粗糙表面上微液滴的数值模拟

本文使用VOF方法将微液滴在粗糙壁面上的接触现象转化为不可压缩两相流动问题,并对其进行三维数值模拟.选择具有柱形突起和槽道两种微结构的壁面进行模拟.计算了不同粗糙系数时液滴在突起结构表面的静止形态和接触角,计算结果和实验数据吻合得较好.和理论模型进行比较,分析了经典模型的适用范围.对于微槽道结构的壁面,计算给出不同方向测量得到的液滴接触角.实现了液滴在倾斜壁面上滑落过程的模拟.液滴沿斜面下滑时,前进角和后退角的变化存在周期性,这一周期性变化和表面粗糙结构密切相关.

Numerical Simulation of Water Droplets on Rough Surfaces

The contact phenomena of the micro water droplets on rough surfaces were treated as incompressible two-phase flows and the three dimensional simulation was achieved.The droplets on the surfaces with pillar and groove structures were simulated.For the pillar structured surfaces with different roughness factors,the static shapes and contact angles of droplets were computed and the results agree well with existing experimental data.The computation results were compared to classical models,whose suitability was testified.For the groove structured surface,the contact angles measured from different directions were obtained.The sliding behavior of droplets was considered.While the droplet slides on the inclined plaue,the advancing and receding angles change periodically and this period has close relationship with the microstructures on the rough surface.