Variation of Zero-Net Liquid Holdup in Gas–Liquid Cylindrical Cyclone (GLCCⒸ)

Novel experimental and theoretical investigations are carried out on zero-net liquid flow (ZNLF) in the upper part of the GLCC. Experimental data are acquired for the variation of the zero-net liquid holdup (ZNLH) and the associated churn region height for air–oil and air–water flow. The experiments are carried out at normal operating conditions below the GLCC operational envelope (OPEN) for liquid carry-over (LCO). The ZNLH measurements for air–oil flow are higher than those for air–water flow. The churn region height is higher for air–oil flow, as compared to the air–water flow, for the same operating conditions. The higher oil viscosity, which results in higher frictional and drag forces, leads to greater oil retention and higher ZNLH for air–oil flow. The churn region height is sensitive to the superficial gas velocity, whereby a small increase of gas velocity results in exponential growth of the churn region height. The correlation developed by Karpurapu et al. (Dynamic zero-net liquid holdup in gas-liquid cylindrical cyclones [conference presentation]. In: ASME 2018 5th Joint US-European Fluids Engineering Summer Conference, Montreal, 2018) for predicting the ZNLH at the OPEN for LCO flow conditions is extended in this chapter to enable the prediction of the variation of the ZNLH and the associated churn region height along the upper part of the GLCC for normal operating conditions below the OPEN for LCO. The predictions of the developed extended correlation for the variation of the ZNLH and the churn region height along the upper part of the GLCC are compared with the acquired experimental data showing discrepancies of 12.7% and 3%, respectively, for air–oil and air–water flows. Uncertainty analysis is performed on the experimental ZNLF gas and liquid superficial velocities, which show a ± 15% average variation of the measured values.