SEPARATION STRUCTURE OF BUBBLY FLOW AROUND A CIRCULAR CYLINDER WITH BUBBLE - BOUNDARY INTERACTION

气泡边界相互作用下圆柱体气泡流的分离结构

• 批准号: 11650165
• 负责人: ICHIKAWA Yasumasa
• 金额: $ 2.43万
• 依托单位: THE UNIVERSITY OF TOKYO
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650165/
• 关键词: BUBBLY FLOW; OUTER FLOW; CIRCULAR CYLINDER; SEPARATION; VOID FRACTION; DRAG COEFFICIENT; CRITICAL REYNOLDS NUMBER; VISUALIZATION; 乱流境界層; 抗力; 圧力分布

In the present research, the bubble behavior in the boundary layer along the cylinder surface is investigated experimentally. The bubble motion is observed by a high speed video from the inside of the cylinder through the transparent wall. The flow behavior in the boundary layer is visualized by an injected dye. In the present experimental conditions, the Reynolds number is corresponding to a sub-critical flow condition for single-phase flow and a super-critical one in the bubbly flow. The laminar separation is disturbed by the passing bubble, and the separation is attached on the surface. This causes that the separation point shifts backward and the form drag is reduced. The following results are also obtained from the photograph and the measurement of pressure distribution around the cylinder. The bubbles break up into small bubbles near the circular cylinder surface due to the strong shear stress in the boundary layer in the larger Reynolds number cases. The pressure distribution around the cylinder approaches to that of the super critical condition with the increase of void fraction.

本文对气泡在沿着圆柱表面边界层中的行为进行了实验研究。气泡的运动是由一个高速视频从圆筒内部通过透明壁观察。边界层中的流动行为是可视化的注射染料。在本实验条件下，雷诺数对应于单相流的亚临界流动条件和泡状流的超临界流动条件。层流分离受到气泡的扰动，附着在表面上。这导致分离点向后移动并且形状阻力减小。根据照片和圆柱周围压力分布的测量，还得到了下列结果。在雷诺数较大的情况下，由于边界层中的强剪应力，气泡在圆柱表面附近破裂成小气泡。随着含气率的增加，圆柱周围的压力分布接近超临界状态。

项目成果

Y.Ichikawa,Y.Matsumoto: "Bubble-Boundary Layer interaction in Bubbly Flow around a Circular Cylinder"ASME FEDSM2000 CD-ROM. 11018. 1-7 (2000)

Y.Ichikawa，Y.Matsumoto：“圆柱体周围气泡流中的气泡边界层相互作用”ASME FEDSM2000 CD-ROM。

Y.Ichikawa, Y.Matsumoto: "Bubble-Boundary Layer interaction in Bubbly Flow around a Circular Cylinder"ASME FEDSM2000. 11018. 1-7 (2000)

Y.Ichikawa、Y.Matsumoto：“圆柱体周围气泡流中的气泡边界层相互作用”ASME FEDSM2000。

市川保正、松本洋一郎: "円柱表面近傍の気泡の挙動"混相流シンポジウム'99講演論文集. 195-196 (1999)

Yasumasa Ichikawa、Yoichiro Matsumoto：“圆柱表面附近气泡的行为”多相流研讨会 99 论文集 195-196 (1999)。