Abstract:

Based on the Fluent platform, the gas-liquid two-phase flow of the sliding wall surface serpentine microchannel was numerically calculated by the CLSVOF method. The results of numerical simulation were in agreement with theoretical computation. At the same time, the slip phenomenon produced on hydrophobic surface was more significant in smaller microchannel which would reduce fluid flow resistance and achieve drag reduction. The calculation results of fluid flow in microchannel with different wall properties show that slip boundary has almost no effect on distribution of cross-section velocity. The location of maximum cross section velocity was influenced when contact angle of upper and lower wall was different. The contact angle and relative roughness had great effect on slip characteristics. Reasonable design of wall wettability and micro roughness element structure can maximize the drag reduction caused by slip phenomenon. Heat transfer effect was better in microchannel under boundary slip compared with no-slip surface. And it was enhanced with the increase of slip velocity.

Key words: microchannel, numerical simulation, boundary slip, two-phase flow

摘要：

基于Fluent平台，采用CLSVOF方法对滑移壁面蛇形微通道气液两相流动进行了数值计算。计算选用的方法与理论结果具有较好的一致性，同时可以表明疏水壁面会产生滑移现象，且在高度较小的微通道内滑移效果更显著，从而减小通道内流体流动阻力，实现减阻；不同壁面性质通道内流体流动情况的计算结果表明，滑移壁面对截面速度分布趋势几乎没有影响，但上下壁面疏水性不同会影响通道截面最大速度分布。此外接触角及相对粗糙度对滑移特性影响较大，合理设计壁面润湿性及微粗糙元结构可以最大限度发挥滑移现象引起的减阻效果；与无滑移壁面相比，滑移壁面微通道内传热效果更好，且随滑移速度的增大，通道换热增强。

关键词: 微通道, 数值模拟, 滑移壁面, 两相流