Author(s): Lennart Jonsson
Linked Author(s):
Keywords: Hydraulic transient; Leak detection; Experimental set-up
Abstract: Hydraulic transients in pipelines are normally looked upon as a problem but could also be considered as a kind of a probe propagating through the pipeline. Measurement and careful analysis of a pressure transient could reveal some valuable properties of the pipeline. Thus a leak in a single pipeline should affect the appearance of the measured transient making it possible to indicate the existence of a leak as well as pointing at the location of the leak. This paper will give some theoretical and experimental evidence for this beneficial use of hydraulic transients. In the first place theoretical computations of the effect of a leak on the transient are discussed concerning the case with a single pipeline at pump stop. It is shown that the transient wave interacts with the leak generating a small pressure rise at the measurement point at the pumping station. The elapsed time between pump stop and the recorded pressure rise can be used for assessing the location of the leak. Secondly, results from transient measurements on an experimental pipeline set-up with simulated leaks are presented. Transients were generated through valve closure at the end of a 135 m long pipeline. Leak flow rates of about 5 – 14 % of the pipe flow were investigated and it was shown that the leak in most cases could be qualitatively traced on the transient measurement and that the leak could be located with an accuracy of a few meters on the basis of a good knowledge of the initial wave propagation velocity.
Year: 2001