Hydraulic vibration excitation has been widely regarded as a promising method of excitation because of its high power density and large output force. However, the alternating pressure in the hydraulic vibration exciter could cause the pilot-operated relief valve (PRV) to open abnormally, which presents a new challenge to the normal operation of the PRV. To determine the abnormal opening characteristics of the PRV under alternating pressure, the effects of structure parameters of the PRV (including diameters of orifices 1 and 2, volume of the pilot valve inlet, volume of the main valve spring chamber, area ratio of the main spool, and main spring pre-compression force and stiffness) on its abnormal opening displacement under alternating pressure were numerically investigated. The calculation results indicate that the abnormal opening of the PRV will be effectively decreased by appropriately increasing the diameter of orifice 1, decreasing the pilot valve inlet and main valve spring chamber volumes, and increasing the area ratio of the main spool and the main spring pre-compression force. The influence of the orifice 2 diameter on the abnormal opening of the PRV is dependent on the diameter range of orifice 1. The reasonable diameters of orifices 1 and 2 are in the range of 0.8-1.2 mm. The influence of the main valve spring chamber volume is more significant than the pilot valve inlet volume. The influence of the main spring stiffness is not significant. INDEX TERMSAlternating pressure, pilot-operated relief valve, abnormal opening, effects of structure parameters, hydraulic vibration excitation.

The present work is aimed at simultaneously reducing the additional flow force on the cone and cavitation intensity in a poppet valve. A prediction model of flow force on the cone and cavitation was established for the poppet valve by using computational fluid dynamics method (CFD) combined with Zwart–Gerber–Belamri cavitation model. The effects of three poppet valve configurations and their parameters on the flow force and cavitation intensity in valves were investigated. The research results indicate that, compared with the poppet valve A, the poppet valve B has an excellent ability to decrease the flow force on the cone, but promotes the cavitation intensity in the valve. The poppet valve C can not only significantly decrease the flow force on the cone but also has the potential to reduce cavitation intensity in the valve. When the parameter h is 6 mm and the parameter t is 2 mm, the flow force and the relative vapor volume in the valve C can be reduced by an average of 44.2% and 100%, respectively.

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The numerical calculation method is used to analyze the wear of the liner of the general structure of a semi-autogenous mill in the axial direction, and the non-uniform wear of each area of the liner is studied to explore the reasons for said wear. The liner is divided into areas along the axial direction, and the discrete element method (DEM) is used to analyze the relationship between the wear volume of each area and the total mass of particles. The composition ratio of the rocks and steel balls in each area, and its relationship with time, are also studied. The results show that the total mass of the particles in the area has a significant effect on the wear of the liner. When the particles are affected by the conical end cover on both sides during the operation of the mill, they will be stratified along the axial direction. The particles with large masses will accumulate on both sides of the mill, and the particles with small masses will be concentrated in the middle of the mill. As a result, the difference between the density and impact energy of rocks and steel balls in each area is caused, and eventually, the mill liner appears to have non-uniform wear.