基于先导控制的新型截止阀动力特性研究

发布时间：2018-01-15 13:27

本文关键词：基于先导控制的新型截止阀动力特性研究　出处：《浙江大学》2011年硕士论文　论文类型：学位论文

【摘要】：通用截止阀驱动往往需要庞大的执行机构,特别是应用于高压大口径的管路系统中时,普遍存在着启闭动作缓慢、驱动能耗高等问题。为此,本课题组研究开发了一种利用阀门内部流体流动产生的压差作为阀门开启动力源的新型先导式截止阀,可满足工业高效、环保、节能的要求,具有很高的工程应用价值。但由于内部流场的复杂性和内部压差的不确定性,新型先导式截止阀动力不确定,从而导致其结构的设计存在盲目性。本文结合Fluent的UDF技术,对新型先导式截止阀进行数值模拟,总结出此阀门的动力特性并进行实验验证。主要研究内容和研究成果如下： (1)针对新型先导式截止阀结构设计盲目性的问题,分析了此阀门通用部分与专用部分设计过程,找出其中存在的人为假设因素,指出解决问题的切入点在于活塞式阀芯底部上下表面间的压差。 (2)简化并建立了新型先导式截止阀三维模型,运用RNG k-ε紊流模型进行了数值模拟,指出阀芯底部上下表面的压差产生的压差力为阀门开启的唯一动力源。同时找出了影响压差大小的因素,为阀门动力特性的研究指明了方向。 (3)数值分析结果显示,产生压差力的两个面上,压力分布不均,编制了UDF程序分别循环提取面上每一个单元的压强,求其平均值并输出,得到活塞式阀芯底部上下表面的压差值并进行网格无关性验证,得到了压差的网格无关解。 (4)对不同因素组合的先导式截止阀进行了数值分析与实验研究。得到了压差随各因素变化情况,并结合流体力学局部阻力损失理论,拟合得到了局部阻力损失系数的工程估算公式以及动力的工程估算公式；按正交试验方法进行实验研究,利用位移传感器测量阀门达到稳定的开启状态时的开度,计算对应的活塞式阀芯底部上下表面压差的实验值,将实验值与相应开度模型下压差的模拟值进行对比,从而验证了本文的模型简化方法与数值计算方法的有效性。本文研究成果对于新型先导式截止阀的优化设计和工程应用具有重要的学术和应用价值。
[Abstract]:The drive of universal globe valve usually needs a huge actuator, especially when it is used in high pressure and large caliber pipeline system, there are many problems such as slow opening and closing, high driving energy consumption and so on. A new type of pilot valve is developed, which uses the pressure difference produced by the fluid flow inside the valve as the power source of valve opening. It can meet the requirements of industrial efficiency, environmental protection and energy saving. But because of the complexity of internal flow field and the uncertainty of internal pressure difference, the dynamics of the new pilot globe valve is uncertain. Therefore, the design of its structure is blind. In this paper, combined with the UDF technology of Fluent, the numerical simulation of a new type of pilot globe valve is carried out. The dynamic characteristics of the valve are summarized and verified by experiments. The main research contents and results are as follows: In order to solve the problem of blindness in the structural design of the new pilot globe valve, the design process of the universal and special parts of the valve is analyzed, and the artificial hypothetical factors are found out. It is pointed out that the key to solve the problem lies in the pressure difference between the upper and lower surfaces of the piston spool. The three-dimensional model of a new pilot valve is simplified and established, and the numerical simulation is carried out by using the RNG k- 蔚 turbulence model. It is pointed out that the pressure differential force caused by the pressure difference between the upper and lower surfaces of the bottom of the valve core is the only power source for the valve to open, and the factors influencing the pressure difference are found out, which points out the direction for the study of the dynamic characteristics of the valve. The results of numerical analysis show that the pressure distribution is uneven on the two planes where the pressure difference force is generated. The UDF program is compiled to separate cycles to extract the pressure of each unit on the surface and to find the average value and output. The pressure difference between upper and lower surface of the piston valve core is obtained and the mesh independence is verified and the mesh independent solution of the pressure difference is obtained. 4) numerical analysis and experimental study of pilot valve with different combination of factors are carried out. The pressure difference varies with each factor, and combined with the theory of local resistance loss in fluid mechanics. The engineering estimation formula of local resistance loss coefficient and the engineering estimation formula of dynamic force are obtained by fitting. According to the orthogonal test method, the displacement sensor is used to measure the opening of the valve to reach a stable opening state, and to calculate the corresponding experimental value of the pressure difference between the bottom of the piston valve core and the upper and lower surface. The experimental results are compared with the simulated values of the pressure difference under the corresponding opening model, which verifies the effectiveness of the simplified model and the numerical calculation method in this paper. The research results in this paper have important academic and applied value for the optimization design and engineering application of the new pilot globe valve.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH134

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