A hybrid system for high temperature tip clearance measurement

A new high-temperature hybrid clearance measurement system for aeronautical and industrial gas turbines has been developed which incorporates all elements required for measuring clearance over individual blades. A ground station performs all control and data reduction functions needed to operate the hybrid probe, returning clearance over every blade around a rotor in engineering units. A software program enables the ground station to be set up for particular rotor and to log clearance measurement data during probe operation. Probe accuracy was demonstrated with a 95 percent confidence limit of +/- micron in measuring distance from the hybrid probe rear datum to each blade tip.