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两端弹性支承输流管道固有特性研究 总被引:2,自引:1,他引:1
输流管道广泛应用于航天航空、石油化工、海洋等重要的工程领域, 其振动特性尤其是系统固有特性一直是国内外学者研究的热点问题. 本文研究了两端弹性支承输流管道横向振动的固有特性, 尤其是在非对称弹性支承下的系统固有特性. 使用哈密顿原理得到了输流管道的控制方程及边界条件, 通过复模态法得到了静态管道的模态函数, 以其作为伽辽金法的势函数和权函数对线性派生系统控制方程进行截断处理. 分析了两端对称支承刚度、两端非对称支承刚度、管道长度以及流体质量比对系统固有频率的影响规律, 重点讨论了管道两端可能形成的非对称支承条件下固有频率的变化规律. 结果表明, 较大的对称支承刚度下管道的第一阶固有频率下降较快; 当管道两端支承刚度变化时, 管道的各阶固有频率在两端支承刚度相等时取得最值; 对于两端非对称支承的管道而言, 两端支承刚度越接近, 第一阶固有频率下降的越快, 而且相应的临界流速越小; 流体的流速越大, 其对两端非对称弹簧支承的管道固有频率的影响更为明显. 相似文献
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分析弹性支承输流管道的失稳临界流速 总被引:5,自引:1,他引:5
研究了两端弹性支承输流管道静态失稳和动态失稳临界流速. 根据梁模型横向弯曲振动模态
函数,由两端弹性支承的边界条件得到了其模态函数的一般表达式. 根据特征方程具体分析
了弹性支承刚度、质量比、流体压力和管截面轴向力等主要参数对失稳临界流速的影响. 数
值计算结果表明,管道在弹性支承下的动力稳定性比较复杂,在较小的弹性支承刚度和较小
的参数范围内,管道主要表现为动态颤振失稳;在较大的弹性支承刚度和较大的参数作用下,
管道的失稳形式主要表现为静态失稳;并且失稳临界流速随流体压力和管截面轴向压力的增
加而下降,随管截面轴向拉力的增加而上升. 相似文献
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关于位移法计算有侧移斜梁的研究 总被引:2,自引:0,他引:2
针对用位移法计算有侧移斜梁时遇到的几个问题进行了研究,利用运动学原理对斜
梁位移进行分析,采用力法对几种常见载荷作用下的斜梁进行理论推导,得到了几
个重要结论: 一是斜梁的侧移计算公式,二是一端固定、一端定向支承(支杆与斜梁斜交时)的有侧移单
跨斜梁的转角位移方程、固端弯矩分别与两端固定支承的水平梁的相同,所以计算此类斜梁
时可以按两端固定支承的单跨水平梁处理. 相似文献
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输液管道动力特性与动力稳定性的有限元分析 总被引:20,自引:3,他引:20
1 引言输液管道动力特性和动力稳定性问题在近30年来受到高度重视,主要是因为它具有广泛的应用价值:如石油管道、热交换器和核反应堆冷却管等;同时这个问题本身也是应用力学中一个引人注目的基本问题.采用有限元法分析输液管道动力特性时,得到的特征方程中的矩阵一般是非对称的,难以求解;或者是由于特征方程中矩阵元素量级相差太大,易出现病态情形.本文很好地处理了这类特征值问题.2 输液管道动力特性的有限元分析 相似文献
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本文研究了两端固定输流管道在其支承简谐运动激励下的混沌运动。运用相平面图、Lyapunov指数、Poincare映射以及运动时间历程等数值分析技术考察了流体流速和激振频率变化对管道运动的影响。结果表明,在所研究的系统中存在包括混沌运动在内的多种复杂运动的参数区域,而且发现有三条通向混沌运动的途径。 相似文献
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分析输流曲管临界流速的迁移矩阵法 总被引:11,自引:1,他引:10
提出了一种分析输液曲管临界流速的方法。与其它方法相比,该方法不但容易处理带任意多个中间支承和变刚度、变曲率的输液曲管问题,而且由于对各段位移、内力关系导出了一系列显式,故不管离散段数多少,最终都只需解一个三阶矩阵方程,因此计算量小、精度高。 相似文献
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Satisfactory scaling from laboratory-scale pipe-flow data to large industrial pipelines is an area of practical concern in the utilization of drag-reducing polymer solutions. From experimental data for pipes 0.0254 m in diameter and above, it is shown that accurate scaling can be obtained using a simple, pocket-calculator method. However, pipes of say, 0.005 m and smaller provide much less accurate scaling data for larger pipes. A detailed study of the velocity profiles in drag-reducing flow indicates a total lack of similarity of the profiles of the very small pipes compared with the larger. 相似文献
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The spectral element method is applied on unstructured tetrahedral elements to solve the Navier–Stokes equations for fully developed laminar flow in pipes with two planar curvatures. Specific implementations of the spectral element method to double curved pipes and parallelization are described. Previous studies on flows in pipes focused on constant curvature or torsion geometries, as well as pipes with varying curvature. This study focuses on the periodic variation of both the curvature as well as torsion by analysing a pipe having two planar curvatures. The effects of the three parameters defining the pipe are studied to isolate the curvature and torsion effect on the magnitude and angle of the secondary flow. Furthermore, the geometric effects on the wall shear stress are studied, as it is an important fluid flow property, especially in blood flows. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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Shervin Khayamyan T. Staffan Lundström L. Håkan Gustavsson 《Transport in Porous Media》2014,101(2):333-348
The transition from laminar to turbulent flow in porous media is studied with a new method. To mimic interconnected pores, a simplified geometry consisting of a pipe with a relatively large diameter that is split into two parallel pipes with different diameters is studied. This is a pore-doublet setup and the pressure drops over the parallel pipes are recorded by pressure transducers for different flow rates. Results show that the flow in the parallel pipes is redistributed when turbulent slugs pass through one of them. The presence of the slugs is revealed by positive skewness in the pressure signals as well as an increase of the standard deviation of the pressure drops and correlation between the pressure drops of the pipes. A frequency analysis of the pressure drops show that lower band frequency pressure variations in one pipe are communicated to the other pipe while higher band frequencies are filtered out. 相似文献
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导出了金属管爆炸胀形估算炸药传递到工件表面能量几何法公式,该法以炸药的比能为基础进行计算,避免了能量法对大多数炸药缺少能量常数C和G试验数据的困难,因而可扩大各种炸药在金属管爆炸胀形中的应用。为炸药用量的估算提供一简单的方法。 相似文献
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管道振动引起辐射噪声场的有限元分析 总被引:1,自引:0,他引:1
对于管束振动引起的辐射声场的分析,利用解析法较为困难.运用有限元分析法对管道耦合振动噪声进行了比较系统的分析,得到一系列有益结果,为振动噪声控制提供了理论依据. 相似文献
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In this paper, the vibration and stability properties of fluid-conveying pipes with two symmetric elbows fitted at downstream
end are investigated. The fluid, after entering from the upstream end, is pushed downwards and eventually exits from the downstream
end fitted with two symmetric elbows. The equation of motion is solved by means of Galerkin’s method with a four-mode approximation.
Calculations are conducted for cantilevered and also for pinned–pinned slender pipes. It is found that the stability of the
pipe system can be greatly enhanced with such downstream elbows. The vibration frequency of the fluid-conveying pipes can
be comfortably controlled due to the downstream elbows with a selection of angle of inclination. The proposed geometry configuration
of fluid-conveying pipes may be useful for the design and improvement of engineering pipeline systems and fluidic devices. 相似文献
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E. Dueymes 《International Journal of Multiphase Flow》1989,15(6):901-909
The flowrate, moisture and pressure drop were measured in a water-steam mixture flowing at a pressure of I MPa in pipes with 0.3 and 1.2 m dia. The results are presented here, along with an original method for assessing pressure drops in a water-steam mixture flowing in such industrial pipes. 相似文献