Time-frequency analysis of acoustic signals for condition monitoring of fluid-filled pipelines

In this paper, a wave propagation model is developed to investigate the wave propagation in fluid-filled steel pipe. Based on the Kennard shell equations the investigation is achieved under the conditions of coupling between the shell elastic acoustic field and the interior fluid acoustic field. Tests are conducted on fluid-filled pipeline blockage detection. An active acoustic source is used to generate acoustic pulse waves into the pipe. The position of the blockage can be obtained from the reflected transient signals. Smoothed Pseudo Wigner-Ville distribution method (SPWVD) has been used to extract the time and frequency features of the propagating waves in the coupling system. Experimental results demonstrate that the proposed approach and SPWVD are effective in detecting the position of the blockage.