Research On Heat And Mass Transfer Characteristic Of Buried Oil Pipeline Leakage Based On Lattice Boltzmann Method

Buried oil pipeline is widely used as a safe and economic transportation method.The length of pipeline has been 60000 kilometers until early twenty-first century.The leakage accident of buried pipeline occurs frequently because of the factors such as pipeline age and artificial destruction.The leakage accident influences not only normal transportation but also leads to environment pollution.The heat and mass coupling diffusion characteristic of the leaking oil medium in soil is the foundation of contaminated soil remediation and leakage detection technology of buried oil pipeline.Therefore,the research on heat and mass transfer characteristic of buried oil pipeline leakage has practical application significance and academic value.The theoretical and simulation researches on heat and mass coupling diffusion characteristics of the leaking medium in soil were conducted.Quartet structure generation set(QSGS)was used to construct soil porous media.The function of three parameters in QSGS was analyzed.D2G9 model of lattice Boltzmann method(LBM)was adopted to simulate oil and water mesoscopic flow respectively in soil with different porosities.Resistance coefficients of oil and water in the soil with different porosities were obtained based on the flow characteristics.Eventually,the relationship between porosity and resistance coefficient was determined.The relationship between porosity and resistance coefficient was imported into macroscopic flow and heat transfer model.Heat and mass transfer processes of leaking medium in soil which has 0.3~0.45 porosities and different leakage location were simulated by using Fluent software.The result shows that: the greater of porosity,the more time diffusing to soil surface was needed of oil.Leakage location had a great effect on heat and mass transfer processes of buried oil pipeline leaking medium in soil.Oil phase presented different variation laws in the processes of heat and mass transfer in soil.The oil phase presented elliptical shape when the simulation became stable.The water phase had little influence on heat and mass transfer processes because water-proportion was small.The temperature of soil around leakage location rose significantly with the leaking medium diffusing into surrounding soil.Because of low heat transfer capability of soil and small leakage velocity,the temperature far away from the leakage location changed slowly.Through this investigation,the method of obtaining oil and water flow resistance coefficient in soil based on LBM is established.Researches on the heat and mass transfercharacteristic of leaking medium in soil were conducted by combining mesoscopic LBM with macroscopic Fluent software.The technique and research results will provide certain reference function for contaminated soil remediation by buried oil pipeline leaking medium and leakage detection technology.