A versatile electrical tomography system and gas/liquid flow facilities

Jacek Nowakowski, Robert Banasiak, Radosław Wajman, Dominik Sankowski

Institute of Applied Computer Science, Lodz University of Technology, 90-924 Lodz, Stefanowskiego 18/22, Poland

Abstract

The article presents application of National Instruments system combined with different ECT/ERT measurement units, for monitoring and controlling two-phase gas/liquid flows. Experiments showed possibilities of applying measurement data acquired from the ECT system for controlling the flow. The experimental results showed, that ECT systems can be used not only for non-invasive measuring and monitoring but also for controlling industrial installations and important flow parameters.

The Process Tomography Laboratory is equipped with gas/liquid two-phase flow installation. It consists of three horizontal and vertical measuring segments with diameters of 25, 40 and 80 mm, which allow to investigate flows in very wide range of flow rate parameters. An electro-pneumatic valve control system allows to direct a flow into a certain piping sub-system according to flow rate requirements. It is equipped with a liquid pump controlled by a Hitachi inverter, Kobold and Enko flow meters for supplying liquid. Air in the piping system is controlled by Brooks flow meters/controllers. All elements are connected to a National Instruments PXI system. Data acquisition and control hardware is controlled by LabVIEW.

The flow measurement system is based on DeCaRT (Denidia Capacitance Resistance Tomography) tomography system, which was designed and built in the Institute of Applied Computer Science during a EU DENIDIA project. Newly designed and fabricated in the Institute ECT sensors with internal electrodes strongly enhanced flow parameters measurement capabilities of the system. ECT data processing is performed by TomoKIS Studio Software System, designed by TomoKIS research group. Flow measurement data are acquired by the ECT system and on-line processed using high performance computing system applying GPU CUDA technology, and transferred to the PXI system. This link closes feedback loop and allows to control the flow in the piping system. The article presents applied software solutions and results of investigation of flow control system.

Keywords: Two phase liquid/gas flow; ECT flow measurements; flow control