Electrical Tomography Technology Research Articles

Numerical study of displacement current phase tomography for gas-water two-phase flow

Electrical Tomography technology is widely used in the research and engineering practice of two-phase flow due to its advantages of non-radiation, non-intrusive and simple equipment structure. However, because of the electrical tomography sensitive field distribution of medium nonlinear (soft), the reconstructed images are often distorted, especially when faced with high conductivity and high dielectric constant two-phase flow (such as oil-field water of high salinity). Displacement current phase tomography (DCPT) is a new electrical tomography technology and it is proposed in 2017. An attractive feature of DCPT is that the relationship between the measured phase and the loss factor has a more extended linear range than the relationship between the measured capacitances in ECT and the permittivity distribution. In this paper, a 12-electrod DCPT with Landweber reconstruction algorithm is applied for gas-water two-phase flow imaging, and the reconstruction results are compared with electrical capacitance tomography (ECT) by numerical examples.

Investigation of Complex Permittivity/Conductivity Distribution by Electrical Tomography

The electrical tomography technology is a multi-phase flow detection technology. This technology has the advantages of non-radiation, non-invasive and visualization, can be widely used in traditional energy field and new energy field. The permittivity and conductivity, as the basic electrical parameters of material, are closely related to the distribution of material in multiphase flow. However, in the actual multiphase flow, due to the non-uniform distribution of permittivity and conductivity in time and space, the accuracy and validity of measuring instruments are challenged. The main target of this research is to investigate the application of electrical capacitance tomography (ECT), electrical resistance tomography with voltage excitation (ERTv) and electrical resistance tomography with current excitation (ERTc) on the multiphase flow with complex permittivity and conductivity distribution. The final objective based on the above research is to provide suitable tomography modual for different multiphase flow process. The experimental results show that ECT is suitable for measuring dry gas-solid fluids. ERTv is better for measuring high water content gas-solid fluids and low conductivity gas-liquid fluids, while ERTc is better for measuring continuous phase conductivity gas-liquid fluids.

Super-sensing technology: industrial applications and future challenges of electrical tomography.

Electrical tomography is a relatively new imaging technique that can image the distribution of the passive electrical properties of an object. Since electrical tomography technology was proposed in the 1980s, the technique has evolved rapidly because of its low cost, easy scale-up and non-invasive features. The technique itself can be sensitive to all passive electrical properties, such as conductivity, permittivity and permeability. Hence, it has a huge potential to be applied in many applications. Owing to its ill-posed nature and low image resolution, electrical tomography attracts more attention in industrial fields than biomedical fields. In the past decades, there have been many research developments and industrial implementations of electrical tomography; nevertheless, the awareness of this technology in industrial sectors is still one of the biggest limitations for technology implementation. In this paper, the authors have summarized several representative applications that use electrical tomography. Some of the current tomography research activities will also be discussed. This article is part of the themed issue 'Supersensing through industrial process tomography'.

Design of capacitance sensor system for void fraction measurement

Simulation and optimization were applied to a capacitive sensor system based on electrical tomography technology. Sensors, consisting of Morgantown Energy Technology Center (METC) axial synchro driving guard electrodes and two sets of detecting electrodes, make it possible to obtain simultaneously two groups of signals of the void fraction in oil-gas two-phase flow. The computational and experimental results showed that available sensors, charactered by high resolution and fast real-time response can be used for real-time liquid-gas two-phase flow pattern determination.