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Regulator valves are used for regulating fluid flow, pressure, temperature, level and other parameters in the field of industrial automation. With changing the opening levels, valves can control fluid flow, pressure, temperature and level. Regulator valves are used for a wide range of control process.At the production sites, regulator valves are used for directly controlling the fluid, especially high-temperature, high-pressure, low-temperature, strong-caustic, flammable, explosive, easy-penetration, toxic, high-viscosity, easy-crystallization and other cases. Improper using will result in difficulties in production process automation, with leading to decline in the regulator quality, even serious accidents. Cavitation is the worst damaging problem in the process of using valves.In this thesis, a regulator valve named DN65 is studied, which is provided by Dalian Kawasaki Co., Ltd. A finite element model is established for a featured opening valve flow channel with Pro-E. The model is simplified by actual work situation. The numerical simulation for fluid flowing in the valve flow channel is completed by Fluent. Repeated simulations for many times are completed with different opening levels. The valve cavitation locations are found, and cavitation critical speeds are got with using dichotomy. Finally, based on various improvements and measures about avoiding cavitation, improved structure is established.Through the above study, it can be concluded:In normal use, strictly controlling of physical parameters, the valve will not be cavitation situation. However, the difficulties of controlling speed or pressure are familiarly appeared. Cavitation is occurred easily. The vapor bubbles appear in the hole and bursts on the bottom of the valve plunger. The valve plunger material has a great impact. Through simulations, valve cavitation critical speeds are got in two situations. One is opening one row holes, and the other is opening two and a half rows holes.3.75m/s is the cavitation critical speed of opening one row holes; and 9m/s is the cavitation critical speed of opening two and a half rows holes. According to the analysis of cavitation, with setting chamfers before and after the hole, the improved structure is established. The result of improved structure simulation shows that it can reduce or avoid the impact of cavitation in the valve. The study provides theoretical principle for future optimizing design, reduces unnecessary repair work, declines maintenance costs, improves economic efficiency.
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