preliminary study on acoustic detection of faults
TRANSCRIPT
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Preliminary Study on Acoustic Detection of Faults Experienced
by a High-Bypass Turbofan Engine
Devin K. Boyle NASA Armstrong Flight Research
Center
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https://ntrs.nasa.gov/search.jsp?R=20140010472 2019-08-31T20:09:56+00:00Z
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Outline
• Background on VIPR research • Introduction to VIPR acoustics research objectives • Motivation • Test setup • Research engine • Preliminary detection of simulated failures • Future work • Conclusion
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VIPR Background
• Vehicle Integrated Propulsion Research (VIPR) project currently in Phase III of ground-based engine testing
• The project is using F117-PW-100 engines (military derivative of PW 2000 used on the Boeing 757) in the 40k-lb thrust class
• Engines are representative of typical high-bypass commercial turbofans
• VIPR is a way to introduce faults that would otherwise be prohibitive
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VIPR Overview Vehicle Integrated Propulsion Research (VIPR) engine tests to support the research and development of Engine Health Management Technologies for Aviation Safety Engine testing is a necessary and challenging component of Aviation Safety technology development. Partnerships make it possible.
Test Objectives:
Demonstrate capability of advanced health management technologies for detecting and diagnosing incipient engine faults before they become a safety impact and to minimize loss of capability
Approach: Perform engine ground tests using high-bypass transport engine
• Normal engine operations • Seeded mechanical faults • Seeded gas path faults • Accelerated engine life degradation through
volcanic ash ingestion testing Partnerships:
• NASA • US Air Force • Federal Aviation Administration • Pratt & Whitney • GE • Rolls-Royce • United States Geological Survey • Boeing • Makel Engineering • Others in discussion
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SDA and High Freq Vibration Sensors
SDA and High Freq Vibration Sensors
Microwave Tip Clearance Sensors
Fiber Optic Temperature Sensors
Thin Film Sensors
Model-based gas path diagnostic architecture Acoustic Engine Health Monitoring
Dynamic Pressure Sensors
Emissions Sensor
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VIPR III Overview
• VIPR III Test Objectives (Summer 2015) – Engine Health Management (NASA):
• Initial steps toward EHM sensor fusion with Advanced Sensors • Demonstrate capability of advanced health management technologies for detecting
and diagnosing incipient engine faults before they become a safety impact and to minimize loss of capability
– Bleed Air Environment Testing (Boeing and Partners) • To evaluate and characterize bleed air sensors, sampling and purification
technologies in a relevant operating environment – Volcanic Ash Ingestion Testing (AFRL and Partners)
• Run engine to end of life • To improve understanding of the effect on the engine of several hours of
exposure to low to moderate concentrations of volcanic ash • Determine how well engine degradation from volcanic ash is detected with an
expanded engine health management system – Pratt & Whitney Testing
• VIPR III is possible with the combined efforts/resources of the consortium
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VIPR Acoustics Research
• Goal: Characterize the engine core, fan, and exhaust acoustics under nominal and off-nominal/seeded fault conditions
– Objective: Obtain engine core, fan, and exhaust acoustic health monitoring (AHM) data under nominal and off-nominal / seeded fault conditions
• Faults introduced during VIPR II included the simulated failures of the engine station 2.5 and 14th stage bleed valves to their failsafe positions
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Motivation
• The use of acoustics, if proven successful in detecting and potentially identifying faults, can progress toward condition-based maintenance
– Ultimate goal is detection and eventual identification of common faults
• External acoustic measurements of engines is a simple and non-intrusive inspection process
• Additionally, microphones may characterize the progression of engine operational degradation
• System doesn’t have to survive the harsh environment of the aircraft
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Test Setup
• Image courtesy Google earth
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Test Setup (Continued)
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NASA Photograph ED13-0228-160
NASA Photograph ED13-0228-157
NASA Photograph ED13-0228-156
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Research Engine
Station 2.5 (LPC Exit)
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14th Stage (HPC)
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Detection of 14th Stage Bleed Valve Fault
• Ramp Acceleration (approx. 1 min. from idle to target power) for normal and fault insertion
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• Jam Acceleration (rapidly from idle to target power) for normal and fault insertion
Detection of 14th Stage Bleed Valve Fault
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• Engine steady operation for normal and fault insertion
Detection of 14th Stage Bleed Valve Fault
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Station 2.5
• Detection of the seeded faults of the station 2.5 proved troublesome
• Several factors contributed to this: – Pressure at the 14th stage bleed valve is an
order of magnitude greater than at station 2.5 – Station 2.5 modulates as the engine transitions
between idle and max power, whereas 14th stage valve is discrete (fully closed to “failed” fully open)
• All of these factors suggest that the magnitude of the noise resulting from the failure of the station 2.5 valve was much lower than from the 14th stage
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Anticipated Future Work
• A greater variety of failures is expected for VIPR III testing (Summer 2015)
• Volcanic ash ingestion offers a tremendous opportunity to detect subtle changes (degradation) to engine performance
• More bleed valve simulated failures • Injection of oil simulating failure of forward
bearing seal • Further analysis of current data set
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Conclusion
• Preliminary analysis of simulated failure of 14th stage bleed valve to its failsafe position suggests feasibility of far field acoustic microphone array to detect the fault
• Fault of station 2.5 bleed valve proved more difficult to detect due to the circumstances
• The results offer justification for continuation of work in this area
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Acknowledgements
• NASA Armstrong Flight Research Center (formerly Dryden Flight Research Center) Center Innovation Fund provided funding for procurement and labor
• Several employees helped in the somewhat arduous setup and takedown process during testing
• Bruel & Kjaer representative from Southern California offered advice on test setup
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Questions?
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