ETD

• Wire mesh sensor

This thesis investigates the non-ideal behaviour of a novel Wire-Mesh Sensor (WMS) capable of simultaneously providing capacitance- and conductance-related measurements. The work aims to characterize the main physical and measurement-related phenomena that can affect the sensor response and lead to deviations from an ideal representation of the local fluid distribution.
The experimental investigation focuses on three main aspects: the influence of capillary and meniscus effects on the liquid–gas interface, the spatial dependence of the measured response within the sensing matrix, and crosstalk between different sensing locations. Controlled filling and emptying experiments are used to evaluate how these effects modify the capacitance and conductance signals under different interface configurations. Particular attention is given to sensing locations that should exhibit equivalent responses under ideal conditions, allowing spatial asymmetries and non-local interactions to be identified.
The experimental results are complemented by potentiometric simulations, which are used to analyse the electric potential distribution within the sensing region and to support the physical interpretation of the observed deviations. The comparison between simulated and experimental behaviour provides insight into the contribution of the electric-field distribution to crosstalk and other non-ideal effects.
The investigation is initially performed using demineralized water and subsequently extended to isopropanol. The comparison between the two experimental campaigns allows the influence of the working fluid and its electrical properties on the sensor response to be assessed, while also identifying phenomena that remain associated with the sensor geometry and measurement principle.
A further part of the thesis explores an additional application of the simultaneous capacitance and conductance measurements. A small experimental loop is developed to investigate the possibility of estimating the temperature of a single-phase liquid from the temperature dependence of its electrical conductivity and dielectric properties.
Overall, the thesis provides an experimental characterization of the main non-idealities affecting the investigated WMS and evaluates their influence on the interpretation of capacitance and conductance measurements. The results contribute to a better understanding of the sensor response and provide a basis for further improvements in measurement interpretation, calibration and future applications of combined capacitance–conductance Wire-Mesh Sensors.