Experimental investigation of coupled frequency and time-domain transient test-based techniques for partial blockage detection in pipelines

Partial blockages commonly exist in pressurized pipeline systems, and the rapid remediation of such faults is required to reduce the wastage of energy as well as to maintain the serviceability of the pipe network. Numerous transient test-based techniques (TTBT) have been developed for detecting pipe defects, with each technique providing different advantages. Two previously developed techniques- pressure signal analysis (PSA) and frequency response analysis (FRA)-are experimentally tested in this study on systems of different pipe material and characteristics. Each method is validated using the experimental data, and the results show that PSA is most accurate for locating the blockage while FRA is most accurate for determining the radial constriction and length of the blockage section. To take advantage of the different strengths of the techniques, a coupling of the two methods is proposed. Experimental application results reveal that both detection accuracy and calculation efficiency are improved when the coupled method is used instead of the original techniques applied individually. Moreover, the results indicate that current TTBTs for partial blockage detection are more reliable in elastic (metallic) pipelines compared to viscoelastic (plastic) pipes.