Comparative Study on Atmospheric Temperature Models for the Buried Hot Oil Pipeline

In previous studies, the atmospheric temperature was generally assumed to be constant during a period (commonly a month) for the numerical simulation on the buried hot oil pipeline. The rationality of this assumption is controversial due to the absence of quantitative results, and thus it needs to be further verified or investigated to make atmospheric temperature approximation more convincing. In this study, based on the changing trend of actual atmospheric temperature, three mathematical models are established and their expressions are presented according to different approximations. And the relationships among these three expressions are obtained by utilizing mathematical derivation. On the basis of three atmospheric temperature models, the weakly unsteady single oil transportation and strongly unsteady batch transportation are numerically simulated, respectively. According to numerical results, the oil temperature at the pipeline ending point and the soil temperature field are compared for these three models. In order to make comparisons more convincing, the influences of the physical properties of crude oil, operation parameters, pipeline parameters and pipeline environments on the deviations of numerical results are compared and analyzed. Finally, based on all comparisons on the deviations of numerical results, the conclusions are drawn, which can provide beneficial reference for the choice of atmospheric temperature models in future numerical simulation study on the buried hot oil pipeline.