Assessment of cavitation erosion on an asymmetric hydrofoil based on energy conversion via a multiscale approach

Abstract

Cavitation erosion is a long-standing issue, which plays a pivotal role in the material damage of much hydraulic machinery. However, despite abundant numerical research on cavitation erosion assessment, bubble dynamics has been commonly overlooked. Consequently, we develop an improved cavitation erosion model based on energy conversion and assess an ALE15 hydrofoil surface by its incorporation into a multiscale approach. Our erosion model stands out in considering the bubble behaviors throughout its entire lifespan to eliminate the influence of bubble oscillation on cavitation erosion. Using the bubble information in the well reproduced cavitating flow, we evaluate both the cumulative and instantaneous cavitation erosion, and the results show satisfactory agreement with the experimental pattern. Our findings demonstrate that frequent vapor-liquid alternations, induced by the collaborative effects of upstream pressure gradients and main flow, increase the potential for erosion risk at the hydrofoil leading edge. Downstream erosion primarily results from secondary shedding and the collapse of U-shaped cavities’ legs. By contrast, the acoustic energy emitted by the shedding cavities traveling farther and upwards away from the hydrofoil leads to negligible erosion on the surface.