NATO RTO AVT128 Meeting, Florence May 16, 2007. Vibro-Meter / Radatec Products & Capabilities Overview Date:15th May 2007 Presented by Pavol Rybarik,

NATO RTO AVT128 Meeting, Florence May 16, 2007


Vibro-Meter / Radatec Products & Capabilities Overview

Date: 15th May 2007

Presented by Pavol Rybarik, Vibro-Meter SA


Contents

Product Overview

Technology Overview


New Technology

High Temperature Sensing of Blade Tips with Microwaves

Long-Life Capability at High Temperature

New sensing platform beyond conventional laser, eddy current, or capacitance based gauges.


Microwave Displacement Sensor Overview

Key Technology Features

— Environment

Ability to withstand high temperatures for measurements in 1st stage turbine

“See through” carbon, flaming natural gas, steam, etc.

Magnetic field immunity

Large bandwidths (limited only by sampling)


Phase-based Microwave Technique

—Electrical Performance High signal to noise ratios (active system)

Very High Frequency Response

—Measurement Resolution less than 1 mil

Large displacement ranges

Self-calibration to eliminate effects of thermal growth.


Sensor Overview

Moving Object

4 2

Patented Technology

Standard Displacement Signal

Microwave Sensor 1 Transmitted Signal

Reflected Signal

3

Non-contact displacement sensor

Phase-based microwave technique

Measures displacement smaller than the transmitted

wavelength


Why Measure Blade Tips?

In the HPT for every 10 mil improvement in clearance1

— Fuel Efficiency increases 1%

— 1% change in HPT clearance reduces NOx 10%,CO2 13% (GE)

Newer engines use compressor bleed air and a model to close clearances open loop

Measuring clearances and closing the control loop can add additional efficiencies

Tip clearance control has been identified as a key technology for future engines

Additional benefits in prognostics, NSMS, and condition-based maintenance

— Dimensional measurements from every blade provide indicators of health


Blade Tip Sensing

Important Measurements

Tip Clearance

Time-of-Arrival

Blade Vibration


Hardware— High Speed Data Processing

— High Temperature Probe

Software— Average & Minimum Clearance

for multiple sensor locations

— Modular, flexible data outputs

T2000 Product Overview

System Solution: Turbine Blade Tip Clearance


System Components

Tachometer Signal Conditioning

Microwave Cable Bulkhead

Electronics Chassis (Compact PCI)

Sensor Card(s)

Ethernet switch

Data Server - 1U rack mount computer

Microwave cabling

Probe

Client / User Interface Computer(s)


System Overview

Sensor Control Computer(SCC)

System Monitor

Ethernet Switch

Sensors 1-12

19" Rack

Remote Computer forDisplay

Probes

Analog Outputs, 0-5VDCProportional to Minimumand Average Clearance

1/rev Input


Electronics Front Panel

Auxiliary analog inputs(currently not used)

Probe Connector (SMA)

Radatec High Speed Test Output

Tachometer (1/rev) InputVoltage Proportional to Average Clearance

Voltage Proportional to Minimum Clearance

System OKLight

MeasureLight

CommunicationLight

RS-232 SerialDebug

RJ-45 Ethernet


System Monitor Main Screen


Alternative Clearance Plot


Probe Calibration

Probes are calibrated to produce direct measurement.

Designed to radiate at a narrow frequency band only-otherwise bounce off the back of the probe

Measuring – (in freq band)

Calibrating – (out of band)

Electronics box

Electronics box

target

target

Eliminates the thermal effects internal to the system.


Sensor Diagnostics

Sense changes in the cable

Breaks in signal chain are localized very precisely—manifest as a parasitic signal return at a particular phase.

Can be used to troubleshoot connections in the probe.

Understand if changes are in the probe vs. in the reading.


System Specifications

Sensor Bandwidth- up to 9 MHz (18 MHz sampling)Same waveforms from near zero RPM to full speed Resolution- +/-0.5 mils Range- 0.500” max typical, >1 inch available upon request Linearity- ~1% of full scale range, target dependent Sample Rate- 100 Hz-20 MHz, speed dependent Onboard Memory- 18 Megasamples Probe Temperature- 1st stage turbine operation Microwave Cabling- 0.142” cable up to 30 feet typical Digital Data Outputs- Displacement waveforms Analog Outputs- Voltage proportional to clearance 0-5 VDC Sensor to PC Communications- 10/100 Ethernet, UDP/IP


Metrology ConsiderationsTipped Blades

— Tapered blade tips with tip grinding cuts a conic section for the blade tip.

— Surfaces are not flat

Axial Shifts— Axial shifts in engine operation

can change cross section presented underneath the sensor

Asymmetric Clearance Changes

— Important to consider that sensors only measure clearance in one location

4 Probes per stage recommended to assess case ovalization and shaft centerline changes.

Cold

Hot

Cold

Hot

Rotation

Direction


Linearization of Sensor with Actual Blades

Two linear stages

Recently upgraded Y-stage to move blade by probe < 2 seconds

Relative radial motion accurate to < 0.25 mils


Typical Linearization


Competing Sensors

Probe Construction (Reliability)

Why do Capacitance gauges fail?

Microwave Capacitance (BICC)

• Electrical Resistance of alumina drops from exposure to temperature

•100 V DC Bias typical

•Insulation Resistance drops and probe shorts out. Needs high resistance

•Probe slowly loses signal as it shorts out

Hastelloy X

SiO2 cableTransparent TBC

Al2O3

• Electrical Resistance not important. Design is 50 Ohm Impedence

•Micro-amps at microwave frequencies

•TBCs, thinner ceramic, more metal increases heat conduction path

NATO RTO AVT128 Meeting, Florence May 16, 2007 23

Large Power Systems Test Parameters

Compressor— 315-380°C gas path

Turbine— 1010°C gas path

Hot Restart Application.


Compressor Data in Land Based Turbine

Shutdown pinch point

Engine shutdown

NATO RTO AVT128 Meeting, Florence May 16, 2007 25

Clearance Close-up


Turbine


Other Possible Measurements

Tip Clearance /Tip Track

Blade Bending/CrackingDisk Cracking

(Two Axes)

Blade Vibration

Torsional DeflectionShaft Bending/RotordynamicsInside turbine/combustion area

Shaft Monitoring

Blade Monitoring


FAQsQ: Can Squealer tip geometry be measured?

A: Yes, but only to the extend that the slow-speed linear stage resolves it. Every blade can be different.

Q: What legwork is required to install in my turbine?

A: A sample blade or cad model of the blade is used to generate an “error map” to provide a correct calibration for the blade as it is installed in the engine. The probe holder is also designed to provide a minimal, but sufficient amount of cooling air to the probe to ensure long life operation.

Q: When can I get one?

A: Please Contact your Meggitt Vibro-Meter sales contacts for further information


FAQs

Q: Does the probe require cooling air.

A: To assure long term operation, purge cooling around the probe is typical. Only small volumes of air (<6 SCFM) are typically required.

Q: What is the maximum probe temperature?

A: The face of the probe is made of material with a rated temperature of 1700C. However, the rear of the probe is made of conventional nickel alloys with long term ratings of 800C. The steep thermal gradient from the interior of the turbine through the wall is considered on a case-by-case basis to ensure long-term, reliable operation of the entire system.

Documents

NATO RTO AVT128 Meeting, Florence May 16, 2007. Vibro-Meter / Radatec Products & Capabilities Overview Date:15th May 2007 Presented by Pavol Rybarik,