矿用对旋风机失速信号特征的诊断与分析

Diagnosis and analysis of stall signal characteristics of coal mine contra-rotating fan

为探究对旋风机失速流动信号的瞬态特征,将对流场信号的瞬时特征具有良好辨识能力的小波分析法引入到对旋风机失速特征的分析中,提出一种FFT技术与小波-时频分析相结合的失速诊断方法。首先,基于出口节流阀模型,对小流量失速工况下对旋风机内部的三维非定常流动进行数值模拟与分析;然后,利用所提出的失速诊断方法,对对旋风机在失速发生时流场中的静压信号进行处理和分析。结果表明:对旋风机在10个旋转周期后进入失速状态,伴随着前缘溢流与尾缘反流的出现而发生。另外,FFT技术从频域角度确定出失速特征表现为70Hz及140Hz频率分量的出现,而小波-时频分析从时频角度发现对旋风机在第10个旋转周期开始出现70Hz及140Hz频率分量,证明了所提出的方法对对旋风机失速流动特征具有较好的诊断分析能力。

In order to explore the transient characteristics of the stall flow signal of the contra-rotating fan,the wavelet analysis method,with its strong ability to identify the instantaneous characteristics of the flow signal,is introduced into the analysis of the stall characteristics of the contra-rotating fan,and a stall diagnosis method combining FFT technique and wavelet-time-frequency analysis is proposed.Firstly,based on the outlet throttle model,numerical simulation and analysis of the 3 D unsteady flow inside the contra-rotating fan under a stall condition is carried out;Secondly,the static pressure signal in the flow field of the fan is processed and analyzed using the proposed stall diagnosis method.The results show that the contra-rotating fan enters a stall state after 10 rotation period,which occurs with the appearance of leading edge overflow and trailing edge backflow.In addition,the FFT technique determines from the perspective of frequency domain that the stall characteristics are manifested as the appearance of 70 Hz and 140 Hz frequency components,while the wavelet-time-frequency analysis found that the contra-rotating fan began to appear 70 Hz and 140 Hz frequency components from the perspective of time-frequency domain at the 10 th rotation period.It is proved that the method proposed has a good performance for the diagnosis and analysis of the stall characteristics of the fan.