A weighted average mesh motion method for transient simulation of erosion wear topography evolution on dynamic wall surfaces

To achieve transient simulation of dynamic wall surface wear topography evolution, User-Defined Functions (UDFs) coupling a wear depth prediction model with a mesh motion method were developed, thereby addressing the low accuracy of wear depth prediction for fixed wall surfaces. To determine the distance and direction of node displacement, an area-weighted average mesh motion method was proposed. The slurry jet impingement test was used to compare the wear depth predicted by different mesh motion methods at various erosion times, which revealed the erosion mechanism of particles impacting the dynamic wall surface. To demonstrate the superiority of the proposed mesh motion method, the effects of mesh size and mesh motion time step on wear depth prediction accuracy were evaluated. The results indicate that the wear depth prediction accuracy of the dynamic wall surface is consistently higher than that of the fixed wall surface. The evolving wear topography alters the near-wall fluid flow and the particle impact velocity and angle, leading to a progressive decline in wear rate over time. Compared to the conventional mesh motion method, the proposed mesh motion method not only achieves higher wear depth prediction accuracy and yields a smoother, more uniform wear topography, but also reduces the sensitivity of prediction accuracy to mesh size and mesh motion time step. The approach can subsequently be used for transient simulation of wear topography evolution in rotating fluid machinery. To ensure the prediction accuracy for complex structures, the curvature normal angle during the discretization of complex surfaces should be controlled below 20°.