An improved Eulerian-Lagrangian method combined with ductile material model for cavitation erosion assessment

Abstract

Abstract Cavitation erosion in hydraulic machinery constitutes a multifaceted, instantaneous physicochemical process resulting in material wear and decreased efficiency. This paper employs an enhanced Eulerian-Lagrangian method to evaluate cavitation erosion. The method captures erosive impact loads released by the non-spherical collapse of near-wall bubbles and integrates them with a one-dimensional ductile material mode, a capability lacking in traditional homogeneous mixture methods. A classic axisymmetric nozzle test case is conducted under four different cavitation numbers (s=0.8, 0.9, 1.09, and 1.6) to validate the reliability of the new approach. Qualitative and quantitative analysis demonstrates that the impact load distribution on the lower and upper walls aligns with experimental measurements. Compared with reference works, the new method accurately predicts the maximum wear position and yields a narrower erosion area closer to the experimental data. Moreover, the relative error of the minimum incubation time at s=0.9 on the lower wall calculated by the new method is 4.67%, and the relative error of the maximum wear rate is 36.6%. This method is pivotal for further studying how various materials respond to cavitation wear. Further analysis reveals that material response patterns are similar under cavitation erosion conditions at s=0.8, 0.9, and 1.09. In contrast, the material surface wear rate is reduced by 46.7%, and the incubation time nearly triples at s=1.6.