Two-phase flow structure of sheet cavitation

TLDR

The study analyzes how Reynolds and cavitation numbers influence the dynamic behavior and vapor flow rate in sheet cavitation. Measurements were obtained in a Venturi cavitation tunnel using a double optical probe, laser velocimetry, wall pressure sensors, and visualization to characterize void fraction, velocity, and vapor flow. The data reveal a complex two‑phase flow with extended reversed flow along the wall and a decreasing void fraction, where bubble dynamics and thermodynamic effects control phase transitions.

Abstract

An experimental study of flow within sheet cavities is performed in a cavitation tunnel equipped with a Venturi-type test section. The flow is investigated by means of a double optical probe allowing void fraction, velocity, and chord length of the vapor structures to be measured. Laser velocimetery, wall pressure measurements, and visualization techniques are also used to characterize the liquid flow around the cavity. The consistency of the experimental results was checked though mass and momentum balances. The effects of Reynolds and cavitation numbers are analyzed. Special attention is given to the dynamic behavior of the flow, and to the vapor flow rate within the cavities. The measurements show a complex two-phase flow characterized by the presence of an extended reversed flow occurring along the solid surface and a regular decrease in void fraction along the cavity. The phase transitions seem to be mainly restricted by the dynamic of the bubbles and thermodynamic effects.