Sediment-wear morphology prediction method of hydraulic machine based on differential-quadrature method

摘要

Damage caused by abrasive wear is a significant problem for hydraulic machinery in rivers with sediments. Traditional prediction methods of abrasive wear morphology with the fixed geometrical boundary are difficult to reflect the physical reality of wear because of the interaction of sediment wear, flow pattern and flow boundary. In this study, a gradual wear method based on the idea of differential-quadrature is established to investigate the asymptotic wear behavior of hydraulic machinery. The average wear rate and depth of voxels on the geometrical boundary can be obtained by the unsteady numerical simulation with RNG k-epsilon turbulent model and DPM multiphase flow model. Segmented voxels of geometrical boundary of flow are reconstructed after a calculation period until the end of the total running time. So, the progressive wear morphologies of flow-passage walls can be revealed step by step. The prediction method is used to predict the wear of the clearance flow in the guide vane. The numerical results are in good agreement with the actual wear depth on the wear surfaces at the actual running time, which indicates that the specified prediction method in this paper is applicable and effective.