Effects of flow conditions on the cavitation characteristics of viscous oil around a hydrofoil

Abstract

Viscous oils, which are media commonly used for fluid power transmission, are characterized by high velocities, temperatures, and pressures when working in fluid components and mechanics. The transient nature of viscous oil makes it susceptible to complex operating conditions, which result in cavitation phenomena and can threaten the normal operation and safety of machinery and components. In this study, a three-dimensional computational fluid dynamics model that accounts for cavitation was developed to study the cavitation characteristics, formation conditions, and development of cavitating flow in viscous oil around a hydrofoil under various flow conditions. Moreover, a visual experimental system in which viscous oil flowed around the hydrofoil was proposed and developed to investigate the cavitation properties with regard to various flow conditions. Both numerical results and experimental data indicated that cavitation occurred on the suction surface of the hydrofoil head, and the cavitation characteristics in viscous oil are significantly influenced by the flow conditions. The maximum vapor volume change rate for the degree of effects on cavitation in viscous oil by flow conditions was calculated to be 1.78 cm3/(m/s), −130.66 cm3/MPa, 0.16 cm3/°C, and 4.52 cm3/°, respectively. Low velocities, high pressures, low temperatures, and small impact angles were proved to be able to suppress cavitation. This study provides a research method, an experimental mean, and data support for cavitation flow of viscous fluids, especially oil. It has significant engineering application significance for the development of fluid machinery.