Research On Harmonic Frequency Synchronous Tracking Method Of Multi-rotor Gas Turbine

Gas turbines are important rotating machinery and equipment in pipelines,ships,aviation and other industries.In order to meet different needs,they have many operating conditions and frequent and rapid changes in operating conditions.In order to ensure the safe and reliable operation of the gas turbine under various operating conditions,it is necessary to monitor the vibration status of the unsteady conditions.Traditional rotating machinery fault diagnosis technology was relatively mature,but it was not suitable for gas turbine condition monitoring under variable operating conditions.Aiming at this problem,the synchronous tracking method of harmonic vibration of multi-rotor gas turbine was studied,which were mainly divided into amplitude trend tracking and waveform extraction of harmonic frequency components.The main research contents are as follows:(1)Aiming at the problem of speed extraction in the absence of a key phase or in a situation where the key phase and vibration were not synchronized,resulting in the problem of target order offset in harmonic vibration analysis,a speed extraction method based on synchronous extraction transformation(SET)was proposed.First,integrated the vibration acceleration signal to obtain the vibration speed signal with obvious rotor power frequency component;then,used the synchronous extraction transformation method to extract the instantaneous frequency(IF)in the vibration speed signal with reference to the speed data with poor synchronization,which was the synchronous accurate speed data.Through the processed of simulation signals and actual gas turbine operation data,compared to several common time-frequency analysis methods,and the Renyi entropy parameter was used to measure the effect of time-frequency analysis,and the effectiveness of the proposed method in the occasion of gas turbines synchronous speed extraction of was verified;(2)To solve the problem of harmonic frequency component tracking in the process of variable load,two methods of order waterfall graph slice amplitude trend tracking based on calculation order tracking(COT)were proposed.Through the analysis of simulation data and engineering data,the two methods were compared in terms of amplitude accuracy and calculation efficiency.The results showed that the equal time intervals order waterfall graph slicing algorithm has obvious advantages in amplitude accuracy and operation time.It means that the proposed algorithm can effectively extract the amplitude trend of the harmonic frequency component of the gas turbine;(3)In order to solve the problems of Kalman filter order tracking method(VKFOT)parameter setting difficulty,long calculation time and order offset,this paper proposed a harmonic component extraction method based on improved VKFOT method.Through analysis of simulation signals and engineering data,it was confirmed that the improved scheme had the following three advantages.It was easy to set the filter parameters,solved the problem of order offset caused by the asynchrony of vibration and speed,effectively improved the calculation efficiency and thus the proposed method can quickly and accurately extract the gas turbine harmonic vibration component waveform.Finally,based on the MATLAB APP Designer platform,a gas turbine harmonic vibration synchronization extraction software for gas turbines and other rotating machinery was programed,covering the two main functions of target order amplitude tracking and harmonic vibration component extraction.The software has laid the foundation for the practical application of harmonic vibration synchronous tracking method in vibration monitoring and fault diagnosis of gas turbines and other rotating machinery.