Investigation On Rotating Blade Vibration Monitoring And Analysis Method

The vibration monitoring of rotating blades is an important part of rotating machinery health monitoring.Blade tip-timing(BTT)vibration measurement technique has been widely used in rotating blades vibration monitoring.This measurement can obtain the arrival time of blades to monitor the vibration frequency and amplitude of all blades of machines and it's convenient to install the blade tip-timing sensors.In this paper,BTT monitoring and analysis system was improved and enriched.The system sampling rate setting method was presented in order to improve the accuracy of the blade vibration monitoring.Nonuniform spectral analysis was added in BTT monitoring and analysis system.Blade vibration monitoring application was realized by some experiments.The main research work of this paper is as follows:(1)According to the laboratory blade vibration test platform and taking into consideration the engineering application,BTT monitoring and analysis system under Lab VIEW development environment was improved and enriched,which was suitable for different blade numbers and locations of BTT sensors.As an important parameter of the safe operation of rotating blades,blade tip clearance measurement was added into the system.(2)In order to improve the accuracy of blade vibration monitoring,the system sampling rate setting method of BTT monitoring and analysis system was put forward based on the accuracy of the blade arrival time and the fluency of the system.(3)The measured data by blade tip-timing is nonuniform and under-sampling.The method of Extended Discrete Fourier transform(EDFT)with multi sampling data was put forward for blade vibration parameters identification.Blade vibration nonuniform spectral analysis module was added into BTT monitoring and analysis system based on this method,which was verified by the simulation and experiment data.(4)The host state of the blade vibration test platform was monitored.The simulation experiments of blade torsion vibration characters and fatigue cracks were completed.These realized the application of blade vibration monitoring.