【作者】 石成；

【导师】 刘晓燕；

【作者基本信息】 大庆石油学院 ， 热能工程， 2007， 硕士

【摘要】 东北管网运行已有三十多年,使用寿命已超过设计寿命。因此,东北管网开挖大修势在必行。而目前的开挖修复研究主要集中于固体力学方面,开挖修复后热力、水力计算的相关报道较少。管道开挖后的散热损失增大,温降快,为了保证热油管道修复和改造过程安全经济运行,有必要从热力学角度对开挖修复过程中的非稳态过程进行研究。本文对开挖修复不停输工况的工艺过程进行了研究。建立了长输管道正常运行时轴向温降、径向温降以及压降计算的数学模型,并给出了模型的求解方法。采用有限差分方法求解了轴向温降及压降,采用有限元方法求解了径向温度场。在管道正常运行的热力历史基础上,建立了长输管道运行时开挖修复的非稳态数学模型,并采用有限差分与有限元相结合的方法进行了求解。研究了大气温度突变对土壤温度场及管道运行管理的影响,给出了大气温度突变一般不会对长输管道造成危害的结论。给出了受热力学条件约束的热油管道运行时最大开挖修复长度的计算方法。采用实验与模拟计算相结合的方法验证了模型的正确性。对管道正常运行及开挖修复运行进行了分析。分析结果表明,管道运行的最不利季节并不是大气温度最低的月份,随着管道埋深的不同有一定的延迟;管道运行修复时的一次最大开挖修复长度主要受开挖起点和出站温度的影响。更多还原

【Abstract】 Northeast pipelines have been working for more than thirty years. So it has to be repaired. At present, most of the study about repair centralize at solid mechanics.The study on thermodynamics and hydraulics of excavating repaired pipeline is few. The heat lost increases and the temperature drops very quickly after digging repair. In order to ensure the safety of hot oil pipeline, it’s necessary to study unstable process by thermodynamics during repair. This paper studies on excavating repair technics process without shutdown. The model of pipeline axial and radial temperature drop and pressure drop during regular function is developed. And the solution is given out. Axial temperature and pressure drop are calculated by finite difference. Radial temperature field is calculated by finite element. On this foundation of thermodynamics, the unstable excavating repair mathematics model is also developed. Both finite difference and finite element are used for solution. The influence to soil temperature field and pipeline function management by atmosphere abrupt change is studied. The conclusion that atmosphere abrupt change won’t influent the gathering pipeline is proposed. The most excavating length calculation method for hot oil pipeline restricted by thermodynamics conditions is also given out. The correctness of model is tested by the combination of experimention and simulation. The normal function and excavating repair function of pipeline are analyzed. The conclusion is given out that the worst season for pipeline function is not the season with lowest atmosphere temperature. There is some delay and it depends on the depth of pipeline. Most excavating length is influenced by excavating start point and outlet oil temperature of station mostly.更多还原