Liu Jing, Yap Yit Fatt, Nguyen Nam-Trung
School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Singapore.
Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Oct;80(4 Pt 2):046319. doi: 10.1103/PhysRevE.80.046319. Epub 2009 Oct 27.
We report numerical and experimental studies on a droplet moving through an array of mirofluidic ratchets. Droplets are formed at a T junction and subsequently forced through microfluidic ratchets in the form of diffuser/nozzle structures. At the same flow rates of the continuous and the dispersed phases, the velocity of the droplet is determined by the viscosity of the continuous phase and the interfacial tension between the two phases. Both numerical and experimental results show that the velocity of the droplet increases with increasing capillary number. The droplet velocity is higher than the mean velocity of the fluid system and increases with increasing viscosity of the continuous phase or decreasing interfacial tension. In all experiments, the droplet moves faster in the diffuser direction than in the nozzle direction. Our findings allow the development of a measurement approach for interfacial tension. The rectification characteristics can be used for the development of micropumps for multiphase systems.
我们报告了关于液滴通过微流体棘轮阵列移动的数值和实验研究。液滴在T型结处形成，随后以扩散器/喷嘴结构的形式被迫通过微流体棘轮。在连续相和分散相的相同流速下，液滴的速度由连续相的粘度和两相之间的界面张力决定。数值和实验结果均表明，液滴的速度随毛细管数的增加而增加。液滴速度高于流体系统的平均速度，并随着连续相粘度的增加或界面张力的降低而增加。在所有实验中，液滴在扩散器方向上的移动速度比在喷嘴方向上快。我们的发现有助于开发一种测量界面张力的方法。整流特性可用于开发多相系统的微型泵。
