THE FRONT SHAPE OF A SPHERE-PROPELLED LIQUID SLUG IN A NATURAL-GAS PIPELINE

A simple calculation model has been developed for predicting the condi tions under which a sphere-propelled liquid slug will maintain a full- bore configuration when travelling in a natural-gas pipeline running t hrough hilly terrain. The model also predicts, among other things, the curvature, length and volume of the sloping front end of the slug. Re sults from laboratory studies in which a sphered slug is simulated by sending a batch of water through a horizontal or inclined perspex pipe , thereby displacing the air in the pipe, are in good agreement with t he model predictions up to a slug velocity of 2 m/s. Above this veloci ty the measured sloping front end is longer than predicted. This is du e to air entrainment in the front end, a phenomenon ignored in the cal culation model. The model has also been applied to a large-diameter na tural-gas pipeline through which a sphere-propelled slug of hydrocarbo n liquid moves.