壁面润湿性对蛇形微通道内两相流流动特性影响的格子Boltzmann模拟

在90°Y形汇流的矩形截面蛇形微通道内,采用格子Boltzmann方法对不同接触角的蛇形微通道内气液两相流动进行了数值计算。首先以空气和水为工作流体对气液两相流动进行模拟研究并通过实验进行验证。验证模型合理性后,根据模拟计算结果,以气液相流速为坐标绘制了不同接触角下的流型图并分析其差异性及原因;同时深入研究了液相黏度和接触角对于弹状流流体力学性质的综合影响;比较了具有不同接触角壁面的蛇形微通道内两相流压降、摩擦因子、壁面摩擦系数和剪切应力的分布规律,并讨论了蛇形微通道内气液两相流动的影响因素。研究表明疏水壁面即接触角大于90°时,微通道内两相流压降、摩擦因子、壁面摩擦系数和剪切应力均低于亲水壁面微通道内相关参数,更利于流体流动。

Lattice boltzmann simulation of gas-liquid flow in serpentine microchannel under different contact angle

In order to study the gas-liquid two-phase flow of 90° Y-junction convergence coil, the method of lattice Boltzmann was adopted.The simulation of gas-liquid two-phase flow with air and water as working fluid was carried out in the serpentine microchannels of rectangular cross section.After passing the verification experiment, according to the calculation results, the flow patterns of different contact angles are plotted with the gas-liquid phase velocity as the coordinate and the effect of contact angle on slug flow was in-depth studied;Meanwhile, the difference of pressure drop and friction factor of two-phase flow under different contact angle in serpentine microchannels were compared; Influence factors of wall friction coefficient and shear stress were also discussed.It showed that hydrophobic wall which means the contact angle is greater than 90 degrees, the two-phase flow pressure drop, friction factor, wall friction coefficient and wall shear stress were lower than related parameters in serpentine microchannel with hydrophilic wall, which is beneficial to fluid flow.