In this work, a Computational Fluid Dynamics model is presented for the analysis of annular air-water flow before a 90° bend with a radius to diameter ratio (r/D) of 1.5, implementing the Volume of Fluid (VOF) model in STAR-CCM+ v9.2. An 8m-long vertical tube with an internal diameter of 0.076 m was studied for ten different air and water superficial velocities. The mean void fraction was compared between the experimental measurements, the CFD model, and a model in OLGA. The CFD and OLGA model presented an average relative error of 8.79 % and 17.05 %, respectively.