Mitigating elbow erosion with a vortex chamber

Abstract

Wear due to particles is often the key factor for pipeline failure. Parts such as elbows, for instance, are particularly prone to erosion issues. In this work, the erosion in a bend equipped with a vortex chamber is investigated numerically. Initially, experimental data are used to validate the CFD model for the standard elbow. Subsequently, a vortex chamber is added to the original geometry, preserving its geometric characteristics (e.g., diameter and curvature radius) as well as the simulation parameters (e.g., boundary conditions, density, viscosity). Based on four-way coupled simulations of the gas–solid flow in both geometries, the comparison between the standard and vortex-chamber elbow results is performed and a detailed analysis of the mass loading influence on the flow and on the penetration rate is carried out. In general, it is found that even at low mass loadings, inter-particle collisions play an important role in the overall flow behavior. The maximum penetration ratio gradually diminishes as the mass loading increases for both geometries. This phenomenon has actually been observed in experiments and is named cushioning effect. Another important finding is that the vortex chamber significantly improves the efficiency of the cushioning effect, reducing the peak of penetration ratio up to 93% when compared to the standard elbow. In both standard and vortex chamber elbows, a layer of particles builds up adjacent to the elbow wall, protecting it from direct particle collisions. By virtue of the vortex motion in the vortex chamber, the shielding effect of the inter-particle collisions is potentialized, mitigating the erosion rate as the mass loading is increased.