Measurement of local two-phase flow parameters of downward bubbly flow in mini pipes
Measurement of local two-phase flow parameters of downward bubbly flow in mini pipes
复制标题
微型管道内向下气泡流局部两相流参数的测量
DOI：
10.1007/s42757-019-0039-5
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Hibiki Takashi
中科院分区：
文献类型：
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作者：
Hazuku Tatsuya;Ihara Tomonori;Hibiki Takashi
为了扩展微小管道内局部两相流动参数的精确数据库，对内径分别为1.03、3.00和5.00 mm的垂直微小管道内绝热气液泡状流进行了实验研究。采用立体图像处理技术，观察了管道横截面的相态分布特征。在不同流动条件(表观气速0.00508~0.0834 m/S，表观液体速度0.208~3.00m/S)下，得到了管内三个轴向位置的局部流动参数，包括管内含气率、索特尔平均气泡直径和界面浓度的分布，并在此基础上对局部流动参数的轴向变化进行了详细的讨论。结果表明，在低液体流量条件下，岩心峰值分布以浮力为主，而在高液体流量条件下，摩擦压力梯度引起的体加速度为主体，形成壁面峰值分布。结果表明，即使在垂直向下流动中，也存在将气泡推向管壁的升力。通过本实验获得的数据库有望用于界面区域输运项的建模、现有升力模型的验证以及各种CFD模拟程序的基准测试。
In order to extend a precise database on local two-phase flow parameters in mini pipes, experiments were conducted for adiabatic gas–liquid bubbly flows flowing down in vertical mini pipes with inner diameters of 1.03, 3.00, and 5.00 mm. A stereo image-processing was applied to observe the phase distribution characteristics in pipe cross-section. The local flow parameters including profiles of void fraction, Sauter mean bubble diameter, and interfacial area concentration in pipe cross-section were obtained at three axial locations in the test pipes with various flow conditions: superficial gas velocity of 0.00508–0.0834 m/s and superficial liquid velocity of 0.208–3.00 m/s. The axial developments of the local flow parameters were discussed in detail based on the obtained data and the visual observation. It was confirmed that the core peak distributions were formed at low liquid flow rate conditions in which the buoyancy force dominated while the wall peak distributions were formed at high liquid flow rate conditions in which the body acceleration due to the frictional pressure gradient dominated. The result indicated the existence of lift force pushing the bubbles towards the pipe wall even in vertical downward flows. The database obtained through the present experiment is expected to be useful in modeling the interfacial area transport terms, the validation of the existing lift force models as well as the benchmarking of various CFD simulation codes.