基于希尔伯特-黄变换的屏蔽泵瞬态信号评估研究

Evaluation Study of Shield Pumps Instantaneous Vibration Signal Based on HHT

屏蔽泵是核设备中重要的旋转设备。屏蔽泵启动过程中的瞬态激励会产生较大的振动及声辐射。分析屏蔽泵启动时的瞬态振动信号的频谱特性,是对其进行评估的基础。本研究主要使用希尔伯特-黄变换(Hilbert-Huang Transform,HHT)方法对屏蔽泵启动过程产生的瞬态信号进行分析与评估。希尔伯特-黄变换作为一种新的自适应方法,对非线性和非平稳信号敏感,主要包括经验模态分解和Hilbert谱分析。对瞬态信号进行经验模态分解(Empirical Mode Decomposition,EMD),得到内部模态函数(Intrinsic Mode Function,IMF)分量及希尔伯特能量谱,计算得到边际谱后即可算出信号的振级,从而对不同点的瞬态信号进行评估。本文采用短时傅里叶变换、小波变换及希尔伯特-黄变换对瞬态信号进行研究,分析结果表明,希尔伯特-黄变换方法能够有效判断出瞬态信号的频域分布,可对瞬态信号进行定量评估。

Shield pump is important rotating machinery on nuclear structures and can generates instantaneous vibration signal which will produce strong vibration and acoustic radiation. Study the spectral characteristics is the foundation for such vibration signal.Hilbert-Huang Transform(HHT) is used to analyze the instantaneous vibration signal during the starting procedure of shield pump.Including of Empirical Mode Decomposition(EMD) and Hilbert spectrum, HHT is a new adaptive method which is sensitive to nonlinear and unsteady signals. Using EMD approach can get the Intrinsic Mode Functions(IMFs) components and Hilbert energy spectrum, then the marginal spectrum can be used for calculating signal’s vibration level which can help to evaluate the signal of different measuring point. The results of three methods(including short time Fourier transform, wavelet transform and HHT) indicate that HHT method can determine the frequency domain effectively and conduct quantitative evaluation.