3D numerical simulation of the pressure-driven flow in a four-electrode rectangular micro-electrochemical accelerometer

Abstract

Pressure-driven flow in a four-electrode rectangular micro-electrochemical accelerometer is investigated through three-dimensional numerical simulation. Two kinds of electrode arrangements along the channel, the anode–cathode–cathode–anode (ACCA) and the cathode–anode–anode–cathode (CAAC) layouts, are studied. When an electric potential difference is imposed between the electrodes, the electrode reaction I 3 − + 2e − ⇌ 3I − occurs at the cathodes, with the reverse reaction occurring simultaneously at the anodes. The electrochemical characteristics of the two types of electrode layouts are studied and compared. It is found that the output electric current first increases till the pressure difference reaches a critical value, then decreases with increasing pressure difference. The critical pressure difference is larger for the ACCA layout and decreases as the aspect ratio. Due to the higher tri-iodide concentration compared to that found in the ACCA layout, when the pressure difference is below the critical pressure differences, the CAAC layout generates larger output electric current. In addition, when the pressure difference is less than the critical pressure difference, the output electric current increases with increasing aspect ratio due to the greater electrode surface area and flow rate.