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.

With an increase of suction efficiency of fresh concrete pumping in confined spaces, the laminar flow state will be damaged by the return flow caused by distribution value direction changes and concrete gravity. This is a fact, but one which is rarely studied. In this work, the flow state, flow velocity, and suction efficiency of fresh concrete pumping are simulated using the coupled smooth particle hydrodynamics and Discrete Elements Method (SPH-DEM). The rheological parameters and Herschel-Bulkley-Papanastasiou (HBP) rheological model are adopted to simulate fresh concrete in the numerical simulation model. The study reveals that the error between the slump experimental result and that obtained by the HBP model is negligible. A model is therefore established for numerical simulations of the suction efficiency of fresh concrete pumping. An experimental concrete pumping platform is built, and the pressure and efficiency data during pumping are collected. A comparison of the numerical simulation with experimental results shows that the error is less than 10%.

The cavitation flow of the cartridge pilot-operated relief valve's main valve port was numerically simulated and studied using Computational Fluid Dynamics (CFD) in our research, and the relief valve structure was modified to decrease cavitation noise. The findings indicate that cavitation in the relief valve occurs mostly downstream of the main valve port and is linked to the wall. Cavitation generation is influenced by the jet at the valve port. The closer the high-speed jet at the valve port is to the valve's inner wall, the more readily cavitation occurs. Conversely, there is less cavitation. This paper reports the effect of the forms and parameters of the main port structure on the jet angle and the morphology of cavitation. The structure of the spool's annular groove has a considerable influence on the cavitation attached to the spool wall and the valve sleeve wall, whereas the outlet position of the relief valve mostly impacts the intensity of cavitation near the valve sleeve wall. Based on this, the relief valve's optimized structure is designed, with which the maximum vapor volume fraction and total vapor volume of the cavitation flow are considerably decreased for various inlet pressures and spool openings. The results of the experiment show that following optimization, the noise of the relief valve drops dramatically, confirming that optimizing the structure has a beneficial impact on decreasing cavitation noise.