Analysis On Heat Transfer And Multiphase Flow In Leakage Process Of Buried Oil Pipeline

The buried oil pipeline is an important way of energy transportation, which is moreconvenient, quick, steady and safe than the aviation, motor vehicle and other transportationmethods. As an engineering equipment，the oil pipeline with increasingly running time willinevitably encounter defects, corrosion, wear and other factors. Therefore, the analysises ofheat transfer of multiphase leakage process of buried oil pipeline are very important forensuring the influence of leakage processes to earth temperature field, which also providetheoretical basis for the buried pipelines’ thermal infrared detection and quick repair.In this dissertation, the physical and mathematical models of buried oil pipeline in thesoil porous media were established when leakage happened, and the initial and boundaryconditions were determined. The multiphase leakage processes of buried oil pipeline in thesoil porous media have been numerically simulated by CFD software and UDF. Consideringthe single/multiphase flow, phase transition and physical property of crude oil, the influenceof leakage process on the earth temperature field, surface temperature, and velocity field inthe porous and mutual influences of multi-point leakage were analyzed. Results showed thatbecause of the different penetration processes and thermal conductivities of oil and water, thesurface temperature trends in the single flow and multiphase flow leakage processes aredifferent. Although the leakage process that considered the phase transition and did notconsider it have the basically same penetration process and surface temperature, the surfacetemperature trends in the process without phase transition lagged behind the ones in the phasetransition process, because the oil phase would give off its latent heat of solidification whilephase transition happened. The surface temperature trends of high viscosity and low viscosityconditions are different, because the oil phase of high viscosity could overcome the buoyancythat is created by the density difference of oil and water and gather behind the leakage point.When the buried pipeline had multi-point leakage, the mutual influences of leakage processesbetween two points must be considered when the axial distance between leakage points is lessthan3m in the setting conditions of this article. The research results had certain references forthe infrared imaging detection of leakage processes of buried oil pipelines and the pollutionrepair of crude oil.