On cavitation occurrence in perforated plates

• The incipient cavitation number of perforated plates is investigated.
• New original results are joined with data from literature.
• The effect of the most relevant geometrical parameters is studied.
• A new predictive correlation is proposed.

The hydraulics of perforated plates has a large impact on the design of water systems; particularly, estimating the inception of cavitation is fundamental for correctly assessing the performances of these devices. The work is focused on the onset of cavitation, as defined by means of the incipient cavitation number. Objects of discussion are the experimental evidences collected in two large laboratory campaigns, in which different plates with equivalent diameter ratio between 0.17 and 0.60, relative thickness between 0.11 and 4.40, and number of holes between 1 and 15 were tested. Literature experimental data, previously checked for consistency, have been added to ours in order to enlarge the experimental database. Such database was firstly employed for investigating the dependence of the incipient cavitation number upon the most relevant parameters and then for providing a formula for its estimation. In details, we propose a new correlation – based on the formula of Tullis (1993) – relating the incipient cavitation number to the discharge coefficient showing a satisfactory agreement with all the available data and therefore having a quite large applicability.

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