The Pipeline Leak Location Techniques Based on Modal Acoustic Emission

Abstract

Due to the multiple modes and dispersive nature of acoustic leak signal propagation in pipeline, the traditional AE cross correlation method was ineffective to location the leak in pipeline. Based on the theory of modal acoustic emission (MAE), two different pipeline leak location techniques are brought forward. One is based on two modes with one sensor; the other is based on one mode with two sensors. The general process is narrated as following three steps. Firstly, based on the theory of guided waves propagation in cylinder, the acoustic leak signals in positions nearby the sensor(s) can be predicted using the information of dispersion characteristics of guided waves in pipeline and the acoustic signal received by the sensor(s). Secondly, by transformed the predicted signals in time and space, two (one) individual modes (mode) of the acoustic signal at the position of the sensor(s) are isolated. By correlated the two modes of the same sensor (one mode of the two sensors), the leak position can be located accurately. The leak location experiments have been carried out to prove the validity of the one sensor and two sensors leak location techniques; it is indicated that the location errors of the two leak location techniques are usually less than 5%, and the techniques can be used to location the leak of pipeline filled with liquid or gas.