New developments by scientists at the National Physical Laboratory (NPL) in Middlesex, UK, may allow aircraft manufacturers to improve efficiency and reduce wastage, to create more efficient jet engines and lower aircraft emissions.
Engines are more efficient at higher temperatures, but if they are to run hot without melting, the engine components need thermal treatment at very specific high temperatures in excess of 1,300 °C. If the treatment temperature deviates too much from the optimum, the treatment can fail.
Thermocouples are calibrated using materials with known (fixed) melting points. But existing reference materials on the very high temperatures required to treat jet engine components have a large uncertainty compared with normal lower temperature fixed points. The new discoveries have reduced the uncertainty of thermocouple temperature sensors at high temperatures to within one degree.
Using a new type of metal alloy, NPL scientists identified a range of reference points for thermocouples beyond 1,100 °C. With the new thermal sensors, component manufacturers can improve thermal treatments, reducing wastage during production of engine parts that can run at higher temperatures.