Abstract: For the exposed crude oil pipelines，the heat capacity of oil in pipelines was much smaller than that in surrounding soil，so the cooling rate of exposed line was much faster than that of the buried line．And it becomes the key to limit shutdown time of oil transport line．Based on the bare hot oil pipeline thermal and hydraulic characteristics， established a pipeline shutdown temperature drop mathematical model．Use finite difference method after simplifying the model，changed the heat transfer partial differential equations into a system of linear equations，then used iterative method to calculate．Compile program diagram of the shutdown temperature drop of temperature field，calculated temperature distribution during different shutdown time．Compared the temperature of the governing center， 1/2 radius of the wall， developed a viable intermittent oil
transportation program．

Key words: Exposed pipeline , Mathematical model , Transfer program

摘要： 裸露原油管线停输后，由于管道中油的热容量要比周围土壤的热容量小得多，所以冷却速度要比埋地管道快得多，成为限制允许停输时间的关键。根据裸露热油管道的热力及水力特征，建立了管道停输后的温降数学模型。将模型简化后采用有限差分方法，把热传导偏微分方程转化为线性方程组后，用迭代法求解。编制了停输温降温度场的程序框图，以实际管道为例计算出不同停输时间管道内的温度分布值。将管线停输后管中心、1/2半径及管壁处温度进行比较，制定出可行的管线间歇输送方案。

关键词: 裸露管线 , 数学模型 , 输送方案