Abstract
The characteristics of flow configuration in pipes are very important in the oil industry due to its role in governing equipment design. In vertical risers, many flow configurations could be observed such as bubbly, slug, churn, and annular flow. In this project, two tomographic techniques have been applied simultaneously to the flow in a vertical riser: the Electrical Capacitance Tomography (ECT) technique and the Capacitance Wire Mesh Sensor (WMS) technique. The employed pipe diameter was 50mm and the superficial studied velocities were 0.06-3.0m/s for gas and 0.06-0.4m/s for oil. Several techniques have been used to analyze the output data of the two tomography techniques such as time series of cross-sectional averaged void fraction, Probability Density Function (PDF), image reconstruction, and liquid hold-up profile. The averaged void fractions were calculated from the output signal of the two measurement techniques and plotted as functions of the superficial velocity of the gas. The flow patterns were identified from the PDF of the averaged void fraction. In addition, it was found that both tomographic techniques are reliable in identifying the flow regimes in pipes.
Highlights
Multiphase flow of gas-liquid mixtures in vertical pipes occurs in industrial equipment and applications such as petroleum industry, boilers, chemical plants, heat transfer equipment with change of phases, nuclear reactor technology, and geothermal energy production
After the gas superficial velocity reached 1.4m/s, the mean void fraction curve in Electrical Capacitance Tomography (ECT) probe has moved higher than the Wire Mesh Sensor (WMS) curve
Examples of time series of cross-sectional average void fraction obtained from WMS tomography technique are shown in Figure 6 which explains the difference between bubble size and the amount of gas-liquid inside the pipe
Summary
The study of multi-phase gas-liquid flow requires accurate measurements of each phase velocity and phase fraction. The project measurement technique that has been installed and used on the vertical facility technique is the novel embracing Capacitance Wire Mesh sensor (WMS) [4]. This device is designed in the Research Center of Helmholtz Centrum Dresden Rossendorf (HZDR), Germany
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