Mean Passage Frequency and Length of Large Bubbles in Bubble Columns

Abstract

Behavior of large bubbles in developing slug flow was studied in batch-type bubble columns of 2, 4 and 8 cm diameter with a perforated plate as the gas distributor.
Mean passage frequency of large bubbles ƒ_CB decreases with height above the gas distributor h because they coalesce with each other into much larger bubbles as they rise.
The empirical equation of mean longitudinal length of large bubble L_CB was obtained for h/D_T<100, where D_T is diameter of the column.
The dependence of L_CB upon h and superficial gas velocity V_g was well explained analytically.
Mean length of liquid slug L_l was obtained and compared with experimental values of various authors. L_l is found to depend upon V_g, h and D_T within experimental conditions.