Non-aliasing reconstruction method of high-speed leaf undersampled leaf apex vibration signals

A vibration signal and undersampling technology is applied in the field of alias-free reconstruction of undersampling blade tip vibration signals of high-speed blades, and can solve the problem of frequency aliasing of reconstructed signals.

Active Publication Date: 2013-12-25
NAT UNIV OF DEFENSE TECH
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Problems solved by technology

However, the actual under-sampled tip vibration signal is not a band-pass signal, which causes serious frequency aliasing in the reconstructed signal

Method used

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  • Non-aliasing reconstruction method of high-speed leaf undersampled leaf apex vibration signals
  • Non-aliasing reconstruction method of high-speed leaf undersampled leaf apex vibration signals
  • Non-aliasing reconstruction method of high-speed leaf undersampled leaf apex vibration signals

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Embodiment Construction

[0050] It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

[0051] The following is based on figure 2 The flow chart of the method of the present invention is shown to realize alias-free reconstruction.

[0052] A non-aliasing reconstruction method for high-speed blade under-sampled tip vibration signals, characterized in that it includes the following steps:

[0053] First, use the tip timing signal acquisition system to obtain under-sampled tip vibration signals

[0054] The blade tip timing signal acquisition system includes a blade tip timing sensor, a speed synchronization reference sensor, a blisk, a high-speed pulse acquisition circuit, an acquisition card and a computer. The blade tip timing sensor is evenly installed on the circumferential shell, and each blade on the blisk A pulse will be generated when passing through each blade-end timing sensor and the synchron...

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Abstract

The invention discloses a non-aliasing reconstruction method of high-speed leaf undersampled leaf apex vibration signals. The method comprises the following steps that (1) a leaf apex timing signal acquisition system is used for obtaining undersampled leaf apex vibration signals, (2) the frequency band range of high-speed leaf vibration performance is determined, (3) leaf apex vibration signals are reconstructed for the first time based on the Shannon sampling theorem, (4) proper wavelet packet decomposition layer numbers are determined to enable the assigned frequency band range is consistent with one frequency band after wavelet packet decomposition, (5) signals in the assigned frequency band range are reconstructed again from the reconstructed signals hat(z)[n] at the first time using wavelet packets, (6) the coefficients of wavelet packets except for the Rth wavelet packet are all set to be zero, and the traditional wavelet packet reconstruction algorithm is utilized for reconstructing signals in the frequency band range of [f0-B0/2, f0+B0/2]. The non-aliasing reconstruction method is simple in process and easy to realize, reconstructed signals are not deflected and not in aliasing, and real and reliable high-speed leaf vibration signals can be provided.

Description

technical field [0001] The invention relates to the field of on-line monitoring of vibration signals of high-speed blades, in particular to a non-aliasing reconstruction method of under-sampled blade-end vibration signals of high-speed blades. Background technique [0002] The blades of gas turbines and aero-engines rotate at high speed in harsh environments such as high temperature and high pressure, which makes the vibration measurement of blades a rather complicated technical problem. The traditional contact blade vibration measurement method, such as the strain gauge measurement method, must install the sensor on the blade to be tested, which is time-consuming and laborious, and it is difficult to monitor the vibration of all blades; in addition, the working life of the contact sensor is short, and its own load and volume It will directly affect the aerodynamic and mechanical properties of the test piece, thus restricting the practical application of this type of technol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01H9/00G01H11/00G06F19/00
Inventor 杨拥民陈仲生胡政杨定新胡海峰谢勇郭彬
Owner NAT UNIV OF DEFENSE TECH
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