HORIZONTAL SLUG FLOW MODELING AND METERING (TWO-PHASE FLOW, DRIFT VELOCITY)

An experimental and theoretical investigation of horizontal two-phase slug flow was performed with the purpose of developing a method to measure the in-situ flow rates of the liquid and the gas phases using non-intrusive devices.; A microcomputer based data acquisition system was used to acquire slug flow data on a 3 in. (76.2 mm) diameter, 1370 ft (418 m) long, horizontal pipeline. These data include the following slug characteristics: liquid holdups in the slug and film, slug and gas pocket lengths, and slug translational velocity. The data were gathered over a wide range of flow conditions in groups of constant superficial liquid and mixture velocities.; The volumetric phase flow rate equation, for either liquid or gas, was developed for slug flow conditions. Within the flow rate equation, a key flow distribution parameter was defined that related the phase velocity in the slug to the translational velocity of the slug. Three models were presented to predict the flow distribution parameter. Two of these models considered only the velocity and the phase distribution profiles, resulting in nearly constant values of the predicted flow distribution parameter for either phase. A third model was developed by considering the gravity induced drift velocity of the gas pocket with respect to the liquid velocity in the slug. This drift model provided superior predictions of the liquid flow distribution parameter. By incorporating this new model, the targeted acceptable accuracy of (+OR-)20 percent for liquid flow rate predictions was achieved for most of the investigated range of normal slug flow. A similar accuracy for the gas flow rate was achieved using a simplified method.