Abstract: With the increasing global demand for energy conservation and renewable energy, low-head turbines play an important role. The cavitation phenomenon of low head Francis turbine will lead to the damage of surface materials of overflow components and affect the safety and efficiency of power generation. In this paper, through researching domestic and international reviews, the key factors of cavitation in hydraulic turbine are expressed, including internal and external factors. The internal factors are the material hardness, plasticity and cavitation resistance of the turbine, the external factors are the surface roughness of the turbine overflow components, the submergence depth of the turbine, the temperature of the water body and the gas content in the water body. The improvement measures were discussed by domestic and foreign scholars for both reasons, and the applications of numerical simulation in the study of cavitation of the turbine were discussed, and the CFD analysis of multiphase transient flow was obtained which is very helpful to understand the flow characteristics and performance of hydraulic turbines. In consideration of demand of engineering and scientific development, some reference directions for the future research of Francis cavitation are given to provide some reference for the research of low head Francis turbine cavitation.

Key words: low-head Francis turbine, cavitation corrosion, instability, numerical simulation