HADES - Optical Hot Air Leak DEtection System

Project Information

HADES

Grant agreement ID: 785450

DOI

10.3030/785450

Project closed

EC signature date 12 February 2018

Start date 1 March 2018

End date 31 December 2020

Funded under

• SOCIETAL CHALLENGES - Smart, Green And Integrated Transport

Total cost

€ 570 000,00

EU contribution

€ 399 000,00

Coordinated by

LUNA INNOVATIONS GERMANY GMBH
Germany

Periodic Reporting for period 3 - HADES (HADES - Optical Hot Air Leak DEtection System)

Reporting period: 2020-07-01 to 2020-12-31

Summary of the context and overall objectives of the project

Light carbon structures are increasingly used in modern aircrafts for reducing weight and thus fuel consumption. The carbon materials are more sensitive to overheating than metals. Hot air ducts are used to conduct air heated by engine exhaust to the cabin heating system. At several locations, those hot air ducts are installed within or in close proximity to the carbon structures. Therefore, reliable and precise hot air leak detection is an essential safety feature of modern aircrafts. The proposed activity aims at developing an innovative, powerful and reliable fibre-optic technology for an aircraft hot air leak detection system and validating it in a representative aircraft environment. State-of-the-art electrical hot air leak detection systems detect and localize leaks in aircraft hot air ducts by analyzing electric shortcuts. However, the response of such systems just indicates that the critical temperature is exceeded. It is impossible to vary the threshold setting along the cable and false alarms due to stray signals are common. Localization of leaks is difficult, and the sensor cables are irreversibly damaged by exceeding the critical temperature. Based on our deep understanding of using fibre-optic sensing systems in harsh and safety-critical environments, NKT Photonics GmbH - LIOS Sensing will select the optimum fibre-optic technology for hot air leak detection in aircrafts, which overcomes the limitations of the electrical systems, complies with the requirements of the tender and fulfils the other essential requirements of aircraft applications. LIOS will demonstrate the technology’s capabilities, using a proof-of-concept system in the NKT Photonics GmbH - LIOS Sensing laboratories. After testing, the demonstrator will be re-design to bring it closer to TRL6, a demonstration within an aircraft environment. The re-designed demonstrator will be installed at the facilities of the topic manager and tested in collaboration with the topic manager.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During the 3rd reporting period, the optimization of the Proof-of-Concept 1 design was executed. Therefore, the algorithms for postprocessing the interrogated optical data from the FGB were improved. In addition, still existing artefacts in the received and post-processed data hve been removed, increasing the overall gain of the system. also the temperature accuracy has been improved for the critical locations, hot-spots. Resulting in the POC2 design
The POC2 was finalized and prepared for testing at the LTS site, as soon as the TRL of 4 was approved and COVID allows travelling. NKTP prepared a remote support for the test campaign, without any NKTP personnel from NKTP at the LTS site. Therefore, the spare parts (second chipset for testing) was used to establish a system for deep analysis and error testing during the potential remote test campaign.
The test-campaign however was cancelled due to missing the TRL of 4, as originally anticipated. LTS confirmed a great step forward for fiber optical sensing technologies in the aircraft industry.
This project has shown a great improvement in fiber based monitoring system, proving a spatial resolution of at least 2.5cm with a high interrogation speed and alarm processing. It also shows the capability of absolute temperature measurement, which improves the current system, by showing also the real temperature along the whole air bleed system in addition to the alarm triggering capabilities.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Expected result of this project is a functional demonstrator showing a superior spatial resolution of at least 2.5cm. The technology is based on a fibre optic Fibre Bragg Grating (FBG) design, which can read more than 1000 FBGs. The time for scanning those FBGs and their data processing and alarming will be levered to a whole new level of few seconds. We are also developing to achieve a temperature accuracy of at least +/-2°C over the whole measurement distance.
This approach is able to set new standards for distributed monitoring and security standards. Localizing a defect, such as a hot air leak in a light carbon structures, that fast and accurate can decrease the probability of consecutive faults and the down time for maintenance and repair works. This can lead to a safer and cheaper operation of aircrafts.
In addition, this technology can be used in a broader industry, where the precise spatial resolution is of importance, such as the process industry.

Schematic of air bleed system