Research on cavitation flow characteristics of rotating disc under different cavitation numbers

Cavitation has always been a research hotspot in the field of fluid machinery. As one of the components of an impeller—the core component of fluid machinery—the hydrodynamic and cavitation characteristics of airfoils are of vital importance to fluid machinery performance. Currently, cavitation flow characteristics around stationary hydrofoils have been extensively studied, but research on rotating hydrofoils remains limited. This paper takes the NACA 0015 airfoil mounted on a rotating disc as a research object. By combining experimental and numerical simulation methods, it investigates the cavitation flow characteristics around the airfoil under different cavitation numbers by varying rotational speed. Meanwhile, based on entropy generation theory, the study analyzes energy loss characteristics in the disc induced by cavitation. Results show that the disc's cavitation number decreases with increasing rotational speed, and cavitation occurs at the airfoil trailing edge under all cavitation numbers, primarily due to wake effects. When the cavitation number σ ≤ 0.55, cavitation emerges on the airfoil suction surface. As the cavitation number decreases, cavitation extends from the leading to trailing edge, intensifying the phenomenon and increasing disc energy loss—largely caused by low-pressure region formation. Studying the rotating disc's cavitation characteristics provides theoretical support for the stable and safe operation of hydraulic machinery.