Submarine Pipeline Leakage Diffusion By The Numerical Simulation

After submarine pipeline leaks,can cause very big effect to the marine environment,and the influence will last for a long time,the effective leak detection technology can be used in the pipeline leak occurs,it can determine the leakage position and grasp the law of the undersea oil spill diffusion quickly and accurately.it can make emergency strategy timely and effective,reduce the impact of oil and gas leakage to the marine environment.Therefore,this paper mainly studies the detection technology of submarine pipeline leakage and the law of leakage diffusion,to provide effective theoretical guidance for the formulation of emergency measures after pipeline leakage,to minimize the damage caused by the accident,and to ensure the safety of life and property of the public.For the detection of submarine pipeline leakage,the essence of pipeline leakage is studied from the knowledge of fluid dynamics.Based on the basic principle of fluid dynamics,a leak detection model is established and an effective leak detection method for submarine pipeline is explored.In order to study the spread of the submarine pipeline leakage factors,respectively for seabed oil pipeline,gas pipeline and oil and gas mixture pipeline leakage diffusion mixed influence factors are studied,using computational fluid dynamics related theory knowledge,The continuity equation,momentum equation and energy equation are used to analyze the two-dimensional pipeline leakage diffusion process of physical model and mathematical model.FLUENT software was used for numerical simulation,and the corresponding initial and boundary conditions were set.For the leakage and diffusion of submarine pipeline,the underwater diffusion behavior of crude oil and natural gas after the leakage was analyzed.Within a short time after the occurrence of leakage,the oil spill enters seawater in the form of jet flow,and the oil spill diffusion is mainly controlled by the initial momentum.The corresponding mathematical model was established,in which the multiphase flow model and the standardized turbulence model were introduced into the governing equation.Finite volume method was used to discretize the governing equation,and k-? algorithm was used to calculate the flow field.Finally,the oil spill diffusion behavior is simulated and analyzed.For the submarine oil pipeline,when the pipeline leaks,the change rule of the movement trajectory after the oil leakage is simulated,and the influence of different leakage aperture and jet velocity on the oil diffusion is simulated.For the gas pipeline,the influence of leakage hole diameter and jet velocity on pipeline leakage diffusion is simulated.and the similarities and differences of the diffusion of crude oil and natural gas after the leakage are compared.For the oil and gas mixture pipeline,the influence of leakage pore diameter and jet velocity on diffusion is simulated first,and then the influence of gas holdup on diffusion movement rule after oil and gas mixture pipeline leakage is simulated.The main conclusions obtained from the above study are as follows: for the oil pipeline,the influence of jet velocity and leakage aperture on the oil spill jet flow during oil spill diffusion is simulated and analyzed.The larger the hole diameter is,the larger the diameter of injection column is.At the same speed,both sides of the oil column developed from no coils to obvious coils.However,when the jet velocity was lower than a certain value,no coils formed on both sides of the oil column.With the increase of the leakage aperture,the upper half of the jet oil column developed from no necking to obvious necking.As for the gas transmission pipeline,compared with the submarine crude oil pipeline leakage,the submarine natural gas leakage has a faster diffusion rate,a larger diffusion range and a more irregular pattern.For oil and gas mixture pipelines,oil with high gas content moves faster than oil with low gas content,and the degree of entrainment is different with the increase of gas content.After pipeline leakage,the scope of accident leakage and diffusion can be roughly estimated according to the diffusion law,which can provide reference for accident disposal and improve emergency control ability.The results can provide reference for dealing with leakage accidents.