Numerical Simulation Study On Leakage Of Urban Direct-buried Thermal Pipeline

With the continuous expansion of cities and the acceleration of urbanization,China ’s central heating industry has made great progress.As the carrier of heat transmission,heating pipe network has frequent problems affecting safe operation.Among these problems,the leakage of buried pipelines is becoming more and more serious.The traditional leakage research based on experimental analysis has poor practical effect and cannot well fit the complex working conditions of the actual site.For urban pipe networks,the intrusion of external water sources such as tap water and sewage will directly affect the safe operation of directly buried thermal pipelines,Traditional research based on the analysis method of leakage cases cannot deeply understand the mechanism of direct buried pipeline leakage.With the help of numerical simulation tools,this paper studies the leakage phenomenon of urban direct-buried thermal pipeline.Through the combination of numerical calculation and case analysis,this paper establishes a simulation model of thermal pipeline and soil environment.Based on the study of the soil temperature field around the pipeline,this paper improves the monitoring method of heat pipeline leakage and external water source intrusion.Using ANSYS software combined with user-defined calculation program,this paper studies the leakage problem of thermal pipeline under different working conditions.Aiming at the common phenomena such as single hole leakage of heat pipe,leakage of water pipe and sewage intrusion,this paper obtains the fluid flow and heat transfer law in soil layer under various working conditions through numerical simulation.In order to better analyze the causes of pipeline leakage,this paper simulates and analyzes the phenomenon of external water intrusion that causes the leakage of urban buried pipelines.The results show that in order to ensure the safe operation of the pipeline,the external water intrusion should be monitored before the pipeline is corroded and leaked.The soil temperature field before and after pipeline leakage and foreign water intrusion shows completely different variation rules,which can be used to effectively judge the pipeline operation conditions.