Drag reduction and turbulent characteristic of rough surface with fins for heat transfer enhancement

强化传热翅片粗糙表面的减阻和湍流特性

• 批准号: 17560156
• 负责人: HAMAKAWA Hiromitsu
• 金额: $ 1.79万
• 依托单位: Oita University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17560156/
• 关键词: fluid dynamics; exhaust heat recovery; drag reduction; Karman vortex; fin

Drag reduction and turbulent characteristics of the rough surface with the fins were experimentally investigated to improve the performance of heat exchanger tube. We measured the distributions of the mean velocity, the intensity of velocity fluctuation, the spectrum of velocity fluctuation and the coherence distribution around the fin tubes by using hot wire, and conducted flow visualization by smoke wire method. As a result following conclusions were obtained.1. The solid fir which mounted roughly on the surface of heat exchanger tube worked as not only the increase of heat transfer area but also the guide vane.2. When the fin pitch was small, the angle between the main flow and the fin was small, and the inclination of the flow on the surface of a tube was small. The flow on the surface of the tube was inclined by the fin.3. When the serrated fin pitch was large, the drag increased compared with the solid fin tube because the flow separated from the edge of sertated fin. And the heat transfer performance decreased because the surface of the fin did not contact easily with the main flow.4. The flow was inclined greatly by the edge of serrated fin when the pitches of serrated fin become small. The cause of the heat transfer enhancement was not only the increase of turbulence by the fin but also the increase of the contact distance between the main flow and the surface of the tube or the fin. The drag increased compared with the solid fin tube because the inclination of the flow was large at the serrated fin tube.5. When the serrated fin pitch become small further, the fluid did not flow inside of the clearance between the fins. Therefore fluid flowed chiefly outside of the fin parts, the heat transfer performance did not increase.

为提高换热管的性能，对粗糙表面加肋的减阻和湍流特性进行了实验研究。用热线法测量了翅片管周围的平均速度分布、速度脉动强度、速度脉动谱和相干分布，并用烟丝法进行了流动显示。结果表明：1.粗糙分布在换热管表面的固体填料不仅起到增加换热面积的作用，而且起到导流叶片的作用.当翅片间距较小时，主流与翅片之间的夹角较小，且流动在管表面上的倾角较小。翅片的存在使管内表面的流动发生倾斜。当锯齿翅片间距较大时，由于流动从锯齿翅片边缘分离，阻力比实心翅片管增大。翅片表面不易与主流接触，换热性能下降.当锯齿翅片间距变小时，锯齿翅片边缘对流动产生较大的倾斜。翅片强化传热的原因不仅在于增加了管内湍流度，还在于增加了主流与管壁或翅片表面的接触距离。与实心翅片管相比，锯齿形翅片管的阻力增大，这是因为锯齿形翅片管处的流动倾角较大.当锯齿状翅片间距进一步变小时，流体不会在翅片之间的间隙内流动。因此，流体主要在翅片部分的外部流动，传热性能没有增加。

项目成果

抗力方向の気柱共鳴現象発生時の格子配列管群からの渦放出

阻力方向发生气柱共振时一组点阵管的涡旋脱落

• 发表时间: 2005
• 期刊: Dynamics and Design Conference 2005 No.05-15
• 作者: K. Watanabe;T. Narumi;H. Watanabe;T.;鳴海 敬倫;鳴海 敬倫;渡部 光太郎;渡部 光太郎;佐々木 直喜;佐々木 直喜;Hiromitsu Hamakawa;西田英一;Hiromitsu Hamakawa;Hiromitsu Hamakawa;濱川洋充;濱川洋充;濱川洋充;Hiromitsu Hamakawa;Hiromitsu Hamakawa;濱川洋充;Hiromitsu Hamakawa;濱川洋充;濱川洋充;西田英一;Hiromitsu Hamakawa;Hiromitsu Hamakawa;Hiromitsu Hamakawa;濱川洋充;濱川洋充
• 通讯作者: 濱川洋充

格子配列円柱群からの渦放出と気柱共鳴現象

点阵圆柱组涡旋脱落与气柱共振现象

• 发表时间: 2005
• 期刊: 大分地方講演会講演論文集 No.058-2
• 作者: K. Watanabe;T. Narumi;H. Watanabe;T.;鳴海 敬倫;鳴海 敬倫;渡部 光太郎;渡部 光太郎;佐々木 直喜;佐々木 直喜;Hiromitsu Hamakawa;西田英一;Hiromitsu Hamakawa;Hiromitsu Hamakawa;濱川洋充;濱川洋充;濱川洋充;Hiromitsu Hamakawa;Hiromitsu Hamakawa;濱川洋充;Hiromitsu Hamakawa;濱川洋充;濱川洋充;西田英一;Hiromitsu Hamakawa;Hiromitsu Hamakawa;Hiromitsu Hamakawa;濱川洋充;濱川洋充;濱川洋充;左少亮二
• 通讯作者: 左少亮二

Effect of Flow Induced Acoustic Resonance on Vortex Shedding from Staggered Tube Banks

• DOI: 10.1299/jsmeb.49.142
• 发表时间: 2006-02
• 期刊: Jsme International Journal Series B-fluids and Thermal Engineering
• 作者: H. Hamakawa;T. Fukano;E. Nishida;H. Ishida

Vortex Shedding from Staggered Tube Arrays with Roughly Mounted Fin

带有粗糙安装翅片的交错管阵列的涡流脱落

• 发表时间: 2006
• 期刊: Proceeding of Asian Joint Workshop on Thermal and Fluid Science 2006
• 作者: K. Watanabe;T. Narumi;H. Watanabe;T.;鳴海 敬倫;鳴海 敬倫;渡部 光太郎;渡部 光太郎;佐々木 直喜;佐々木 直喜;Hiromitsu Hamakawa;西田英一;Hiromitsu Hamakawa;Hiromitsu Hamakawa
• 通讯作者: Hiromitsu Hamakawa

気柱共鳴騒音に及ぼす格子配列管群内のキャビティサイズの影響

点阵管组空腔尺寸对气柱共振噪声的影响

• 发表时间: 2006
• 期刊: 第16回環境工学総合シンポジウム2006講演論文集 No.06-10
• 作者: K. Watanabe;T. Narumi;H. Watanabe;T.;鳴海 敬倫;鳴海 敬倫;渡部 光太郎;渡部 光太郎;佐々木 直喜;佐々木 直喜;Hiromitsu Hamakawa;西田英一;Hiromitsu Hamakawa;Hiromitsu Hamakawa;濱川洋充
• 通讯作者: 濱川洋充