Numerical simulation of isothermal upward two-phase flow in a vertical tube of annular section

Abstract

A numerical simulation of a vertical, upward, isothermal two-phase flow of air bubbles and water in an annular channel applying Computational Fluid Dynamics code (CFD) was carried out. The simulation considers an Eulerian frame, with two-fluid model, specific correlations for turbulence model considering the dispersion and bubble induction turbulence. The work intends to assess whether the code represents the physical phenomenon accurately by comparing the simulation results with experimental data obtained from literature. The annular channel adopted has equivalent hydraulic diameter of 19.1 mm, where the outer pipe has an internal diameter of 38.1 mm and inner rod 19.1 mm. To represent this geometry, a three-dimensional mesh was generated with 960000 elements, after a mesh independence study. The void fraction distribution, taken radially to the flow section is the main parameter analyzed besides interfacial area concentration, interfacial gas velocity, diameter and distribution of bubbles.