•High-fidelity CFD model for predicting fluid forces and vortices of hydraulic valve is developed.•Results of the CFD models are verified by self-built visualization test rig.•The difference in fluid forces between two typical valve discs is revealed.•The coupled effect of groove depth and valve opening on fluid force is quantified. Nuclear safety valve is a critical piece of equipment in a nuclear power plant, which is used to prevent irreversible damage caused by a sudden increase in pressure. However, there are some instances wherein valves may fail to function properly, which can have significantly impact the safety of the entire pressure/energy system. The main causes behind this phenomenon is the effect of fluid-structure coupling between the fluid force and valve disc. To better understand the fluid force, a high-fidelity computational fluid dynamics (CFD) model is established to predict the behavior of fluid forces and the location of vortices in the valve. Moreover, a visual fluid force test rig is used to verify the accuracy of the CFD model. Based on the validated CFD model, the mechanism of fluid force differences for two typical valve discs are analyzed in detail, together with the univariate effects of groove depth and valve opening on the fluid force. Based on the univariate analysis results, the coupling effect of groove depth and valve opening on fluid force is quantified using the supervised learning algorithm and Sobol sensitivity analysis. The study provides a new perspective on the characteristics of valve fluid force, and highlights the significant potential of dynamic control and energy conservation of valves. Display omitted