Numerical Simulation Of Oil Spill Diffusion In Underwater Oil Pipeline

Due to the impact and corrosion of seawater,submarine oil pipelines are prone to different degrees of damage,resulting in oil leakage.Because of the special operating environment and technical limitations of submarine oil pipelines,it is important to study and apply the oil spill diffusion model for solving the migration and diffusion problems of submarine pipelines after oil spills.In this paper,the oil diffusion model of submarine oil pipelines is established to simulate the diffusion law of oil spills in seawater.The diffusion process of oil spills under different influencing factors such as different density,oil spill rate and water flow velocity are studied.The trajectory of the spilled oil,the range of diffusion and the time of reaching the water surface are determined.The maximum horizontal migration distance and time of the crude oil with different densities in the water are calculated,and the dimensionless calculation formula is obtained.Finally,the estimation formulas for migration and diffusion distance of spilled oil on water surface are given.The results show that with the increase of crude oil density,the time of reaching the maximum horizontal migration distance increases,and the maximum horizontal migration distance decreases first and then increases;with the increase of oil spill velocity,the time of reaching the maximum horizontal migration distance decreases,and the maximum horizontal migration distance of oil spill increases;with the increase of water flow velocity,the time of reaching the maximum horizontal migration distance of oil spill increases,and the maximum horizontal migration distance is also increasing.In order to simulate the migration and diffusion process of oil spill on water surface,considering the dynamic processes of oil spill such as water surface expansion,convection,turbulence and the effects of evaporation,emulsification and dissolution,a two-dimensional migration and diffusion model of oil spill on water surface was established,and the corresponding numerical solution algorithm was proposed.The oil spill diffusion process under different conditions such as different wind speed and water velocity was studied.The effects of environmental parameters such as wind speed and water flow speed on oil film migration and diffusion are analyzed,and the migration and diffusion trajectories of oil spill under non-uniform flow field are simulated.The results show that the higher the velocity of wind or water flow,the faster the oil spill diffuses downstream;at the same time,in the initial stage(within a few hours),the oil film area increases significantly and the thickness becomes thinner,and the oil film gradually becomes dispersed;evaporation,emulsification and dissolution factors have relatively small influence on the oil spill migration and diffusion,while non-uniform flow field has a great influence on the direction and velocity of oil spill diffusion,and complex flow.Oil spill trajectory prediction in the field is of great significance for accident handling.Finally,this paper summarizes the treatment methods of oil spill accident on water,and gives the calculation method of oil fence layout under specific circumstances.The results of this study can provide effective guidance for emergency response measures of oil spill accidents in submarine pipelines.