高温壁面润湿性对气层稳定性及其壁面滑移性能的分子动力学研究

针对流体在纳米通道的小尺度效应,采用分子动力学方法模拟了传热效应以及流体流动行为,研究在壁面温度影响下,不同润湿性壁面上方气层生成状态以及流体流动时气层的稳定特性和相应的减阻性能.结果表明:当壁面为纯疏水壁面时,不能形成气层;疏水基底+亲水组合壁面形成不规则气层;纯亲水壁面和亲水基底+疏水组合壁面能形成规则气层.当流体流动时,疏水基底+亲水组合壁面气层消失,而纯亲水壁面和亲水基底+疏水组合壁面气层较为稳定.纯疏水壁面主流区域速度较大,而纯亲水壁面主流区域最低.对于壁面滑移速度,存在气层的壁面滑移速度与纯疏水表面相对接近,甚至稍优于纯属疏水表面,而疏水基底+亲水组合壁面滑移速度最小.

Molecular dynamics study on the effect of high temperature wall wettability on gas layer stability and wall sliding performance

In view of the small-scale effect of fluid in nanochannels, molecular dynamics methods are used to simulate the heat transfer effect and fluid flow behavior, and the gas layer formation state above the wall with different wettability and the stability of the gas layer during fluid flow under the influence of wall temperature Characteristics and corresponding drag reduction performance. The results show that when the wall is purely hydrophobic, no gas layer can be formed; hydrophobic substrate + hydrophilic combined wall can form an irregular gas layer; purely hydrophilic wall and hydrophilic substrate + hydrophobic combined wall can form a regular gas layer. When the fluid flows, the hydrophobic substrate + hydrophilic combined wall surface gas layer disappears, while the purely hydrophilic wall surface and the hydrophilic substrate + hydrophobic combined wall surface gas layer are relatively stable. The main flow area of the pure hydrophobic wall has a higher velocity, while the main flow area of the pure hydrophilic wall is the lowest. For the wall slip velocity, the wall slip velocity of the gas layer is relatively close to that of the pure hydrophobic surface, even slightly better than that of the pure hydrophobic surface, while the hydrophobic substrate + hydrophilic combined wall slip velocity is the smallest.