叶尖定时技术在转子叶片故障排除中的应用

The principle and data processing method of the non-contact vibration measurement system based on blade tip timing (BTT) were introduced, and applied for analyzing losing-corner fault of aero-engine compressor blades of the fifth stage. The axial and circumferential positions of timing-tip sensors were optimized. Leading and trailing edges of three typical blades (original profile, optimized profile and chamfered profile blades) were measured by non-contact vibration measurement, and the natural frequency and magnitude of the whole blades were obtained. Comparing the vibration parameters of the leading edge with the trailing edges of original profile and optimized profile blades, the resonant amplitudes were almost same. Comparing the vibration parameters of the leading edge of three typical blades, the resonance speeds of the optimized profile blades were a little higher than those of original profile blades, and those of the chamfered blades were larger than the optimized profile blades. Comparing the vibration parameters of the trailing edge of original profile and optimized profile blades, the resonance speeds of the optimized profile blades were a little higher than those of original profile blades. It can be judged that the main reason of the original profile blades occurring losing-corner fault was that the blades were resonant at the working speeds of 4 200 r/min. The resonant speeds of the optimized profile blades were about 40 –80 r/min higher than the original profile blades, leading to the reduction of the losing-corner fault. The resonant speeds of the chamfered blades were about 140 –180 r/min higher than the original profile blades, and the fault can be eliminated.