Study On Erosion Dynamics Behavior Of Gas Gathering Pipelines

As the main transportation mode of natural gas,pipelines play an important role in the exploitation and transportation of natural gas.The gas flow carries a certain amount of solid particles due to sand production and other reasons,particles keep impacting components of the pipelines like the elbow which leads to a certain degree of erosion damage.Given that Pipeline erosion is not only related to operation parameters and particle properties but also pipe steel's characteristics,the erosion dynamics of natural gas gathering pipelines was studied and the distribution of erosion in the elbow of the gas gathering pipeline was analyzed.Aiming at the commonly used 20#steel in natural gas gathering pipeline,a dynamic finite element model of particle impact target was established and verified by test.The J-C plasticity model and failure criteria were used in the model to simulate the failure of materials.The dynamic behavior of particle erosion was studied through this model.The changes in energy,stress and morphology at the micro level were analyzed.The influence of particle shape,particle size,impact velocity and impact angle on the erosion rate of 20#steel was obtained.Combined with the simulation results,an erosion prediction equation for 20#steel was established.It was found that when the particles were at low angles of attack,they were mainly micro-cut to 20#steel and had a strong destructive effect at a 45° angle of attack.Based on the FEM simulation,the erosion model of natural gas gathering pipe elbows was established using CFD and its effectiveness was verified.In the model,the RNG k-?turbulence equation was selected to simulate the flow field.The influence of high pressure was considered by establishing UDF gas state equation.The DPM module was used to calculate the particle trajectory,and the SIMPLE algorithm was used to solve the pressure-velocity coupling equation.Finally the influence of elbow angle,ratio of bending radius to diameter,air pressure,gas velocity,and particle density on the distribution characteristics of elbow erosion was obtained by numerical simulation.In summary,this paper combined FEM and CFD to study the influence factors of elbow erosion of natural gas gathering pipe for 20#steel and improved the erosion prediction ability of gas gathering pipe for 20#steel.The work has important engineering significance for control of elbow erosion wear and safe production of gas field gathering system.