Study of the influence of transducer-electrode and electrode-wall gaps on the acoustic field inside a sonoelectrochemical reactor by FEM simulations

The influence of transducer-electrode and electrode-wall gaps on the spatial distribution of the acoustic pressure inside a sonoelectrochemical reactor has been studied by employing a linear acoustics-based model accounting for vibrations of the reactor walls. A FEM (Finite Elements Method) software package was used in order to simulate the response curves of the system, the distribution of the acoustic pressure and the deformation of the surrounding walls. Attenuation of the acoustic energy in the liquid due to the presence of cavitating bubbles was introduced using an attenuation coefficient, enabling to study its influence in the available working frequency range of the ultrasonic transducer (19–21 kHz). Acoustic energy stored in the liquid was plotted as a function of frequency in order to obtain the response curves of the sonoelectrochemical system, exhibiting different resonance peaks for each studied configuration. The proper election of the reactor configuration and setting of the working frequency of the transducer allows the formation of pressure antinodes near the electrode favouring cavitation events in this zone, and helping to minimize the cavitation-induced erosion of the sonotrode commonly observed during experiments.