A porous media numerical prediction of void fraction and drift velocity in two-phase flow across horizontal tube bundles

The two-fluid model and the porous media concept are applied to the prediction of void fraction and drift velocity in two-phase flows across horizontal tube bundles. Numerical results are compared with experimental data, obtained for in-line and staggered tubes bundles with different tube pitch-to-diameter ratios. It is shown that the two-fluid model is able to predict the void fraction with acceptable accuracy with the single set of closure laws, without the need for the introduction and adjustment of empirical coefficients which would fit calculated data for a specific tube bundle geometry. It is found that the drift velocity can not be considered as being constant in two-phase flows across tube bundles. The proposed numerical methodology is an advantage in regard to the application of empirical correlations between void fraction and nondimensional two-phase flow parameters, because these empirical correlations comprise free coefficients, which have to be adjusted for specific tube bundle geometry.