Phase Inversion and Associated Phenomena in Oil-Water Vertical Pipeline Flow
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Bibliographic record
Abstract
Phase inversion and its associated phenomena are experimentally investigated in co-current upward and downward oil-water flow in a vertical stainless steel test section (38 mm I.D.). Oil (ρo=828 kg/m3, µo=5.5 mPa s) and tap water are used as test fluids. Two inversion routes (w/o to o/w and o/w to w/o) are followed in experiments where either the mixture velocity is kept constant and the dispersed phase fraction is increased (type I experiments), or the continuous phase flow rate is kept constant and that of the dispersed phase is increased (type II experiments). By monitoring phase continuity at the pipe centre and at the wall it was found that phase inversion does not happen simultaneously at all locations in the pipe cross-section. In type I experiments, the velocity ratios (Uo/Uw) where complete inversion appeared acquired the same constant value in both flow directions, although the phase inversion points, based on input phase fractions, were different. In contrast to previous results in horizontal flows, frictional pressure gradient was found to be minimum at the phase inversion point. The interfacial energies of the two dispersions before and after phase inversion, calculated from the measured drop sizes, were found to be different in contrast to the previously suggested criterion of equal energies for the appearance of the phenomenon. In type II experiments the phase inversion point was found to depend on mixture velocity for low and medium velocities but not for high ones. In all cases studied an ambivalent region, commonly reported for inversion in stirred vessels, was not observed. L'inversion de phase et ses phénomènes associés sont étudiés expérimentalement dans un écoulement huile-eau dans une section d'essai en acier inoxydable verticale (38 mm de diamètre intérieur). De l'huile (ρo=828 kg/m3, µo=5,5 mPa s) et de l'eau du robinet sont utilisées comme fluides d'essai. Deux voies d'inversion (de w/o à o/w et de o/w à w/o) sont étudiées dans les expériences, dans lesquelles soit la vitesse de mélange est gardée constante et la fraction de phase dispersée est augmentée (expériences de type I), ou soit le débit de phase continue est gardé constant et la phase dispersée est augmentée (expériences de type II). En surveillant la continuité des phases au centre de la conduite et à la paroi, on a trouvé que l'inversion de phase n'arrive pas simultanément à tous les endroits de section transversale de la conduite. Dans les expériences de type I, les rapports de vitesse (Uo/Uw) où apparaît l'inversion complète, acquièrent la même valeur constante dans les deux directions de l'écoulement, même si les points d'inversion de phase, basés sur les fractions de phase d'entrée, sont différents. Contrairement aux résultats antérieurs dans les écoulements horizontaux, on a trouvé que le gradient de pression frictionnel était minimum au point d'inversion de phase. Les énergies interfaciales des deux dispersions avant et après l'inversion de phase, calculées d'après les tailles de gouttes mesurées, s'avèrent différentes que dans le cas du critère antérieurement suggéré pour l'apparition des phénomènes. Dans les expériences de type II le point d'inversion de phase s'avère dépendre de la vitesse du mélange pour des vitesses faibles et moyennes mais non pour des vitesses élevées. Dans tous les cas étudiés, on n'a pas observé la région ambivalente couramment signalée pour l'inversion en réservoir agité.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it