Characterisation and decoupling of electromagnetic properties in liquid–solid system using high-frequency electromagnetic tomography

In the liquid–solid fluidised system with conductive fluid and magnetic catalysts, the monitoring of electrical conductivity and magnetic permeability is essential to maintain the desired operating conditions. Conventional electromagnetic tomography (EMT) techniques applied to fluidised beds are limited to magnetic phase detection, while conductivity measurements still rely on contact methods or multimodal integration. Therefore, this study presents a non-contact approach for the characterisation and decoupling of electromagnetic properties in solid–liquid systems with a high-frequency EMT sensor. A pre-calibrated vector decomposition method is developed for the simultaneous estimation of conductivity and permeability. The effectiveness of the method is verified through experiments with magnetite saline dispersions in various concentrations, which give average estimation errors of 3.44% and 0.16% for the conductivity and permeability estimation, respectively. In the imaging experiments, a modified Landweber algorithm integrating Nesterov momentum and weight assignment is developed and applied to the reconstruction, contributing to fast convergence and enhanced image quality. Furthermore, distributions of conductive phase and magnetic phase are decoupled through the reconstruction of distinct voltage response components. • Decoupling electromagnetic properties of liquid–solid systems using EMT. • Vector decomposition method for conductivity and permeability estimations. • Modified Landweber algorithm enables fast convergence and phase-decoupled EMT images.