Study of Capillary Filling Dynamics in a Microchannel

Abstract

Capillary filling dynamics in a micro channel and different aspects of this type of flow has remained a long-acting problem in the last decade considering its numerous applications in various fields. In this study, an attempt has been made to study the influence of certain parameters on the equilibrium height attained by the liquid in the micro channel. Lucas Washburn equation has been modified using the concept of phase change and vapour recoil and also accommodating the entrance effects in terms of added mass. The formulated governing equation was used to study the effect of parameters such as: phase change, aspect ratio and properties of the liquid numerically using MATLAB. Two different liquids water and ether has been used in the analysis. It was found that phase change by evaporation resulted in lowering of liquid rise. Also the oscillations in water were found to be damped more than those in ether. It was also revealed that liquid rise increased with increasing aspect ratio and with increase in aspect ratio, the change in equilibrium height gradually decreased. The effect of contact angle on the flow characteristics was also studied.