A method and device for on-line monitoring of blade vibration tip timing when the rotational speed is not constant

Abstract

The invention discloses a blade vibration blade tip timing online monitoring method and device during inconstant rotation speed, wherein the method comprises the following steps: 1) obtaining a bladetip timing signal sequence and a rotation speed signal sequence during blade vibration; 2) constructing a blade tip timing angular domain uniformly sampled blade vibration displacement model; 3) establishing a reconstruction formula for the blade vibration blade tip timing angular domain undersampled reconstruction signal; 4) calculating the order spectrum of the blade vibration blade tip timing angular domain undersampled reconstruction signal and extracting synchronous vibration order; 5) calculating the spectrum waterfall plot of the blade vibration blade tip timing angular domain undersampled reconstruction signal to extract the asynchronous vibration frequency. The method can reconstruct the blade tip timing vibration signal with inconstant rotation speed, and the reconstructed signalhas no order aliasing. The method can simultaneously recognize the synchronous and asynchronous vibration characteristics of the blades, and the calculation process is simple and easy to implement. The high-order vibrations can be identified with very few blade tip timing sensors so as to save installation costs and space.

Description

technical field [0001] The invention relates to the technical field of on-line monitoring of high-speed blade vibration, in particular to a method and device for on-line monitoring of blade vibration and tip timing when the rotational speed is not constant. Background technique [0002] High-speed blades are key moving parts in rotating machinery such as gas turbines and aeroengines. High-speed blades are prone to various faults in extreme service environments. These faults are mostly caused by vibration, including synchronous and asynchronous vibrations. The main reason is that high-speed blades are subjected to cyclic alternating loads such as centrifugal force and aerodynamic force, which can easily induce high-cycle fatigue damage and produce tiny cracks; when the damage is severe, the blade will drop corners, drop blocks, or even break directly, resulting in huge safety hazards. For this reason, online monitoring of the vibration generated by high-speed blades, research...

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Problems solved by technology

[0006] Aiming at the above-mentioned technical problems in the related art, the present invention provides a method and device for on-line monitoring of blade vibration blade tip timing when the rotational speed is not constant. Efficient reconstruction of signals and simultaneous identification of technical issues of synchronous and asynchronous vibrations of high-speed blades

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