Coupled static deformation of rotating blades measurement based on tip timing and validation using laser displacement sensors

Abstract

A new method of measuring the static deformation of rotating blades based on BTT is proposed and examined in experiments. To achieve high accuracy and robustness, the method utilizes coordinates on both the suction surface and the pressure surface from multiple probes and fits them to the complete tip profile. To realize this, a backward fitting algorithm is designed which solves the deformation parameters in a coupled fashion. Hardware advancement is also implemented where the departure time instants besides the arrival time instants of each blade are collected. A novel validation method using the laser displacement sensor is also presented to provide a benchmark. In the laboratory experiment, it is found that the new method could reduce the calibration uncertainty to 43%–61% by taking the suction surface into account. Compared to the existing methods, the measurement error of the new method is also the smallest. The proposed method has been validated on a single-rotor compressor rig.