Studies of the Interaction of Ionic Liquid and Gas in a Small-Diameter Bubble Column

Gas bubbling through a column of ionic liquid has been investigated using high-speed video and a conductivity method to measure a cross-sectionally averaged void fraction. For comparison, other liquids with similar physical properties, e.g., a glycerol/water mixture and glycerol/water with dissolved potassium chloride, were also employed. Air was used for the gas phase. The similarities and differences of flow characteristics were observed from the images. The differences in flow patterns were revealed by analysis of the time series of conductance signals in the form of the probability density function, autocorrelation, and power spectrum density. Furthermore, the velocities and frequencies of flow structures were deduced. The flow characteristics of ionic liquid were found to be similar to those of the other liquids studied.