This research took the DN50 butterfly valve as the research object and studied the flow situation of butterfly valves with different shafts. The resistance characteristics, flow state, characteristics, and flow instability of butterfly valves with different structures were studied by experiments and numerical simulations. Research shows that the flow separation occurs at the edge of the valve disk, and the drag of the valve disk fluctuates nonperiodically with time. Under different opening degrees, the velocity distribution downstream of the valve varies, and the effect of the shaft on the velocity fluctuation is different. Finally, the unstable region of flow downstream of the valve is determined. This study provides a reference for the use and optimization of butterfly valves.

When internal flows go through a valve with a small opening degree, high-speed jet flows are induced, which causes the erosion of the valve core and affects the stability of the flow field. Setting guiding plates in the valve behind the valve core has the function of reducing the adverse effect of high-speed jet flows. In this work, numerical simulations were carried out to investigate the effect of the guiding plate on flow and resistance coefficient, velocity and pressure distributions and flow stability downstream of the valve. The number of guiding plates was changed from 0 to 3 and the opening degree was varied from 0 to 100% at intervals of 10%. A guiding plate with holes in it plays the role of bypassing and guiding flow. Under the action of the guiding plate, the flow coefficient obviously decreases, the gap flow between the valve core and the valve wall in the top of the valve are modified, and the gap flow even disappeared in the valve with 3 guiding plates. It was found that setting the guiding plate can improve the performance of the ball valve, reducing the internal erosion and increasing the stability of valve downstream flow efficiently.

As the key control equipment for the transmission of the fluid medium, butterfly valves are widely used in transmission systems of media in the energy, chemical industry, metallurgy, aerospace engineering, and other fields, playing an important role in the stability and reliability of system operation. When the flow cross section suddenly changes, the pressure rapidly decreases the downstream, leading to cavitation in butterfly valves. Cavitation causes serious erosion and damage in the valve core and pipeline surface, resulting in leakage and noise problems in butterfly valves, which seriously affects the regulation performance and lifetime of butterfly valves. In this study, numerical analyses are conducted to investigate cavitation evolution at the transient regulation of a butterfly plate through a butterfly valve model. Moreover, the effects of the valve opening degree and rotating speed on the cavitation volume and distribution, rate of cavitation volume change, growth–collapse rate of cavitation, and correlation between cavitation and vortex in the opening and closing processes of butterfly valves are investigated. Due to the influence of transient regulation and flow hysteresis, the characteristic parameters and evolution of cavitation exhibit different behaviors in the opening and closing processes of butterfly valves.

Cavitation and its resulting erosion exert a significant influence on the performance and longevity of hydraulic machinery. This study provides a comprehensive review of numerical prediction methods for cavitation erosion, emphasizing computational approaches. Although traditional experimental techniques (high-speed imaging and acoustic measurements) allow direct observation, their high cost and limited applicability under complex operating conditions restrict their practicality. Therefore, computational fluid dynamics serves as an essential alternative for evaluating cavitation erosion. This review systematically examines mainstream prediction methods, including fluid–structure interaction (FSI), micro-jet models, and energy-balance approaches, and elaborates on their theoretical foundations, computational frameworks, and applicable domains. In recent years, energy-balance models and advanced turbulence simulations have enhanced prediction accuracy through measurable indicators such as local energy density and impact energy. These models are widely applied to investigate multi-bubble cavitation mechanisms and to predict local impact intensity, providing high computational efficiency under relatively simple flow conditions. Micro-jet models estimate wall loading through parameters such as jet velocity and peak pressure, making them effective for assessing erosion from near-wall single-bubble collapse; however, their performance is constrained in multi-bubble interactions and asymmetric collapse scenarios. FSI methods, employing variables such as wall pressure, material stress, and plastic deformation, enable high-fidelity multiphysics coupling and yield detailed simulations of single-bubble cavitation and fatigue damage, although at substantial computational cost. They are therefore more appropriate for localized mechanism analysis and high-precision design optimization. Despite substantial progress, challenges remain in multiphysics coupling, experimental validation, and data-driven model optimization. This review aims to provide theoretical insights that guide future research on cavitation-erosion modeling and its engineering applications.