3D Printing of a miniature turbine blade model with an embedded fibre Bragg grating sensor for high-temperature monitoring

Abstract

Rapid advances in 3D printing enable the construction of complex metal structures. However, sensor embedding within 3D printed metal structures has been challenging due to its extremely high-temperature condition. Here, we embedded an optical fibre sensor for temperature monitoring within a Ni-alloy miniature turbine blade by directed energy deposition (DED) printing. To endure the high-temperature condition, a fibre Bragg grating (FBG) sensor was electroplated with a Ni layer, and various 3D printing parameters were optimised. In particular, to minimise the accumulation of thermal energy in the FBG sensor, ‘line-by-line printing and stop’ process was applied around the sensor. The embedded sensor accurately measured temperature cycling up to 500°C with the sensitivities of 28.3 and 27.2 pm/K in heating and cooling cycles, respectively. Finally, an FBG sensor was successfully embedded in a miniature turbine blade by our DED process, demonstrating its feasibility for high-temperature monitoring.