Particle size distribution effects on cavitation erosion in sediment suspensions

Abstract

Synergistic cavitation–particle erosion often occurs in high-speed sediment-laden flow in hydraulic structures and machines. However, erosion prediction is challenging due to the unclear relationship between erosion and the characteristics of sand- and silt-sized sediments, particularly the sediment particle size distribution (PSDS). In this study, vibratory erosion tests for carbon steel were conducted in suspensions of continuously graded sand–silt mixtures, and the influence of PSDS characteristics, such as the number of modes and sand-to-silt ratios, was investigated. The results indicated that both the total sediment concentration and PSDS parameters had a major impact on synergistic erosion. The changes in the PSDS patterns resulted in different erosion behaviors, even when the sand and silt concentrations were fixed. Based on the viscosity-enhancing effects of silt particles and the impinging effects of sand particles, a new theoretical model for determining the particle impact energy was developed by incorporating PSDS. A deeper understanding of the influence of PSDS and the application of the PSDS-based model can help predict and prevent synergistic erosion.