Ir Comparitive Materials Evaluation For Gas Turbine Kesseli Et Al

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR 27th Annual Conference on Composites, Materials and Structures January 27-30, 2003 Jim Kesseli, Shaun Sullivan, and Michael Swarden; Ingersoll-Rand Energy Systems S.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

Š Following a low risk

development path that will yield significant performance increase for PowerWorks™ products in 2003 „

Introduce ceramic turbine rotor to operate within proven limits of today’s technology Š Size and manufacturing limits Š Temperature Š Stress

„

Use metallic alloy for turbine housing and down-stream section, including recuperator.

70 kWe PowerWorks™ Microturbine Cogen System

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

Trade Study Final Conclusions: Š Formula for Success: „

Define cycle to utilize IR’s highly durable, low-cost stainless steel recuperator Š Gas inlet temperature below 700 C Š Moderate turbine inlet temperature (TIT) (1000 to 1020 C) - to

avoid unacceptable recession and coating cost/complexity Š Resulting rise in pressure ratio to 4.8 to 5.2 „

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

statistical failure predictions

„

Build from Kyocera’s proven manufacturing base Š Adopt experience form high volume turbocharger

manufacturing Š Keep rotor diameters below about 100-mm

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

PowerWorks™ - Frame 3 Heat To User

Unchanged balance of plant Counterflow Recuperator

Ceramic rotor

400 ° F

Waste Heat Recovery

Combustor

Exhaust

Gasifier Compressor Air Inlet

Power Turbine

Gasifier Turbine

Gearbox

Unchanged

Electric Power To User

Generator Utility Power

Metallic power turbine (IN713LC) All new and improved aero-components (compressor + 2 turbines)

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

Cycle selection - Defining recuperator stainless alloy, sets options for PRc and TIT 0.46

o

TIT=1400 C

Simple Recuperated Cycle

CMT design target

0.44 o

TIT=1300 C

LOCUS OF RECUPERATOR o INLET TEMP = 800 C

LHV Electrical Efficiency

0.42 o

TIT=1200 C

0.40 o

TIT=1100 C

0.38 o

TIT=1000 C o

Tamb=15 C, 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

0.36 LOCUS OF RECUPERATOR o INLET TEMP = 700 C (Max for Alloy-347)

0.34

o

TIT=900 C

0.32 2

3

4

5

6

7

8

9

Cycle Pressure Ratio

10

11

12

13

14

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

Performance optimization within proven and conservative limits of monolithic Silicon Nitride

Š Gasifier Turbine Aerodynamic and Thermodynamic Specifications

Š TIT = 1000 C Š Expansion ratio = 2.1 Š Physical Speed = 97,500 RPM Š Rotor tip speed = 485 m/s Š Running clearance, inducer tip = 0.46 mm (0.018 in.) Š Running clearance, exducer tip = 0.30 mm (0.012 in.) Š Minimum blade thickness at inducer tip = 2 mm (0.080 in) Š Minimum blade thickness at exducer trailing edge = 1.1 mm

(0.044 in) Š Nozzle-less turbine housing Š Blade geometry must be “pullable” form mold Š 100 mm rotor size limit

Blade Design - for pure radial mold release OK

OK

7

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

State of the art Radial Inflow Turbine Efficiency vs Specific Speed 90%

from Rohlik (NASA SP-290)

Efficiency (total-to-static)

85%

Today's Frame 3 PowerWorks - Gasifier - Power Turbine

80%

CMT Targets - Gasifier - Power Turbine

75%

70%

Nss ~ 0.9

65%

Nss ~ 0.6

A conservative η target was set due to perceived compromises on shroud clearances and blade thickness

60%

0.0

0.2

0.4

Specific Speed

0.6

0.8

1.0

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

1.2

1.4

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

State of the Art Centrifugal-Compressor Polytropic Efficiency vs Specific Speed 90% Polytropic Efficiency (total-to-total)

from Rogers (91-GT-77)

85% CMT

Standard PowerWorks Frame 3

target 80%

75%

CMT has more favorable specific speed - hence should get better efficiency 70% 0.4

0.5

0.6

0.8

0.9

Specific Speed

1.0

1.1

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

PowerWorks CMT : Ambient Temp Effect on Power and Efficiency

Revised to 72 kWe (including gas booster)

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

CMT Turbine Rotor Boundary Conditions for life analysis Š Transient date derived from Frame 3 startup conditions „

„

Hot and cold startup (transient) conditions derived form representative PowerWorks measurements. Transient data scaled to CMT application: Š Temperatures scaled from 870 C to 1000 C TIT Š Speeds scaled from 72,000 to 97,500 RPM Š Rate of acceleration scaled by the ratio of the inertias of the Frame

3 PowerWorks and the CMT rotor

Š Steady state data derived from BANIG™ computer simulation

* BANIG is a trademark of Concepts NREC

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

CMT Rotor Cold Start TIT vs. Time During Cold Start

2000

100000

1000 C gas inlet temp

1600

80000

1200

60000 RPM

800

40000

400

20000

0 0:00:00

0 0:00:10

0:00:20

0:00:30 Time

0:00:40

0:00:50

0:01:00

RPM

TIT (F)

TIT

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

CMT Rotor Hot Start

TIT vs. Time During Hot Start 2000

100000

1000 C gas inlet temp

TIT

1600

80000

1200

60000

800

40000

400

20000

0 0:00:00

0 0:00:10

0:00:20

0:00:30 0:00:40 Time

0:00:50

0:01:00

RPM

TIT (F)

RPM

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

CMT Rotor Heat Transfer Coefficients Š Steady state heat transfer

Re < 90,000 :

Nu = 0.332 ⋅ Re1/ 2 ⋅ Pr1/ 3 Re > 90,000 :

Nu =

Cf

htc BTU/ft2F MAROON 40 YELLOW 75 LTBLUE 125 PURPLE 175 PINK 210 DARKBLUE 305

5

Radius (in.)

coefficients derived from computer simulation of rotor performance Š heat transfer coefficient calculated using:

color

6

4 3 2 1 0

⋅ Re⋅ Pr

2 1/ 2 1 + (12.7 ⋅ (C f ⋅ (Pr 2 / 3 − 1)))

0

1

2

Z-dimension (in.)

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

CMT Rotor Steady State Temperatures Š TIT = 1000 C Š Maximum adiabatic Wall Temperature = 905 C Š Maximum rotor temperature difference = 60 C (excluding cooled attachment)*

* low rotor temp gradients characteristic of low expansion ratio and high thermal conductivity - both serving lower thermal stress

2 kW ~534 C

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

CMT Rotor Steady-State Stresses (Principle) Š Kyocera stipulated design target of 200 MPa for SN237 Š Steady 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 MPA All blade and root is below 200 MPa

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

Thermal-Only Stresses (steady-state) Typical blade stress = 8 MPa (< 1KSI)

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

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

CMT Rotor Worst Case Stresses Š Worst Cases: „

Vane Š 234 MPa @ 38 sec. into Cold Start

„

Bore Š 282 MPa @ 54 sec. into Cold Start

„

Back Wall Š 278 MPa @ Steady State

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

CMT Rotor Transient Stresses

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

CMT Rotor Cold Start Stress Profiles 1st Principle Stress Distribution Speed and Thermal Gradient Loading 45.00

1st Principle Stress ksi

40.00 35.00

Back Wall Fillet Vane

30.00

Bore

25.00 20.00 15.00 10.00 5.00 0.00 0

50

100

150

200

250

Time - sec.

300

350

400

450

500

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Fig 26.

Kesseli et. al

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

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Fig 27.

Kesseli et. al

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

et. al IRES CMT Gasifier Rotor, Kesseli Campbell Diagram

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

50000

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

45000 40000

Frequency - hz

35000 30000 25000

1st Mode, Exducer Bending

20000 15000

817% Frequency Margin 3/Rev Excitation

10000

1/Rev Excitation

5000 0 0

10000

20000

30000

40000

50000

60000

70000

Rotor Speed - rpm Fig 28.

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

80000

90000

100000

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

CARES Analysis based on ORNL Materials Data Base Material

Data year

Manufacturer

SN282

2001

Kyocera

SN237

2001

Kyocera

AS800

1995

Honeywell (Formerly Allied Signal

NT154

1989

St. Gobain (formally Norton)

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

CARES Model Results Steady State

SN 237 - 2001 Vintage Material 38 Seconds

54 Seconds

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

SN 282 - 2001 Vintage Material 38 Seconds

54 Seconds

Probability of Failure 0.000000032730000 0.000075857000000 0.000034566800000 Reliability 0.999999967270000 (7 nines) 0.999924143000000 (4 nines) 0.999965433200000 (4 nines) Failure Rate 30553009 13183 28929 Steady State

AS 800 - 1995 Vintage Material 38 Seconds

54 Seconds

Probability of Failure 0.000000021028900 0.000017031300000 0.000008595400000 Reliability 0.999999978971100 (7 nines) 0.999982968700000 (4 nines) 0.999991404600000 (5 nines) Failure Rate 47553605 58715 116341 Steady State

NT 154 - 1989 Vintage Material 38 Seconds

54 Seconds

Probability of Failure 0.000237266000000 0.011407100000000 0.008427090000000 Reliability 0.999762734000000 (3 nines) 0.988592900000000 (1 nine) 0.991572910000000 (2 nines) Failure Rate 4215 88 119 Notes from Steve Duffy: • 38 second condition appears to be worst case

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

Survival Rate at 38s Volume Flaw Analysis

Number of Initial Spin Ups Before Failure Occurs

800000 700000

660419

600000

SN 237 SN 282 AS 800 NT 154

500000 400000 300000 200000 100000 0

13183

58715

88

Silicon Nitride Materials

Stress Analysis· Reliability Analysis kgf/mm2

155.8MPa

Transient (38sec. 89,292rpm) Probability MFracture G T-IR 38b x zof Rotor(SN237) j m (SN 237) 1.0 T otal(A V E) T otal -σ T otal σ T otal -2σ T otal 2σ T otal -3σ T otal 3σ

237.2MPa

Fractuer P robability,P f

0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.00

0.50

1.00

1.50

2.00

2.50

[ ^ [ Speed ] /(~89,292 89,292rpm ) Rotational 27

Stress Analysis· Reliability Analysis kgf/mm2

154.0MPa

Transient (54sec. 97,533rpm) Fracture Probability ofxRotor(SN237) M G T-I R 54b z j m

(SN 237)

1.0 T otal(A V E) T otal -σ T otal σ T otal -2σ T otal 2σ T otal -3σ T otal 3σ

232.4MPa

Fractuer P robability,P f

0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.00

0.50

1.00

1.50

[ Rotational ^ [ ] Speed/97,533 (~ 97,533rpm )

2.00

2.50

28

Stress Analysis· Reliability Analysis kgf/mm2

206.8MPa

Steady State (97,500rpm) M G T-IR ^ ] ¶ j m Fracture Probability of Rotor(SN237) (97500rpm ,SN 237) Surface Internal Ave.

1E+0

184.2MPa

Fractuer P robability,P f

1E-1 1E-2

\ + (A ve) Internal )-2σ \ Surface + (95%Low \ Surface + (95%U ppj +2σ Internal

1E-3

M G T 40,000H r -6 P f=0.925~ 10

1E-4 1E-5 1E-6 1E-7 1E-8 1E-9 1E-2

1E-1

1E+0

1E+1

1E+2

Tim e(hour

1E+3

1E+4

1E+5 29

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

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

- Excellent blade true position and blade profile dimensional control - Excellent surface finish - Coordinate generation error resulted in ultra-thin blades

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

Evaluation Development Cold Spin Test

Cold spin test equipment

Cold spin system

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

Evaluation Development Cold Spin Test

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

Spin pit after rotor burst at 167,197 RPM

SN237 rotor fragments

Rotor-less spindle

Cold Spin Test Results

Room temperature, Material :SN237 Design Speed :97,500rpm Burst Speed = 167,197 (sample #1, only sample) Burst Speed ratio = 171% (Burst/Design) Burst Stress factor (N^2) = 2.9

kgf/mm2

225.5MPa

M G T-I R R [ h ofj Rotor(SN237) m (SN 237) Fracture Probability 1.0

As-fired machined Internal

172.9MPa

Fractuer P robability,P f

0.9 0.8 0.7

Test specimen burst!

T otal

0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.00

0.50

1.00

1.50

2.00

2.50

[ ^ [ ] Speed/97,500 (~ 97,500rpm RPM ) Rotational

3.00

34

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Materials Evaluation-

Kesseli et. al

performed on first 2 rotors

(February -October at ORNL)

Š Disk Test Specimens „ „

Core drill 6 mm X 0.5 mm (~ 200 samples) Bi-axial bending test

Š Flexure bar test „ „

3 X 4 X 60mm bars Bending test

Š Tests and evaluations to be performed for CARES data base „

„

Obtain bulk properties at various positions and orientations within the rotor at 900 to 1000 C Flexure test at 1000 C, after 1000-hr sustained load (nominally 200 MPa)

Š Micro structural analysis, Fractography Š High-velocity, steam injection test at 1000 C (for recession analysis)

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

IR CMT Contributions to the Industry Š Optimized elliptical blade fillet and back-face scallop

model to minimize stress in ceramic rotors Š Improved aero design models to optimize rotor for foreign object damage (FOD) tolerance Š Established reference rotor design and transient boundary conditions for which various materials may be evaluated Š Provide a viable engine for long-term evaluation of commercially viable ceramic turbine

COMPARATIVE MATERIALS EVALUTION FOR A GAS TURBINE ROTOR

Kesseli et. al

Next Steps: Š ORNL materials re-calibration with samples

form actual test rotors (Milestone: Confirm CARES, 5/2003) Š Install and test in PowerWorks 70 kWe engine Milestone: η = 36% LHV, 6/2003) Š Engine endurance test (Milestone: ~ 3000 lab test hours, 10/2003) Š Engine Field Test (Milestone: retrofit approx. 20 units, 2004)