An experimental study on two-phase characteristics of vertical injection of gas through a slot nozzle into a liquid bath

Abstract Two-phase flow characteristics of gas injection through a slot nozzle into a liquid bath were studied experimentally. A dual-sensor electrical probe measurement system was used to obtain the distributions of multiple two-phase flow parameters. Measurements were conducted under various gas flow rates, nozzle widths and at different planes vertical to the slot nozzle. It is found that the void fraction, interfacial area density and bubble frequency show peak value in the nozzle center and decrease rapidly away from the nozzle exit. Both the void fraction and interfacial area density increase drastically with increasing gas injection rates, while the bubble frequency remains almost unchanged. However, the effects of two different nozzle widths (0.1 mm and 0.5 mm) on the above three parameters are not significant. As the measurement plane deviates from the center plane vertical to the slot nozzle, all the above three parameters show slight decreasing trends indicating the bubble plume is contracting to the nozzle center downstream. For the measurement zone 15 mm above the nozzle exit, the apparent bubble diameter and velocity remain almost constant in the whole flow field for each flow configurations. Moreover, good self-similarities were demonstrated for void fraction, interfacial area density and bubble frequency, with their profiles being able to collapse into a Gaussian function.