MACROSCOPIC LAW SIMULATION OF LEAKAGE MEDIUM DIFFUSION IN BURIED OIL PIPELINE BASED ON ENVIRONMENTAL PROTECTION REQUIREMENTS

摘要

Oil pipelines are widely used as an efficient and economical way of oil transportation.At present,various countries have established a huge underground oil pipeline system.With the increase in the age of oil pipelines in use,as well as the impact of natural conditions such as corrosion and man-made damage,the occurrence of leaks in ground oil pipelines becomes more frequent.The leak not only affects the normal operation of the pipeline,but also brings huge disasters to the natural ecological environment.The heat and mass coupling transfer characteristics of the pipeline leakage oil medium spreading in the soil are for remediation of contaminated soil and the foundation of buried oil pipeline leak detection technology.Fluent software was used to simulate the heat and mass transfer process of the leakage medium of buried oil pipelines in the soil with porosity ranging from 0.3 to 0.45 and different leakage locations.Studies have shown that when the leak position is directly below the pipe,the change trend of the oil phase shape changes from a semicircle to an apple shape,and finally to an ellipse.The trend of the leak position directly above changes from a semicircle,an inverted apple shape,and finally to an ellipse shape.The change trend of the leakage position on the left side is from cashew to ellipse.When the leak is directly below,at the same moment,the area of the oil phase decreases with increasing porosity.The greater the porosity,the longer the volume of the oil phase appears "appleshaped" and diffuses to the surface.As the leaking medium gradually enters the surrounding soil,the temperature of the soil around the location of the pipeline leakage rises significantly,and the soil has a low heat transfer capacity and a small flow velocity of the leakage medium,resulting in a slow change in soil temperature away from the leakage.