Heat-flux measurement using fibre-Bragg-grating Fabry-Perot sensors

We describe a fibre Fabry-Perot heat-transfer sensor that is capable of per forming the high-spatial-resolution measurements required in turbomachinery research. The all-fibre cavity operates as a calorimeter embedded perpendi cular to the test surface. The cavity incorporates a Bragg grating as the i nternal reflector, producing a mechanically robust sensor suitable for aero dynamic measurements. We present experimental results from an impinging flo w rig, comparing the optical sensor with a thin-film resistance gauge subje cted to a step increase in heat flux of 30 kW m(-2).