Study On Sand Erosion Wear Law Of Elbow Pipe And Tee Pipe

In the pipeline transportation process of the oilfield,the sand particles carried by the fluid will impact the pipeline and cause erosion of the pipeline,especially at the position of elbow and T-tee,which is likely to cause pipeline failures and affect the safety of gathering.Therefore,studying the erosion law of sand particles carried in the pipeline transportation process on elbows and T-tee is of great significance for improving the life of the pipeline and reducing the maintenance cost of the pipeline.In order to study the erosion wear law of sand particles on elbow and T-tee in the pipeline transportation process,this paper studies the erosion wear law of solid sand on elbow and Ttee under different fluid velocity,sand size and mass flow rate in water,oil and gas fluid media.At the same time,the erosion wear law of sand particles on the elbow in slug flow is studied under different gas-liquid apparent velocity and curvature radius.The main work contents and results are as follows:(1)In the elbow,with the increase of the fluid velocity,sand size and sand mass flow,the maximum erosion rate of the elbow increases.When water and oil are used as the sand-carrying medium,the erosion distribution on the elbow has high similarity.The erosion position is mainly located on the outer arch wall surface of the elbow pipe and the inner wall surface of the outlet section.When air is used as the sand-carrying medium,the erosion position only exists on the outer arch wall surface of the elbow pipe.When the sand diameter is 0.025 mm,the erosion is the most serious at the outer arch wall of 60° to 90° elbow section.When the sand diameter increases to 0.05 mm,the most severe erosion position moves to the entrance,which is located at the outer arch wall of 45° to 60° elbow section.When the sand diameter continues to increase,the most serious erosion position remains unchanged.(2)In the T-tee,with the increase of fluid velocity and sand mass flow rate,the maximum erosion rate of the T-tee increases.With the increase of the sand particle size,the maximum erosion rate of the T-tee decreases rapidly at first and then tends to be flat.Small diameter sand particles will produce a greater erosion rate.When water and oil are used as the sand-carrying medium,the most severe erosion position of the T-tee is located at the neck of the tee.When air is used as the sand-carrying medium,the most severe erosion position is located at the bottom of the opposite of the branch pipe of the T-tee.When the sand particle diameter is0.025 mm,the erosion wear area becomes a bullet shape.When the sand particle diameter is0.1mm,the erosion wear area turns into a circle.(3)The method of combining the VOF model and the DPM model is used to study the erosion wear law of elbow caused by solid sand particles in slug flow.Under different sizes of sand particles,the erosion wear law of elbow is analyzed by changing the gas-liquid apparent velocity and the curvature radius of elbow.With the increase of the gas-liquid apparent velocity,the maximum erosion rate of elbow increases.The larger the sand particle diameter is,the greater the increase of the maximum erosion rate of the elbow is,and the most serious erosion is located on the outer arch wall of the elbow section at 70°?90°.As the curvature radius increases,the maximum erosion rate of elbow decreases.The maximum erosion rate of elbow decreases by 47.7%,50.3%,50.1%,40.9% when the sand diameter is from 0.1mm to 0.4mm.The larger the sand diameter is,the greater the maximum erosion rate is,but the decreasing ratio of the maximum erosion rate decreases.The curvature radius of elbow increases from1.5D to 6D,and the most severe erosion position changes from the outlet of elbow section to the inlet of elbow section.In this paper,the sand erosion wear law of elbow and T-tee is studied,which has practical significance for the prevention and control of erosion wear in oilfield pipeline transportation.