Influence and prediction of oil film migration in submarine pipeline spills under multiple factors

Oil spills endanger the survival of marine species and the maritime environment. As a result, this study constructs a three-dimensional diffusion model of oil spills from pipeline ruptures and analyses the diffusion law of oil films created on the sea surface under various conditions. The model's accuracy was validated using actual oil spill tests, and the oil spill similarity model was further established using similarity theory. The results show that as the leaking aperture grows within 2–3 s, the high concentration centre area of the oil film on the sea surface expands, and the oil film protrudes to the right. From the inside out, the oil film produces a convex elliptical oil film with a high-low concentration form. As the leakage rate rises, a convex, elliptical, large-area oil film of low-high-low concentration forms. During this time frame, the oil leak has not yet developed an oil film at a flow rate of 0.3 m/s. This is due to the fact that horizontal migration speed has a large influence on vertical migration speed, increasing the horizontal migration distance underwater and lengthening the time needed to achieve the development of the sea surface oil film area. With increasing leakage aperture and leak rate, the lateral diffusion length, longitudinal diffusion breadth, and oil spill area of the oil film rise. However, when the velocity of the water flow increases, it decreases. Furthermore, the quadratic fitting curves of the longitudinal expansion length, longitudinal diffusion width, and oil spill area of the oil film were fitted under various influencing factors to predict the diffusion law of the oil film on the sea surface, which is critical for protecting the marine environment.