Two-phase co-current flow simulations using periodic boundary conditions in horizontal, 4, 10 and 90° inclined eccentric annulus, flow prediction using a modified interFoam solver and comparison with experimental results

Two-phase oil and gas flow were simulated in an entirely eccentric annulus compared with experimental data at horizontal, 4, 10, 90° inclination. The gas-phase was sulphur hexafluoride the liquid phase a mixture of Exxsol D60 Marcol 82 for inclined cases (5–16), pure horizontal (1–4). diameter outer inner cylinders 0.1 0.04 m, respectively, domains 0.05 m domain. studied consist fractions between 0.3 0.65 velocities from 1.2 to 4.25 m/s. mean pressure gradient is within 33% expected behavior all cases. In contrast, low-velocity exhibit significant deviation, drastic over-prediction by as much 200–335% 1 2. two remaining (3 4) are 22% gradient. Cases 13–16 replication 5–8 increased inclination; 6.5% increase due hydrostatic pressure. By comparing 1–4 previous published simulations lower eccentricity, we found decrease 30–40%, which line existing literature, although single-phase flows. holdup profiles good agreement when fractional data; wave slug frequencies match 0.5 Hz; however, closer inspection, it apparent that there amount phase-mixing experiments. When increasing mesh density 115 k cells/m 2 million cells/m, significantly more mixing, but still unable produce conventional slugs. simplified case, slugs observed grid sizing × mm, whereas cells roughly 1.5 mm.