Experimental and Numerical Investigation of Two-Phase Patterns in a Cross-Junction Microfluidic Chip

Abstract

Two-phase microfluidic systems have been found in a wide range of engineering applications. Accurate determination of the two-phase flow patterns in microchannels is crucial to selecting appropriate predictive tools for pressure drop, heat and mass transfer in the microfluidic devices. Most of the prevailing two-phase flow maps developed using visualization techniques are unable to reveal the fundamental mechanisms responsible for the formation of specific flow pattern under given flow conditions. In this work, the high-speed photographic method is employed to study the liquid-gas two-phase flow in a cross-junction microfluidic chip with a rectangular cross section of 300 μm by 100 μm. The dynamics of bubbly, slug and annular flows are investigated. Numerical models using the VOF approach are developed to simulate the two-phase mixing and flow pattern formation in the microfluidic device. The roles of the inertia, viscous shear and surface tension forces in forming various two-phase flow patterns are discussed. The experimental results and the simulation data together provide a comprehensive phenomenological description of the key parameters and processes that govern the two-phase flow pattern formation in microfluidic devices.