Partial Blockage Detection in Pipelines by Frequency Response Method

A new technique is presented utilizing the frequency response for the detection of partial blockages in a pipeline. In the system frequency response, a partial blockage increases the amplitude of the pressure oscillations at even harmonics. Such an increase in amplitude has an oscillatory pattern, the frequency and amplitude of which may be used to predict the location and size of a partial blockage. In this technique, the pressure transient history at only one location is sufficient, and the history of the transient in the pipe prior to blockage is not needed, which is an advantage over a number of other available techniques, in addition to being simpler to use. It is shown that the technique successfully detects the location of a blockage in a number of simple systems with blockage size as small as 10%. The technique is verified by comparing the computed results with those computed by the method of characteristics and with measurements from simple laboratory setups. A number of practical issues and limitations for field implementations are discussed.