Electrical Capacitance Tomography (ECT) and gamma radiation meter for comparison with and validation and tuning of CFD modeling of multiphase flow

Abstract

Electrical Capacitance Tomographic (ECT) approach is increasingly seen as attractive for measurement and control applications in the process industries. Recently, there is an increased interest in using the tomographic details from ECT for comparing with and validating and tuning CFD models of multiphase flow. Collaboration with researchers working in the field of CFD modeling of multiphase flows give valuable information for both groups of researchers in the field of ECT and CFD. By studying the ECT tomograms of multiphase flows under carefully monitored inflow conditions of the different media and by obtaining the capacitance values, C(i,j,t) with i=1...N, j=1,2,...N and i ≠ j obtained from ECT modules with N electrodes, it is shown in this paper how the interface heights in a pipe with stratified flow of oil and air can be fruitfully compared to the values of these obtained from ECT and gamma radiation meter (GRM) for improving CFD modeling. Monitored inflow conditions in the present study are flow rates of air, water and oil into a pipe which can be positioned at varying inclinations to the horizontal, thus emulating the pipelines laid in sub-sea installations. It is found that ECT based tomograms show most of the features seen in the GRM based visualizations with nearly one-to-one correspondence to interface heights obtained from these two methods, albeit some anomalies at the pipe wall. However, there are some interesting features the ECT manages to capture, features which the GRM or the CFD modeling apparently do not show possibly due to parameters not defined in the inputs to the CFD model or much slower response of the GRM. Results presented in this paper, indicate that a combination of ECT and GRM and preferably other sensor modalities with enhanced data fusion and analysis combined with CFD modeling can help to improve the modeling, measurement and control of multiphase flow in the oil and gas industries and in the process industries in general.