肋条结构对输油管道减阻效果的仿真分析毕业论文
2021-04-19 01:23:24
摘 要
随着对资源的依赖性越来越高,资源的运输就越加显得重要,据称世界能源的1/3-1/2都被用于克服运输过程中的阻力,而局部损擦阻力损失只占其中的1%-2%,摩擦阻力的增加使管道运输的能耗加剧、效率下降,管道壁面磨损严重, 缩短管道使用寿命;还会使管道压力波动加剧, 幅值提高, 随机性增加,管线振颤加剧,降低管道流动稳定性 , 从而对管道运输系统的安全构成严重威胁。因此减小运输过程中的沿程阻力损失就显得亟不可待。本文主要的研究为V型沟槽输油管道减阻特性,使用的工具为建模工具SolidWorks和具有先进的数值方法与强大的前后处理功能的Fluent。研究方法为利用SolidWorks完成对光滑的输油管道与V型沟槽输油管道的建模,再用Fluent进行后处理从而研究出流体在不同的输油管道中的沿程阻力系数并总结出规律。本文选用A型h=0.85mm,s=1.7mm和B型h=1.5mm,s=1.7mm两种尺寸V型肋条结构以及光滑壁面的管道,使用Fluent软件进行数值模拟仿真,探究V型肋条的减阻机理以及肋条表面流场的阻力特性。通过比对三种结构近壁面的剪切力云图、速度云图、湍动能云图、压力云图、涡量等值线云图得出以下结论:(1)肋条结构相比光滑壁面具有一定的减阻能力,本文选取的两种尺寸的肋条结构中,A型肋条即h=0.85mm,s=1.7mm相比较于B型肋条h=1.5mm,s=1.7mm具有更好的减阻效果。(2)减阻工况下,肋条结构使得边界层的湍动能减少,降低了湍流边界层内的流体的速度脉动,使得边界层内流体的运动变得更加平缓,形成稳定的二次涡流,从而使得肋条结构具有了减阻效果。
关键词:肋条结构 管道减租 数值模拟 阻力系数
Abstract
With the increasing dependence on resources, the transportation of resources becomes more and more important. It is said that the 1/3-1/2 of the world energy is used to overcome the resistance in the transportation process, and the local friction loss is only 1%-2%. The increase of friction resistance increases the energy consumption and efficiency of the pipeline transportation, and the wall wear of the pipeline is serious. It can shorten the service life of pipeline, increase the pressure fluctuation of pipeline, increase the amplitude, increase the randomness, increase the vibration of pipeline, reduce the stability of pipeline flow, and pose a serious threat to the safety of pipeline transportation system. Therefore, it is urgent to reduce the resistance loss in the transportation process. The main research of this paper is the drag reduction characteristic of the V groove oil pipeline. The tool used is the modeling tool SolidWorks and the Fluent with advanced numerical method and powerful back and back processing function. The research method uses the SolidWorks to complete the modeling of the smooth oil pipeline and the V groove oil pipeline, and then the FLUENT is used to study the drag coefficient of the fluid in different oil pipelines and to sum up the law. In this paper, A h=0.85mm, s=1.7mm and B type h=1.5mm, s=1.7mm two sizes V rib structure and smooth wall pipe are used to simulate the numerical simulation using Fluent software to explore the drag reduction mechanism of the V ribs and the resistance characteristics of the surface flow field of the ribs. The following conclusions are obtained by comparing the shear force cloud map, velocity cloud map, turbulent kinetic energy cloud map, pressure cloud map and eddy volume contour map of the three structures near the wall. (1) the rib structure has a certain resistance reduction ability compared to the smooth wall. In the two sizes of the rib structure selected in this paper, A ribs are h=0.85mm, s=1.7mm phase comparison. The B rib h=1.5mm and s=1.7mm have better drag reduction effect. (2) the structure of the ribs reduces the turbulent kinetic energy of the boundary layer and reduces the velocity pulsation of the fluid in the turbulent boundary layer, making the movement of the fluid in the boundary layer more slow and forming a stable two swirl, thus making the rib structure having a drag reduction effect.
Key Words:Rib structure;pipeline rent reduction;numerical simulation;drag coefficient
目录
第1章 绪论 1
1.1研究背景与意义 1
1.1.1研究背景 1
1.1.2研究目的及意义 1
1.2国内外研究现状 2
1.3研究内容 3
第2章 理论基础 1
2.1沿程阻力系数 1
2.2流体控制方程 1
2.3数据处理方法 2
2.4本章小结 3
第3章 模型建立 4
3.1物理模型 4
3.2网格划分 7
3.3设置及求解 9
3.4本章小结 9
第4章 结果分析 10
4.1 肋条切应力分析 10
4.2沿程阻力系数 11
第5章 全文总结与研究展望 12
参考文献 13
致谢 15
绪论
1.1研究背景与意义
1.1.1研究背景
随着社会的发展、科技的进步,人类对于能源的使用量越来越大,对其的依赖性也越来越大,目前各国都在设法应对各种能源与环境问题,我国由于人均资源少,环境容量有限,西部生态脆弱,问题尤为突出,而要解决这些问题首先要从节能开始。据称,世界能源的1/3-1/2被用于克服运输中的摩擦。在管道运输出中,一部分能量用于客服地形高差所需要的势能,另一部分就是克服油品在沿管路流动过程中摩擦造成的能量损失,而管道摩擦损失又包括沿程阻力损失和局部阻力损失,长直管道的局部摩擦阻力损失约占全部损失的1-2%,因此为了减小管道摩擦损失并提高运输效率,探索减小沿程阻力损失的方法成为管道减阻的主要手段。
1.1.2研究目的及意义
减阻技术我们之所以到今天还在不断的研发和寻求更高的突破,是因为其对于我国的运输效率,能源节省上有些重大的意义。
(1)对于社会来说,减阻技术的再研究与再发现有利于资源最大化的利用,在节省能源上,能够作出巨大贡献,同时,减阻能够提高工作效率,提高材料的寿命和减少劳动力。