This work studied the capability of a commercial CFD code in modelling two-phase flow from a header through two branches. The geometry considered in this study consists of a rectangular tank with two horizontal outlet branches of the same diameter d=6.35 mm, separated by a distance L centre to centre L∕d=1.5 with their centrelines falling in a plane inclined an angle θ = 30° from the horizontal. A block-structured, hexahedral computational mesh was used. The gas–liquid flow was computed using the inhomogeneous, free surface model of ANSYS CFX. Mesh-independence tests were conducted and the solutions of the discretized equations were progressed in time using a small time step size (≈ 0.0001 s). Results were obtained for the critical heights of the interface at the onsets of gas and liquid entrainment at both branches, as well as the outlet mass flow rate and quality during two-phase discharge. Good agreement was found between the numerical results and the available experimental data and correlations.