Numerical Analysis of Erosion Resistance of Elbow with Bionic Inner Surface Structure

Pipeline erosion is an important problem that cannot be ignored in gas-solid two-phase flow. Erosion damages not only waste materials, consume energy and reduce equipment efficiency, but also accelerate equipment failure and reduce service life of equipment, resulting in greater economic losses. To solve this problem, from the perspective of bionics, the anti-erosion characteristics of transverse groove bionic surface with the triangle groove, rectangle groove and isosceles trapezoidal groove in gas-solid two-phase flow elbow were designed by referring to the body surface morphology of desert tamarisk and desert scorpion, and the erosion law of the elbow with bionic surface was discussed under different flow rates and mass flow rates. The best combination of erosion resistance was obtained by orthogonal test simulation design. CFD-DPM method, Finnie erosion model and Realizable k-ε model with vortex modification were adopted to carry out numerical simulation on the anti-erosion characteristics of the elbow with bionic surface structure by considering the bidirectional coupling between particle and fluid and study the effect of different flow rates and particle mass flow rates on the erosion. On the basis of numerical simulation, orthogonal test method was used to analyze the effect of three main parameters of the triangle groove bionic structure on anti-erosion characteristics. The numerical simulation results showed that the erosion of the elbow with bionic surface structure mainly occurred at the bottom of the groove in the 35°-60° area of the elbow, and the erosion was less in the concave area at the top. The three kinds of groove surface bionic structures could improve the wear resistance of the elbow. The maximum erosion rate of the ordinary elbow was 1.2×10-4 kg/(m2·s). The triangle groove had the best erosion resistance, and the maximum erosion rate was 38.33% higher than that of the ordinary elbow, followed by that of rectangle groove, which was 28% higher, and that isosceles trapezoidal groove, which was only 8.33% higher. The variation trend of the maximum erosion rate of the three biomimetic surface structures was the same as that of the ordinary elbow at different flow rates and particle mass flow rates, and the order of anti-erosion performance did not change with the change of flow rates and particle mass flow rates. Orthogonal test results showed that the affecting factors of erosion in the triangle groove were groove spacing, groove width and groove depth in turn. Under the simulation conditions, the best combination was the triangle groove with width of 4 mm, depth of 4 mm and spacing of 3mm, and the anti-erosion performance was improved by 41.5% compared with that of ordinary elbow. The bionic surface structure of the groove enhances the turbulence intensity of the fluid, leading to the flow field change around the groove structure, which is easy to be drawn by the fluid and reduces the collision between the particles and the wall. The height difference between the top and bottom of the groove absorbs the kinetic energy of particle collision and reduces the collision velocity, thus reducing erosion. The surface bionic structure with the best erosion resistance is the triangle groove, rectangle groove and isosceles trapezoidal groove. The affecting factors of erosion in the triangle groove are groove spacing, groove width and groove depth. This conclusion can provide a new idea for the design of anti-erosion characteristics of elbow. © 2023 Chongqing Wujiu Periodicals Press. All rights reserved.