纳米通道内表面浸润性对气泡的作用

运用分子动力学模拟方法研究了在质量力驱动下不同浸润性壁面纳米通道中气泡的分布及其运动状况, 提出了一种统计纳米通道中气泡运动速度的方法. 结果显示, 在亲水性壁面的纳米通道中, 气泡位于通道中间, 气泡的运动速度接近但小于通道中心流速, 在势能强度较大时, 壁面吸附的分子较多, 气泡也较大, 反之则气泡较小; 对超疏水性壁面, 气泡则位于固壁附近, 两个壁面形成对称的一对气泡, 气泡的运动速度接近但大于边缘速度. 流体总的流动速度随着流体粒子与壁面粒子作用的减弱而增大, 滑移速度则逐渐从负转变为正.

Effects of Surface Wettability on Bubbles in Nanochannels

Molecular dynamics simulations were carried out to study the distribution and movement of bubbles in nanochannels with different wettabilities when the fluids were driven by mass force. A method for calculating the velocity of a bubble in a nanochannel was presented. Results reveal that bubbles are present in the middle of nanochannels with hydrophilic surfaces and their velocities are close to but lower than the flow velocity in the middle of the nanochannel. At higher potential energies, the bubbles are larger because the surface absorbs more particles.Otherwise, the bubbles would be smaller. Two bubbles are symmetrical on both surfaces of the nanochannel when their surfaces are superbydrophobic and their velocities are close to but larger than the flow velocity at the edge of the nanochannel. The fluid flow speeds up as the interaction decreases between fluid molecules and wall particles while the slip velocity gradually changes from negative to positive.