The high-frequency testing facility comprises of 5 straight pipes, 6.5 meters in length, that are connected to two water-filled reservoirs at their ends. The pipes differ in nominal diameter and/or material. Specifically, there are 4 HDPE pipes with their nominal diameter ranging from 2 to 6 inches, as well as a 3-inch copper pipe. A special feature of the setup is the provision for interchangeable sections on the 3-inch copper and one of the two 3-inch HDPE pipes. These 50 cm sections may be replaced by smaller nominal diameter pipes to emulate the presence of a blockage, or by a pipe with a side discharge valve that simulates a leak. Therefore, it is possible to evaluate the response of both healthy and defected pipelines without the need of extensive system reconstruction or downtime.
The applicable transducers on the setup are primarily the Brüel & Kjær Type 8104 and Type 8103 that may be utilized either as hydrophones or acoustic projectors. The transducers are inserted in the pipes through the openings to the reservoirs, and are mounted via bespoke 3D printed bases with embedded magnets that form a pair with another magnet on the outside of the pipe wall. This novel mechanism allows for the precise positioning of the transducers in both longitudinal and radial directions. Lastly, the vibrations of the pipe wall under an acoustic source within the pipe are monitored with Brüel & Kjær Type 4326-A Triaxial Accelerometers, mounted on the outer surface of the pipe.
The setup has been extensively used for pipe characterization under wideband acoustic signals, and for the successful leak and blockage localization in high-resolution (in the order of centimeters).