Acoustic emission is an important parameter, which is assessed during the testing of new gas turbines to analyse their performance and noise levels. In its current form, assessment requires a set of expensive far-field microphone arrays elaborately installed around the turbine in a specialised testing facility. Distributed acoustic sensing is a novel sensing technique that uses optical fibre as a sensing element to measure acoustic vibrations. Using a distributed acoustic sensor (DAS) system can simplify the testing procedure significantly, and reduces the cost and size of the testing system by a considerable amount. This development will allow for inflight measurement of the acoustic vibrations of mounted engines to determine engines’ performance, noise level, and their imminent failure. This in turn leads to a quieter and safer aircraft and improved fuel efficiency.
Technological advantages
- Mapping the acoustic vibrations of gas turbines
- Inflight noise emission measurement over the frequency range of 50Hz ~ 10kHz and sound pressure range of 80dBC ~ 140dBC
- Capable of mapping the temperature distribution deep inside the engine core
Technology Roadmap
DAS is a relatively new technology which has been used mainly in the oil and gas industries. The spatial resolution of the commercially available systems is in the range of 1m ~ 10m, which is not suitable for this application. We have demonstrated a DAS system with a special resolution of 30cm. A special resolution of 1cm can be achieved by modifying the current sensing technique. In addition, higher frequency and sensitivity ranges can be achieved by further improving the digital signal processing procedure.
Collaboration opportunity
The estimated cost of this project is £600,000 over three years. The work includes developing a high-speed data streaming system, signal processing software, and boxing and testing the setup in the ISVR Facility. EPSRC funding schemes are available to reduce the overall cost by up to 50 per cent.
If you would like to know more, please contact Ali Masoudi a.masoudi@southampton.ac.uk