Numerical study on the leakage and diffusion temperature field characteristics of buried CO2 pipeline
Buried CO2 pipelines inevitably run the risk of leakage,causing great economic losses and human casualties.Therefore,it is necessary to study the distribution of the temperature field near the leakage point of the buried CO2 pipeline in depth.In this paper,the Computational Fluid Dynamics(CFD)software FLUENT is used to carry out numerical simulation research.The physical model of the full-scale buried pipeline is established by coupling the porous medium model,multiphase flow model,and phase change treatment model.The change of leakage diffusion temperature field at different positions of the pipeline is studied.The results show that the top leak simulation shows a low-temperature line directly above the leak due to the phase change and jet effect of CO2,and the minimum temperature also decreases continuously.Under the action of pore resistance and gravity,the kinetic energy of the CO2 jet gradually dissipates,making it unable to continue to maintain the shape of the jet.The low-temperature line does not continue to pass to the soil surface due to the heat transfer and soil influence.In the case of lateral leakage of buried CO2 pipeline,due to the loss of turbulent kinetic energy,CO2 cannot maintain the ejection state and gradually shows a downward diffusion state under the influence of gravity.After reaching a steady state,the temperature around the leakage port decreases by about 42 K.When the diameter is less than 8 mm,the leakage state of CO2 becomes more intense as the diameter of the leakage increases,and the horizontal velocity vector of CO2 ejects from the leakage port increases;when the diameter reaches 8 mm,the velocity vector reaches the maximum;when the diameter is larger than 8 mm,the leakage state of CO2 becomes stable again,and then the velocity vector gradually decreases with increasing the diameter.
safety engineeringburied pipelineComputational Fluid Dynamics(CFD)leakage and diffusiontemperature field
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