Creating a Standard Light Source for improved temperature measurements on gas turbines

Sensor Coating Systems, looking to reduce the temperature measurement uncertainties of its thermal history technology, approached National Physical Laboratory (NPL) for help. The technology consists of applying a luminescent coating to a component, exposing it, under normal operational conditions, to its maximum temperature, and determining the optical properties of the coating following exposure.

With suitable calibration, the temperature of exposure can be determined using the thermal memory of the coating – i.e. offline thermometry. The
measurement capability can be used from 150 °C to 1600 °C, making the technology useful for the evaluation and design of mission-critical components in harsh environments. The development of these tools will enable improved measurements on gas turbine parts for power generations, jet engines or automotive parts. Consequently, assisting in the reduction of costs, improving efficiency and lowering emissions.

Scientists at NPL and SCS have developed a portable standard light source (SLS) based on a high-power LED,
which can be configured to simulate precisely and reproducibly the light emitted by SCS’s coating. NPL is currently developing novel phosphorescent thermometry solutions for online temperature measurements in harsh environments, and because of this, it is uniquely placed to understand SCS’s technical challenges and quickly provide a solution. 

Making use of the SLS has given SCS a robust mechanism to validate and homogenise different instruments without the need to measure an actual luminescent coating and will
ultimately create a mechanism for product standardisation.

Dr Gavin Sutton, Principal Research Scientist, NPL, said: “Working in partnership with SCS through the Analysis for Innovators (A4i) programme has provided a mechanism to greatly enhance the impact of the collaboration in a relatively short period of time. By bringing to bear NPL’s prior experience in online phosphor thermometry, we were able to quickly and effectively understand SCS’s requirements and find the most suitable solution.” 

Dr Jörg Feist, Managing
Director, Sensor Coating Systems, said: “We found the collaboration with NPL engineers and scientists extremely satisfying throughout the entire project. The work was intense but very fruitful.  Both sides brought their specialists together and generated a truly new instrument which will enable the calibration and standardisation of lifetime decay sources around the world. As a direct outcome of the project, SCS decided to embark into an even more challenging project with the team at NPL in 2020.”