Analysis of Fluid Pulsation Characteristics and Its Suppression Method Design for One-Side Slide Spool of Counter Balance Valve

The main spool of one-side sliding spool of the counterbalance valve is affected by the steady-state hydrodynamic force and vortex, which is detrimental to spool stability. Therefore, it is necessary to compensate the hydrodynamic force and suppress the vortex. For one-side slide valve spool, the introduction of a damping tail will compensate hydrodynamic force, thus suppressing the effect of flow force on the control characteristics of the spool. However, the damping tail structure is highly susceptible to vortex formation, which will lead to fluid pulsation and energy dissipation and to the extreme case of self-excited oscillatory fluid whistling. The flow field characteristics of the one-side valve spool with damping tail were analyzed by numerical simulation model. The results showed that the damping tail can effectively suppress the amplitude of the flow force, but at the same time led to the formation of vortex. To suppress the vortex, the structure of damping tail was optimized by rounding the edge and j oint of the damping tail, the vortices formed by fluid shear instability and the dead vortices formed by velocity gradient could be suppressed respectively, avoiding the pressure pulsation phenomenon and enhancing the stability of the spool.