论文标题:三偏心蝶阀的结构分析与动力学研究
Applied Research of Light-Weighting Technique for Aluminum Easy Open Can
论文作者 吴健
论文导师 杜兆年,论文学位 硕士,论文专业 化工过程机械
论文单位 兰州理工大学,点击次数 361,论文页数 67页File Size2607k
2003-05-01论文网 http://www.lw23.com/lunwen_974097/ 蝶阀;三偏心;干涉;动水力矩;密封力矩;设计
butterfly valve; tri-eccentric;interference;dynamic moment;seal torque;design
随着工业技术的发展，普通软密封蝶阀已满足不了工业上的需求，金属硬密封蝶阀很快被开发出来，而三偏心结构蝶阀是蝶阀发展、演化过程中最高级的一种，但是目前国内还没有对它作深入的研究，还没有形成一个比较完善的理论分析体系，致使三偏心蝶阀的发展及应用受到一定程度的限制。 本文主要分析了三偏心蝶阀的结构，给出了三偏心的定义，推导出了蝶板截面的几何方程及其性质，结果表明，沿蝶板厚度的平行截面轮廓线为标准的椭圆形，进而推导出了蝶板几个主要截面的几何参数(长轴、短轴)与三个偏心之间的函数关系；考虑到蝶板启闭过程中避免与阀体及阀座发生干涉，结合蝶板的启闭扭矩，确立了三偏心蝶阀回转中心的适宜区域。对于三偏心蝶阀回转中心的选择是否合适，本文提出了一个检查密封副干涉的方法，设计了相关的程序并进行了验证，给出了程序运行的部分结果。 采用经验公式来计算三偏心蝶阀的动水力矩，误差比较大，本文根据三偏心蝶阀的结构特点，利用理想流体的定常、无旋流动的假定，用有限差分法在直角坐标系中求解拉普拉斯方程，得到蝶板截面上的压力分布，从而计算出蝶板在各个开度下的动水力矩，设计出了求解的程序，给出了程序运行的结果并进行了数据处理从而得到了动水力矩曲线，总结了它的变化规律。 本文还对三偏心蝶阀的密封力矩作了推导并进行了定性的分析，结果表明，对于同一口径的三偏心蝶阀，密封力矩与蝶板的厚度近似成反比；与径向偏心距近似成正比，变化也很明显；而轴向偏心距对密封力矩的影响不是很大；密封力矩随着蝶板所在的圆锥半锥角的增大而有所增加。为此，本文还分别给出了相应的密封力矩曲线图。 基于上述的理论分析，由已知参数设计出了三偏心蝶阀的三维图形。
With the development of the industrial technology,the general soft seal butterfly valve has not been satisfied with the demand in the industry, so the metal seal butterfly vavle has been developed.The tri-eccentric butterfly vavle is the most advanced during the butterfly valve development and evolvement.But,at present, the tri-eccentric butterfly valve has not been studied thoroughly at home,and has not been formed a perfect theory system, brought about the limitation of the tri-eccentric butterfly vavle in its development and application to a great extent.The paper analyzed the struture of the tri-eccentric butterfly vavle at length, defined the tri-eccentric butterfly valve ,educed the geometry function and its characteristic about the section of the butterfly disc.The results indicate: the parallel contour line across butterfly disc thickness is normal ellipse, thereby eslablished function relations between its geometry parameters(long axis and short axis) of three primary sections of the butterfly disc and the tri-eccentricity;In order to avoid interference between the butterfly disc and the valve seat as well as the valve body, combining the torque, we obtained the feasible range about the rotation center of the tri-eccentric butterfly vavle. In succession, we should test whether the rotation center of the tri-eccentric butterfly vavle was right, brought forward a method to test the seal fit interference,designed the program about the seal fit interference and gave the corresponding results which the program was run.If applied experiential formula mechanically to calculate the dynamic moment of the tri-eccentric butterfly vavle , its errors for the results would be larger. The paper, by virtue of the postulate of flow with fixed constant, eddiless of ideal liquid ,calculated laplace equation by finite difference method in rectangular coordinates ,gained pressure distribution on the butterfly disc section , thereby figured out its dynamic moment under each opening angle and the method was feasible for calculating dynamic moment of symmetry or not ,designed the program and described the curve of dynamic moment.Finally, the paper infered their laws.The paper deduced the seal torque of the tri-eccentric butterfly valve and gave it a qualitative analysis. The results indicated :for the tri-eccentric butterfly valve with the same caliber,theseal torque would decrease with the butterfly disc thickness increasing;the seal torque would increase with the radial eccentricity increasing;however,the axis eccentricity effected on the seal torque minutely;the seal torque would increase with the half cone angle increasing appreciably of the cone which the butterfly disc belonged to. so,we gave the seal torque curves respectively.Based on the theory analysis above-mentioned, according to the given parameters, we designed the three dementions figure of the tri-eccentric butterfly valve.
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