摘要
在详细分析水轮机空化信号特点的基础上,总结了适合于空化信号分析的小波基函数应具有的特点;为避免信号小波包分解的盲目性,文中采用了区间小波包分解方式,即有针对性地对空化信号进行深层次分解。结合水轮机模型空化状态观测结果,对相应状态下监测的空化超声波信号进行小波包时频分布特性和频带能量分布特性分析,得出了水轮机空化超声波时域信号幅值调制特性和频域能量分布随空化系数变化的关系,验证了小波包频带分析技术对水轮机空化信号分析的有效性。
The characteristics of wavelet basis that is applicable for the processing of cavitation acoustic emission signal are summarized based on the analysis of the characteristics of the acoustic emission signal emitted by cavitation in hydraulic turbines. Besides, local decomposition of wavelet packet are proposed and employed in signal processing to improve the efficiency of decomposition. Aided with the pictures of cavitation, taken in the cavitation tests on the model turbine, with different cavitation coefficients, the ultrasonic signal of cavitation corresponding to each cavitation coefficients are analyzed via the time-frequency distribution and energy distribution. The relationships between the amplitude modulation in time domain as well as energy distribution in frequency domain and cavitation coefficients are achieved via model tests. The effect of frequency bandwidth analysis of wavelet packet has been proved.
出处
《大电机技术》
北大核心
2009年第1期43-48,共6页
Large Electric Machine and Hydraulic Turbine
关键词
水轮机
空化
小波包
区间分解
时频分布
幅值调制
频带能量
hydraulic turbine
cavitation
wavelet packed
local decomposition
time-frequency distribution
amplitude modulation
energy distribution
