A Comprehensive Erosion Prediction Method for Gas/Liquid/Sand Multiphase Flow

Sand particles induced erosion of the piping system and fittings is a concern for many industrial practices. The local flow behavior is one of the primary factors that determine the severity of erosion as well as the location where the erosion occurs. Extensive research has been conducted experimentally and numerically to study the erosion phenomena in single-phase (i.e. gas or liquid) flow systems and a variety of erosion prediction models have been developed. Nevertheless, very limited work has been done to investigate the erosion in multiphase (i.e. gas/liquid) flow systems, which is mainly due to the extreme complexity of the phenomena. A comprehensive procedure is proposed to estimate the erosion for sand particles entrained in gas/liquid multiphase flow systems. This procedure combines the mechanistic analysis approach and numerical simulation approach. In this procedure, the dominant flow characteristics of a given flow pattern are analyzed and the corresponding representative single-phase flow is proposed. Such that the erosion problem in this multiphase flow is simplified as one in the representative single-phase to which a single-phase Computational Fluid Dynamics (CFD) based erosion prediction model is applied. Meanwhile, the effective sand mass ratio is introduced to reflect the influence of individual flow patterns on the erosion process by applying a unified mechanistic multiphase flow prediction model. The calculated erosion from the single-phase flow weighted by the effective sand mass ratio yields the estimated erosion for the multiphase flow. Applying this approach, the erosion in elbows is calculated for bubbly flow, annular and annular-mist flow and slug flow and compared with the experimental data in literature. Agreement between the simulations and the data is reasonable, which indicates that the proposed method is an effective tool to estimate the erosion in multiphase flow.