51. Experimental Investigation on the Accuracy of Blade Tip Timing Spectral Analysis Methods
- Author
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Zhicheng Xiao, Yiming Meng, and Hua Ouyang
- Abstract
The amplitude of spectral analysis of the tip timing data from individual blade observations is significant to turbomachinery health monitoring and aeroelastic researches. The accuracy of non-uniform discrete Fourier transform (NUDFT), extended discrete Fourier transform (EDFT), and compressed sensing (CS) is studied systematically. The benchmark data is obtained on a novel test bench where blade tip displacement can be acquired by laser displacement sensor directly. In the experiment, all three methods can successfully recognize the dominant 1F vibration but fail to discover the underlying 1T component. The accuracy of NUDFT to estimate the transient amplitude is approximately 69%. For EDFT and CS, the values are 30% and 84%, respectively. The number of cycles included in an analysis batch is found to influence the results. The robustness of the methods is discussed. The three methods are applied to a single-rotor rig and NSV is discovered in a field test. All of them could capture the frequency feature. It is determined that the blade is vibrating in the first flex mode. The difference between the measured frequency and the simulation is only 2.7%. Regarding the amplitude, CS yields the most convincing estimations.
- Published
- 2022
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