Optimisation of electrode dimensions of ERT for non-invasive measurement applied for static liquid–gas regime identification

•This paper explained the optimisation of the dimensions of the non-invasive ERT electrodes for the mixtures applications which is focus on static liquid–gas regime.•The rectangular copper is chosen as the electrodes mounted on the periphery of the pipe wall. The 2D simulation based on COMSOL Multiphysics software was used to identify the significant width and height of the non-invasive ERT electrodes.•The optimised size of the non-invasive ERT electrodes is chosen by the sensitivity of the sensor to penetrate through the insulation vessel. The higher the electricity to penetrate through the insulation vessel, the better the non-invasive ERT system to works for mixtures. That sensitivity of the size of electrodes is determined by the output of normalised current values and analysed by using graphs. Later, several experiments also conducted for the verification purpose. The non-invasive technique is one of the favourite methods applied in process plants, compared to other sensing techniques. Due to certain advantages, this technique is also implemented in process tomography such as in non-invasive ERT systems for multiphase mixtures. The purpose of this paper is to investigate the optimum size of the area of the electrode in terms of the width and height for the non-invasive ERT system that can be applied for a static liquid-gas regime. Based on a quasi-static electric field, a 2D simulation using finite element model software (COMSOL Multiphysics) was used to analyse the simulation results. As a result, by applying several widths and heights to the system, 18.5° and 200 mm in width and height, respectively, were chosen as the optimum dimensions to be applied for a 100 mm outer diameter and 2 mm thick acrylic pipe for the non-invasive ERT electrode. Later, experiments were conducted to obtain the tomogram for image verification. Thus, it is believed that the implementation of the optimised area of the electrode can allow the electricity to be emitted and significantly detected. The non-invasive ERT system will also give an alternative way for industry to monitor the performance of process plants.