Study On Horizontal Elbow Erosion Law In Liquid-Solid Two Phase Flow

With the development of oil fields entering late stage,the ratio of sand content in transmission media increases year by year.As an important device in petroleum industry,oil and gas pipelines,which delivers oil and gas from well to joint station,is suffering from erosion damage more and more obviously.Due to effect of many inherent characteristics,like geometric shape,Inertial force,centrifugal force,et al,elbow become a serious erosion area of oil and gas pipeline system.The erosion at the elbow,particularly perforation,is a serious threat to oil and gas production,which will later become detrimental to national interests,thus the study on the erosion of elbow is imminent.The research status of erosion empirical model and erosion mechanism model is studied.The results show that different erosion models have different applicability,and different models need to be selected according to different working conditions.The model theory provides a theoretical basis for the horizontal elbow erosion experiment.In this paper,two sets of tube flow experimental devices and detachable test elbows were designed,and the erosion behavior in 90 ° horizontal elbow was studied by means of experimental test and numerical simulation.Through combining analyses of two unique methods,weight loss measuring method and surface observing method,erosion characteristics of different areas will be determined,erosion rates of different areas will be quantified.Study on liquid-solid 90-degree horizontal bend erosion test.The results show that the serious area of horizontal elbow erosion mainly exists in the bottom of the connection between elbow and elbow straight pipe section and the bottom of outlet straight pipe section.The horizontal elbow outer portion erosion rate is greater than the inner erosion rate;The horizontal elbow inlet erosion rate is greater than the erosion rate at the entrance.Study on slug flow 90-degree horizontal bend erosion test.The results show that there is a significant change in the area of serious erosion-damage area,the main erosion location exists in the outer middle of the elbow and elbow straight pipe connection.Numerical simulation of 90-degree elbow pipe liquid-solid two phase flow erosion situation,the results showed that with the increase of particle mass flow、flow velocity,the erosion rate of specimensat different locations of 90-degree horizontal elbow increases.With the increase of sand diameter,bend maximum erosion rate showed a trend of decrease before increase.The change of the operating pressure in the pipe has little effect on the erosion rate.The change in the direction of the elbow will affect the erosion rate and the distribution of the erosion areaThe mechanism of erosion of metal target by single grain sand was studied by ANSYS / LS-DYNA numerical simulation.The depth of the erosion pits increases with the impact rate of sand and the grain size of sand.The impact angle is inversely proportional to the size of the plastic strain zone and proportional to the depth of the erosion pits.With the edges and corners of the sand will exacerbate erosion and damage behavior.