Numerical simulation of two-phase flow in a microchannel for evaluating liquid film thickness and its Reynolds number dependency

Abstract

In this study, the liquid film thickness of slug flow in a microchannel was numerically investigated. Particularly, we focused on a flow regime with high Reynolds and capillary numbers; these dimensionless number were independently modified to investigate their effect on the liquid film thickness. The results based on the turbulence model confirmed that the liquid film thickness tends to remain constant in the low Reynolds number region; whereas it sharply increases when the Reynolds number reaches a certain value. However, this increase stops once a certain value of Reynolds number is reached, and the liquid film thickness tends to remain constant in the high Reynolds number flow regime. These results tend to agree with the experimental results from previous studies. Moreover, the liquid film thickness calculated under the laminar condition was similar compared to that based on the turbulence model, except in the high Reynolds number region. Under the laminar condition, the liquid film thickness in the high Reynolds number region did not converge to a constant value but kept increasing. The results of this study suggest that the shear stress acting on the bubble interface, which appears in the form of Reynolds stress, seem to prevent the liquid film thickness from increasing.

Keywords

• two-phase flow
• microchannel
• capillary
• liquid film
• numerical simulation