickness at exducer trailing edge = 1.1 mm(0.044 in)Nozzle-less turbine housingBlade geometry must be “pullable” form mold100 mm rotor size limit

7OK

OK

Blade Design - for pure radial moldrelease


State of the art Radial Inflow Turbine Efficiency vs Specific Speed

60%

65%

70%

75%

80%

85%

90%

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

Specific Speed [N*(m/rho)^.5] /[DH0s^.75]

Effic

ienc

y (to

tal-t

o-st

atic

)

from Rohlik (NASA SP-290)

Today's Frame 3 PowerWorks- Gasifier- Power TurbineCMT Targets

- Gasifier- Power Turbine

Nss ~ 0.9

Nss ~ 0.6

A conservative η target wasset due to perceivedcompromises on shroudclearances and bladethickness


State of the ArtCentrifugal-Compressor Polytropic Efficiency vs Specific Speed

70%

75%

80%

85%

90%

0.4 0.5 0.6 0.8 0.9 1.0 1.1Specific Speed

Poly

trop

ic E

ffici

ency

(tot

al-to

-tota

l)

from Rogers (91-GT-77)

Standard PowerWorks Frame 3CMT

CMT has more favorable specific speed - hence should get better efficiency

target


PowerWorks CMT : Ambient Temp Effect on Power and Efficiency

Revised to 72 kWe (including gas booster)


CMT Turbine Rotor Boundary Conditions for lifeanalysis

Transient date derived from Frame 3 startup conditionsHot and cold startup (transient) conditions derived formrepresentative PowerWorks measurements.Transient data scaled to CMT application:

Temperatures scaled from 870 C to 1000 C TITSpeeds scaled from 72,000 to 97,500 RPMRate of acceleration scaled by the ratio of the inertias of the Frame3 PowerWorks and the CMT rotor

Steady state data derived from BANIG™ computersimulation

* BANIG is a trademark of Concepts NREC


CMT Rotor Cold StartTIT vs. Time During Cold Start

0

400

800

1200

1600

2000

0:00:00 0:00:10 0:00:20 0:00:30 0:00:40 0:00:50 0:01:00

Time

TIT

(F

)

0

20000

40000

60000

80000

100000

RP

M

RPM

TIT

1000 C gas inlet temp


CMT Rotor Hot StartTIT vs. Time During Hot Start

0

400

800

1200

1600

2000

0:00:00 0:00:10 0:00:20 0:00:30 0:00:40 0:00:50 0:01:00

Time

TIT

(F

)

0

20000

40000

60000

80000

100000

RP

M

RPM

TIT 1000 C gas inlet temp


CMT Rotor Heat Transfer Coefficients

Steady state heat transfercoefficients derived fromcomputer simulation of rotorperformanceheat transfer coefficientcalculated using:

0

1

2

3

4

5

6

0 1 2

Z-dimension (in.)

Rad

ius

(in.)

color htcBTU/ft2F

MAROON 40YELLOW 75LTBLUE 125PURPLE 175

PINK 210DARKBLUE 305

3/12/1 PrRe332.0 ⋅⋅=Nu

)))1(Pr(7.12(1

PrRe2

3/22/1 −⋅⋅+

⋅⋅=

f

f

C

C

Nu

:000,90Re <

:000,90Re >


CMT Rotor Steady State TemperaturesTIT = 1000 CMaximum adiabatic Wall Temperature = 905 CMaximum rotor temperature difference = 60 C(excluding cooled attachment)*

2 kW~534 C

* low rotor temp gradients characteristic oflow expansion ratio and high thermalconductivity - both serving lower thermalstress


CMT Rotor Steady-State Stresses (Principle)

Kyocera stipulated design target of 200 MPa for SN237Steady state critical stress location is at back wall fillet

currently evaluating to 275 MPa (at bore)can be further alleviated with larger fillet, if necessary

275 MPAAll blade and root is below 200 MPa


Thermal-Only Stresses (steady-state)

Max wall stress at fillet = 86 MPa (12.5 KSI)

Typical blade stress = 8 MPa (< 1KSI)


CMT Rotor Worst Case StressesWorst Cases:

Vane234 MPa @ 38 sec. into Cold Start

Bore282 MPa @ 54 sec. into Cold Start

Back Wall278 MPa @ Steady State


CMT Rotor Transient Stresses


1st Principle Stress DistributionSpeed and Thermal Gradient Loading

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

0 50 100 150 200 250 300 350 400 450 500

Time - sec.

1st P

rinci

ple

Stre

ss k

si

Back Wall FilletVaneBore

CMT Rotor Cold Start Stress Profiles


Fig 26. IRES, CMT Rotor Design #4, Dynamics Analysis Results.

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR Kesseli et. alIRES CMT Gasifier Rotor, Campbell Diagram

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000

Rotor Speed - rpm

Freq

uenc

y - h

z

2nd Mode, Vane 2nd Bending, Primarily at Exducer

1st Mode, Exducer Bending

3/Rev Excitation

817% Frequency Margin

1/Rev Excitation



CARES Analysis based on ORNL Materials Data Base

Material Data year Manufacturer

SN282 2001 Kyocera

SN237 2001 Kyocera

AS800 1995 Honeywell (FormerlyAllied Signal

NT154 1989 St. Gobain (formallyNorton)


CARES Model Results

Notes from Steve Duffy:• 38 second condition appears to be worst case

Steady State 38 Seconds 54 SecondsProbability of Failure 0.000000000747451 0.000001514190000 0.000001025080000Reliability 0.999999999252549 (9 nines) 0.999998485810000 (5 nines) 0.999998974920000 (5 nines)Failure Rate 1337880343 660419 975534



Steady State 38 Seconds 54 SecondsProbability of Failure 0.000237266000000 0.011407100000000 0.008427090000000Reliability 0.999762734000000 (3 nines) 0.988592900000000 (1 nine) 0.991572910000000 (2 nines)Failure Rate 4215 88 119

NT 154 - 1989 Vintage Material

AS 800 - 1995 Vintage Material

SN 282 - 2001 Vintage Material

SN 237 - 2001 Vintage Material


Survival Rate at 38sVolume Flaw Analysis

660419

1318358715

880

100000

200000

300000

400000

500000

600000

700000

800000

Silicon Nitride Materials

Num

ber

of In

itial

Spi

n U

ps

Bef

ore

Failu

re O

ccur

s

SN 237SN 282AS 800NT 154

27

kgf/mm2

Transient (38sec. 89,292rpm)

237.2MPa

155.8MPaM G T-IR 38b x z j m (SN 237)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.00 0.50 1.00 1.50 2.00 2.50

[ ^ [ ] (~ 89,292rpm )

Fractuer Probability,Pf

Total(AVE)

Total

Total

Total

Total

Total

Total

Fracture Probability of Rotor(SN237)

Rotational Speed / 89,292

-σσ

2σ

3σ

-2σ

-3σ

Stress Analysis· Reliability Analysis

28

kgf/mm2

232.4MPa

154.0MPaTransient (54sec. 97,533rpm)

M G T-IR 54b x z j m (SN 237)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.00 0.50 1.00 1.50 2.00 2.50

[ ^ [ ] (~ 97,533rpm )


T otal(AVE)

Total

Total

Total

Total

Total

Total


Rotational Speed/97,533

-σ

σ

2σ

3σ

-2σ

-3σ


29

kgf/mm2

Steady State (97,500rpm)

184.2MPa

206.8MPa

M G T-IR ^ ] ¶ j m(97500rpm ,SN 237)

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

1E-2

1E-1

1E+0

1E-2 1E-1 1E+0 1E+1 1E+2 1E+3 1E+4 1E+5

Tim e(hour


\ + (Ave)

\ + (95%Low)

\ + (95%Uppj

M G T 40,000Hr

Pf=0.925~ 10-6


Surface Internal Ave.

Surface Internal -2σ

Surface Internal +2σ



First Kyocera SN237 rotors fabricated for IR CMTProgram (12/02)

- Excellent blade true positionand blade profile dimensionalcontrol- Excellent surface finish- Coordinate generation errorresulted in ultra-thin blades


Cold spin test equipment Cold spin system

Evaluation Development

Cold Spin Test


Cold Spin Test

Evaluation Development


Spin pit after rotor burst at 167,197 RPM

Rotor-less spindleSN237 rotor fragments

34

Room temperature, Material :SN237Design Speed :97,500rpmBurst Speed = 167,197 (sample #1, only sample)Burst Speed ratio = 171% (Burst/Design)Burst Stress factor (N^2) = 2.9225.5MPa

172.9MPa

kgf/mm2

Cold Spin TestResults

M G T-IR R [ h j m (SN 237)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.00 0.50 1.00 1.50 2.00 2.50 3.00

[ ^ [ ] (~ 97,500rpm )


Total

As-firedmachinedInternal


Rotational Speed/97,500 RPM

Testspecimenburst!


Materials Evaluation- performed on first 2 rotors(February -October at ORNL)

Disk Test SpecimensCore drill 6 mm X 0.5 mm (~ 200 samples)Bi-axial bending test

Flexure bar test3 X 4 X 60mm barsBending test

Tests and evaluations to be performed for CARES data baseObtain bulk properties at various positions and orientations withinthe rotor at 900 to 1000 CFlexure test at 1000 C, after 1000-hr sustained load (nominally 200MPa)

Micro structural analysis, FractographyHigh-velocity, steam injection test at 1000 C (for recessionanalysis)


IR CMT Contributions to the Industry

Optimized elliptical blade fillet and back-face scallopmodel to minimize stress in ceramic rotorsImproved aero design models to optimize rotor forforeign object damage (FOD) toleranceEstablished reference rotor design and transientboundary conditions for which various materials maybe evaluatedProvide a viable engine for long-term evaluation ofcommercially viable ceramic turbine


Next Steps:ORNL materials re-calibration with samplesform actual test rotors (Milestone: ConfirmCARES, 5/2003)Install and test in PowerWorks 70 kWeengine Milestone: η = 36% LHV, 6/2003)Engine endurance test (Milestone: ~ 3000 labtest hours, 10/2003)Engine Field Test (Milestone: retrofit approx.20 units, 2004)

ir comparitive materials evaluation for gas turbine kesseli et al

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