Importance of Accounting for Finite Particle Size in CFD-Based Erosion Prediction

Being capable in predicting the removal of material from a surface subjected to the impingements of solid particles within a carrier liquid is of considerable industrial interest. This phenomenon, called impact erosion, is of concern in many applications due to its severe technical and economic consequences. The use of Computational Fluid Dynamics (CFD) techniques for impact erosion prediction is a challenging approach to avoid the cost and complexity of laboratory testing. A well-established methodology exists for CFD-based erosion estimation, consisting in the simulation of the slurry flow by an Eulerian–Lagrangian two-phase model followed by the application of an empirical erosion correlation to estimate the loss of material produced by each particle-wall impact. One of the main assumptions of this approach is that the solids are treated as massive point particles, even if, from a theoretical point of view, this approximation may be too simplistic, as it requires the particle size to be infinitesimal. The objective of the present study was, primarily, to assess how the point–particle treatment of the dispersed phase may affect the accuracy of CFD-based erosion prediction models. Based on these findings, numerical strategies were proposed in order to correct for the induced error without the need of resorting to a fully-resolved description of the slurry flow, which would not be affordable in practical applications due to its excessive computational burden. As a first step, reference was made to the benchmark case of slurry abrasive jet impingement test. The obtained results will open the way for addressing more complex flows in future research.