Erosion and Wear Characteristics of Y-Shaped Bifurcated Pipes

[Objective] Designing the shape of bifurcated pipes has long been a focus in water diversion projects. Current research on the erosion of pipes by sediment-laden flows remains limited, and studies specifically on the erosion and wear of Y-shaped bifurcated pipes are even rarer. This study aims to investigate the erosion and wear characteristics of Y-shaped bifurcated pipes and optimize their shape. [Methods] We employed numerical simulation and physical model experiments to investigate the solid-liquid two-phase flow within Y-shaped bifurcated pipes during the standalone operation of the main pipe. The influence of an elliptical arc chamfer scheme on the hydraulic and wear characteristics of the bifurcated pipe was explored. The numerical simulation results demonstrated strong consistency with the experimental data, validating the reliability of the numerical simulation method. [Results] (1) During standalone operation of the main pipe, compared with the bifurcated pipe with a circular arc chamfer, the bifurcated pipe with an elliptical arc chamfer had a more open space and gradual variations in the flow cross-section, resulting in smoother internal flow patterns. Its head loss coefficient was smaller, reduced by 6.9% compared to the circular arc chamfer pipe. The local low-pressure distribution at the bifurcation angle significantly improved, and the minimum pressure increased by 1.47 m water head compared with the circular arc chamfer bifurcated pipe, indicating that the elliptical arc chamfer bifurcated pipe could effectively improve the low-pressure distribution and enhance the bifurcated pipe’s cavitation resistance. (2) When the main pipe operated independently, the wear on the bifurcated pipe was most severe near the inlet and outlet of the main pipe, followed by the crotch area, while the branch pipe area experienced the least wear. The particle mass flow rate had the greatest impact on the wear distribution of the bifurcated pipe, followed by the particle impact velocity. By adopting an elliptical arc chamfer, the water flow could move smoothly, and the mass flow rate of particles acting on the pipe walls was reduced, thereby mitigating wear at the main pipe outlet and the crotch area of the bifurcated pipe. The average wear at the corresponding positions was reduced by 22.26% and 21.03%, respectively, compared to the circular arc chamfer bifurcated pipe. [Conclusions] During standalone operation of the main pipe, compared with bifurcated pipes with a circular arc chamfer, bifurcated pipes with an elliptical arc chamfer demonstrate a 1.47 m water head increase in minimum pressure and significant reduction in abrasion at the main pipe outlet and the crotch area. These findings indicate that elliptical arc chamfer bifurcated pipes effectively enhance both cavitation resistance and abrasion resistance of bifurcated pipes, providing valuable references for bifurcated pipe design.