| LI Xiao-lei,MA Xiao-wen,CHANG Yun-le,ZHANG Hui-chen.Effects of Surface Wettability on Interfacial Drag Reduction in Micro-channel[J],46(6):42-48 |
| Effects of Surface Wettability on Interfacial Drag Reduction in Micro-channel |
| Received:May 30, 2017 Revised:June 20, 2017 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2017.06.007 |
| KeyWord:micro-channel wettablity hydrophobic wall single-side slip velocity double-side slip velocity drag |
| Author | Institution |
| LI Xiao-lei |
1.Dalian Maritime University, Dalian , China; 2.Tsinghua University, Beijing , China |
| MA Xiao-wen |
Dalian Maritime University, Dalian , China |
| CHANG Yun-le |
Dalian Maritime University, Dalian , China |
| ZHANG Hui-chen |
Dalian Maritime University, Dalian , China |
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| Abstract: |
| To reduce the flow drag in micro channel, by the technology of laser manufacturing, self-assembled monolayer(SAM) technique and chemical coating, three kinds of surfaces with different wettabilities were obtained. Then the micro-channels whose wall surfaces were constituted by theses surfaces, were manufactured. The flow fields of these micro-channels were tested by the microscopic particle image velocimetry (µ-PIV), including the single wall’s slip experiment and the double walls’ slip experiment. The contact angles were 114.6°, 142.7°, 155.4° after SAM deposition, microstructure manufacturing(MM) and SAM deposition, MM and chemical coating on silicon wafer, respectively. The slip velocities were 0.018, 0.022, 0.029 m/s on hydrophobic specimen B、C and superhydrophobic specimen D wall surface when they were combined the micro-channel with A specimen. The average flow velocity in B-D micro-channel increase 0.85% than that of in B-C micro-channel. The averasge flow velocity in C-D micro-channel increase 5.25% than that of in C-C micro-channel. There are obvious slip velocities near the hydrophobic surfaces, and the slip velocity increases with the enhance of the wall’s hydrophobicity. When the two walls of channel are both hydrophobic, the slip velocity of the other wall will decrease with the increase of one wall’s hydrophobicity, but the effect of the other wall’s hydrophobicity on drag reduction will improve. The position of the maximum velocity locates on the region which is closer to the wall with stronger hydrophobicity, instead of the center part of channel. Moreover, the bigger the difference between the two wall's wettability, the greater the deviation. |
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