A PROCEDURE TO PREDICT SOLID PARTICLE EROSION IN ELBOWS AND TEES

A semi-empirical procedure has been developed for predicting erosion r ates in pipe geometries, such as elbows and tees. The procedure can be used to estimate safe operating conditions and velocities in oil and gas production where sand is present. In the proposed procedure, a con cept is introduced that allows determination of erosion rate for diffe rent pipe geometries. In the procedure, based on empirical observation s, the erosion rate is related to the impact velocity of sand particle s on a pipe fitting wail. A simplified particle tracking model is deve loped and is used to estimate the impact velocity of sand particles mo ving in a stagnation region near the pipe wall. A new concept of equiv alent stagnation length allows the simplified procedure to be applicab le to actual pipe geometries. The ''equivalent stagnation regions'' of an elbow and a tee geometry of different sizes are obtained from expe rimental data for small pipe diameters, and a computational model is u sed to extend the procedure to larger pipe diameters. Currently, the p rediction method applies to mild steel and accounts for the effects of sand size, shape, and density,: fluid density, viscosity, and flow sp eed; and pipe size and shape. The proposed method has been verified fo r gas and liquid flows through several comparisons with experimental d ata reported in the literature. The results of the model accurately pr edict the effects of sand size and fluid viscosity observed in the exp eriments. Furthermore, predicted erosion rates showed good agreement w ith experimental data for gas, liquid, and gas-liquid flows in several 50.8-mm (2-in.) elbows and tees.