表面润湿性对微通道界面减阻特性的影响

发布时间：2018-03-01 19:23

本文关键词： 微通道润湿性疏水壁面单侧速度滑移双侧速度滑移阻力　出处：《表面技术》2017年06期 　论文类型：期刊论文

【摘要】：目的降低微通道的流动阻力。方法借助激光加工、自组装技术和化学涂覆技术,在Si基底上制备了3种不同润湿性的表面,通过组装获得具有不同润湿性壁面的微通道。采用微观粒子成像测速技术(μ-PIV),对构建的微通道单侧滑移流动和双侧滑移流动进行测试。结果 Si表面沉积自组装分子膜、微结构加工结合自组装分子膜沉积及构筑微结构后,进行纳米二氧化硅涂覆的接触角分别为114.6°、142.7°和155.4°。亲水壁面A与疏水壁面B、C和超疏水壁面D组成的微通道,B、C和D壁面的滑移速度分别为0.018、0.022、0.029 m/s。B-D通道的平均流速比B-C通道提高了0.85%,C-D通道的平均流速比C-C通道提高了5.25%。结论疏水壁面处均存在较明显的滑移速度,且壁面疏水性越强,滑移速度越大。当两侧壁面均为疏水壁面时,一侧壁面疏水性的提高可以增加另一侧壁面疏水性对整体减阻效果的影响,但会迫使另一侧疏水壁面的滑移速度减小。流场中最大速度位置会偏向疏水性较强的一侧壁面,且两侧壁面润湿性的差距越大,其偏离距离越大。
[Abstract]:Objective to reduce the flow resistance of microchannels. Methods three kinds of wettable surfaces were prepared on Si substrates by laser processing, self-assembly and chemical coating techniques. The microchannels with different wettable wall surfaces were assembled and measured by microparticle imaging velocimetry (渭 -PIVN). The single and bilateral slip flows of the constructed microchannels were measured. Results the self-assembled molecular films were deposited on the Si surface. After microstructural processing combined with the deposition of self-assembled molecular films and the construction of microstructures, The contact angles of nano-silica coating were 114.6 掳/ 142.7 掳and 155.4 掳respectively. The slip velocities of the hydrophilic wall A and the hydrophobic wall B _ (C) and the superhydrophobic wall D were 0.018 ~ 0.022 ~ 0.022 ~ 0.029 m / s. B-D channel respectively. The average flow velocity of 0.85 and C-D channel was increased 5.25% than that of C-C channel. Conclusion there is a significant slip velocity on the hydrophobic wall. When both sides are hydrophobic, the increase of hydrophobicity on one side can increase the effect of hydrophobicity on the overall drag reduction. However, the slip velocity on the other side of the hydrophobic wall will be reduced. The maximum velocity position in the flow field will be inclined to the wall with strong hydrophobicity, and the larger the wettability gap between the two sides is, the greater the deviation distance will be.
【作者单位】：大连海事大学;清华大学;
【基金】：国家自然科学基金(51275064,50975036)~~
【分类号】：TB306

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