NON-INTRUSIVE MEASUREMENT OF VOLUME AND MASS USING ELECTRICAL CAPACITANCE TOMOGRAPHY

摘要

Electrical capacitance tomography (ECT) has been used for some years to measure the concentration distribution within multiphase flows and processes. ECT is a relatively low resolution measurement, but it has many advantages, including being non-intrusive and fast. Recent developments of twin-plane systems have enabled measurements to be made of velocity as well as concentration. We have developed techniques to establish from these measurements the volume, mass and velocity of flow structures in two-component flows, and in particular the mass and velocity of large individual particles and groups of particles in solids/gas flow systems. Results are presented in the paper for simple gravity-drop flows of partly-filled plastic spheres, plastic beads, and also for the conveying of granular material in a pilot plant. We show that resolution of mass to within a few grams is possible on objects of individual mass of between 2g and 35g. We also show measurements of flow structure volumes in vertical solids conveying pipes of approximately 50mm diameter. General comparisons are made with high-speed video photography of some of the flows, and the in the case of gravity-drop flows the accuracy of the mass measurement is established using weighing.