The research was performed in order to obtain the physical picture of the movement of condensed droplets and solid particles in the flow of natural gas in elbows and T-junctions of the linear part of the main gas pipeline. 3D modeling of the elbow and T-junction was performed in the linear part of the gas main, in particular, in places where a complex movement of multiphase flows occurs and changes its direction. In these places also occur swirls, collisions of discrete phases in the pipeline wall, and erosive wear of the pipe wall. Based on Lagrangian approach (Discrete Phase Model – DPM), methods of computer modeling were developed to simulate multiphase flow movement in the elbow and T-junction of the linear part of the gas main using software package ANSYS Fluent R17.0 Academic. The mathematical model is based on solving the Navier–Stokes equations, and the equations of continuity and discrete phase movement closed with Launder–Sharma (k–e) two-parameter turbulence model with appropriate initial and boundary conditions. In T-junction, we simulated gas movement in the run-pipe, and the passage of the part of flow into the branch. The simulation results were visualized in postprocessor ANSYS Fluent R17.0 Academic and ANSYS CFD-Post R17.0 Academic by building trajectories of the motion of condensed droplets and solid particles in the elbow and T-junction of the linear part of the gas main in the flow of natural gas. The trajectories were painted in colors that match the velocity and diameter of droplets and particles according to the scale of values. After studying the trajectories of discrete phases, the locations of their heavy collision with the pipeline walls were found, as well as the places of turbulence of condensed droplets and solid particles. The velocity of liquid and solid particles was determined, and the impact angles, diameters of condensed droplets and solid particles in the place of collision were found. Such results provide possibilities for a full and comprehensive investigation of erosive wear of the elbow and T-junction of the linear part of the gas main and adjacent sections of the pipeline, and for the assessment of their strength and residual life.
Purpose: To investigate the strength of tees with regard to their erosion wear, it is necessary to consider the complex three-dimensional geometric shape of the erosion worn inner surface of the tee. In addition, the study of the strength of the erosion worn tees of the main gas pipelines is complicated by the occurrence of additional stresses caused by changes in the direction of movement of the gas stream, resulting in an uneven pressure distribution in the inner cavity of the tee, and the temperature difference in its walls. Design/methodology/approach: Methodology for complex numerical three-dimensional simulation of the stressed state of tees of the main gas pipelines, taking into account the gas-dynamic processes that occur in the places of these defects, erosion wear of the tee wall, temperature difference in the tee walls. Findings: The acceptable parameters of erosion defects of tees of gas pipelines, and residual life of tees with erosion defects of the wall should be determined. Research limitations/implications: The developed model does not take into account internal corrosion and corrosion products as an additional erosion factor. Further studies plan to develop a model of corrosion-erosion wear of pipeline elements. Practical implications: The developed technique allows determining the location of erosion defects, estimating the strength and determining the residual life of tees with erosion wear of the wall in order to ensure their reliability, to rank such defects according to the degree of danger, to determine which of them are critical and need an immediate repair. Originality/value: Based on the gas-dynamic processes occurring in the internal cavity of the main gas pipelines’ tees, the complex three-dimensional geometric form of wall erosion defects, and temperature difference, the technique of three-dimensional simulation of stress state of the main gas pipelines’ tees is developed.
The purpose of this work is to ensuring the strength of main gas pipelines bends by studying the peculiarities of single-phase and multiphase flows movement through the internal cavity, the processes of erosion wear and the wall stress state. The problem of synergistic influence of gas-dynamic processes (uneven pressure distribution in the internal cavity), temperature difference and erosion wear on the stress state of the bends of main gas pipelines was solved by numerical simulation. Based on the results of simulation the processes of bends erosion wear, an algorithm for three-dimensional simulation of bend walls erosion defects was developed. The complex three-dimensional geometric shape of the erosion defects of the bend wall varied according to the rate of erosion wear process. This algorithm made it possible to determine the regularities for the influence of the bend erosion defects magnitude on bends stress state. It was established that considering the maximum depth of bend erosion defects 9.6 mm, 10.5 mm and 11.9 mm, the equivalent stresses in the deepest places of the erosion defect were greater than on the concave side of the bend and in straight sections of the pipeline.
Purpose: The purposes of this article are to study the effective ways of increasing the hydraulic efficiency of gas gathering pipelines of the Yuliivskyi oil and gas condensate production facility (OGCPF); to calculate the operation efficiency of gas gathering pipelines of the Yuliivskyi OGCPF and develop a set of measures to monitor their condition and improve their hydraulic characteristics; to investigate the technology of cleaning the inner cavity of flowlines of gas-condensate wells with foam, to perform the feasibility study on the prospects of its application in practice. Design/methodology/approach: The technology of cleaning the inner cavity of flowlines of gas-condensate wells with foam was investigated to objectively evaluate its application and determine the effectiveness of this measure. The research was carried out within the framework of research and development work by the specialists of the Ukrainian Scientific Research Institute of Natural Gases. Findings: The results of production studies showed that due to cleaning the flowlines of gas-condensate wells (No.85 and No.60) from the accumulation of liquid, the coefficients of their hydraulic efficiency increased by 12% and 7%, respectively. Measures taken to clean the inner cavity of the flowlines from liquid have proven their efficiency and can be recommended for other flowlines of wells at other production fields. Research limitations/implications: Based on the characteristics of gas gathering pipelines, it is reasonable to conduct experimental studies on the use of the proposed technology of cleaning the inner cavity with foam in the case of increasing its multiplicity. Practical implications: Using the wells of the Yuliivske oil and gas condensate field as case studies, the operating parameters were measured and the pressure losses along the length of the flowlines were calculated. According to the results of calculations at two wells (No.85 and No.60), a significant excess of the actual value of the flow friction characteristic over the theoretical value was established. To reduce excessive pressure losses due to the presence of liquid and improve the hydraulic characteristics of the wells, their inner cavities were cleaned using foam with the expansion ratio from 40 to 100. Originality/value: It is important to note that the advantages of foam piston include: ease of use, no occurrence of hydraulic shocks and preventing stuck during movement in the gas pipeline, application in both straight and inclined sections, no wear of the elements of the cleaning equipment, a rather efficient cleaning of gas pipelines.
22. Dozatory nepreryvnogo deystviya s kompensaciey vozmushcheniya vhodnogo potoka materiala / Shuhin V. V., Marsov V. I., Suetina T. A., Kolbasin A. M. // Mekhanizaciya stroitel'stva. 2013. Issue 2. P. 32-34. 23. Popov V. L. Mekhanika kontaktnogo vzaimodeystviya i fizika treniya.
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