Analysis of the erosion effect of solid particle characteristics in water vapor on seamless carbon steel elbows

Abstract Aiming at the erosion failure problem of seamless carbon steel 90° elbows in high-temperature and high-pressure steam transmission systems of thermal power plants, this study was conducted to accurately reveal the regulatory mechanism of solid particle characteristics and gravity effects on erosion rules. Based on COMSOL Multiphysics software, a numerical model of steam-solid particle two-phase flow was established, coupling the k- ω turbulence model with the particle tracing method for fluid flow. A multi-model comparison strategy, with the E/CRC model as the primary approach and the Finnie, DNV and Oka models as supplementary methods, was adopted to carry out systematic simulations. Key factors including particle density, particle size, mass, shape factor, inlet velocity, mass flow rate, and gravity in the direction perpendicular to the pipeline were focused on to investigate their influence rules on the maximum erosion rate and incident acute angle of elbows. The results show that under the working conditions of this study, particle density has a low sensitivity to the erosion rate; particle size, mass, shape factor, mass flow rate and inlet velocity all exert a positive effect on the maximum erosion rate; gravity in the direction perpendicular to the pipeline will reduce the maximum erosion rate. Meanwhile, particle density, particle size, mass and inlet velocity can reduce the incident acute angle to varying degrees; particle shape factor and mass flow rate have no significant influence on it; gravity in the direction perpendicular to the pipeline can increase the incident acute angle. This study clarifies the core control rules of elbow erosion under the action of multiple influencing factors, which provides key theoretical support and engineering technical reference for erosion prediction, protective structure design and service life extension of steam pipelines in thermal power plants.