Author(s): Alessandro Pagano, Umberto Fratino
Linked Author(s): Umberto Fratino
Keywords: Perforated plates, experimental setup, dissipative performances, cavitation detection.
Abstract: Perforated plates are widely adopted in hydraulic pressurized systems mainly as flow conditioner or, when coupled with control devices, to originate a fixed pressure loss for limiting the onset and the intensity of cavitation phenomena. Several studies were performed through numerical models and laboratory activities to describe key aspects of the hydraulics of single and multi-hole orifices. Particularly, most of the studies aimed to identify the hydraulic conditions affecting their behavior in terms of either dissipative performances or cavitation development. The hydraulic behavior of such devices mainly depends on geometrical features, such as the equivalent diameter ratio ?, the dimensionless plate thickness t/dh, the number nh and disposition of the holes. Due to the multiplicity of influential parameters and the complexity deriving from the joint analysis of their role, multiple tests are required in order to cover a sufficiently wide range of configurations. Pressure scale effects may also affect the performances of these devices. New experimental data, collected through tests which were carried out at Politecnico di Bari, were integrated to the results on recent studies in order to provide additional information. The present paper focuses on single-hole orifices which were tested in variable flow conditions. Some findings for orifices where ? ranges between 0. 3 and 0. 63 and t/dh ranges between 0. 1 and 0. 36 were discussed. The remarkable dependency of the dissipation characteristics of the devices, expressed in terms of pressure loss coefficient Eu, discharge coefficient Cd, and cavitation intensity upon the above mentioned geometrical parameters were discussed
Year: 2017