Effect of surface wettability on flow instability in micro-nozzle

Recently, researches of microfluidics have been widely studied, because microfluidic systems have been used in several fields such as lab-on-a-chip in medicine, colloid thruster in aerospace, microhydrodynamic in engineering, etc. To handle and control the liquid in the microsystems, the hydrophobic and hydrophilic characteristics on a surface are very important properties. In this study, we performed numerical simulation to investigate the effect of surface wettability in microchannel on the flow characteristics. For the hydrophilic and hydrophobic surfaces arrangement, when the flow reaches the interface region, the meniscus shape changes from concave to convex and the velocity near the centre increases. We can present more efficient method to control the microflow in several microfluidic systems.