Papers by Keyword: Elbow

Abstract: Elbow pipes are important pipeline components in hydrocarbon transportation systems, and they were prone to erosive wear by the impact of abrasive particles. A discrete phase modeling (DPM) and numerical simulation of the liquid-sand transportation process was carried out focused on the investigation into the influence of carrier fluid viscosity on erosion distribution of carbon steel 90° elbows. The accuracy of the predicted results was validated by comparison with experimental data. CFD simulations have been carried out by combining DPM to predict the erosion rate and particle impaction regions in carbon steel 90° elbow with a diameter of 50.8 mm. The fluid viscosity is set for 1cP, 5cP, and 15 cP with an inlet velocity of 8 m/s, and the size of sand particles is 200 μm. While the maximum erosion rates enhance with an increase in fluid viscosity, the location of maximum particle impaction has been specified to be adjacent to the outlet for 1 cP and 5 cP carrier fluid viscosity. It is also found that increasing the viscosity does not considerably alter the average erosion rate. Moreover, the increase in carrier fluid viscosity with the same flow velocity influences maximum erosion rate and yields 1.45 times higher erosion rates at 15 cP compared to 5cP and 1cP. This is mainly due to severe sand impaction at the side of the elbow wall.

Abstract: In recent years, the oil and gas industries have been developing significantly. In this regard, there was a great need for the construction of main pipelines, which consist of pipes and connecting parts. The production of connecting parts of pipeline has not been studied enough to date. This article describes the process of stamping halves of stamped-welded elbows. During the stamping operation, the workpiece wall is thinned. The process of modeling this operation in a software of modeling by finite element method Deform-3D is described. The place of the greatest thinning of the wall was determined with the help of Deform-3D. The results of modeling and experimental production coincided. The main factors that may influence the degree of thinning were identified. Experimental calculations were performed in Deform-3D with a variation of these factors. As a result of the experiments carried out, the most significant factor was determined and an option was proposed to solve the problem of wall thinning. Solving this problem will help reduce the cost of production by 1.5 times.

Abstract: Pipes in power plants generally subjected to high pressures and temperatures. These are connected by elbow, T-joints to get the continuity between different stages. Due to excessive joints the outlet velocity and pressure will drops by considerable amount. Stresses will be produced due to high pressure and temperature of fluid flow, which in turn creates the failure of the pipes. The turbulence of the fluid passing through the pipes will also plays a vital role to decide the outlet pressure and velocity. In this present study pipes are connected by the elbow joint are considered and observed the effect of pipe thickness, turbulence intensity and length of elbow on outlet pressure, velocity, von mises stress and turbulence kinetic energy. It results that with increase in pipe thickness and length of elbow, the velocity, von mises stress and turbulence kinetic energy are decreases but with increase in turbulence intensity, the velocity and turbulence kinetic energy are increases.

Abstract: The local wall thinning(LWT) is a kind of common volume defect in pressure pipe. The limit loads of elbows with LWT under pressure, bending moment, torque and their combined loads have been studied in detail by orthogonal experimental design and finite element method. The results have shown that the influence of depth and circumferential length of LWT on the limit load is more obvious compared to that of axial length when an elbow is under pressure, bending moment or torque. The change of limit bending moment and torque with the depth of LWT and circumferential length is significant for an elbow under combined bending moment and torque. At last, the safety assessment equations for elbow under combined in-plane closing bending moment and torque were proposed by regression analysis.

Abstract: The elbow total implant is in appearance a simple orthopedic device, with few components and no complex mechanisms. In spite of the reported successful surgical interventions, there are still many medical reports which show that a certain percentage of the implants fails.In our work we conceptually approach a computer assisted design of a Coonrad-Morrey like total elbow implant and simulate the mechanical behavior by finite element analysis, for three different loads (10 N, 50 N, and 100 N). Materials used for simulation were Ti, TiNi and Ti6Al4V for the metallic components, and UHMWPE for bushing polymeric components. Through our results we confirmed the practical observations, namely that the hinge mechanism is an important region where the failures initiates from, as the highest stress is concentrated on the polymeric components.

Abstract: Elbow as common components in the gas pipeline fails easily to natural gas carrying solid particle erosion in the process of practical work. From the viewpoint of hydromechanics, the paper analyses the flow field distribution of manifold pressure and gas-solid trajectory by using the Gambit model and Fluent software in view of the right-angle elbow and numerical simulation of the adjacent manifold. The result obtains the situation about the manifold inner wall by the solid particle erosion wear. The simulation results show more intuitively the elbow, the most prone to erosion part in the manifold adjacent area and shape in erosion. Meanwhile, the paper analyses the factors affecting the occurrence and development of erosion.

Abstract: According to the principle of harmonious dimensions, the qualitative distribution model of the internal pressure on elbow pipes were determined; Through FLUENT numerical simulation, the internal pressure were given under 96 kinds of gas fluid conditions; By analyzing the variation of the internal pressure with flow and geometrical parameters, the variation of the internal pressure distribution within the elbow pipes has been studied; By means of 1stOpt nonlinear fitting package, the formula of three-dimensional internal pressure distribution was determined; Compared with the numerical results, the maximum relative error is 0.012%. The formula provides theoretical bases for strength check, the transport pipeline and wall thickness design of the high pressure, high velocity elbow.

Abstract: This paper discusses the plastic limit load of elbows without defects and with local thinned area (LTA) in the extrados under combined pressure and in-plane closing bending moment. Finite element analysis (FEA) and experiments have been used. The results of FEA show that, for the elbows without defects, when the ratio of pressure to the limit pressure (P/PL) is smaller than 0.469, the limit moment of elbows increases with the increasing pressure; when the ratio (P/PL) is bigger than 0.469, the limit moment of elbow decreases with the increasing pressure. For the elbows with LTA, the FEA results show that with different LTA the variation of the limit load of elbows to the pressure is different. Perhaps, the limit moment of elbows always decreases with the increasing pressure. It is also likely that the limit moment of elbows increases with the increasing pressure and then decreases with the increasing pressure. The results of FEA are consistent with the experimental results. By fitting the results of FEA, the safety assessment figure for elbows under combined pressure and in-plane closing bending moment is drawn.

Abstract: S elbow in Zhijing River is one of the key parts in the East Gas Transmission Pipeline Project. It brings a great deal of uncertainty and risk factors for pipeline pigging operations. By analysis on dynamic of pig pigging and the impact over bending, this paper established the finite element model, simulated pigging process on the condition that the operating parameters of the pipeline pigging operations were given, analyzed the relationship among pipeline pressure, foam pigging speed and pipe stress, then obtained the security of pipeline pigging operations.

Abstract: This paper gives an overview of erosion mechanisms in elbows in oil and gas production systems. The nature of the erosion process itself makes it very difficult to develop some definitive methods or models to prevent or predict the erosion in elbows in all conditions. This paper provides a review of the subject which will help petroleum engineers to handle the erosion problems in oil and gas industry. This review is given of different erosion mechanisms connected with sand erosion and the factors that influence them, and then the review goes on to look at particulate erosion in elbows in more details. Conclusions are then drawn based on the above analyses.