Erosion Wear Fatigue Analysis And Life Prediction Of Typical Pipeline Structures

Pressure piping is an indispensable transportation equipment in industrial production.How to ensure the safe operation of pipeline has always been a hot topic in the fields of industrial and academic.Especially in the field of transporting pipelines in the petrochemical industry,the transported articles contain more impurities,erosion wear of the particles and corrosion of the medium as well as mechanical damage(such as scratches,sanding,collisions,etc.)can cause damage to the pipe wall.Erosion wear fatigue failure is one of the common forms of failure in various cases of pipeline system failure.Thinning of pipeline erosion wear leads to local stress concentration and micro cracks are induced to form erosion wear faults,makes pipeline fatigue failure prematurely.This failure always occurs to typical structure of pipeline(elbow,reducer and three-way pipe,etc).Therefore,as a "weak link" in the pipeline system,this paper takes the typical structure of the pipeline as the research object,studies the rules and characteristics of the erosion wear of the solid particles on the pipe wall by the numerical simulation analysis method,and based on the erosion wear faults,studying the impact of erosion wear factor on the fatigue life of pipeline,the related life prediction of pipeline has an important role in ensuring the stable operation of the pipeline,reducing the blindness of detection and improving work efficiency,and provides the foundation for the actual analysis and application of the project.The main research contents include:(1)The failure mechanism of the erosion wear of the typical structure of the pipeline(elbow reducer and three-way pipe)was analyzed.Based on the theory of particle erosion wear,the factors affecting the erosion wear were analyzed.Through reviewing the literature,the erosion mechanism of typical pipe erosion wear was analyzed.(2)The typical structural model of the pipeline was established by ANSYS Workbench and the corresponding meshing was established.The initial conditions and boundary conditions of the numerical simulation were determined.The Fluent module was used to simulate the fluid field,and the pressure field and velocity field of the fluid were obtained.The influence of flow field distribution under different working conditions was also discussed.(3)The law of erosion wear of single particle under different inflow position was studied.On the basis of this,for a plurality of uniformly distributed particles,the law of the effect of medium flow velocity,particle size and mass flow on the pipeline erosion was analyzed,and the area of severe erosion wear under the analysis condition was determined.(4)Considering the effect of thermal effect on the strength of pipeline structure,the coupling analysis of the elbow,reducer and three-way pipe with erosion wear faults under erosion wear was carried out.It was found that there was a serious stress concentration at the fault,Analyzed the factors that affect the stress value of the fault,and determined the factors that affect the erosion wear fatigue of the typical structure of the pipeline.(5)Based on the Kriging method,simulation calculation was carried out in Matlab software and a semi-parametric pipeline life prediction model is proposed.