Numerical analysis of the liquid film thickness for gas-liquid flows on the separated pattern: closing parameters influence

Abstract

The separated flow is a two-phase flow pattern in ducts constituted by two sub-patterns, stratified and annular. These two sub-patterns present a thin liquid film in contact with the pipe wall and a gas core that drags liquid droplets from the film. Experimentally determining the liquid film thickness is a challenging task with high limitations. Therefore, mathematical models based on the physical aspects of the phenomenon are developed and employed to estimate the liquid film thickness. Several parameters are essential for closing these models, including the entrainment fraction of the droplets and the interfacial friction factor, which are often modeled through empirical correlations. This work evaluated the influence of the entrainment fraction of the droplets and the interfacial friction factor on the film thickness prediction using various empirical correlations. For this purpose, a computational code was developed to solve the implicit equation of the f ilm model. The results obtained for the film thickness were compared with experimental databases from the literature for horizontal stratified and vertical annular flow. The combination of both correlations that produces the best results from the obtained deviations was identified.