Theoretical characterization of a gas path debris detection monitoring system based on electrostatic sensors and charge amplifiers

The electrostatic detection of gas path debris has been proposed in literature as a tool to monitor mechanical component faults along the combustion gas path of turbo-machines. In this paper we discuss the general theoretical characterization of a debris detection monitoring system based on electrostatic sensors and charge amplifiers. We first provide the analytical expression of the time-varying charge induced by the moving debris on the sensor surface. After introducing a simplified electric model of the charge amplifier, we discuss the effects of the amplifier bandwidth on the shape of the output voltage signal. Theoretical results have been validated with experiments.