Mechanistic model of slug flow in near-horizontal pipes



A mechanistic model of slug flow based on a set of mass and momentum conservation equations and a number of empirical closure relations is presented. It is then shown that a simplified version of the model, which physically corresponds to the flow of long liquid slugs(long slug model, LSM), can be immediately derived from the general model. The LSM is much simpler than the general model; at the same time, the predictions obtained in the two cases are very similar, when the comparison is limited to the computation of the pressure gradient and the mean liquid holdup. The LSM successfully correlates a large set of experimental measurements relative to three pipe diameters(18, 50 and 90 mm), four inclinations (0°, ±3°, 0.3°), and two pipe lengths(17 and 34 m).