The Best RANS Turbulence Model for Low Liquid Heights Flow; Case of the Interface in a Stratified Two-Phase Flow

Abstract

To simplify studies involving horizontal stratified two-phase gas-liquid flows when using CFD calculations, a transposition of the flow geometry is made. The gas flow is thus confined between the upper wall of the fixed pipe and a lower moving wall at the liquid velocity. The equation set-up is based on the balance equations for mass and momentum. The turbulent viscosity is modelled by a turbulence formulation. Five RANS models are used. To find the best turbulence model to be used in this study, simulations of four experiments made by Lopez (1994), for low heights of liquid, are performed. In a straight cross-section of the duct, the vertical and horizontal profiles of longitudinal velocities obtained by CFD calculations are compared to those obtained experimentally. An evaluation of the relative differences for the dimensionless position of the peak and the velocity at this peak shows that the standard k - ε model is the turbulence formulation that gives the best results.

Keywords: two-phase flow, stratified, interface, moving wall, CFD, turbulence models