MECHANISTIC MODEL OF SLUG FLOW IN NEAR-HORIZONTAL PIPES

A mechanistic model of slug flow based on a set of mass and momentum c onservation equations and a number of empirical closure relations is p resented. It is then shown that a simplified version of the model, whi ch 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 predict ions obtained in the two cases are very similar, when the comparison i s limited to the computation of the pressure gradient and the mean liq uid holdup. The LSM successfully correlates a large set of experimenta l measurements relative to three pipe diameters (18, 50 and 90 mm), fo ur inclinations (0-degrees, +/-3-degrees, 0.3-degrees), and two pipe l engths (17 and 34 m).