Numerical Simulation Of Three-dimensional Soil Temperature Field Due To Buried Thermal Pipeline Leakage

Pipeline is one of the most popular transportation equipments, has its particular advantagesin transporting liquid, gas and serum. Pipeline is considered the most safe and economicmethod in the transportation of energy. However accidents may occur in pipeline, like otherengineering facilities. With the development of pipeline transportation, the increase of amountand age, the unexpected erosion, abrasion and disfigurement by natural or artificial reasons, theaccident of leak becomes more and more frequent, resulting in serious economic losses andsocial impacts. So pipeline leakage detection and location is significance. To use leading-edgetechnology—fiber-optic sensor or thermal infrared imaging technology—in real-time detectingpipeline leakage, it is needed to conform the temperature rules of the temperature field beforeand after leakage of buried pipeline. These rules not only provide theoretical basis of the twonew technologies but also help to dispose the fiber-optic sensor in right way.Based on the reasons mentioned above, the main work in this paper as following:1 Physical and mathematical models of temperature field before and after the leakage ofthe thermal pipeline are set up. The seepage influence is considered in the later mathematicalmodel. Thermodynamics and the hydromechanics boundary condition are given. The two andthree dimension computational model are provided based on different types of leakage.2 FLUENT, one of CFD software, is Adopted to study the steady temperature field beforethe leakage of the buried thermal energy pipeline. Next, the unsteady temperature field in threeand two dimensions, caused by the hole or crack, are calculated, respectively.3 Through comparing with the experimental data, the simulation result tallies withexperiment perfectly. So the simplify model in this research is rationality and CFD is reliabilityin calculating the earth temperature field of the pipeline leakage.4 The earth temperature field is obtained by applying the numerical simulation techniqueto the actual condition model. Rules of steady and unsteady temperature field are summarized.Criterion which can judge the form and the quantity of pipeline leakage is proposed, accordingto the change of heat-affected zone . a method of right disposing the fiber-optic sensor is alsoproposed in this paper.Some qualitative and quantity conclusions are acquired in this paper, which can offertheoretical foundation for the application of the optical fiber examination technology and theinfrared image formation examination technology in pipeline leakage detection. It is helpful indetecting the accident earlier and the real-time on-line examination of the thermal energypipeline. The models established in this paper, which can be used in different areas and actualconditions are general.