The Instability Analysis And Monitoring Of Axial Compressor

As the one of three major components of gas turbine,compressors may be influenced by many factors in the process of operation,deviate from steady station,get into instable station,and make the performance of gas turbine reduced greatly.Therefore,for avoiding or quitting instability as soon as possible,improving the efficiency and stability of compressor,it is important that how to detect the instability signal and provide an effective instability monitoring method.The main research contents are as follows:1.The design of axial flow compressor operation monitoring system.Combining the actual condition of three stages axial flow compressor to design the components of hardware and the function of software of axial flow compressor operation monitoring system;Adapting the variable area of channel geometry to induce instability,and carried out instability test under 2400r/min,4800r/min,7200r/min.The test results indicated that the axial flow compressor operation monitoring system operated steady,and achieved the function of data collection,display,storage,the feature extraction of instability and early warning.2.The analysis of frequency domain features.Firstly,removed the error value by Pauta criterion,processed by Hanning window function and Butterworth lowpass filter.Secondly,analyzing frequency spectrum of signal,clarified the surge frequency of compressor rig was 2~3Hz in dynamic pressure and sound pressure,the frequency of rotating stall was about 30% of the rotating frequency,and the difference between amplitude of rotating stall,mild surge and deep surge exceeded one magnitude.At last,discussed the feasibility of monitoring method based on the frequency domain features.The conclusion proved that the frequency domain features analysis was directly perceived,the parameters that needed to design were little,the accuracy rate of early warning was high under the high frequency resolution condition.And distinguished the rotating stall,mild surge and deep surge,recording to the different width and amplitude of frequency.3.The analysis of time domain statistics features.Firstly,made the data of stability and instability processed by Kalman filter.Secondly,analyzing the time domain statistics parameters that be sensitive to instability of signal,clarified the time domain statistics parameters features that in the signal of pressure,sound and vibration.At last,proved the autocovariance and variance was not affected by other variable working condition,the threshold value was clear,suitable for dynamic pressure and sound pressure signals,and two kinds of statistics parameters can be monitored comprehensively.And discussed the feasibility of monitoring method based on the statistic features.The conclusion proved that the statistics features analysis was high time resolution,the threshold value was easy to choose,and the accuracy rate of early warning was high.4.The design of air bleed control system and the experimental validation of on-line monitoring system.Firstly,designed the software and hardware of air bleed system.Secondly,validated the reliability of on-line monitoring system through the instability experiment.