Thermal effects on fibre optic pressure sensor during free piston compression experiments

Abstract

Experiments in the study of transient aerodynamics typically require pressure measurements with a high spatial and temporal resolution. Inexpensive pressure sensors based on extrinsic Fabry-Perot fibre optic interferometry are capable of measurement with a high spatial and temporal resolution. However, previous work has shown that such fibre optic pressure sensors are very sensitive to temperature.We use an engineering software package (ANSYS) to model the thermal effects in the sensor for the reflected shock conditions. Our results indicate that the fibre optic pressure sensors can be employed in the shock tube without any shielding for 20 ms with reasonable accuracy. However, unshielded sensors in high pressure and temperature conditions will not produce accurate measurements, nor will they survive multiple experiments.