The Effect of Geometric Parameters of Gas Pipeline Bends on Internal Pipe Erosion Processes

The influence of diameter, bending angle and bending radius of gas pipelines bends on the location and extent of their erosion wear is investigated. The research is carried out with the help of CFD (Computational Fluid Dynamics) simulation using the Lagrangian approach (Discrete Phase Model) in the ANSYS Fluent R19.2 Academic software. The mathematical model of the continuous-phase motion is based on the solution of simultaneous Navier-Stokes equations, the continuity of closed two-parameter k-ε model turbulence with the corresponding initial and boundary conditions. The motion trajectories of the dispersed phases are monitored by integrating the equations of forces acting on the particles. The simulation of erosion wear of the gas pipeline bends is performed using Finney equation. The investigations are carried out for five different external diameters of the pipeline bends (89 mm, 219 mm, 530 mm, 1020 mm and 1420 mm). The angles of the bends are 30°, 45°, 60°, and 90°, and the bend radii are DN, 1.5 DN, 2 DN, 2.5 DN, and 3.5 DN. Natural gas was selected as the continuous phase, and sand was selected as the dispersed phase. The flow rate of the disperse phase, the motion velocity of the dispersed and continuous phases at the inlet of the bend and the pressure at the outlet of every simulated bends are assumed to be the same. The simulation results are visualized in the ANSYS Fluent postprocessor by constructing erosion velocity rate fields on the contours of gas pipeline bends. On the basis of the visualized results, it is determined that the largest influence on the location of the erosion wear of the pipeline bends is caused by the bend radius, and the largest effect on the amount of the erosion wear is caused by bend diameter. The influence of the geometric parameters of the bends on the location of their maximum erosion wear field is established. Graphical dependences of maximum velocity of erosion wear of gas pipeline bends on their geometric parameters are constructed.