Enhancement of Mass Transfer into a Falling Liquid Film by Two-Dimensional Waves

二维波增强落下液膜的传质

• 批准号: 05650201
• 负责人: NAGATA Takashi
• 金额: $ 1.47万
• 依托单位: UNIVERSITY OF RYUKYUS
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05650201/
• 关键词: Liquid Film; Surface Wave; Gas Absorption; Mass Transfer; Liquid Film Type Absorber; 液膜式吸収器; 吸収器

Two-dimensional waves are excited on a falling laminar water film with input of controlled disturbances. and the augmentation in absorption rate of the film from the surrouding gas by the waves are experimentally determined at the room temperature. Two-dimensional waves appear on the whole surface of the film in the range of wave frequencies 10-30Hz, and otherwise waves coalesce with each other to become three dimensional. The augmentation decreases momotonecally with wave frequency at low Reynolds numbers Re<20. while increases at high Reynolds numbers Re>20. Two-dimensional waves increase in absorption rate with Reynolds number. and the rate becomes 2.5 times larger than the values for flat surface films at Reynolds numbers Re>50.Taking account of these results and the numerical observations by Nagasaki and Hijikata (1990) and others, the double boundary layr model is built up, inwhich the mass transfer coefficient alpha is expressed as alpha=xiROO<3.46Dlpif_w>, where D and f_w are diffusivity and wave frequency, introducing the parameter for sweeping motion of high concentration layr near the surface by the waves xi. It is found that the parameter is a function only of wave velocity at the given physical properties of the liquid and increases monotonically with wave velocity.

在输入可控扰动的情况下，在下降层流水膜上激发二维波。并在室温下实验测定了波对薄膜对周围气体的吸收率的增加。在10- 30 Hz的波频率范围内，二维波出现在膜的整个表面上，否则波彼此合并成为三维波。在低雷诺数Re 20时，增大量随波频单调减小<20. while increases at high Reynolds numbers Re>.二维波的吸收率随雷诺数的增加而增加。在雷诺数Re&gt; 50时，传质速率比平板膜大2.5倍。考虑到这些结果和长崎和Hijikata（1990）等人的数值观测，建立了双边界层模型，其中传质系数α表示为α =xiROO<3.46Dlpif_w>，其中D和f_w为扩散系数和波频，引入波浪xi对近地表高浓度层扫掠运动的参数。结果表明，在给定的液体物理性质下，该参数仅是波速的函数，并随波速单调增加。

项目成果

吉村、野底、長田: "周期的に誘起された表面波による液膜のガス吸収促進" 第31回日本伝熱シンポジウム講演論文集. 2. 769-771 (1994)

Yoshimura、Nosoko 和 Nagata：“周期性诱导表面波促进液膜中的气体吸收”第 31 届日本传热研讨会论文集 2. 769-771 (1994)。

N.P.Yoshimura,T.Nosoko and T.Nagata: "Characteristics of Two-Dimensional Waves on a Falling Liquid Film" submitted to Chemical Engineering Science.

N.P.Yoshimura、T.Nosoko 和 T.Nagata：“降落液膜上的二维波的特征”提交给《化学工程科学》。

野底、吉村、長田: "二次元表面波を伴う層流流下液膜のガス吸収のモデル化" 第32回日本伝熱シンポジウム講演論文集. in press. (1995)

Nosoko、Yoshimura 和 Nagata：“二维表面波层流下液膜中的气体吸收建模”第 32 届日本传热研讨会论文集（1995 年）。

T.Nosoko,T.Nagata and K.Oyakawa: "A Study on a Draining Film Associated with Condensation or Evaporation" The International Symposium on Two-Phase Flow Modelling and Experimentation,in press.(1994)

T.Nosoko、T.Nagata 和 K.Oyakawa：“与冷凝或蒸发相关的排水膜的研究”，国际两相流模拟和实验研讨会，出版中。（1994 年）

T.Nosoko,T.Nagata et al: "Visualization of draining film profiles by laser interferometry" 3rd Asian Symposium on Visualization,pp.438-441 The Visulization Society of Japan,1994.p.209-p.218 (1993)

T.Nosoko,T.Nagata 等人：“通过激光干涉测量法实现排水膜轮廓的可视化”第三届亚洲可视化研讨会，第 438-441 页 日本可视化学会，1994.p.209-p.218 (1993)