关键词: 云空化结构演化, 空化模型, 隐式大涡模拟, 能量输运, 侵蚀风险预估

Abstract: Cavitation occurs commonly in fluid equipment. The collapse of the cloud cavitation structure releases extremely high pressure, which is usually considered the main cause of material cavitation erosion damage. This work aims to analyze the cavitation evolution and collapse and its erosion risk based on a numerical method. The implicit large eddy simulation method and a cavitation model based on local flow-field correction were applied to simulate the fluid fields of a three-dimensional NACA0015 hydrofoil with different cavitation numbers. The evolutionary process of the cavitation flow structure was investigated, and the erosion risk prediction model based on energy transport was used to estimate the cavitation risk area. The main conclusions are as follows: (1) The cavitation model based on local flow-field correction can better predict the cavitation volume, and the implicit large eddy simulation method can better capture the various forms of un-steady cavitation flow structures. (2) Different cavitation numbers have different effects on the cavitation occurrence intensity, evolution characteristics, and collapse location. When σ = 1.19, the cavitation structure is relatively stable, the maximum length of the attached cavity is 0.4 of the foil chord length, and the collapse location of the exfoliating cavity is 0.6. When σ = 1.07, the maximum length of the attached cavity is 0.5, and the collapse position of the detached cavity is 0.7. When σ = 0.95, the cavity structure evolves vio-lently, multiscale cavities are shed together, the maximum length of the cavity attached to the surface of the airfoil is 0.7, and the collapse location of the shed cavity is near the foil trailing edge. (3) The prediction model based on energy transport can be used to predict the risk area of erosion damage on the foil surface caused by cavitation cavity collapse.

Key words: evolution of cavity structure, cavitation model, implicit large eddy simula-tion, energy transportation, prediction of erosion risk area