Characterization of vertical oil–water two-phase flow: Flow patterns, holdup, and electrode sensitivity analysis using capacitive sensors

• A capacitive sensor designed to predict the two-phase flow patterns of water/oil • Seven distinct flow patterns are identified via high-speed photography • The double-ring electrode exhibits high levels of noise and error • The TRFLC type demonstrated the best responses to variations in the two-phase flow The accurate prediction of flow patterns and liquid hold-up is critical for effectively designing and operating liquid-liquid separation equipment. In this paper, the feasibility of different electrode configurations, flow patterns, and holdup for the vertical two-phase flow of water and diesel has been experimentally investigated using a new capacitive sensor. The experimental results showed that for all regimes, the TRFLC electrode had a higher sensitivity than the double-ring, concave, and spiral electrodes, and the lowest sensitivity was related to the double-ring electrode, which had more errors than other electrodes. Holdup was measured using quick-closing valves (QCVs). Seven flow patterns were identified using high-speed photography in the test section, A transparent tube 1.5 m long with an inner diameter (ID) of 0.254 m (1 inch). The observed flow patterns included very fine dispersed water-in-oil(VFD W/O), dispersed water-in-oil(D W/O), transition flow(TF), oil-in-water slug(O/W Slug), dispersed oil-in-water (D O/ W), very fine dispersed oil-in-water(VFD O/W), and mixed flow. Sensor-based numerical analysis can be inferred and concluded that even in non-transparent, non-metallic pipes, the flow patterns and holdup for vertical two-phase water-oil flows can be predicted using sensor data. In general, holdup and flow pattern in two-phase liquid-liquid flows in vertical pipelines are very important in the industry.