LAUSR

The impeller is one of the core components of a large-scale centrifugal compressor, and its performance directly affects the stability and safety of the centrifugal compressor. The non-contact measurement technology, blade tip timing (BTT), has attracted generous attention in the blade vibration monitoring of rotating impellers. Based on the existing BTT technique, the blade vibration displacement and the blade vibration effective value was used to evaluate the running status of the centrifugal compressor, and a novel rotation speed-based surge identification (RSSID) method was proposed to analyze the surge frequency. Moreover, the cracked blade was detected by monitoring the natural frequency of the blade. A healthy impeller (ky96) and a fault impeller (ky50) with a cracked blade were monitored at the large-scale centrifugal compressor test rig. The blade vibrational alarm threshold for the surge condition is established in agreement with the experimental results, and the surge frequency obtained by the RSSID method matches well with the conclusions of the pressure pulsation signal. The results of the experiments with varying speed show that the natural frequency of the cracked blade deviates significantly from those of the other blades, and the conclusion can be more persuasive by considering the effect of the cracked blade on the standard deviation of the natural frequencies of the other blades. This study is of great importance for running status monitoring and rotating blade fault diagnosis of large-scale centrifugal compressors.