Transient gas and high-viscosity-liquid intermittent flow in horizontal and near horizontal pipes



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Transient two-phase gas and high-viscosity-liquid flow in horizontal pipes was investigated with the aim of developing a transient Drift-flux model capable of predicting gas and high viscosity liquid transient flow. Experimental investigation was done using a 0.0381 m (1.5 in) ID two-phase flow loop facility to study the effects of viscosity on Drift-flux model hydrodynamic parameters. The facility was first validated using air-water as test fluids before air-high viscosity experiments began. Synthetic gear oil was used as the high viscosity liquid phase. Air-high viscosity oil experiments were conducted using nominal viscosities of 0.14 Pa∙s and 0.28 Pa∙s. Experiments were conducted to determine drift velocity of air in high viscosity liquids, generate flow pattern maps, and study steady-state slug flow hydrodynamics. Transient air-oil experiments were conducted starting at one steady-state condition, changed to a different steady-state condition, and ending on that condition. Experimental observations show that viscosity significantly affects the hydrodynamic parameters such as drift velocity which become slower due to high viscous forces, shorter slug lengths, higher slug frequency and more. A Drift flux model was developed based on the Zuber and Findlay algebraic slip relationship. The model was solved using a hybrid shock capturing scheme often used for gas dynamics. The model was validated using the results obtained from Experimental studies for steady-state slug flow slug body liquid holdup and transient slug flow pressure drop. The model successfully simulated the hydrodynamic behavior of the pressure wave during transients. An average relative error of 11.55% was observed for the predictions pressure drop. Liquid hold predictions were underestimated but were reasonably predicted.



Two-phase, High-viscosity, Drift-flux, Pipes, Hydrodynamics