Impedance estimation along pipelines by generalized reconstructive method of characteristics for pipeline condition assessment

Reliable and efficient pipeline condition assessment in water transmission mains is required to locate deteriorated sections, such that water authorities can rehabilitate or replace vulnerable sections to prevent pipe failure. In this paper, a novel method is developed to estimate pipeline impedance and pipeline wall thickness through hydraulic transient testing. The recently developed reconstructive method of characteristics (RMOC) algorithm is generalized in the current research by relaxing the requirement of a dead-end boundary. Instead, the generalized RMOC as proposed requires two adjacent pressure transducers placed at any interior locations along a pipe to record head variations in a controlled transient event. The parameters along the pipeline can be analytically determined though the smart use of a method of characteristics (MOC) analysis backwards in time. The configuration required by the proposed method makes it applicable in the real world. The proposed approach is first verified by a numerical experiment, where three sections with different wall thicknesses (representing deteriorated sections) are successfully identified. The new technique is then verified by a laboratory experiment, where wall thickness and location of two sections with wall class changes are identified.