Multimodal imaging of multiphase flows with electromagnetic flow tomography and electrical tomography

In many fields of process industry, it is essential to be able to accurately measure the volumetric flow rates and mass flows of different materials flowing in the process pipes. To estimate the volumetric flow rate of a certain phase, the volumetric fraction and the flow velocity field of the phase in a cross-section of the process pipe need to be known. Electrical tomography (ET), such as electrical resistance tomography, can be used for measuring the cross-sectional volumetric fractions in two-phase flows. For velocity field metering, electromagnetic flow tomography (EMFT) techniques have recently been developed. By combining the multimodal information from the ET and EMFT modalities, volumetric flow rates in process pipes can be estimated. This paper reports the results from experiments applying a multimodal imaging approach utilizing an earlier developed EMFT system and a commercial ET system, combined for measuring the volumetric flow rates in a laboratory flow loop. The studies undertaken in the paper demonstrate that the proposed multimodal imaging approach can produce reliable volumetric flow rate and mass flow rate estimates in laboratory environment in the cases of oil-water and solids-water flows.The relative errors of the estimated volumetric flow rates in the case of oil-water flows, with the average flow velocity between 0.79 ms-1 and 1.17 ms-1, were found to be in the range of 7.8-9.5%, the average being 8.2%.