Time-domain Analysis of Laboratory Experiments on the Transient Pressure Damping in a Leaky Polymeric Pipe

The pressure damping occurring in pressurized pipes with a leak during transients has been examined as a diagnostic tool – the so-called transient damping method (TDM) – mainly from the theoretical and numerical point of view. On the contrary, the experimental data are limited to few cases. As a consequence, there is a need of an extensive experimental analysis of the role played on the pressure damping by leak parameters (size, location and initial pressure). On the basis of the laboratory tests executed on a polymeric pipe, it is shown that, while the magnitude of the injected pressure wave does not affect the damping, the initial pressure, the leak size and location influence it plainly. Moreover, an experimental evidence is provided of the ambiguity in the time-domain of the transient pressure damping pointed out by numerical experiments. Precisely, it is demonstrated that different combinations of the leak parameters can lead to the same pressure damping. The obtained results indicate that the TDM can give a reliable assessment of the pipe status only if it is integrated with other diagnostic tools, such as the interpretation of the pressure signal during the first characteristic time of the pipe.