Multiscale simulation of the hydroabrasive erosion of a pelton bucket: bridging scales to improve accuracy

Authors

Sebastián Leguizamón - Ecole Polytechnique Fédérale de Lausanne (EPFL)
Ebrahim Jahanbakhsh - Ecole Polytechnique Fédérale de Lausanne (EPFL)
Siamak Alimirzazadeh - Ecole Polytechnique Fédérale de Lausanne (EPFL)
Audrey Maertens - Ecole Polytechnique Fédérale de Lausanne (EPFL)
Francois Avellan - Ecole Polytechnique Fédérale de Lausanne (EPFL)

Abstract

The hydroabrasive erosion of hydraulic machines is a widespread problem which entails efficiency degradation, cavitation enhancement and the need for expensive repairs. Although numerical simulations of erosion can be very useful both for  understanding and predicting the process, its multiscale nature render it very  difficult to simulate. We first present a previously validated multiscale model of erosion which consists of two coupled submodels: On the microscale, the sediment impacts are simulated by means of comprehensive physical models. On the macroscale, the turbulent sediment transport and erosion accumulation are calculated. We then present a multiscale simulation of the erosion of a full-scale Pelton bucket impacted by a sediment-laden water jet. The simulation results, such as the sediment flux or the average impact angle and velocity distributions on the bucket surface, bring insight into the erosion process. Furthermore, they explain the resulting erosion distribution, which is in very good agreement with the experimental erosion measurements available in the literature for the same test case.