Experimental and Eulerian-Lagrangian numerical investigation on cavitation erosion characteristics in Venturi pipes with different divergent angles

Hydrodynamic cavitation (HC) is widely found in fluid machinery and has emerged as a significant technology in several engineering fields. To investigate the erosion characteristics caused by HC, experimental tests under varying conditions are conducted in this study using a Venturi test section with different divergent angles. The qualitative erosion risk distributions under different conditions are represented through paint experiments, showing that the erosion risk increases as the divergent angle decreases. Subsequently, a Eulerian-Lagrangian multiscale cavitation model is adopted to simulate HC in the test section. This model directly resolves large-scale cavities using the volume of fluid (VOF) method and simultaneously tracks sub-scale discrete bubbles using a discrete bubble model (DBM). A modified aggressive indicator [Li et al., Int. J. Mech. Sci. 262, 108,735 (2024)] is incorporated into the multiscale cavitation model to account for the erosion power produced by multiscale cavitation behaviors, thereby reproducing the distribution of cavitation erosion risks. Simulations corresponding to the experimental conditions are conducted, and the results show that the simulated cavitation features align well with the experimental observations. Furthermore, the cavitation erosion risk distributions predicted by the present model agree well with the paint tests, confirming the reliability of our model.