Experimental Research on Layout of Acoustic Emission Detection Sensor for Valves Internal Leakage
To research the influence of sensor layout on the acoustic emission detection effect of valve internal leakage,a test platform for valve internal leakage acoustic emission detection is built.Three acoustic emission sensors with the same parameters are installed in the upstream,body and downstream of the valve respectively,and the leakage acoustic emission signals are collected simultaneously under different leakage rate conditions.Wavelet packet decomposition and reconstruction,extracting the average energy of the signal root mean square(RMS)and linear fitting and other methods are used to analyze the collected signals for feature extraction.The extraction results show that the output signal amplitudes of the three position sensors are close to linear with the change of the leakage rate.Among them,the acoustic emission sensor installed at the downstream of the valve has more concentrated output signal energy and the best linearity of amplitude with the change of the leakage rate;the acoustic emission sensor installed at the upstream of the valve has the worst linearity of output signal amplitude with the change of the leakage rate.Based on existing research,the measured data of the upstream,body and downstream sensors of the valve are compared through the experiment.The experimented results show that,by installing the sensor at the downstream near the valve,it can effectively improve the accuracy of the acoustic emission detection of the internal leakage rate of the valve and provide a basis for the estimation of the remaining life of the valve.
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