Electrode Polarization Impedance and Its Application in Flow Rate Measurement of Conductive Liquid: A Review

Electrode polarization concept is an old one and has been used in numerous applications. It exists when a metallic electrode comes in contact with the conductive fluid. Basically, in the biomedical field, the concept of electrode polarization is used for measuring biosignals like ECG, EEG, and EMG. Nowadays, its application is not only limited in the biomedical field but also used in general applications such as for measuring the conductivity of the liquid and flow rate. In this article, we make a general review of the fundamental properties of electrode polarization impedance, its dependency on specific parameters. Then, we review certain equivalent circuit models used to describe the physical phenomena in the formation of the ionic double layer. Following this, we enumerate the applications of electrode polarization impedance in the flow rate measurement of conductive liquid and the variation in the polarization impedance-based flowmeter characteristics concerning specific designing parameters such as frequency, electrodes area, space between the electrodes, temperature, and roughness.