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Comments on “Drag Reduction Phenomenon in Viscous Oil-Water Dispersed Pipe Flow…” regarding slip ratio
  • Oscar Rodriguez,
  • Iara Rodriguez
Oscar Rodriguez
University of Sao Paulo
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Iara Rodriguez
Universidade Federal de Lavras
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Peer review status:ACCEPTED

16 Mar 2020Submitted to AIChE Journal
23 Mar 2020Assigned to Editor
23 Mar 2020Submission Checks Completed
04 May 2020Editorial Decision: Accept

Abstract

In Rodriguez et al.1 an analytical expression was deduced to predict the slip ratio in dispersed oil-water flow. Although the quantitative agreement was quite good, the expression systematically underestimated the slip ratio. New experimental data of similar flows were collected in two different experimental facilities in pipes of different materials and diameters (26 mm and 82.8 mm i.d.). Oil-water flow data collected within a range of mixture Reynolds numbers from 1∙105 to 20∙106 in glass, acrylic and steel pipes with oil viscosities varying from 7 to 220 mPa.s were used to deduce a more generic correlation for slip ratio as a function of the mixture Froud number (5 < Fr < 70). The underestimation of the slip ratio was corrected. The new slip-ratio correlation can be used to significantly improve the prediction of volumetric fraction in flow situations where turbulent dispersion of oil in water occurs.