Upward air-water bubbly flow characteristics in a vertical square duct

垂直矩形ダクト内水-空気上昇気泡流の特性

Sun, H.*; 功刀 資彰*; Shen, X.*; Wu, D.*; 中村 秀夫  

Sun, H.*; Kunugi, Tomoaki*; Shen, X.*; Wu, D.*; Nakamura, Hideo

Gas-liquid bubbly flows exist in channels with various shape and size. Though many experiments have been done in circular pipes, those in a non-circular duct are limited. For the development of gas-liquid bubbly flow model, detailed measurements were carried out for an air-water bubbly flow in a square duct (0.1360.136 m) by X-type hot-film anemometry and multi-sensor optical probe. Local flow parameters of void fraction, bubble diameter, bubble frequency, axial liquid velocity and turbulent kinetic energy were measured in 11 flow conditions for bubbly flow with the area-averaged void fraction ranging from 0.069 to 0.172. A pronounced void fraction peak was observed in quarter square area. The maximum values of both axial liquid velocity and turbulent kinetic energy intensity then appeared in the corner region. It is pointed out the bubble accumulating effect in the corner region changed the distributions of axial liquid velocity and turbulent kinetic energy intensity significantly.