Virtual Product Development for Power Plant Inspections · 2011. 2. 24. · Ultrasonic Methods Pulse Echo 1.) Pre-Cleaning 2.) Apply acoustic couplant 3.) Place ultrasonic sensor,

Roland Moser

Virtual Product Development for Power Plant Inspections

Rapperswil, 22.04.2010

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

P 2

Agenda

1. Introduction

2. Fundamentals of Non Destructive Testing

3. Application of NDT in Inspection Technologies

4. Need for virtual design

5. The CIVA software and its recent developments

6. Conclusion


P 3

Agenda

1. Introduction





6. Conclusion


P 4

Present in 70 countries

Sales : €14.2 billion

Around 95’000 employees

Power

N° 1... in turnkey power plants

N° 1... in hydro turbines and generators

N° 1... in service for utility power generation

N° 1... in air quality control systems

Transport

N° 1... in very high-speed trains, high speed trains and tilting trains

N° 2... in urban light rail and tram systems, commuter and regional trains,

services, signalling and systems

One in four of the world’s light bulbs is powered by Alstom technologies

1.Introduction

ALSTOM


P 51.Introduction

A typical Gas – Combined Cycle Plant

Gas Pipeline

Grid

Boiler

Stack

Air intake

Gas Turbine

Steam TurbineGenerator


P 61.Introduction

Power Plant Components

Gas Turbine Rotor Generator Stator

Steam Turbine RotorBoiler


P 7

Agenda

1. Introduction





6. Conclusion


P 8

2. Fundamentals of NDT

Classification

NDT Methods

Dye

- Dye Penetrant

- Magnetic Particles

Ultrasonic

- Pulse-Echo

- Time of Flight

- Phased Array

- EMAT

- Acoustic emmision

- Laser ultrasonics

- Surface waves

- Guided waves

Electromagnetic

- Eddy Current

- ACFM

- ACPD

- Barkhausen testing

- DCPD

- Flux Leakage

- Remote Field Testing

- Holographic Inferometry

- Shearography

Radiographic

- X-Ray

- Isotopes

- Neutron radiography

- X-Ray fluorescence

Used within Alstom Power

A big variety of physical processes can be used for NDT

Thermal

- Flash thermograpy

- Thermosonics

- Eddy Current ind.

- Laser induced


P 9


Classification

Many solutions to a particular NDT problem

Detect Surface Flaws Detect Volume Flaws

NDT Methods

Dye

- Dye Penetrant

- Magnetic Particles

Ultrasonic

- Pulse-Echo *

- Time of Flight *

- Phased Array *

Electromagnetic

- Eddy Current *

- ACFM *

- ACPD *

Radiographic

- X-Ray

- Isotopes

Thermal

- Flash thermography

- Thermosonics

Surface Flaws

Volume Flaws

* Can be automized

Probe


P 10


Dye Methods

Dye Penetrant Testing

1.) Pre-Cleaning

2.) Application of Penetrant Dye

3.) Excess Penetrant Removal

4.) Application of Developer

5.) Inspection, photographic recording

6.) Post Cleaning

Flurescent

Ambient light

Detects surface cracks:


P 11


Dye Methods

Magnetic Particle Testing

1.) Pre-Cleaning

2.) Application of Magnetic Dye

3.) Apply Magnetic Yoke

4.) Inspection, photographic recording

5.) Post Cleaning

i @ 50Hz

Flux lines „leave“ the test piece, concentrate the magnetic particles


Flurescent


P 12


Electromagnetic Methods

Eddy Current Testing

1.) Pre-Cleaning

2.) Screening using Coil Sensor, detecting flaws

3.) Sizing flaws

High ability to detect flaws down to a size of 50µµµµm, but limited sizing

capabilities.

Eddy Current testing is a volumetric method:

A deep narrow crack can have the same signal response like a shallow wide crack.


Flexible Coil Array

i @ 200kHz

V0 Vcrack

V0 < Vcrack


P 13


Thermal Methods

Flash Thermography

1.) Pre-Cleaning

2.) Optional: Apply black paint

3.) Inject heat using a flash lamp

4.) Observe the cool-down of the object

5.) Optional: Clean-off the black paint

Detects surface and near surface flaws and delaminations:

Flaws influence the cool-down rate

IR Camera

6000 Watt for 10 ms


P 14


Radiographic Methods

Digital X-Ray

1.) No pre-cleaning

2.) Place X-ray source and detector

3.) Detect flaws based on transmission differences

Detect and size all flaws

X-rayCut

Digital X-ray with 50 µµµµm resolution

5mm

Vacuum tubeAnode (W, Mo or Cu)

Cathode

Digital receptor pixels

Electrons

+-

X-rays

Flaw “shadow”


P 15


Ultrasonic Methods

Pulse Echo

1.) Pre-Cleaning

2.) Apply acoustic couplant

3.) Place ultrasonic sensor, send one burst of sound

4.) Detect echoes from sound bursts

Oil, water or gel

Backing material

Crystal

Detects volumetric flaws:

t

S

t

S

∆∆∆∆t

Backwall Echo

Crack echo

Crack depth = ∆∆∆∆t · v

v = velocity of sound

Electrodes


P 16

2.Fundamentals of NDT

Ultrasonic Methods

TOFD (Time Of Flight Diffraction)

1.) Pre-Cleaning

2.) Apply acoustic couplant

3.) Place two ultrasonic sensors, Emitter and Receiver

4.) Detect echoes from crack corners

Oil, water or gel

Size volumetric flaws:

Crystal

E R

Housing and wedge

h

d

Crack of height

h at depth d

Surface wave: t1

“Upper corner” wave: t2

“Lower corner” wave: t3Backwall echo: t4

Compare t1, t2, t3 and t4 to find

depth d and height h

Typical Screen output

Fixed distance

Fixed distance

Modern TOFD equipment


P 17


Ultrasonic Methods

Phased Array

Concept: Why move the sensor when you can move the ultrasonic beam?

Solution: Superposition of small waves (Christian Huygens, 1678)

Use of many small crystals instead on one big one.

Excite the small crystals at different times:

The crated “macro-wave” is a programmable combination of the “micro-waves”

Disc 2Weld

Disc 1

10 small

crystal stripes

Wedge

Beam steering

Distance to flaw

Flaws

Finite element simulation

Wedge10 small crystal stripes

Excitation Voltage

Sound beam


P 18

2.Fundamentals of NDT

Ultrasonic Methods

Phased Array

Another illustrations of its capabilities:

Beam focusing

15 small crystal stripes

Excitation

Voltage

Finite element simulation

Sound beam

Metal


P 19

Agenda

1. Introduction





6. Conclusion


P 20


Generator Inspection


P 21




P 22




P 23


Steam Turbine Inspection

Manual Method

Automated Method

4h / Disc

30min / Disc


P 24


Steam Turbine Inspection


P 25

Agenda

1. Introduction





6. Conclusion


P 26

A diversified fleet requires various customized NDT solutions

Steam Turbines

ABB, ALSTOM, Asea, BBC, AEG, AEI, AKZ, AP, ATM, ATP, BTH, CEM, DGI, Escher Wyss, GEC, GT, IT, Jugoturbina, KT, Lang, LMZ, MAN, MFO, MV, Rateau, SEW, Towax, Zamech

Generators

ALSTOM, ABB, Asea, BBC, ACEC, AEI, BTH, Cenemesa, CEA, Dolmel, EE, Electrosila, Ganz, GEC, Marelli, MV, Rateau

Boilers Gas Turbines

ABL, CE, CEC, EVT, ICAL, Mague, NEI-ICL, PBS, Stein, Sulzer

BBC, ABB, ALSTOM


Inspection Demand


P 27

0

10

20

30

40

50

60

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49

An aging installed base requires NDT to increase lifetime

Average age: 24 years

0

20

40

60

80

100

120

140

160

180

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49

Steam turbines Generators


0

20

40

60

80

100

120

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61

Boilers


Un

its

Un

its

Un

its

Age [years]

Age [years]

Un

its

Age [years]

0

5

10

15

20

25

30

35

40

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52

Gas turbines



Inspection Demand


P 28

NDT is a key technology for aging installed base


Missions for NDT

Example: Steam Turbines

Four missions:

• Prevent damages

• Predict remaining lifetime

• Check the quality of repairs

• Ensure quality of reconditioning

Central Bore

Pin Roots

Girth Welds


P 29


Calibration

Real Cracks:

1.) Casting defects, inclusions, porosities

2.) Fatigue Crack (HCF, LCF)

3.) Stress Corrosion Crack

It is difficult to produce “as real” artificial cracks

Half circle shaped crack front

Crack “age” lines

Sudden fracture

Slow crack propagation

Small crack at the surface

Many branches

Crack initiation from inclusion


P 30


Missed Defects and False Calls

The two main errors in NDT

Missed defects: The inspector does not see a real crack because its signal is buried in the instrument’s noise (in the “Grass”)

False calls: The inspector sees a signal that he interprets as being a crack and initiates an action (e.g. scrap or repair of the part)

Example: Choosing the right instrument amplification.

A proper calibration and experience is key for NDT

NDT instrument amplification [dB]min

100%Gain Knob

max

Missed Defects

False Calls


P 31


Sizing

Flaw sizing capabilities:

Method selection and proper simulation is critical

Actual flaw depth d [mm]

d

Measured

depth [mm]

1 2

1

2

Ideal S

ensor

Eddy Current

ACFM / ACPD

Ultrasonic Time-of-Flight (TOFD)

Surface breaking crack:


P 32

Agenda

1. Introduction





6. Conclusion


P 33

5. CIVA Software and case study

Principle

CIVA is an analytical simulation software for NDT probe or systemdevelopment.

CIVA was initially developed for the nuclear industry, but is now the industry standard software for power plant and aerospace NDT, as well.

CIVA has 3 physics solutions available with ultrasonic testing [UT],eddy current testing [ET] or radiographic testing [RT].

Special feature: Semi-analytical methods rather than fully numerical methods (finite elements, finite differences, etc.), and the development of models integrated into software modules usable byoperators who are not simulation specialists.


P 34


Development Project

1 Post-Doc senior software developer, 2 years

Post-Doc works at French Nuclear Energy Agency (CEA) near Paris

Experimental verification by Alstom Field Inspectors

Results to be implemented in future versions of CIVA

Simulation of various Phased Array sensors Simulation of various defects


P 35


Problem

In-situ ultrasonic inspection of curvilinear fir-tree blade roots

Standard blade configuration of large nuclear steam turbines

Note the curved blade root and the shape of the blades

Real blade Test Mock-Up


P 36


Limitations of CIVA

Approximation : pièce CAO «Approximation : pièce CAO «Approximation : pièce CAO «Approximation : pièce CAO « 2.5D2.5D2.5D2.5D »»»»CIVA could not calculate « real » 3D

Rotation Extrusion

3D Represen

CIVA CIVA CIVA CIVA was initially designed was initially designed was initially designed was initially designed to to to to simulate weld simulate weld simulate weld simulate weld inspectionsinspectionsinspectionsinspections


P 37


Limitations of CIVA

CIVA could not calculate rebounds from flancs to defects, even in 2D(Indirect echoes)

1. 2.

3.

Ultrasonic sensor

Defect

CIVA CIVA CIVA CIVA was initially designed was initially designed was initially designed was initially designed to to to to simulate weld simulate weld simulate weld simulate weld inspectionsinspectionsinspectionsinspections


P 38

Without multiple rebounds

Échos supplémentaires Échos supplémentaires Échos supplémentaires Échos supplémentaires dus au défautdus au défautdus au défautdus au défaut


Limitations of CIVA

CIVA could not calculate multiple rebounds

New development: with multiple rebounds

Rebounds


P 39


Development work

Implementation of indirect echoes

DiffractionDiffractionDiffractionDiffractionCornerCornerCornerCorner

„Crack“Multiple rebounds


P 40


Development work

Implementation of indirect echoes

Typical output Model calibration and verification

using automated NDT

Ultrasonic sensor


P 41


Development work

Implementation of real 3D


P 42

Conclusion

Virtual development saves time and money:

1. No need for dedicated testblocks in real steel

2. Quick adaptation to new geometries

3. Fast feasibility check

4. Design aid to develop new sensors


P 43

Questions

www.power.alstom.com

Documents

Virtual Product Development for Power Plant Inspections · 2011. 2. 24. · Ultrasonic Methods Pulse Echo 1.) Pre-Cleaning 2.) Apply acoustic couplant 3.) Place ultrasonic sensor,