Ships and Offshore Structures, Volume.12(2), pp.233-243, 2017

Numerical study of erosion in critical components of subsea pipeline: tees vs bends

Author(s): H. Pouraria, J.K. Seo & J.K. Paik

Abstract:
Elbows are a vulnerable part of piping systems in erosive environments. Traditionally, plugged tees are used instead of elbows
when the erosion rate is high. However, the advantage of plugged tees over elbows in large-scale pipelines is unclear. A
comprehensive computational fluid dynamics study was carried out to predict the erosion rate in plugged tees and elbows. A
numerical method was first used for aluminium elbows and tees with available experimental data through which the accuracy
of the numerical solution was verified. After validating the model, numerical modelling was used to compare the erosion
rates of plugged tees and elbows in varying geometrical conditions, ranging from 0.0254 to 0.6 m diameter carbon steel
pipes transmitting multiphase gas/sand flow. The effects of internal flow velocity and sand particle size on erosion rates were
also investigated. The numerical results revealed that the erosion ratio between plugged tees and elbows strongly depends
on the internal diameter of the pipe, the flow velocity and particle size. Hence, the influence of these parameters should be
considered for proper selection of the fittings to be used. Finally, numerical modelling of erosion in two subsea jumpers
outfitted with standard elbows and plugged tees was presented.