Effect of Inclined‐Tube on the Removal Performance of Fine Sediment in a Gravity Sedimentation Tank

ABSTRACT Addressing limitations in fine sediment particle removal within gravity sedimentation tanks, this study investigates three inclined tube configurations: straight with an angle of 60° (ITS), V‐shaped with angles of 60° and 60° (ITV1) and V‐shaped with angles of 60° and 45° (ITV2), alongside a control group without inclined tubes. Three sediment sizes (0–150, 0–200 and 0–250 μm) and two flow rates (36 and 72 m 3 ·h −1 ) were tested. Numerical simulations were conducted to examine the mechanisms behind sediment removal. Compared with the control, the use of inclined tubes significantly reduced the sediment concentration by 34%–64% and the median particle size by 36%–65%. V‐shaped tubes outperformed straight tubes, especially the ITV2. This improvement was attributed to flow redistribution, expanding the sedimentation area, while the sedimentation tubes promote better flow uniformity than straight tubes through secondary flow redistribution. Furthermore, the inclined tubes showed notable differences in the removal of large, medium and small particles, with the most significant reduction in medium‐sized particles, achieving a 36%–65% decrease compared with that of the control. This study clarifies the effects of different inclined tube designs on fine sediment removal, providing insights for optimizing sedimentation tanks in agricultural irrigation systems.