Tip clearance optical measurement for rotating blades

The radial tip clearance of engine blades is the distance of blade tip to casing, and the usual clearance is about 1-2mm. Generally there are many electromagnetic interferences in clearance environment, so the paper adopts an optical-fiber sensor to measure the tip clearance while the blades are rotating from lowest speed to the highest speed. With no touchable mode and less size, the sensor doesn´t affect the work of status of engine. The sensor can efficiently eliminate the effect of tip surface reflectivity variation and light source fluctuation to measurement results; The sensor can also reduce the effect of inter-angle between the measured tip surface and sensor end surface to the results greatly.