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考虑水分迁移、冰水相变的影响,采用热传导模型和水热耦合模型对埋地热油管道停输过程中土壤温度场的变化进行数值计算,得到了不同时刻土壤温度场的变化规律和管内原油轴向温降曲线。研究表明:热油管道停输后,由水热耦合模型和热传导模型计算的管道轴向温降和空间径向不同位置土壤温度差异较大,前者计算得到的温度场明显高于后者的计算结果,而轴向温降速率前者明显低于后者;且随着停输时间的延长,水热耦合模型得到的土壤温度场等值线几乎呈中心对称的椭圆形分布,等温线移动相对较慢。水分迁移和冰水相变对埋地管道非稳态传热影响较大,计算时不可忽略。
Considering the influence of water migration and ice water phase transition, the heat transfer model and the water-heat coupling model are used to calculate the change of soil temperature field during the shutdown of buried hot oil pipeline. The variation law of soil temperature field and the variation of the crude oil Axial temperature drop curve. The results show that after the shutdown of hot oil pipeline, the difference between the axial temperature drop and the soil temperature at different positions in the radial direction calculated by the hydrothermal coupling model and the heat conduction model are quite different. The temperature field calculated by the former is obviously higher than the latter As a result, the former was significantly lower than the latter in terms of axial temperature drop rate. With the extension of shutdown time, the contour of soil temperature field obtained by hydrothermal coupling model was almost elliptical with central symmetry and the isotherm was relatively moving SLOW. Water migration and ice-water phase transition have a great influence on the unsteady heat transfer of buried pipelines, which can not be ignored in the calculation.