Investigation On Characteristics Of Gas-Liquid Slug Flow In Hilly Terrain Pipeline

Gas-liquid slug flow is a flow pattern that commonly encountered in oil-gas mixingtransportation, the transportation pipelines often be laid in different angles because of thetopography,these multi-undulate pipelines aggravate the instability of two-phase flow,cause hydrodynamicor severe slug flow.This paper studies how the slug flow characteristics changes in hilly-terrain experimentpipelines with a diameter of54cm and length of68m. The main contents and conclusions of research arefollowing:In the case of gravity force,liquid will accumulate in the junction of horizontal to upward anddownward to upward pipeline,gas&liquid velocity and the angle of pipeline are the two main factors affectthe liquid amount.“New slug” will forms when enough liquid accumulated,two mechanisms are found inthis experiment to control the forms of “new slug”: Kelvin-Helmholtz instability mechanism and slugstability mechanism.Slug length and velocity will increase when the slug goes through the upward pipeline,the growth ratewill increase with the increase of angle.From our experiment we find the length growth rate ranges from1.0to1.6.(1°、3°、6°),two main factors contribute to the grow of slug length:the backflow of liquidfilm and the liquid accumulation in low-lying place.Slug length will decrease when it goes through thedownward pipeline,the dissipate rate increase with the the increase of angle.Taitel&Dukler(1976) flowregime map is good at forecasting the flow pattern in downward pipeline:Stratified flow and slug flowappear in the downward pipeline of multi-undulate pipeline if smooth stratified flow and slug flow areforecasted by T-D flow regime.Slug is dissipating when stratified wave flow is forecasted.On the basic of experiment and literature this paper built a model to calculate the slugflow parameters in hilly terrain pipelines,the variation of slug length origins from thedifference of liquid film parameters.