Reduction of skin friction and two-phase flow structure beneath wall in horizontal rectangular channel
Reduction of skin friction and two-phase flow structure beneath wall in horizontal rectangular channel
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水平矩形通道壁下摩阻的减小与壁下两相流结构
DOI：
10.1016/j.oceaneng.2022.110846
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发表时间：
2022
影响因子：
5
通讯作者：
Hibiki Takashi
中科院分区：
文献类型：
--
作者：
Hazuku Tatsuya;Ihara Tomonori;Hibiki Takashi
从改进船体空气润滑减阻方法的角度出发，对长3.0米、间隙0.05米、宽0.2米的水平矩形流道内的两相流进行了实验研究，模拟了外部两相流。使用剪应力传感器和双传感器探头采集了摩擦阻力和局部两相流动参数的数据库，包括含气率分布和气体弦长。在距气泡喷口0.930、1.43和1.93m的三个轴向位置进行了两相流结构的测量。在室温和表观液体速度<；Jf>；范围为0.832~3.00nm/S和表观气速<；Jg>；范围为0.0232~0.714µm/S的流动条件下，获得了72组数据，讨论了入口长度、液气流量对壁下相态分布特性的影响。气泡层厚度被重新定义为长度尺度。在本实验条件下，气泡层厚度对液体流量和入口长度的变化不是很敏感，而对气体流量有很强的依赖性。气泡层的平均含气率高度依赖于液体流量，并随表观液体速度的增加而减小。相反，气体流量对平均含气率的影响并不显著。证实了空气润滑的减阻效果与气泡层的平均含气率之间存在很强的相关性。所得数据可望用于界面输运项的模拟、漂移通量模型本构方程的建立、外部两相流减阻的模拟以及未来各种CFD程序的基准测试。
From the viewpoint of the improvement of the air lubrication method for the ship's hull resistance reduction, an experimental study was conducted for two-phase flow in a horizontal rectangular channel with a length of 3.0 m, a gap of 0.05 m, and a width of 0.2 m, which simulates the external two-phase flow. The database on frictional drag and local two-phase flow parameters, including void fraction profile and gas chord length, was collected using a shear stress sensor and a double sensor probe. Measurement of two-phase flow structure was performed at three axial positions ofz= 0.930, 1.43, and 1.93 m from the bubble injection port. The wall shear stress was obtained atz= 1.93 m. A total of 72 datasets are acquired a room temperature and at flow conditions of superficial liquid velocity <jf> ranging from 0.832 to 3.00 m/s and superficial gas velocity <jg> ranging from 0.0232 to 0.714 m/s. The effects of entry length, liquid and gas flow rates on the phase distribution characteristics beneath the wall were discussed. The bubble layer thickness was newly defined as the length scale. The bubble layer thickness was not so sensitive to the changes in the liquid flow rates and the entry length, and highly dependent on the gas flow rates in the present experimental conditions. The mean void fraction in the bubble layer was highly reliant on the liquid flow rate and decreased with the superficial liquid velocity. In contrast, the insignificant effect of gas flow rate on the mean void fraction was confirmed. A strong correlation between the drag reduction effect due to the air lubrication and the mean void fraction in the bubble layer was confirmed. The obtained data are expected to be used for the modeling of the interfacial area transport terms, development of the constitutive equations of the drift flux model, modeling of the drag reduction for the external two-phase flow and the benchmark tests of various CFD codes in the future study.
小直径管内气泡流界面面积输运实验研究
影响因子：
3.8
作者：
T. Takamasa;T. Goto;T. Hibiki;M. Ishii
通讯作者：
M. Ishii