Determination of Flow Patterns and Void Fraction of Multiphase Flows Using Electrical Capacitance Tomography

A. E. Corlett

National Engineering Laboratory, East Kilbride, G75 0QU ACorlett@nel.uk

ABSTRACT

An experimental study of an electrical capacitance tomography (ECT) system in multiphase flow was made at the National Engineering Laboratory. Its aim was to examine the system’s flow pattern recognition and void fraction measurement capabilities. A commercial ECT system was used together with a custom-made sensor spoolpiece. The test envelope spanned a wide range of multiphase flow conditions involving mixtures of crude oil, water and nitrogen gas. The water fraction was varied between 5% and 90% and two different water phases, tap water and a MgS04 solution, were used.

Results indicated that the ECT system was most suitable for flow pattern identification purposes at low water fractions, although slug and stratified regimes could be identified at higher water fractions. Void fraction measurement was not found to be particularly successful. The sensitivity map and image reconstruction algorithm used were found to be critical factors in the quality and reliability of the generated results.

Keywords electrical capacitance tomography, multiphase flow, flow patterns, pipeline