Numerical Simulations of Two-Phase Flows in Micro Gas/Liquid Mixing Sections

Abstract

This paper presents a numerical study of multiphase flows in a micro gas/liquid mixing section. The numerical simulation tool is based on the level set advection equation coupled with incompressible Navier-Stokes equations in both the gas and liquid phases. The numerical scheme is based on a standard staggered Marker and Cell (MAC) grid for discretization. The spatial discretization is carried out by using a fifth order Weighted Essentially Non-Oscillatory (WENO) scheme for the convective terms and a second order discretization for all other terms. The numerical simulation tool is used to study a cross-shaped gas/liquid mixing section which produces monodisperse gas bubbles coflowing with liquids in a micro-channel. The surface tension, liquid flow rates and gas flow rates are varied to study the bubble generation process. A simple theoretical model is also developed to predict the size of the bubbles generated. The numerical results are in good agreement with both the theoretical and experimental results. Further simulations are carried out with a T-shaped mixing section to validate the proposed theoretical model. All numerical simulations are also checked and found to be grid independent.

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