摘要
埋地油气管道通过潮湿地区或永冻地带时 ,由于管内介质与周围土壤相互热力作用 ,使管道周围土壤中水分汽化或冰土解冻 ,出现干燥圈或融化圈现象 ,进而使得土壤和管道发生不均匀的下沉 ,使管道受力发生变化 ,有时甚至会破坏管道结构的完整性 ;同时 ,在干燥圈或融化圈内的土壤热物理性质也将发生变化 ,若不考虑这种变化 ,必然会影响热力计算的合理性。因此分析管道周围土壤干燥圈或融化圈变化对管道系统的设计、施工和管理是十分必要的。文中考虑油气管道对其周围土壤的影响和半无穷大土壤的传热 ,提出了描述土壤传热的数学模型。由于该模型涉及到相变及相变界面的变化 ,属于斯特凡 (Stefan)问题。通过一定的数学处理得到了计算干燥圈或融化圈的特征线方程 ,并采用差分法进行求解特征线方程 ,获得了满意的结果 ,表明该计算方法是可行的。
The warm oil/gas will cause evaporation of moisture or thawing of ice rich soil adjacent the pipeline when the pipeline goes through the moist zone or permafrost, resulting in dry or thaw settlement of the pipeline and heterogeneous sinking of the oil and gas pipeline, which makes the force borne by the pipeline changing, even damages the integration of the pipeline. Also, the physical property of the soil in the dry or thaw circle will vary. Omitting the variation, the reasonableness of thermal calculation will be influenced. Therefore, it is necessary to analyze the variation of the dry or thaw circle around the pipeline for pipeline design, construction and management. In this paper, considering the influence of oil/gas pipeline on the around soil and the heat transmission of semi-infinite soil, a mathematic model that describes heat transmission of soil has been developed. Since it involves the phase change and multiphase interface change, the model belongs to Stefan issure. With treating the model mathematically, the characteristic equation is derived to calculate the dry or thaw circle. The equation is solved with difference methods, and the satisfactory results are obtained, which verifies the calculation method is feasible.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2003年第6期140-143,共4页
Natural Gas Industry
