The operation of pipelines has been affected by the corrosion caused by water deposited in some low sections of liquid products and natural gas pipeline. Flushing out the deposited water by flowing diesel has become a popular method. This research focused on a local water-diesel flow system with low Uos, in which the flow pattern, velocity and shear stress were analyzed through 2D simulation conducted by FLUENT software based on the grid independent strategy; meanwhile the simulations were verified by comparison with the published data.
Under the shear from flowing diesel with laminar flow, the flow pattern was found mainly as smooth and wavy stratified flow. The velocity of diesel phase becomes similar-parabolic distribution with an offset upwards in the radical direction, while there are reflux and eddy inside the residual water. Because of the presence of residual water, the shear stress of the walls become negative, and it increases along the two walls to the interface radically and increases to the maximum on the interface. The average velocity of residual water was found to increase linearly with the superficial velocity of oil flow.