Fluid–Structure Coupling Analysis of the Vibration Characteristics of a High-Parameter Spool

High-performance control valves are essential components in power plants. High-parameter control valves are specialized valves for controlling high-pressure, high-flow, high-temperature, and highly corrosive media. Control valve performance is critical for the stable operation of power plants. The multi-stage counter-flow passage is a common structure in pressure-reducing control valves, effectively mitigating cavitation and erosion on the valve walls. However, in practice, vibration issues in multi-stage passage valves are particularly pronounced. This study employs FSI (fluid–structure interaction) to simulate the vibration characteristics of multi-stage passages. Flow field data for the multi-stage passage are obtained through FLUENT software. A time-frequency analysis of the lift coefficient in the multi-stage passage flow field was performed. The vibration characteristics of the valve core’s inlet and outlet surfaces were studied using Transient Structural software. The results show that when high-pressure fluid passes through the valve core’s passage, it undergoes buffering, steering, and rotating motions, leading to a gradual pressure drop and generating resistance and lift. These phenomena are primarily caused by vortex shedding in the flow field, with the dominant frequency observed to be approximately 5400 Hz. Additionally, as the valve core progresses through the P1 phase at the inlet and the P2 phase at the outlet, the vibration intensity gradually decreases, reaching a minimum in the sixth phase, before increasing and peaking in the final stage. Analysis of the flow field characteristics within the valve core passage reveals the significant impact of vortex shedding on the valve core’s vibration and lift. Phase analysis of the valve core’s vibration intensity further clarifies its behavioral changes at different operational stages. These findings help optimize the design of multi-stage buffering valve cores, improving their performance and stability.