Study on the erosion wear in pipe fittings

Abstract

In the pipeline system for liquid carrying particle, local erosion wear broken has become the main damage mechanism of pipe in the fracturing operations of oil-gas engineering as a large number of particles continually impact on the inner surface of pipes. Computational Fluid Dynamics simulation was performed to determine the evolutionary process of erosion wear in tubing connector, which was the weakness of pipeline system, and a new way to predict the pipeline safety was provided. Based on the Euler method, the volume fraction of the particulate phase and interphase momentum exchange were included in the liquid flow equations due to the influence of dense particle on fluid flow, and the particle trajectory were calculated in the Lagrange frame by analyzing the forces from the interaction of liquid and particle and particles collision. With the erosion damage model, the erosion rate/depth in the connector was calculated to reconstruct the mesh model of shoulder with 5 tori. Torus 1 is closest to axis while torus 5 is on the outmost wall of the connector. During the erosion event, greatest erosion and hence surface deformation occurs on tori 1 and 2, and this affects the surrounding flow and particle movement. After 10 h, there was a dramatic drop in the maximum erosion rate, which illustrated a conservative prediction for pipeline service life if the initial erosion rate was used. A physical erosion experiment was also performed to identify the weight loss and erosion characteristic of the inner surface with erosion time of 55 h. It was observed that the erosion simulations provided relative errors within 18% for erosion length and weight loss compared to the experimental values and a valid simulation method for the erosion evolution was proposed to predict the erosion life of tubing connector.