Experimental and numerical investigations on transient multiscale bubble behaviors in CuSO4 aqueous solution electrolysis cell

Abstract

The present investigation demonstrates the transient multiscale bubble behaviors including the bubble homogeneous nucleation, continuous growth, disordered collision and coalescence, and disturbed detachment under the anode in the CuSO4 aqueous solution electrolysis process by experimental and numerical methods. The combined approach of the volume of fluid (VOF) method and discrete phase model (DPM) is applied to solve the macro bubbles’ surfaces and track the micro bubbles’ trajectories, respectively. The link between the macro continuous and micro dispersed bubbles is achieved by the discrete-continuum transition model (DCTM). The dumbbell and the gourd morphologies are revealed in both experiment and numerical simulation during the binary bubble collision and coalescence. The predicted maximum bubble thickness and maximum bubble coverage present reasonable matches to the experimental data. The results show that the large coalescing bubbles can extend the bubble collision period and increase the fluctuation amplitude of the bubble interface. Increasing the current will increase the bubble collision velocity and shorten the contact time before bubble coalescence, moreover, the recovery time of the oscillating bubble from coalescence to the stable state is also prolonged. Increasing inclined angles of the anode can increase the bubble velocity and decrease the bubble diameter.