【作者】 童成彪；

【导师】 周志雄； 许明；

【作者基本信息】 湖南大学 ， 机械工程， 2010， 硕士

【摘要】 蝶阀作为广泛使用的管道控制设备,它的可靠性、节能性、制造和运行成本对于国民经济具有重要的意义。在蝶阀设计中,关于如何降低蝶阀的流阻、蝶阀流阻的测算、蝶阀水力矩的计算、蝶阀各个开度的非均布载荷情况和强度分析、密封副的分析和计算等一直是设计中的难点。传统设计中一般采用试验分析和查阅设计手册的方法,这不仅耗时较长,而且加大了设计制造成本。本文旨在采用一种现代设计方法——有限单元法,对某型橡胶软密封蝶阀设计的主要难点进行了深入的研究和分析：(1)阐述了蝶阀的应用领域及其重要意义,介绍了蝶阀的基本结构、基本性能及特点,进而指出了当前蝶阀设计中的主要设计方法和存在的主要问题,导出了本课题的研究背景和研究意义,阐述了与课题相关的流体理论；(2)建立了某型橡胶软密封蝶阀的参数化几何模型,并建立了结构静力学仿真分析有限元模型,分析了该橡胶软密封蝶阀在全关状态下的应力、变形结果,根据分析结果,改进了该橡胶软密封蝶阀的结构,并取得较好的效果；(3)为了分析流过蝶阀的流体,建立了一种计算流阻系数的有限元模型、利用Cosmosflow分析了管道的沿程压力损失、计算了蝶阀在多种开度下的流阻系数,通过与实验值比较,证明这种分析计算是有效的；提出了一种能有效减小流阻系数的蝶板过流面,并对这种过流面的流阻系数进行了验证；建立了分析蝶阀流态的有限元模型,并计算了多种开度下的流态,对各个开度的压力、流速和流线进行了分析；(4)基于水泵站工况的蝶阀,建立一种流固耦合分析的有限元模型,并进行了多开度工况下的流固耦合分析,得出了蝶阀在各个开度的应力和位移值,从而得出了阀门全关状态是应力、应变最大状态的结论；比较了该模型计算出的水力矩结果与理论计算水力矩结果,得出了最大水力矩时蝶阀的开度；分析并且比较了常流量下和变流量下的蝶阀气蚀,得出了各个开度的气蚀系数,得出了容易产生气蚀的情形；提出了应避免阀前后出现高压差工况从而避免气蚀的观点,进而提出几种防止气蚀的方法；(5)采用ANSYS软件,建立了蝶阀密封分析的有限元模型,获得了密封圈厚度方向压缩位移与径向尺寸的变化关系曲线；分析了蝶板的旋转过程,提出了蝶板与阀体开始接触的最佳旋转角度,并提出了几种改进密封面的方案。本论文采用有限单元方法,对蝶阀设计存在的强度、刚度、流阻、流态、密封等方面的问题进行了全面的分析,对于实现阀门设计从经验设计向科学设计的逐渐过渡具有重要意义。更多还原

【Abstract】 The butterfly valve is wildly used as a control device for the pipe. Its reliability, energy efficiency, manufacturing and operating costs for the national economy are of great significance. It has been the difficulties in butterfly design on reducing and calculating flow resistance, calculating water torque, analyzing load conditions and strength under several opening degree of the valve, calculating sealing performance, and so on. In traditional design, designers usually designed butterfly valve by testing and inspection manual, which not only takes longer, and also increased cost. In this dissertation, the main difficulties are investigated in designing the soft rubber seal butterfly valve by the finite element method (FEM). It is expounded as follow:Firstly, it introduces structure, main performances and features, application fields and significance of butterfly valve. Then the main methods for butterfly valve design and main problems in the methods are reviewed, and then the research background and meaning are discussed. Also related fluent theory is introduced.Secondly, a parameter geometry model and a structural static finite element model of the butterfly valve are built. Then the stress and deformation of the valve are analyzed in fully closed state. Afterwards, optimize the structure of the butterfly valve and achieve better performance.Thirdly, in order to analyze the fluid flow through the butterfly valve, the dissertation built a finite element model for calculating the flow resistance coefficient, and calculated the pressure loss of the pipe using Cosmosflow. Then it calculated the flow resistance coefficient of several opening degrees. Compared with experiment result data, the analysis result of flow resistance coefficient is valid. Afterward, optimize the butterfly plate, which can reduce the flow resistance coefficient. Also, a finite element model was built for analyzing valve flow, and the pressure, flow rate and streamlines of several opening degrees were analyzed.Fourthly, it built a fluid-structure interaction (FSI) finite elements model of butterfly valve working on pump station. And it analyzed the model on several opening degrees conditions. The analysis results show that the valve fully closed when the stress and strain is the largest. Hydraulic torque of the valve was analyzed using the FSI finite elements model on several opening degrees. Compared the hydraulic torque with the result calculated by theory, the opening degree is acquired when the hydraulic torque is the largest. The dissertation analyzed the cavitations erosion under constant flow and variable flow. The cavitations erosion coefficient of several opening degree and conditions which prone to cavitations erosion are acquired by compare the analyzed results. And it point out that butterfly valve should avoid excessive pressure difference between two sides of the valve plate so that control the cavitations erosion. Also it provides several methods to prevent the cavitations erosion.Lastly, the dissertation built and analyzed a finite elements model for analyzing sealing performance. And obtain the curve between compressed displacement and radial dimension of sealing ring. Then the progress of valve plate’s rotation was analyzed, and the best degree when the plate and bottom started to contact is acquired. Also, it proposes several programs to improve sealing the surface.The dissertation analyzed the strength, stiffness, flow resistance coefficient, flow status and sealing performance in the butterfly valve design using finite element technique. It helps to realize the transition from traditional design to modern design.更多还原