Volume flow rate measurement in vertical oil-in-water pipe flow using electrical impedance tomography and a local probe

This paper presents the use of a high-performance dual-plane electrical impedance tomography (EIT) system and a local dual-sensor conductance probe to measure the vertical upward cocurrent oil-in-water pipe flows. Experiments were carried on a flow loop with a transparent 2.5-m-long, 80-mm inner diameter test section using kerosene and tap water. The flow conditions were predominantly of the dispersed type, with nonslip oil volume fractions of 9.1, 16.7, and 23.1, respectively, and with two groups of different mixture velocities. A sensitivity coefficient back-projection algorithm was adopted to reconstruct the flow distributions from the EIT measurement data, and then the oil in situ volume fraction was calculated based on a Maxwell relationship with temperature compensation. The oil velocity distribution was obtained using a pixel-to-pixel cross-correlation method. A local intrusive conductance probe was adopted to supply a reference measurement of oil volume fraction and velocity profiles. The oil volume fraction and velocity distributions from the two techniques were compared and good agreement was found. A further calculation of the water velocity distributions and flow rates was implemented through the drift flux approach and the results were analyzed and discussed.