【作者】 原瑞增；

【导师】 李维仲；

【作者基本信息】 大连理工大学 ， 制冷及低温工程， 2012， 硕士

【摘要】 气-液两相流中气泡的运动现象在自然界和工程领域中广泛存在。化工、能源、动力和石油等工程行业中均涉及对气泡运动现象的研究。但是,由于受认知程度和实验研究设备的局限性,对液体中气泡在管道壁面的运动特性这一方面的研究还不全面。鉴于此种情况,本文在结合国家自然基金项目的基础上,应用高速摄影技术和计算机图像处理技术,研究了单气泡在上升过程中与圆管壁面的相互作用问题,初步探讨了气泡在复杂几何流道圆管壁面之间的上升、滚动、反弹和贴附等运动变形特性和规律,主要研究内容包括以下几个方面：1、自行设计并搭建了一个可视化实验装置。选用透光性能优良的有机玻璃材料作为复杂几何流道实验观察段的主体部分；通过对多种光源的分析与比较,采用碘镍丝灯作为光源,得到了清晰度非常高的图像；设置了注气泵和调节阀,实现了单气泡的等时间隔均匀释放。2、编制了一整套完善的图像处理程序和数据后处理程序。采用编程思想最优的Canny算子作为图像处理中边缘检测的核心算法,并加以专业的图像分析处理软件Image-Pro Plus6.0作为辅助工具；数据后处理程序以Matlab软件为基础编制而成。3、通过图像处理程序和数据后处理程序获得了不同工况下,气泡在上升过程中运动轨迹和形状的演变过程,以及气泡的旋转角、速度、Re数和阻力系数等参数的变化曲线。4、实验结果表明：单个气泡在复杂几何流道内中以“S”形路线摆动上升,并伴随着滚动和自旋运动；上升过程中的形状变化和运动轨迹与圆管壁面的构成排列情况有关；气泡的速度、Re数和阻力系数均随Eo数的增加而增加,并且在上升的中间阶段变化程度较大,极小值和极大值交替出现；竖直管间距的增加使单气泡的各个动力学参数的变化程度减弱；不同注气位置发射的气泡在经过连续的圆管壁面后达到相同的运动状态。但在上升过程中的初始和中间阶段,注气位置对气泡的形状、旋转角、速度等参数有影响,并且气泡首先接触的圆管壁面对其上升运动的影响作用较大。更多还原

【Abstract】 The research on the behavior of bubble movement in the gas-liquid two-phase, which exists in nature and many engineering fields, is involved in chemical, energy, power and petroleum engineering industries. However, due to limitations of knowledge and experimental equipment, the bubbles’behaviors across the pipe wall in the liquid is far from comprehensive. Given above situation, on the basis of the National Natural Science Foundation Project, employing high-speed photography and computer image processing technology, the rising single bubbles interacting with the tube wall was studied. The laws of deformation of the bubbles between the tube bundles, rebounding, rolling and adhesion of the bubble nears the tube bundle were stated preliminarily. This research mainly includes the following aspects:1. The experimental apparatus was self-designed. The main part of the experimental observation recorded by high-speed camera was made of the Lucite glass; High definition images could be obtained by using the iodine-nickel filament lamp as lighting source through a comparative analysis of multiple light sources. The release of single bubbles would be interval uniform by setting up the pump and micro-regulating valve.2. Canny edge detection algorithm, the best ladder edge detection algorithm, was selected as the key tool to deal with the images, with the Image-Pro Plus6.0as an auxiliary tools.3. The law of the trajectory, deformation, rotation angle, velocity, Re number and drag coefficient of the bubbles during the rising course were obtained under different working conditions. The rebound of the bubble in the tube wall, adhesion, rolling and sliding are compared and analyzed during the rising course.4. The experimental results show that:as for a single bubble in the liquid, it was spiraling up with the rolling and spinning, which was effected by arrangement mode of the tube bundle; the bubble velocity, Re number and drag coefficient increased as the Eo number increased, and in the medial stage, the minimum value and maximum value appeared alternately; the dynamic parameter of the bubble reduced as vertical tube spacing increased; the bubbles sprayed from different injection position achieved the same state. But in the initial and the middle stage, the shape, the rotating angle, velocity et al were also affected by the injection position, and the bubble was mainly affected by the first tube contacted in the rising course.更多还原