Turbomachinery prognostics and health management via eddy current sensing: current developments

This paper describes selected aspects of an ongoing program of prognostics and health management for jet engines and other turbomachinery. The primary enabling technology developed to date is a magnetic sensor relying for its operation on high-frequency eddy currents actively induced in passing fan or turbine blades. We summarize the sensor principles, sketch the processing approach used to extract health-related information from the sensor output, illustrate the sensor performance with results from engine tests, and describe the near-term and continuing prognostics and health management program in which the sensor is integrated.