No abstract

No abstract

No abstract

No abstract

In the oil and gas industry, sand particle erosion damage to elbows is a common problem. The ability to predict erosion patterns is of great importance for sizing lines, analyzing failures, and limiting production rates. Computational fluid dynamics (CFD) can be utilized to study the erosion behavior and mitigate the erosion problem for safety purposes and greater equipment longevity. In order to alleviate the adverse results of sand erosion in elbows, the current study investigated the potential of the geometrically induced swirl flow generated from flow passing through a four-lobed twisted pipe upstream of an elbow. To this end, first, the airflow in a standard elbow equipped with different swirl pipes was simulated using the SIMPLE method, then an Eulerian-Lagrangian approach was employed to track the particles, and finally, the erosion rate was computed. The simulation results indicated that the elbow’s maximum erosion rate with twisted pipes placed upstream of the elbow is lower than the one obtained for the standard pipe. In addition, as the twisted pipe position gets closer to the bend, the erosion rate further reduces. Thus, swirling flows provide a promising prospect as a mechanism to control the erosion rate in elbows.

Fracking (fracturing) is of great importance for enhancing oil and gas production from low permeability reservoirs. Since in fracking fluid, suspension of sand particles are used, the erosion failure of fracturing equipment has become an increasing concern. Accordingly, investigation of erosion of commonly used fittings such as ball seats in order to decrease its adverse consequences has attracted considerable attentions. Although the erosion wear of gas-solid flows in the pipe sudden expansion was investigated in the literature, the effect of particle size, ball seat shape and the contraction configurations on the erosion-induced wear is not fully understood. This study is aimed to explore the most erosion-resistant configuration of a ball seat under various operational conditions. A CFD model is used and a wide range of geometries are investigated. The studied configurations are categorized in three main groups including single cone, double cone and curved cone. In each category, different cone angles and curve styles are considered. The results showed that, among the single cone ball seats, the cone angle of 15° is the most erosion-resistant configuration. It was also shown that the third-order curve style cone has the best erosion performance.

In gas and oil industry, erosion damage to pipelines' bends and elbows due to the presence of sand particles has been a challenging issue. In this study, a computational model approach was used to evaluate the erosion rates at di erent vertical return bends: sharp bend, standard elbow, 180 pipe bend, and long elbow. The air ow in the pipe was simulated using the SIMPLE method and the k ! SST turbulence model. An Eulerian-Lagrangian approach was used to predict particle trajectories and related erosion rates. Di erent particle sizes and mass ow rates were considered, and Oka model was used in these simulations to evaluate the erosion rate. Under the same condition, the simulation results indicated that the sharp return bends experienced the highest erosion rates, and the 180 bends experienced the lowest erosion among the studied con gurations. It was also found that the erosion rate was linearly proportional to the mass ow rate of particles for all cases studied. contributions are in the elds of computational uid dynamics, multiphase ows, particle transport, heat transfer, thermal systems, and energy management.

Since curved pipes are widely used in industrial equipment, predicting multiphase flows in these geometries is of great importance. In the present study, a computational model for predicting the velocity profile is developed and used to study the developing turbulent gas-liquid flows in curved pipes. In order to discretize and solve the three-dimensional steady-state momentum equations, the finite volume scheme on staggered grids besides central difference and QUICK scheme have been used. Moreover, the k-ε model is employed to reflect the nature of turbulence in the flow. In order to address the needs for sooner convergence and convenient mapping of the physical domain, the computations have been performed in a new toroidal coordinate system. Particle tracking has been done using Lagrangian approach in which two-way coupling regime is considered. In terms of validation, the numerical simulation results for the straight duct (infinite curvature), have been compared with the analytical solution and previous experimental results. Moreover, injection of particles through the flow indicates that, in each section of the bend, trade-off between centrifugal and pressure gradient forces plays a key role on particles motion. In last section, the effects of particle diameter and bend curvature on particle motion have been examined.