Experimental Investigation of Solid Particle Dynamics and Erosion in Gas Gathering Pipeline Elbows

Solid particle erosion is a major cause of gas pipeline damage, increasing maintenance costs and shortening pipeline lifespan. Elbows, among pipeline components, are particularly vulnerable with shorter lifespans. This study used lab-scaled experiments to investigate large sand particles (>200 microns and >800 microns) and airflow dynamics in horizontally oriented elbows (90 and 45 degrees), simulating gas-gathering pipeline conditions. High-speed video analysis helped understand the intricate dynamics of inertia-driven sand particles colliding with the elbow wall. Laser Doppler Anemometry measured sand particle velocities, especially near the wall where impacts occurred. Additionally, special paints were used to visualize the erosion pattern on the elbow's inner wall, and metal specimens were attached to critical locations for erosion rate analysis. Results revealed highly complex sand particle dynamics influenced by turbulence and particle-flow interactions. Asymmetric surface erosion patterns occurred due to gravity effects on inertial particles. Erosion rates on metal samples varied across elbow locations, correlating with the sand particle flow pattern. The region 30-45 degrees past the elbow experienced significant particle path changes, increasing susceptibility to erosion. In typical pipeline conditions with high air velocity and a large Stokes number, sedimentation was minimal, but low gas velocity conditions resulted in substantial sedimentation.