Investigation of the erosion wear mechanism of bend pipes for the action of multiphase flow in CO₂ flooding industry

Purpose This study aims to investigate the mechanism underlying erosion caused by solid–liquid–gas multiphase flow in pipeline transportation. In CO 2 flooding projects, the process of pipeline oil transportation is often accompanied by the presence of a small quantity of sand particles. Owing to the interaction of multiphase fluid flow (solid–liquid–gas), the inner walls of pipelines, particularly at bend locations, frequently experience significant erosion wear. Design/methodology/approach In this study, experimental data from existing literature are integrated with computational fluid dynamics to systematically analyze the influence of key parameters, including particle concentrations, flow rates and velocities, on the erosion rate within coupling pipes. Through a rigorous comparative analysis of multiple erosion prediction models, the volume of fluid (VOF) model and the discrete phase model (DPM) are identified and used as the most appropriate methods for the current investigation. Findings The findings indicate that particle concentration and flow rates are the primary influencing factors on erosion rates, with the outer wall of curved pipes identified as the primary area of erosion and the maximum erosion rate is 1.539 × 10 –2 kg/m 2 /s. Additionally, this study integrates 90° bend pipes with reducer pipes and compares their performance to standalone pipe structures. The results indicate that the maximum erosion rate of the coupling pipe decreases by up to 40% under various working conditions. Research limitations/implications Through a rigorous comparative analysis of multiple erosion prediction models, the VOF model and the DPM are identified and used as the most appropriate methods for the current investigation. Practical implications This study provides theoretical foundations and technical support for the engineering design and maintenance of coupling pipes, offering scientific guidance to reduce pipeline erosion and prolong equipment lifespan. Social implications Owing to the interaction of multiphase fluid flow (solid–liquid–gas), the inner walls of pipelines, particularly at bend locations, frequently experience significant erosion wear. Originality/value The present work provides theoretical foundations and technical support for the engineering design and maintenance of coupling pipes, offering scientific guidance aimed at reducing pipeline erosion and prolong equipment lifespan.