Experimental investigation on local flow structures of upward cap-bubbly flows in a vertical large-size square channel

Sun, Haomin   ; Kunugi, Tomoaki*; Yokomine, Takehiko*; Shen, X.*; Hibiki, Takashi*

Taking the importance of gas-liquid two-phase flows in large square channels for advanced nuclear reactors, such as ESBWR, we experimented with upward cap-bubbly flows in a large square channel. Local void fractions, axial gas velocities, and interfacial area concentrations for two bubble-size groups were measured at three axial locations. Based on the database, cap-bubbly flow characteristics in a large square channel were understood. The existing drift-flux and interfacial area concentration correlations were validated. The void fraction covariances were obtained and used to validate their existing correlations.