Periodic Reporting for period 2 - Batista (Blade Tip Timing System Validator)
Período documentado: 2020-09-02 hasta 2021-09-01
One of the main objectives in the design of a rotating component is to obtain the vibration response to ensure that the mechanical loads encountered in operation do not result in excessive stress that can cause fatigue failures. Today this is achieved through modelling, laboratory tests and engine testing with the most common method being the use of strain gauges, the application of which are expensive and often unreliable in a gas turbine environment.
There are a number of reasons for requiring a new technology and most hinge on both the lead-time and cost of application. Today’s gas turbine development programs are up to 50% shorter than those of a decade ago and the machines operate at increasingly higher speeds and temperatures. Instrumentation failure is high, as is the mortality of a strain gauge in such an environment.
The objective of the project BATISTA, funded through Clean Sky Joint undertaking, was to study Blade tip timing (BTT) technology in order to sustain its future use to produce data suitable to support certification of compressor blades while providing saving in terms of cost and timescale compared to the currently used technologies. This project provides a complete validation strategy for the use of BTT in aero compressors by performing a full test on a representative compressor stage under controlled conditions and validating the results against an FE model, strain gauges and LVD.
The project has been completed and has addressed all of the objectives covering many of the uncertainties encountered when using BTT.
Main drivers of uncertainty have been identified and controlled and the outcome of the project shows that BTT data has similar uncertainties to strain gauges, which themselves are not perfect.
The conclusions of the project have allowed to progress on the application of BTT technology to aero compressors/boosters for use in component certification.
In this project we have demonstrated through analysis and through physical measurement that the use of BTT as a measurement of blade displacement and ultimately the determination of blade stress is a viable alternative for strain gauges and has similar uncertainties.
The project has:
- Identified the need for a fully validated FEM for both technologies
- Identified a process for how BTT data can be correlated to both strain gauges and FE models.
- Demonstrated that the measurement made by BTT are comparable to the strain gauges and result in similar uncertainties.
There are a number of reasons for requiring a new technology and most hinge on both the lead-time and cost of application. Today’s gas turbine development programs are up to 50% shorter than those of a decade ago and the machines operate at increasingly higher speeds and temperatures. Instrumentation failure is high, as is the mortality of a strain gauge in such an environment.
The objective of the project BATISTA, funded through Clean Sky Joint undertaking, was to study Blade tip timing (BTT) technology in order to sustain its future use to produce data suitable to support certification of compressor blades while providing saving in terms of cost and timescale compared to the currently used technologies. This project provides a complete validation strategy for the use of BTT in aero compressors by performing a full test on a representative compressor stage under controlled conditions and validating the results against an FE model, strain gauges and LVD.
The project has been completed and has addressed all of the objectives covering many of the uncertainties encountered when using BTT.
Main drivers of uncertainty have been identified and controlled and the outcome of the project shows that BTT data has similar uncertainties to strain gauges, which themselves are not perfect.
The conclusions of the project have allowed to progress on the application of BTT technology to aero compressors/boosters for use in component certification.
In this project we have demonstrated through analysis and through physical measurement that the use of BTT as a measurement of blade displacement and ultimately the determination of blade stress is a viable alternative for strain gauges and has similar uncertainties.
The project has:
- Identified the need for a fully validated FEM for both technologies
- Identified a process for how BTT data can be correlated to both strain gauges and FE models.
- Demonstrated that the measurement made by BTT are comparable to the strain gauges and result in similar uncertainties.
The project was organised in four work packages that were selected to mimic the way BTT is applied in industry's with strain gauge experience and capabilities.
WP1 BTT Measurement Technology Evaluation:
In this work package all of the instrumentation required was identified and procured/modified.
- All software required was developed and validated.
- A rotor was obtained and instrumented with strain gauges
- The blades were used to develop the ‘calibration’ process
- A telemetry system was designed, manufactured and tested.
- All instruments were calibrated.
- In addition, and due to Covid-19 travel restrictions, network systems were configured so that remote operation could be implemented.
WP2 Test facility preparation:
All of the mechanical design work and manufacture was completed in this work package. This is similar to building, installing, connecting instrumentation, operating the plant and running of a typical compressor test program.
WP3 FEM analysis and model validation:
This work package provided the predicted and measured data allowing blade deflection to be converted to strain. It identifies the uncertainty in each of the calibration processes and provides supporting data to the other work packages.
The BTT model validation was completed and predicted stress to deflection ratios were made. Six blades were supplied to the facility and the calibration process was tested.
Drivers of uncertainty were identified and reported.
Predicted test uncertainty was derived from the calibration data and included in the final report.
WP4 Experiment owner and program management:
In this work package the facilities and capabilities of each of the partners was assessed and any gaps found were identified and resourced. The overall objectives are used to derive the local equirements and monitor the progress of them.
The planning and risk management were carried out.
All deliverable and milestones were prepared.
The Communication and dissemination (which continues after the project closure) was carried out mainly through the project website which has been a success resulting in sales of BTT equipment for partners ITASCR and EMTD which is part of the exploitation expected.
In the future is expected that further research is performed including the application for further study at Manchester University for a visiting PhD student, and in terms of dissemination, a number of papers are being prepared for publication after the project completion.
WP1 BTT Measurement Technology Evaluation:
In this work package all of the instrumentation required was identified and procured/modified.
- All software required was developed and validated.
- A rotor was obtained and instrumented with strain gauges
- The blades were used to develop the ‘calibration’ process
- A telemetry system was designed, manufactured and tested.
- All instruments were calibrated.
- In addition, and due to Covid-19 travel restrictions, network systems were configured so that remote operation could be implemented.
WP2 Test facility preparation:
All of the mechanical design work and manufacture was completed in this work package. This is similar to building, installing, connecting instrumentation, operating the plant and running of a typical compressor test program.
WP3 FEM analysis and model validation:
This work package provided the predicted and measured data allowing blade deflection to be converted to strain. It identifies the uncertainty in each of the calibration processes and provides supporting data to the other work packages.
The BTT model validation was completed and predicted stress to deflection ratios were made. Six blades were supplied to the facility and the calibration process was tested.
Drivers of uncertainty were identified and reported.
Predicted test uncertainty was derived from the calibration data and included in the final report.
WP4 Experiment owner and program management:
In this work package the facilities and capabilities of each of the partners was assessed and any gaps found were identified and resourced. The overall objectives are used to derive the local equirements and monitor the progress of them.
The planning and risk management were carried out.
All deliverable and milestones were prepared.
The Communication and dissemination (which continues after the project closure) was carried out mainly through the project website which has been a success resulting in sales of BTT equipment for partners ITASCR and EMTD which is part of the exploitation expected.
In the future is expected that further research is performed including the application for further study at Manchester University for a visiting PhD student, and in terms of dissemination, a number of papers are being prepared for publication after the project completion.
.The work carried out during the project implementation allows to confirm that BTT technology is a viable alternative for the currently used technologies (e.g. strain gauges) when it comes to the measurement of blade displacement and the consequent determination of blade stress. This has permitted to progress towards the future use of the technology for the use in certification processes, which will accelerate the testing processes and reduce the cost.
In terms of specific results, the consortium has demonstrated that:
- BTT is easier to fit and has similar uncertainties to strain gauges.
- BTT real time integral vibration capability is more limited
- Integral vibration can be predicted and post processed data gives a better result.
- BTT real time non-integral capability is superior to strain gauges.
- Sensor technology still needs more evaluation.
- Blade modelling is key to the process (no different to strain gauges)
- Confidence in BTT capabilities needs to be gained through experience (no different to strain gauges).
- Creating open format data will allow further methods to be researched.
- Demonstrates that BTT is a real world tool rather than an academic exercise.
- It needs to be understood that not all BTT functions have been validated by the supplier.
- Not all probes/sensors are suitable for BTT.
- Investigate the damping effects of strain gauges on small blades and its contribution to variability.
- Remove the operator errors through automation.
In terms of specific results, the consortium has demonstrated that:
- BTT is easier to fit and has similar uncertainties to strain gauges.
- BTT real time integral vibration capability is more limited
- Integral vibration can be predicted and post processed data gives a better result.
- BTT real time non-integral capability is superior to strain gauges.
- Sensor technology still needs more evaluation.
- Blade modelling is key to the process (no different to strain gauges)
- Confidence in BTT capabilities needs to be gained through experience (no different to strain gauges).
- Creating open format data will allow further methods to be researched.
- Demonstrates that BTT is a real world tool rather than an academic exercise.
- It needs to be understood that not all BTT functions have been validated by the supplier.
- Not all probes/sensors are suitable for BTT.
- Investigate the damping effects of strain gauges on small blades and its contribution to variability.
- Remove the operator errors through automation.