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Erosion damage in a standard elbow [2].

Erosion damage in a standard elbow [2].

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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 different vertical return bends: Sharp bend, standard elbow, 180° pipe bend, and long elbow. The airow in the pipe was simu...

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... addition, the secondary ow, usually formed in the curvature downstream, changes the movement of the particles and results in a greater particle impingement on the walls [1]. Figure 1 shows erosion damage to the inner wall of a standard elbow along the outer radius [2]. ...
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... perform the butterry grid, the pipe cross-section is divided into ve blocks, as shown in Figure 4(a), and structured quadrilateral grid is applied to the blocks; then, the grid is extended to the entire pipe. In this Figure, N1 and N2 are the numbers of grids on the lines on the cross-section. The distance of the rst node to the surface is 0.025 mm, which leads to a mean value of y+ of 1 on the rst node away from the wall. ...
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... ows with low viscosity and density, particle Stokes number is usually greater than 1, and the sand particles do not follow the streamlines and gain direct forward motions, which in turn lead to severe collisions with the walls and, subsequently, a high level of erosion. The maximum erosion rate for diierent particle mass ow rates is shown in Figure 10 for the sharp elbow. On average, the erosion rate caused by 300 m particles at the rst bend is by 20% higher than that of 150 m particle at the same particle ow rates. ...
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... within the distance between the two bends, the 150 m particles accelerate to a higher velocity due to their smaller mass and cause a greater erosion rate at the second bend compared to 300 m particles. Mean particle velocity contours in several sections between the two bends are depicted in Figure 11. It is seen that the 150 m particles at the distance between the two bends accelerate to a higher velocity than 300 m particles and have a higher particle-wall impact velocity at the second bend. ...
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... the eeect of particles' diameter on the erosion rate is not much as compared to particle velocity in this geometry. In addition, Figure 10 shows that the erosion rates caused by 300 and 150 m particles at the second bend are lower by 59% and 37%, respectively, as compared to the rst bend. ...
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... Figure 12, the contours of erosion rate are shown for the particles of 300 m and ow rate of 10 kg/day at the rst and second bends. In this case, the maximum erosion occurs at the rst bend and along the line on the outer wall, as shown in Figure 13. ...
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... Figure 12, the contours of erosion rate are shown for the particles of 300 m and ow rate of 10 kg/day at the rst and second bends. In this case, the maximum erosion occurs at the rst bend and along the line on the outer wall, as shown in Figure 13. The proole of the erosion rate along this line is depicted in Figure 13. ...
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... this case, the maximum erosion occurs at the rst bend and along the line on the outer wall, as shown in Figure 13. The proole of the erosion rate along this line is depicted in Figure 13. This gure shows that the peak in the erosion rate is located on the outer wall and in the direction of the pipe center. ...
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... 300 m particles, however, the erosion rate at the second bend is 40% lower than that at the rst bend. The erosion rate contours for 300 m particles for the rst and second bends are shown in Figure 14. The maximum erosion at the rst and second bends occurs at angles of 42 and 58 , respectively. ...
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... contour of the erosion rate caused by 300 m particles in the long elbow is shown in Figure 15. Under the same conditions, the maximum erosion rates caused by both 150 and 300 m particles are on average 26% lower than that of the standard elbow at the rst bend. ...
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... erosion pattern at the second bend is similar to that at the rst bend, yet with lower intensity. This is consistent with Figure 16, where the maximum erosion rate at diierent particle mass ow rates for the second bend is lower than that for the rst bend. Wang and Shirazi [37] developed an equation for the ratio of the erosion rate of long elbow (ER r=D ) and standard elbows (ER std ). ...
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... on this equation, the erosion rate caused by 150 and 300 m particles carried by air in long elbows (r=D = 3) is 20% lower than that of standard elbow, which is in good agreement with the results of this study. For the 180 pipe bend, the proole of the erosion rate caused by 300 m particles at diierent angles is shown in Figure 17. In addition, it is shown that the maximum erosion occurs at 18 from the inlet of the bend. ...
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... the same conditions, the erosion is decreased by 67%, 64%, and 52% for sharp bend and standard and long elbows, respectively, when the 180 pipe bend is used. The contour of the erosion rate caused by 300 m particles in the 180 pipe is shown in Figure 18. For this connguration, the location of maximum erosion is similar for 150 m sand size. ...
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... to the increased curvature of return bend and a consequent decreased disturbance in the ow eld, the erosion rate is signiicantly reduced. The maximum erosion rate at diierent mass ow rates is shown in Figure 19. According to this gure, the eeect of particles' diameter on the erosion rate is not much in this geometry. ...
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... the same conditions, employing 180 pipe Figure 19. Maximum erosion rate at the 180 pipe bend with respect to the particle mass ow rate. ...
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... addition, the secondary yow, usually formed in the curvature downstream, changes the movement of the particles and results in a greater particle impingement on the walls [1]. Figure 1 shows erosion damage to the inner wall of a standard elbow along the outer radius [2]. ...
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... perform the butterry grid, the pipe cross-section is divided into ove blocks, as shown in Figure 4(a), and structured quadrilateral grid is applied to the blocks; then, the grid is extended to the entire pipe. In this Figure, N1 and N2 are the numbers of grids on the lines on the cross-section. The distance of the erst node to the surface is 0.025 mm, which leads to a mean value of y+ of 1 on the erst node away from the wall. ...
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... dows with low viscosity and density, particle Stokes number is usually greater than 1, and the sand particles do not follow the streamlines and gain direct forward motions, which in turn lead to severe collisions with the walls and, subsequently, a high level of erosion. The maximum erosion rate for diierent particle mass sow rates is shown in Figure 10 for the sharp elbow. On average, the erosion rate caused by 300 m particles at the erst bend is by 20% higher than that of 150 m particle at the same particle eow rates. ...
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... within the distance between the two bends, the 150 m particles accelerate to a higher velocity due to their smaller mass and cause a greater erosion rate at the second bend compared to 300 m particles. Mean particle velocity contours in several sections between the two bends are depicted in Figure 11. It is seen that the 150 m particles at the distance between the two bends accelerate to a higher velocity than 300 m particles and have a higher particle-wall impact velocity at the second bend. ...
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... the eeect of particles' diameter on the erosion rate is not much as compared to particle velocity in this geometry. In addition, Figure 10 shows that the erosion rates caused by 300 and 150 m particles at the second bend are lower by 59% and 37%, respectively, as compared to the erst bend. ...
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... Figure 12, the contours of erosion rate are shown for the particles of 300 m and dow rate of 10 kg/day at the erst and second bends. In this case, the maximum erosion occurs at the erst bend and along the line on the outer wall, as shown in Figure 13. ...
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... Figure 12, the contours of erosion rate are shown for the particles of 300 m and dow rate of 10 kg/day at the erst and second bends. In this case, the maximum erosion occurs at the erst bend and along the line on the outer wall, as shown in Figure 13. The proole of the erosion rate along this line is depicted in Figure 13. ...
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... this case, the maximum erosion occurs at the erst bend and along the line on the outer wall, as shown in Figure 13. The proole of the erosion rate along this line is depicted in Figure 13. This sgure shows that the peak in the erosion rate is located on the outer wall and in the direction of the pipe center. ...
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... 300 m particles, however, the erosion rate at the second bend is 40% lower than that at the erst bend. The erosion rate contours for 300 m particles for the erst and second bends are shown in Figure 14. The maximum erosion at the erst and second bends occurs at angles of 42 and 58 , respectively. ...
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... contour of the erosion rate caused by 300 m particles in the long elbow is shown in Figure 15. Under the same conditions, the maximum erosion rates caused by both 150 and 300 m particles are on average 26% lower than that of the standard elbow at the rst bend. ...
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... erosion pattern at the second bend is similar to that at the erst bend, yet with lower intensity. This is consistent with Figure 16, where the maximum erosion rate at diierent particle mass sow rates for the second bend is lower than that for the rst bend. Wang and Shirazi [37] developed an equation for the ratio of the erosion rate of long elbow (ER r=D ) and standard elbows (ER std ). ...
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... on this equation, the erosion rate caused by 150 and 300 m particles carried by air in long elbows (r=D = 3) is 20% lower than that of standard elbow, which is in good agreement with the results of this study. For the 180 pipe bend, the proole of the erosion rate caused by 300 m particles at diierent angles is shown in Figure 17. In addition, it is shown that the maximum erosion occurs at 18 from the inlet of the bend. ...
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... the same conditions, the erosion is decreased by 67%, 64%, and 52% for sharp bend and standard and long elbows, respectively, when the 180 pipe bend is used. The contour of the erosion rate caused by 300 m particles in the 180 pipe is shown in Figure 18. For this connguration, the location of maximum erosion is similar for 150 m sand size. ...
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... to the increased curvature of return bend and a consequent decreased disturbance in the eow weld, the erosion rate is signiicantly reduced. The maximum erosion rate at diierent mass sow rates is shown in Figure 19. According to this sgure, the eeect of particles' diameter on the erosion rate is not much in this geometry. ...
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... the same conditions, employing 180 pipe Figure 19. Maximum erosion rate at the 180 pipe bend with respect to the particle mass sow rate. ...

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