Improving Spatial and Temporal Resolution of Electrical Impedance Tomogram (EIT) by Partial Imaging with Limited Measurements (PILM)

In the past few decades, EIT systems have been successfully applied to many different industries, such as petroleum, chemical and energy. The performance of existing EIT-based multi-phase flow metering is, however, still challenging, due to incapability of current EIT systems for providing both qualitative spatial and temporal resolution at the same time. On the other hand, one important characateristics of multi-phase upward pipeline flow is that the flow regimes can be assumed in radial symmetrical over the cross-section of the pipe under investigation, which means the central area of a tomogram can be utilised to approximate the whole tomogram when calculating multi-phase flow characteristics, e.g. concentration and velocity. This paper proposes a novel approach to achieve reasonable spatial and temporal resolution for multi-phase flow metering by partially imaging multiphase flow with limited measurements by means of reducing the number of injection and measurement pairs during gauging process, without changing the original configuration of 16-electrode based EIT system, and back projection based image reconstruction. Experiments were conducted in terms of visualising static objects in a phantom and metering gas-water 2-phase upward vertical flow. The results demostrated that the proposed approach generates comparable tomograms to the ones obtained by conventional 16-electrode EIT system, and offers a great temporal resolution, which is suitable for velocity extraction using conventional cross-correlation method, which further improves the performance of EIT-based multi-phase flow metering