抄録
Void fraction data were obtained for air-water and air water with surfactant flows in a vertical channel with two subchannels simplifying a triangle tight lattice rod bundle. The data had the trends that the void fraction was lower in air-water system than air-water with surfactant one, and the void fractions for both systems were lower than those calculated by various correlations in literatures for circular pipe flow. In order to study the cause of the data trend, for annular flows as a first step, the void fraction was calculated by a two-fluid model subchannel code using several wall and interfacial friction correlations, and by assuming the liquid film to be uniform over the wall perimeter. The best agreement between the calculation and the experiment was obtained when NASCA correlation for wall friction force and modified RELAP5/MOD2 correlation incorporating reduced surface tension effects for interfacial friction force were used.
