Effect of pipe size on erosion measurements and predictions in liquid-dominated multiphase flows for the elbows

Solid particle erosion in pipelines and pipe fittings occurs when solids are produced in the oil and gas industries during transporting fluids. Erosion of elbows in series for liquid-dominated flows has gained recognition as many oil fields operate in deep-water subsea flow lines and also in conventional wells onshore. Although significant data is available for gas-dominated flows, the data for liquid-dominated flows are scarce and limited to 50.8 mm pipe elbows in dispersed bubble flow only. Thus, it is essential to determine erosion for different pipe sizes to investigate the pipe size effect and for different flow regimes. This work conducts experiments in vertical liquid-solid flows, and liquid-gas-solid churn flows to examine erosion using 340 μm sand particles in 50.8 mm and 76.2 mm standard SS316 elbows in series separated at a distance of three diameters between them. In addition, flow visualization and paint-removal experiments are conducted to predict the erosion patterns in the elbows. Furthermore, Computational Fluid Dynamics (CFD) simulations are performed to simulate the experimental conditions. Eulerian and VOF multiphase models with different turbulence models are used in CFD simulations to predict erosion on the elbows in series and compare with the experimental results. The CFD results, when modified to account for the lubrication effects of the liquid, can predict the experimentally observed erosion pattern and the magnitudes.