Modified correction for predicting slip velocity of oil-water two-phase bubble flow in large-diameter pipes

The slip velocity between phases is an important parameter for evaluating the volumetric flow rate of each phase in vertical pipes. This paper presents an improved empirical correction for calculating the slip velocity of two-phase, oil-water bubble flows in large-diameter vertical pipes, based on a series of experimental tests. Water holdup data were obtained through experiments on an oil-water mixture flowing through a transparent test section in a 16-m-long vertical pipe with an inner diameter of 124 mm. The water holdup ranged from 0.58 to 1, and the observed flow pattern was bubble flow. Based on these experimental data, a modified correction was developed to improve the accuracy of the prediction of slip velocity for oil-water bubble flow systems. In addition, the proposed correction was validated against published experimental data for pipes with diameters of 2–6 in. The performance of the proposed correction against an experimental dataset (from our tests and published data) was also compared with that of six other, widely accepted corrections. The proposed correction predicted the slip velocity of two-phase, oil-water bubble flow in large-diameter vertical pipes more accurately than previous corrections did. © 2021, Saudi Society for Geosciences.