A comparative survey on the boiling flow in different geometries using the Drift-Flux model

In this study, thermal-hydraulic parameters of a two phase flow in different channels of a same hydraulic diameter is studied. The Drift-Flux model is adopted for two phase flow investigations where four principal conservation equations are discretize phased using the mesh staggered finite volume technique. The boiling flow parameters at the sub-cooled condition are compared in three different channels with square, triangular and circular cross sections. Also, a square array sub-channel frequent in boiling structures (LWR fuel assemblies included) is added to our consideration. To perform analyses, a code is developed based on the Drift-Flux model and the resulting system of equations is solved through the Newton method. At first, results of the developed code for a circular channel is validated against the experimental data. We then focus on the changes of thermal hydraulic parameters such as void fraction, pressure, mixture velocity and mixture enthalpy in the mentioned geometries as a result of the variation in problem parameters e.g. mass flux, inlet temperature, outlet pressure and heat flux. Solutions also demonstrate that the geometry has as a noticeable impact on the boiling flow parameters especially on the void fraction.