Session: Student Poster Competition

Submission Number: 187283

Towards Full-Surface Thermal Mapping With Imaging-Based Thermal History Coatings 

The transition towards net-zero energy systems and higher efficiency aero and gas turbine engines is driving operation at increasingly high firing temperatures. These conditions introduce extreme thermal stresses and reduce component lifetimes. Consequently, precise surface temperature data is required to support component design and validate models. The understanding of complex cooling mechanisms such as micro cooling structures found in combustor panels is critical for the identification of hot spots and thermal gradients.

This poster examines the development of a novel imaging-based system capable of capturing the past maximum surface temperature of aerospace and power generation components using luminescence data from Thermal History Coatings (THCs).¹ It also explores the technical challenges associated with transitioning from sequential single point measurements to full surface mapping.

THCs address this industrial demand by recording the maximum surface temperature experienced by a component. After a component has been thermally loaded and cooled down, the coating is optically excited and the emitted luminescence is measured and calibrated to temperature, enabling non-destructive, offline temperature determination across a wide range (150 °C to over 1,600 °C). THC readout is commonly performed using single point optical probing, where a laser excites a 1mm diameter region and emitted luminescence is collected by a photodetector.

Single-point THC measurements provide high experimental control and precision. The probe can be positioned perpendicular to the surface at a fixed working distance, and excitation power and detected signal levels can be adjusted to maintain linear response. Single-point systems are also fast enough to fully capture the detailed luminescence signal from the coating. High-resolution temperature maps can be constructed by systematically moving the probe across the surface, providing detailed insight into thermal gradients and hot spots.² However, measuring 10,000 sequential data points requires days of measurement time.

Imaging based luminescence readout offers a route to overcome this limitation by enabling simultaneous acquisition of millions of spatially resolved data points, in minutes instead of days. However, this removes many of the controls inherent to single point probing. Excitation cannot be independently tuned per pixel, complex components cannot be uniformly illuminated, surfaces are not perpendicular to the detector, and surface distance varies across curved geometries.

This poster presents a conceptual framework for imaging-based THC readout, demonstrating how angle, distance, and signal-dependent effects can influence measurements, and shows how an imaging system can accurately capture luminescence events even without the speed of a photodetector, enabling high-resolution, full-surface thermal mapping of complex turbine components.

 

[1] Araguas Rodriguez, S, Bouten, T, Parsa, E, Ishaque, I, Parsons, C, Krsic, G, Counte, J, Axelsson, L, Karagiannopoulos, S, & Feist, J. "Utilising Thermal History Coatings for the Assessment of Hydrogen Fuel on Combustor Temperatures." Proceedings of the ASME Turbo Expo 2025: Turbomachinery Technical Conference and Exposition. Volume 5: Energy Storage; Fans and Blowers; Heat Transfer: Combustors; Heat Transfer: Film Cooling. Memphis, Tennessee, USA. June 16–20, 2025. V005T11A003. ASME. https://doi-org.ezp.lib.cam.ac.uk/10.1115/GT2025-152181

[2] Hickey, J, Lee, J, Counte, J, Rai, K, Lee, K, Mun, Y, Araguas Rodriguez, S, Karagiannopoulos, S, Hong, G, & Feist, JP. "Unique High-Resolution Temperature Mapping of Stage 1 Turbine Vane in a Long-Term Engine Test." Proceedings of the ASME Turbo Expo 2024: Turbomachinery Technical Conference and Exposition. Volume 13: Heat Transfer: General Interest / Additive Manufacturing Impacts on Heat Transfer; Wind Energy. London, United Kingdom. June 24–28, 2024. V013T13A025. ASME. https://doi-org.ezp.lib.cam.ac.uk/10.1115/GT2024-126737

Presenting Author: Carl Parsons University of Cambridge

Presenting Author Biography: Robotics Development Engineer at Sensor Coating Systems and Industrial Fellow with the Royal Commission for the Exhibition of 1851, currently undertaking a PhD at the University of Cambridge. Current work focuses on developing laser diagnostic systems to advance industrial temperature measurement for the energy and aerospace sectors.

Authors:

Carl Parsons University of Cambridge
Solon Karagiannopoulos Sensor Coating Systems Ltd.
Simone Hochgreb Cambridge University
Jörg Feist Sensor Coating Systems Ltd.