The Synchronized Formation of Uniform Size Bubbles under Applied AC Potential

Abstract

It was found that gas bubbles produced in distilled water developed in exact synchronization with the frequency of an AC potential applied between a nozzle and an opposite earth electrode. The lower limit of frequency of synchronization was similar to the natural bubbling rate without the applied potential. The upper limit was decided by the inner diameter of the nozzle, i.e. the frequency became higher when nozzle size was decreased. The frequency range was from about 10 to 4, 800 Hz within the conditions of these experiments.
The upper or lower limits of the synchronizing regions were decided by the functions of the applied potential and the inner radius of nozzles where the frequency was constant. The diameter of bubbles being formed synchronously was determined directly by gas flow rate and applied frequency; moreover, the bubbles were essentially uniform in size. In these experiments, uniform bubbles ranging from about 150μm to 5 mm in size were obtained successfully, although they had been difficult to produce by normal methods. The proposed technique should be useful for application in industry and research laboratories where controlled uniform bubbles are required.