存在残余液体的微管道中的表面张力驱动流动

Surface tension driving flows into microchannels with residual liquid

许多微流体系统涉及到存在残余液体的微管道中由表面张力驱动的注入流动问题。该文利用非定常N av ier-S tokes方程,采用VOF模型追踪运动界面,以CSF模型考虑表面张力的影响,使用有限体积法对存在不同形态残余液体的微管道中不可压缩流体的表面张力驱动的注入流动进行了数值模拟。结果表明,与不含残余液体的情况相比,管道内存在附着于管壁的液滴时,入口流量下降,但液体的注入效率反而略有提高;而管道内存在封闭液柱时,入口流量明显降低,而且会在管道中形成随液体一同运动的气泡,不利于液体注入。这些结论对于相关微流体系统的设计具有借鉴意义。

Liquid filling flows driven by surface tension forces into microchannels with residual liquid were numerically simulated using the finite volume method with volume of fluid （VOF） interface tracking methodology and the continuum surface force model for the surface tension. The analyses considered the residual liquid as liquid drops and liquid columns. The liquid drops on the wall reduce the liquid flow rate but slightly increase the filling efficiency. The liquid columns also reduce the liquid flow rate while producing gas bubbles in the channel, which handicap the liquid filling. These conclusions can be used to design filling procedures for micro-fluidic devices.