Investigation Into The Structure And Mechanics And Performanc Eof Water Hydraulic Control Valve

Water hydraulic is a growing technology area mainly due to environmental, safety and cleanness reasons. Water hydraulic systems have proved to the best technology alternative in some industrial sectors such as food, paper, steel and power industry. Due to low viscidity, high vaporization pressure and erosion of water medium, water hydraulic pressure controlled valves (particularly water hydraulic relief valve) face technical difficulties such as erosion, cavitation failure and liquid-proof under high pressure. In order to improve the dynamic and static performances of water hydraulic pressure controlled valves, new operation principles and internal structures of valves must be applied. Along with hydraulic systems developing to high speed, high pressure and micro systems, especially development of water hydraulics, cavitation is more and more outstanding.The development and the present status of water hydraulic are introduced. Contents of the water hydraulic in research and difficulty are sum up. The present statuses of water hydraulic valve, the key problems are described as well as intention, meaning of the thesis.As one of the key components of water hydraulic system, water relief valve plays an important role in water hydraulic system. Applying commercial simulation software Matlab, the dynamic characteristics of water relief valve was numerically investigated with different parameters. The simulation results indicate that the water relief valve has good performance and can be adopted in practical application.The cavitating flow through a water hydraulic cone valve was performed by the CFD (Computational Fluid Dynamics) to obtain static pressure distribution images. The flow field distributions were obtained with different opening size as well as different cone angle. The effects of opening size as well as cone angle on cavitation intensity in the water hydraulic poppet valve were numerically investigated.According to the effect of orifice configuration on the cavitation, the several poppet configurations of a relief valve were designed in order to suppress cavitation, the cavitating flow simulation for different configuration were performed and compared in order to find an optimal configuration. Simulation results show that throttle orifices based on special structure can effectively restrain cavitation at same...