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一、问题的提出输油管正确的热工计算方法,是合理设计加热站的加热负荷、站间距及输油管顺利投产和运行管理的重要科学依据。地下输油管是浅埋构筑物,其传热过程受到地面温度年变化的影响。根据我国在华北某地区的观测,地面以下一米处地温年波幅达10℃,两米处为7.25℃。因此,输油管起输、常输和停输的传热过程是边值条件较为复杂的三维非稳定传热问题。目前,输油管的热工计算方法是应用汇源法求解得到的,为此,对定解条件作了如下
First, the problem put forward The correct thermal calculation of pipeline, is a reasonable design of the heating station heating load, station spacing and smooth production and operation of the pipeline an important scientific basis. Underground pipeline is a shallow buried structure, the heat transfer process by the ground temperature changes in the year. According to China’s observation in a certain area in North China, the annual amplitude of annual temperature reaches 10 ° C at a point below ground and 7.25 ° C at two meters. Therefore, the process of heat transfer from the pipeline to the input, to the normal transmission and the stop of transmission is a three-dimensional unstable heat transfer problem with more complicated boundary conditions. At present, the thermal calculation method of the pipeline is obtained by using Huiyuan method. For this reason, the conditions of the solution are as follows