Pressure drop, void fraction and flow pattern of vertical air-silicone oil flows using differential pressure transducer and advanced instrumentation

New data for pressure drop, void fraction and flow pattern in a vertical riser using air–silicone oil as the system fluid are reported in this work. A differential pressure cell (DP cell) was used to measure the pressure drop. In addition, void fraction data were recorded simultaneously using an electrical capacitance tomography (ECT) and wire mesh sensor (WMS). The flow patterns were determined using probability density function (PDF) of void fraction and also using a reported flow pattern map. A comparison between present experimental data and reported air–water data was carried and different levels of agreement were achieved. The PDF obtained from the output of the DP cell for spherical cap bubble and slug flows were significantly different those obtained from the ECT and WMS. A comparison between experimental data of void fraction and pressure gradient against some 10 selected empirical correlations was carried out using statistical analysis, Mean Square Error (MSE), Root Mean Square Error (RMSE) and Mean Absolute Percentage Error (MAPE), and different levels of agreement were obtained. The Greskovich and Cooper correlation gave the least MSE, RMSE and MAPE values of 0.0007908, 0.013 and 3.05%, respectively for slug flow