Abstract
Experimental data on void fraction and frictional pressure drop were obtained for vertical upward bubbly flow in 5 and 9 mm i.d. circular pipes, and those on the interfacial friction force were obtained by substituting the above data into an equation derived from the one-dimensional two-fluids model. The test liquids were a Poly-oxy-ethylene lauryl ether water solution, a 72 wt% glycerin water solution and a tap water at 30 ℃ to study surface tension and liquid viscosity effects, while the test gas was air at near atmospheric pressure. In addition, the interfacial area concentration and the drag coefficient data were determined from the bubble diameter, void fraction and interfacial friction force data. These data were used to validate representative two-fluid model codes, TRAC-PF1/MOD1 and RELAP5/MOD2. Since the prediction by the codes did not fit well the present data, we newly developed and tested some correlations of the interfacial area concentration and the drag coefficient for bubble flow. A result of such experiments and validity tests of the present correlations together with familiar ones in literatures are described in this paper, and the superiorities of the present ones have been demonstrated.
