Bubble formation in quiescent liquids under constant flow conditions

In this investigation, a simple equation has been theoretically developed to predict the bubble detachment diameter in quiescent liquids under constant volumetric gas flow conditions. The equation is valid in the bubbling regime up to transition to the jetting regime and for liquids with very low up to very high viscosities. Known experimental measurements were used to examine the validity of the developed equation. The present measurements cover gas Weber numbers from about 0 up to 4, liquid dynamic viscosities from 10−3 up to 1 Pa s, and nozzle diameters from 0.2 up to 6 mm. The comparison between the theoretical predictions and the experimental measurements is satisfactory; the deviations lie in most cases within ± 10%.