Water hammer detection based on FIV online analysis using a distributed fiber optic sensor

Abstract

In long-distance oil pipelines, the abnormal flow state of the fluid in the pipeline can cause continuous water hammer effects, which can damage the pipeline and even cause leakage or collapse. Based on this phenomenon, this paper proposes a new, to the best of our knowledge, detection method based on sensing optical fiber and phase-sensitive optical time-domain reflectometry (φ-OTDR) system to solve the problem of continuous water hammer detection in long-distance pipelines. The method uses a non-invasive, low-cost, real-time approach to monitor pipeline wall deformation characteristics and assess flow-induced vibration (FIV) intensity by statistically distinguishing water hammer signals from normal vibration signals and calculating the peak-to-average ratio (PAR) of these signals. Experimental results show that the FIV status of different types of pipelines can be effectively monitored by calculating the PAR of water hammer signals and vibration signals. The measured PAR based on the φ-OTDR system has high consistency with the PAR variation trend of simulation results, the distributed fiber optic sensor is less affected by environmental factors, and its detection distance and anti-interference ability are better than those of high-precision commercial triaxial acceleration sensors.