An experimental study of linear and chaotic bubble formation in liquid columns under electrostatic potentials

The dynamics of bubble formation from a single submerged nozzle in a liquid-filled column was studied using various gas nozzle designs and sizes. Bubble formation can be characterized as reproducible sequences of stable or unstable bubble events. Return maps (Poincare sections), can be used to depict and characterize the transitions in bubbling dynamics as parameters are changed. With increasing flow rates the system tends to follow the period-doubling route to chaos, although the bifurcation details vary with nozzle geometry. The effect of electrostatic potential (applied across the gas Injector nozzle) on bubble formation was also studied. Bubble formation patterns here are found to be significantly altered by potential magnitude as well as the nozzle design and orifice size. The sensitivity of bubble formation to the electrostatic potential was found to be greater with the capillary nozzles. The Button nozzle at elevated electrostatic potentials has shown the ability to drive bifurcations and shift the location and stability of fixed points of the system. This movement of the attractor in response to electrostatic potential changes demonstrates the possibility of implementing bubble control using electrostatic potential as a manipulating variable.