Measurement of internal temperatures in engine-scale gas turbine blade with fiber optic sensors

Conference item

Further improvements in performance of gas turbine engines require increases in turbine entry temperature. As these temperatures continue to exceed the material properties of turbine blades, complex cooling configurations, advanced manufacturing techniques, and thermal barrier coatings are required to protect blades from damage. While external surface temperatures can be measured to evaluate the effectiveness of such systems, limited techniques exist to capture internal metal temperatures due to the small size of engine-scale blades and the complex cooling configurations they contain. However, knowledge of these temperatures is essential to optimizing and managing thermal gradients within the blade and ensuring blade life. The capability to measure internal metal temperatures would enable more comprehensive analyses of blade performance and life, contributing invaluable data to the research and development process. This paper explores the use of fiber optic sensors to measure temperature fields with high spatial resolution in difficult-to-access blade locations. Changes in temperature can be monitored through changes in the reflected wavelength of fiber Bragg gratings, or narrow band filters inscribed in the core of an optical fiber. The gratings are resistant to the harsh conditions and high temperatures present in gas turbines. Many gratings can be written along a single waveguide with a diameter of 0.15 mm, resulting in a minimally invasive instrumentation technique. In this investigation, a cooled, engine-scale turbine blade is instrumented with fiber optic sensors and exposed to high temperatures in the Oxford High Temperature Linear Cascade at the Oxford Thermofluids Institute.

Authors: Berexa, EK; Coulton, B; Fells, JAJ; Ireland, PT

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Institute of Aeronautics and Astronautics
• Host title: AIAA SCITECH 2024 Forum
• Publication date: 2024-01-04
• Event title: AIAA Science and Technology Forum and Exposition (AIAA SciTech Forum 2024)
• Event location: Orlando, Florida, USA
• Event website: https://aiaa.org/events/2024-aiaa-science-and-technology-forum-and-exposition-aiaa-scitech-forum/
• Event start date: 2024-01-08
• Event end date: 2024-01-12
• DOI: 10.2514/6.2024-2574
• EISBN: 9781624107115
• Language: English