Erosion caused by sand particles is a serious problem facing the oil and gas industry. Predicting pipe erosion due to sand transport is a complex process in multiphase flows due to the complex nature of the flow. Existing erosion studies are however focused on single phase flow conditions which are conservative and could lead to under-/ over-engineering because actual fluid flow in pipelines is multiphase. There is therefore a need for in-depth analysis of the complex interaction between the multiphase fluid and transported sand particles. This study employs CFD modelling techniques to investigate the complex interactions between the multiphase fluid and transported sand particles in pipes, and the subsequent effect on pipe erosion rate and location under varying operating conditions. In view of this, the Eulerian Multifluid-VOF Model coupled with Interfacial Area Transport Equations have been employed to simulate airwater two phase flow and the result shows good agreement with experimental data. This fluid flow results have been employed in investigating sand erosion in multiphase flow through pipes. The Eulerian Multifluid-VOF model has been coupled with the Lagrangian framework for particle tracking and an appropriate erosion correlation has been employed to predict the pipe erosion rate. The pipe was observed to erode more 45 degrees into the elbow and maximum erosion rate is 4.028e-6 kg/m 2 s. These results are in acceptable range when compared to available data. Erosion rate was also observed to be transient.

This study investigates the effects of elbow on the transition and development of multiphase flow using computational fluid dynamics modelling techniques. The Eulerian - Multifluid VOF model coupled with an Interfacial Area Transport Equation has been employed to simulate air-water two-phase flow in a pipe with two standard 90 degree elbows mounted in series. Turbulence effects were accounted for by the RNG k-ε model. The effects of separation distance on two-phase flow development have been studied for initial slug and churn flow regimes. Computational fluid dynamics simulation results of phase distribution and time series of void fraction fluctuations were obtained and they showed good agreement with available experimental data. The results show that for initial slug flow regime, there is no flow regime transformation upstream and downstream of the two elbows. While at initial churn flow regime, flow regime transformation occurs at different sections of the flow domain before and after the two elbows. It was noticed that irrespective of the flow regime, the amplitudes and frequencies of void fraction fluctuation become smaller as the fluid flows along the pipe. Changes in the separation distance between the two elbows have larger effects on the flow at churn flow regime.