Study on the Enhancement of Gas Absorption into a Falling Liquid Film Caused by Surface Waves and Modelling of the Gas Absorption

表面波引起的下降液膜中气体吸收增强的研究及气体吸收建模

• 批准号: 08650270
• 负责人: NOSOKO Takehiro
• 金额: $ 1.41万
• 依托单位: University of the Ryukyus
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650270/
• 关键词: Falling Liquid Film; Surface Wave; Gas Absorption; Mass Transfer; Vorticity; 馬蹄形渦; 重力波; 表面張力波

To understand why the surface waves drastically enhance the gas absorption into a falling liquid film and model the absorption, we investigated the dynamics of three-dimension surface waves on the falling liquid film. The major results of this investigation may be summarized as follows.Surface waves separated well from each other (solitary waves) were excited on a water film falling down a vertical surface by introducing controlled temporal disturbances of constant frequencies into the film entrance, and the response of the waves to spatial disturbances generated by perturbations located just below the film entrance is analyzed. The results show that the two-dimensional waves of small phase velocities are unstable to spatial disturbances of large wavelengths and transform into three-dimensional waves having sinusoidal wave fronts, while the waves of intermediate and large phase velocities are unstable to small wavelength disturbances and their wave fronts bend to form several U-shapes on each front. The U-shapes (or ' s) originate from the perturbations, U' and they align in a row with the corresponding perturbations. When a single perturbation is put on the film, a 'U' orginating from the perturbation leads to the generation of a new 'U' on either side, i.e.a self-induced lateral propagation occurs.It is pointed out that these surface waves hold vortices occurring in a shear layr bounded by a solid surface and a free liquid-gas interface, and the U-shaped waves resemble both the LAMBDA-vortices and horseshoe-shaped vortices observed in boundary layrs on walls.

为了理解表面波对气体在下降液膜中的吸收作用并模拟吸收过程，我们研究了三维表面波在下降液膜上的动力学。本文的主要研究结果如下：通过在水膜入口处引入恒定频率的受控时间扰动，在垂直表面下降的水膜上激发了相互分离的表面波(孤立波)，并分析了表面波对位于入口处的扰动产生的空间扰动的响应。结果表明，小相速度的二维波对大波长的空间扰动不稳定，并转变为具有正弦波前的三维波，而中、大相速度的波对小波长扰动不稳定，其波前弯曲形成多个U形波阵面。U形(或‘S)起源于扰动U’，它们与相应的扰动排成一行。当对薄膜施加单次扰动时，扰动产生的“U”形波在两侧产生一个新的“U”形波，即发生自感横向传播.文中指出，这些表面波具有发生在以固体表面和自由液气界面为边界的剪切层中的旋涡，而U形波既类似于在壁面边界层中观察到的兰姆达涡，也类似于在壁面边界层中观察到的马蹄形旋涡.

项目成果

T.Nosoko, S.Gima and T.Nagato.: "Experimental Observation of Three-Dimensional Wave Evolution on a Falling Liquid Film" Proceedings of 11th International Heat Transfer Conference. (印刷中). (1998)

T.Nosoko、S.Gima 和 T.Nagato.：“下落液膜上三维波演化的实验观察”第 11 届国际传热会议论文集（1998 年）。

野底・儀間・長田: "流下液膜に生ずる馬蹄形表面波(渦)の成長過程" 第35回日本伝熱シンポジウム講演論文集. (印刷中). (1998)

Nosoko、Gima 和 Nagata：“下落液膜中产生的马蹄形表面波（涡流）的生长过程”第 35 届日本传热研讨会论文集（1998 年）。

野底武浩・長田孝志・儀間悟: "流下液膜に生ずる馬蹄形表面波(渦)の成長過程" 第35回日本伝熱シンポジウム講演論文集. (発表予定). (1998)

Takehiro Nosoko、Takashi Osada、Satoru Gima：“下降液膜中产生的马蹄形表面波（涡流）的生长过程”第 35 届日本传热研讨会论文集（1998 年）。

Nosoko, T.et al.: "Experimental Observation of Three-Dimensional Wave Evolution on a Falling Liquid Film" Proceedings of 11th International Heat Transfer Conference, Kyongju, Korea, Aug. (in print). (1998)

Nosoko, T.等人：“降落液膜上三维波演化的实验观察”第 11 届国际传热会议论文集，韩国庆州，8 月（印刷版）。

Nosoko, T.et al.: "Evolution of Horseshoe-shaped Waves on a Falling Liquid Film" Proceedings of 35th National Heat Transfer Symposium of Japan, Nagoya, May. (in print). (1998)

Nosoko, T.等人：“下落液膜上马蹄形波的演化”第 35 届日本全国传热研讨会论文集，名古屋，5 月。