Electrochemical sensor to determine direction of chemical flow: Fluid dynamics analysis on sensing probe structure

Abstract

Here we report the results of our investigations on designing an amperometric electrochemical sensor probe with multiple disk working electrodes. The sensor can not only detect a chemical substance dissolved in water but also can determine the direction of its flow by using the shielding effect that appears between closely arranged working electrodes. Analysis of angular response characteristics of the sensor using an empirical model of the shielding effect has shown that at least four electrodes are required to determine the two-dimensional chemical flow direction. We have then fabricated a sensor probe with quadruple disk electrodes. Computational fluid dynamics simulations and sensor response measurements have shown that the proposed sensor responds to the local flow direction near the sensor surface. Therefore, the favorable probe design has turned out to be to arrange sensor electrodes on a round surface to avoid flow separation and backflow generation near the sensor electrodes.