Study On The Influence Of Leakage Combustion Of The Lancang River Across The Gas Pipeline On Parallel Pipelines

Gas Pipeline and Crude Oil Pipeline of Sino-Burmese Pipeline use parallel laying to pave pipelines after entering the Chinese border from Ruili, Yunnan province, and the distance of the parallel laying is as long as 1100 km, which includes a total of 39 river crossing section projects. One of those crossing projects, The Lantsang Crossing Project, which is paved parallelly with three pipelines that consist of Sino-Burmese Crude Oil Pipeline, Sino-Burmese Gas Pipeline and Petroleum products Pipeline of Anning-Baoshan Line, is considered to be one of major controlling engineering. During the period of operation, there are many factors causing gas pipeline leakage combustion, even causing secondary accident that bring devastating damages to parallel pipelines and crossing pipe bridge. The influence study that combustion of gas pipeline leakage produces an effect on parallel pipelines is not only beneficial to formulate scientific and efficient, pointed emergency maintenance plan after accident, improve the efficiency of first-aid maintenance and reduce accident loss as far as possibly, but also conductive to provide theory basis knowledge for pipeline design, operational management and safe operation about the parallel pipelines of Lantsang crossing project or similar pipelines. This thesis based on joint research method of the CFD technique and theoretical calculation, the major researching contents and results are as follows:(1) According to the thesis researching background, purpose and significance, the thesis investigated related theoretical research, numerical simulation of jet fire and thermal stress and their development trend at home and abroad; and done data collection of geographical environment of the Lantsang Crossing Project, operational parameters of parallel pipelines, medium characteristics of gas pipeline transportation, provided basic data for the following theoretical study and simulation study.(2) Theoretical analysis of the process that combustion of gas pipeline leakage produces an effect on parallel pipelines was implemented, including gas pipeline failure reason analysis, gas pipeline leakage fault tree and pipeline failure form and pipeline failure criterion, etc. Provide theoretical basis for below simulation research ideological line, simulation results analysis and judgement of simulation results.(3) Setting a hypothesis that regard the Small Hole Leakage Model as Convergent Nozzle Model, and using theoretical calculation formulas of Convergent Nozzle Model computed theoretical value of leakage parameters; based on the method of CFD numerical simulation study, designed numerical simulation schemes, established geometric model of the Small Hole Leakage Model, completed analog pretreatments such as meshing generation and simulation parameter settings. According to the simulation results, collected reliable leakage simulation parameters by analyzing of 31 experiment scheme,310 groups simulative data and explored the change rule; Then using means of comparison and analysis to study theoretical calculation values and simulation calculation values, verify whether the assumption that regard the Small Hole Leakage Model as Convergent Nozzle Model is right, and deduce a leakage pressure correction coefficient and Leaking Pressure Modifier Formula that used for Small Hole Leakage Model based on CFD numerical simulation study.(4) Based on the method of CFD numerical simulation study, established a coupling project schematic of simulation research project with multi-physical fields coupling theory; established geometric model of combustion flow field, oil pipeline and products pipeline of the Lantsang Crossing parallel pipelines, completed analog pretreatments such as meshing generation and simulation parameter settings in Fluent software module, Steady-state thermal analysis module and Static structural analysis module. According to pipeline failure criterion, combined with the simulation results to analysis simulation data such as Jet Flame, radiation intensity, heat flux of parallel pipelines, equivalent stress of parallel pipelines, etc. drew a conclusion that leakage combustion of gas pipeline will cause crude oil pipeline and petroleum products pipeline have failure consequences in daily operation conditions.(5) According to daily operation parameters of Sino-Burmese gas Pipeline, formulated a series of experimental schemes of numerical simulation scheme at different influential factors, setd respectively the Pipeline pressure, Leakage aperture, Leakage direction and Distance between parallel pipelines and gas pipeline as the experimental variables, combined with the simulation results to analyze contrastively the impact that Jet Flame produces on parallel pipelines from Jet Flame and the radiation intensity, Coupling temperature, Coupling pressure, Heat Flux of parallel pipelines and equivalent stress of parallel pipelines in five aspects, obtained a series of conclusions such as the change law of impact that leakage combustion of Sino-Burmese gas Pipeline produces on parallel pipelines under different influencing factors, failure starting time of parallel pipelines, leakage dangerous angle range, etc.(6) Combined with above conclusions under different influencing factors, took a comprehensive analysis, then propose a series of jet fire protection measures of parallel pipelines such as coating thickness type fire retardant coating, setting the fire alarm devices, preparing fire fighting apparatus, etc.