Structure of Bubbly Round Condensing Jets

A theoretical and experimental study of turbulent bubbly condensing jets is reported. Tests involved initially monodisperse carbon dioxide bubbles in water (∼ 1 mm diameter bubbles with initial gas volume fractions of 2.4 and 4.8 percent) injected vertically upward in still water. Measurements were made of mean and fluctuating phase velocities, mean bubble diameters, mean bubble number intensities, and mean concentrations of dissolved carbon dioxide. Three theoretical methods were used to interpret the measurements: (1) locally homogeneous flow analysis, assuming infinitely fast interphase transport rates; (2) deterministic separated flow analysis, where finite interphase transport rates are considered but bubble/turbulence interactions are ignored; and (3) stochastic separated-flow analysis where both finite interphase transport rates and bubble/turbulence interactions are considered using random-walk methods. Both finite interphase transport rates and the turbulent dispersion of bubbles were important for present test conditions; therefore, only the stochastic separated flow analysis provided reasonable agreement with measurements.