Transient response of discrete partial blockages in laminar pressurized flow: Insights into pressure and velocity variations by Computational Fluid Dynamics

Understanding the interaction between pressure waves and partial blockages in pipe systems is crucial for enhancing noninvasive detection methods based on the execution of transient tests. Although laboratory and one-dimensional numerical models have also provided valuable results from the practical point of view, analyzing the transient response of partial blockages in terms of local flow field characteristics is of great interest. This paper examines the transient response in laminar flow conditions of partial blockages by using a Computational Fluid Dynamics model. In particular, the time history of pressure and local velocity of transient events is examined during the early phase characterized by the first pressure wave reflected by the partial blockage. Laminar conditions are chosen for their minimal risk in real pipe systems as they give rise to small overpressures. The behavior of discrete partial blockages at two locations is analyzed in detail, with a pipe with no blockage scenario as a reference. Simulations of discrete partial blockages with different severity confirm that the reflected pressure wave contains enough information for locating and characterizing partial blockages. The obtained results provide critical insights for the organization of transient tests toward the detection of partial blockages.