J4 ›› 2012, Vol. 9 ›› Issue (1): 99-109.doi: 10.1016/S1672-6529(11)60102-9

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A Numerical Study on Pressure Drop in Microchannel Flow with Different Bionic Micro-Grooved Surfaces

Jing Cui1, Yabo Fu2   

  1. 1. School of Airport, Civil Aviation University of China, Tianjin 30300, P. R. China
    2. College of Physics and electronic engineering, Taizhou University, Taizhou 318000, P. R. China
  • 出版日期:2012-03-31
  • 通讯作者: Jing Cui E-mail:j_cui@cauc.edu.cn

A Numerical Study on Pressure Drop in Microchannel Flow with Different Bionic Micro-Grooved Surfaces

Jing Cui1, Yabo Fu2   

  1. 1. School of Airport, Civil Aviation University of China, Tianjin 30300, P. R. China
    2. College of Physics and electronic engineering, Taizhou University, Taizhou 318000, P. R. China
  • Online:2012-03-31
  • Contact: Jing Cui E-mail:j_cui@cauc.edu.cn

摘要:

The studies of bionics reveal that some aquatic animals and winged insects have developed an unsmoothed surface pos-sessing good characteristics of drag reduction. In this paper, four types of bionic surfaces, placoid-shaped, V-shaped, rib-let-shaped, and ridge-shaped grooved surfaces, are employed as the microchannel surfaces for the purpose of reducing pressure loss. Lattice Boltzmann Method (LBM), a new numerical approach on mescoscopic level, is used to conduct the numerical investigations. The results show that the micro-grooved surfaces possess the drag reduction performance. The existence of the vortices formed within the grooves not only decrease the shear force between fluid and wall but also minimize the contact area between fluid and walls, which can lead to a reduction of pressure loss. The drag reduction coefficient (?) for these four types of micro-structures could be generalized as follows: ?ridge-shaped > ?V-shaped > ?placoid-shaped > ?riblet-shaped. Besides, the geometrical optimizations for the ridge-shaped grooves, which have the highest drag reduction performance, are performed as well. The results suggest that, for the purpose of drag reduction, the ridge-shaped grooves with smaller width to height ratio are recom-mended for the lower Reynolds number flow, while the ridge-shaped grooves with larger width to height ratio are be more suitable for the larger Reynolds number flow.

关键词: microchannel, bionic, grooves, drag reduction, lattice Boltzmann method

Abstract:

The studies of bionics reveal that some aquatic animals and winged insects have developed an unsmoothed surface pos-sessing good characteristics of drag reduction. In this paper, four types of bionic surfaces, placoid-shaped, V-shaped, rib-let-shaped, and ridge-shaped grooved surfaces, are employed as the microchannel surfaces for the purpose of reducing pressure loss. Lattice Boltzmann Method (LBM), a new numerical approach on mescoscopic level, is used to conduct the numerical investigations. The results show that the micro-grooved surfaces possess the drag reduction performance. The existence of the vortices formed within the grooves not only decrease the shear force between fluid and wall but also minimize the contact area between fluid and walls, which can lead to a reduction of pressure loss. The drag reduction coefficient (?) for these four types of micro-structures could be generalized as follows: ?ridge-shaped > ?V-shaped > ?placoid-shaped > ?riblet-shaped. Besides, the geometrical optimizations for the ridge-shaped grooves, which have the highest drag reduction performance, are performed as well. The results suggest that, for the purpose of drag reduction, the ridge-shaped grooves with smaller width to height ratio are recom-mended for the lower Reynolds number flow, while the ridge-shaped grooves with larger width to height ratio are be more suitable for the larger Reynolds number flow.

Key words: microchannel, bionic, grooves, drag reduction, lattice Boltzmann method