Residual Strength Evaluation Method Of Gas Pipeline With Internal Corrosion Defects Considering The Effect Of Fluid Flow

Over the past decade,China's natural gas industry has entered a stage of rapid development,especially the completion of the main destruction of west-east national gas transmission project,the transport volume of the rapid increase of domestic gas,the pipeline industry in all aspects of performance increases.High-strength steel pipe with high yield strength,large diameter,thin wall,corrosion resistance and other characteristics,and therefore has gradually replaced the normal grade steel pipes,to become the world's major gas pipeline.Since the operating pressure of the high-strength steel pipe is high,coupled with relatively thinner ordinary steel pipe wall,effects of small volume defects in the internal pipeline to safe operation of pipelines residual life can not be ignored.At present,domestic and foreign high-strength steel pipe assess the remaining life is still relatively one-sided,largely ignored the high-pressure fluid flow within the pipe.So consider pipe flow under the effect of the impact analysis within the cylinder volume type defects remaining life of high-strength steel pipe has a very important role and significance.This papercombine with the existing theoretical research results,in consideration of pipe flow situation,stress concentration in the analysis tube volumetric defectand evaluating containing volumetric defects of high-strength steel pipe strength residual strength,to provide theoretical guidance and technical support to high-strength steel pipeline key positions within the volumetric defect strength evaluation.The main contents are divided into the following areas:First,this paper introduces the background in recent years on related research including volumetric defects of remaining life assessment of high-strength steel at home and abroad,and analyzes the characteristics of different studies,summed up a few more representative of the theoretical model.Presenting insufficiency of existing researches,innovation of this paper is to clarify that consideration of a defect in the pipe flow in case of stress analysis.Secondly,this paper chooses a pipe of Shaanxi-Beijing Gas Pipeline tier as a three-dimensional modeling example,the pipe section with reference to the X70high-strength steel gas pipeline.This paper uses software to introduce major operations ofANSYS modelingand calculations.Explore how the length,depth and width of defects affectthe residual strength ofpipeline.Specific analysis process shows by way of charts and present paper resulting analytical data and results.Finally,depending on the defect parameters for high-strength steel pipe remaining life impact,comparative analysis of high-strength steel pipe difference failure mode in the presence of different defect parameters,combined with the existing evaluation methods of the pipeline remaining life,proposed theoretical guidance for the actual operation of the pipeline.