Experiments and Modelling of Liquid Accumulation in the Low Elbow of a Gas/Liquid Pipeline

Abstract

This study considers the removal of accumulated liquid in the lower elbows of gas/liquid pipelines by the gas flowing over the liquid pool, i.e. at zero net liquid flow (ZNLF) conditions. Measurements were performed in a V-shaped section of a pipeline, prefilled with a finite amount of liquid. The maximum gas velocity at which liquid still remains in the V-section, as well as the liquid holdup and pressure gradient at these (critical) conditions were measured for several combinations of fluids and pipe inclination angles. The results were compared with the predictions of a mechanistic model, which was modified to account for the recirculation in the stagnant liquid layer at critical conditions.