Flow regimes of oil product carrying impurity in undulate pipeline

Oil product carries impurity while it flows in oil product pipelines. In order to research this issue, the experimental loop system of oil product carrying water and impurity was established to explore the flow regimes of oil carrying impurity. Then, the contrast experiment of oil carrying water was carried out. And finally, the oil flow field was numerically simulated by means of large eddy stimulation (LES) and the effect of flow field on impurity movement was analyzed. It is shown that the solid-liquid two-phase flow regimes of oil carrying impurity are divided into 3 types, i.e., grain flow, moving bed flow and fixed bed flow. With the decreasing of grain content, the flowing velocity of oil product increases and the transition of flow regime from moving bed flow to grain flow speeds up. Impurity sedimentation point is situated at the high position behind the updip section where the boundary layer at the lower part thickens and the oil drag force decreases. The secondary flow is favorable for impurity accumulation. Whether the impurity deposits at the impurity sedimentation point depends on the flowing velocity of oil product, but it isn’t related to the grain content. Small-volume water mass is similar to impurity grains, and it can also deposit at the impurity sedimentation point. The research results provide assurance for the safe transportation of product oil pipeline.