Numerical investigation of the erosion reduction in elbows using separate and helical inner ring

Abstract

This study presents a comprehensive numerical investigation of erosion in bends equipped with inner rings as a novel geometric concept for erosion control. The research aims to assess the effectiveness of these innovative configurations in reducing erosion through rigorous computational fluid dynamics (CFD) simulations. Numerical modeling for the gas-solid two-phase flow has been carried out based on one-way coupling using an Eulerian-Lagrangian approach. The CFD model employed in this work incorporates the RNG k-ε turbulence model for flow solution, the Oka model for simulating surface erosion, and the Grant and Tabakoff model to account for particle-wall collisions. The primary focus of the investigation is to evaluate the erosion reduction capabilities of different inner ring configurations. By systematically varying the number of inner rings, the study elucidates the influence of this parameter on erosion mitigation. The obtained numerical results are analyzed in terms of erosion patterns, erosion reduction percentages, and the integral erosion surface criterion. The findings reveal the elbow with two separate inner rings as the most effective configuration, exhibiting a remarkable decrease in erosion of up to 43 % compared to the standard elbow. Moreover, based on the integral erosion surface criterion, the elbow with five separate inner rings emerges as a more desirable alternative to the standard elbow. In addition, the study investigates the impact of an elbow with helical inner rings configuration on erosion. It is observed that this configuration intensifies flow velocity, thereby accelerating particle motion and leading to increased erosion along the outer wall.

Keywords

• CFD
• Elbow
• Erosion
• Gas-solid two-phase flow
• Erosion mitigation