Flow pattern analysis of the oil-water batch transportation using a wheel flow loop

Oil-water batch transportation is a new method to reduce pipeline corrosion based on the concept of flow management. Its good corrosion inhibition performance has been preliminarily verified in the previous study. But the previous research is only limited to a certain length of horizontal pipe and only two basic flow patterns are discussed, including stratified flow and dispersed flow. To further expand the batch transportation concept on reducing corrosion in oil-water pipe flows, the evolution of the oil-water interface in the marine riser pipe was evaluated by using a wheel flow loop and was investigated via the CFD simulation. The results show that the water-driving-oil interface kept more stable than the oil-driving-water interface and the oil film could attach longer to the pipe surface compared with water. Four types of flow patterns can be identified in the batch transportation mode, i.e., annular flow, stratified flow, dispersed flow, and transition flow between annular flow and dispersed flow. The result of parameter analysis suggests that the initial oil volume fraction and flow rate are the key factors governing the total length of the oil-continuous section Lo, which determines the corrosion mitigation efficiency of the batch transportation mode in vertical pipe flow.