Measurement of bubble nucleation rates by an acoustic method

Abstract

Bubbles which form at the surface clearly affect the efficiency of electrodes during their residence. The residence time is related to the detachment rate, and the surface density of bubbles is strongly affected by the nucleation rate. A new acoustic technique for detecting the bursting of bubbles at a free liquid surface, and hence for measuring bubble nucleation rates, is reported here. In suitable circumstances, the number of bursts is closely correlated with the number of bubbles actually nucleating, and this has allowed a testing of theoretical equations [1] for the heterogeneous nucleation of bubbles on various surfaces. It is pointed out, however, that the description of the mechanism implicit in the derivation of the equations referred to in [1] may not be correct, and that there is good reason for believing that it will not in general be applicable for calculating bubble hetero-nucleation rates.