Experiments on two-phase gas-liquid flow using Exxsol D80/SF6 and Nexbase 3080/SF6 has been performed and the data for Uso = 0.7 and 0.9 m/s have been reported. Of particular interest were the use of the high viscosity oil Nexbase 3080 and the high density SF6 gas to provide fluid properties similar to real fluids in industrial cases. The experiments involving the low viscosity Exxsol D80 was conducted for comparison. The results from simulations using the OLGA point model were compared with the experimental data. Interfacial shear stresses and friction factors were estimated for the experiments and compared to correlations. (1) OLGA successfully predicted both holdup and pressure drop for the low viscosity oil experiments, but failed for the experiments with the high viscosity Nexbase 3080 oil. OLGA predicted both pressure drop and holdup for the Nexbase 3080/SF6 experiments well up to an Usg of about 2.5 m/s. It was at this point that OLGA started to predict slug flow while the flow in the experiments actually was stratified. At Usg higher than 2.5 m/s OLGA predicted the pressure drop to be 30 - 80 % too high with the deviation increasing with increasing Usg. The holdup was predicted up to 30% too low for medium Usg. At high Usg, or about 9 m/s, the holdup predicted by OLGA was close to the measured holdup again. (2) Dynamic simulations with the OLGA slug tracking module gave better predictions of the pressure drop and holdup, but there were still significant deviations at medium Usg. (3) The estimated interfacial shear stress was larger for the Nexbase 3080/SF6 experiments compared to the Exxsol D80/SF6 experiments. For the Nexbase 3080/SF6 experiments there was a jump in the interfacial shear stress when the superficial gas velocity was higher than 6 m/s, which corresponded to a transition to turbulent flow. (4) The investigated interfacial friction factor correlations produced mixed results. The values from the correlations of Wallis and Ottens et al. were almost constant with increasing Usg, and in general an order of magnitude too low when compared to both the Exxsol D80 and Nexbase 3080 experiments. The correlation of Andritsos and Hanratty fitted the Nexbase 3080 experiments relatively well For the Exxsol D80 experiments the correlation fitted best at low and high Usg, while it was a factor of 2 too low at medium Usg.
Investigation of horizontal two-phase gas-liquid pipe flow using high viscosity oil: Comparison with experiments using low viscosity oil and simulations
Untersuchung der horizontalen zweiphasigen Gas-Flüssigkeitsströmung unter Verwendung von hochviskosem Öl: Vergleich mit Experimenten mit niedrigviskosem Öl und Simulationen
2011
15 Seiten, 9 Bilder, 2 Tabellen, 14 Quellen
Conference paper
English
High viscosity liquid effect on two-phase slug length in horizontal pipes
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