The effect of a nonuniform electric field on the formation, coalescence and detachment of air bubbles injected into a stagnant, isothermal liquid through an orifice is studied to identify characteristic bubble behavior patterns. The results of the experimental visualization suggest significant differences in bubble shape and size caused by the electric field. The electric field was applied between a flat, circular and horizontal ground electrode and a spherical, off-axis top electrode. During formation the bubble was tilted towards or away from the upper electrode under the influence of the electric field. The direction of the tilt alternated (even in a single experiment), however, in the majority of the cases the bubble trajectory tilted towards the top electrode. The detachment frequency increased under the influence of the electric field, which indicates decreased bubble volume for lower volume flow rates. The effect of the electric field on vertical bubble coalescence was analyzed and quantified in terms of the detachment time.

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