Objectives To address the operational instability, vibration, and abnormal noise in a specific steam turbine unit, this study proposes a method for modifying the internal flow characteristics of the control valve through an internally-cut valve core structure.

Methods Initially, a full-scale high-precision modeling method was employed to establish the complete geometry of the flow passage of the control valve. Subsequently, two types of internally-cut valve cores were designed based on principles of supersonic expansion suppression. A multi-scale hybrid mesh strategy incorporating various boundary layer types was implemented, with convergence accelerated through iterative computations.

Results Experimental validation showed a discrepancy of less than 5% between test measurements and simulation results for key parameters across various valve core configurations, confirming the accuracy and reliability of the numerical method. The optimized steam flow characteristics in both the throttling region and the valve core bottom area of the novel design effectively reduce energy losses and vibration noise caused by asymmetric flow patterns. Furthermore, the innovative structure reduces hydrodynamic forces on the valve core base by 20%-30%, significantly suppressing broadband flow-induced vibrations in both the control valve and the turbine unit.

Conclusions The valve core configuration has a significant impact on flow field characteristics. The internally-cut valve core design proposed in this study provides valuable insights for optimizing flow field distribution and offers technical guidance for improving the performance of similar steam turbine control systems.