No abstract

Experimental pressure-drop data for vertical two-phase air-water flow across horizontal tubes is presented for gas mass fractions in the range 0.0005-0.6 and mass fluxes in the range 25-700 kg/m 2 s. The square inline tube bundle had one column containing ten tubes and two columns of half tubes attached to the walls.The tubes had a diameter of 38 mm and a pitch to diameter ratio of 1.32. This data and air-water and R113 vapour-liquid data available in the literature are compared with the predictions from two kettle reboiler models, the one-dimensional model and a one-dimensional formulation of the two-fluid model.The one-dimensional model was implemented with three separate void fraction correlations and one twophase friction multiplier correlation. The results show that the two-fluid model predicts air-water void fraction data well but R113 data poorly with pressure drop predictions for both being unsatisfactory. The one-dimensional model is shown to predict pressure-drop and void fraction data reasonably well, provided a careful choice is made for the void fraction correlation.

No abstract

No abstract