Department of Civil Engineering, Higher Education Complex of Bam, P.O. Box 76615314, Bam, Iran.
Department of Water Engineering, Faculty of Civil and Surveying Engineering, Graduate University of Advanced Technology, P.O. Box 76315116, Kerman, Iran.
Sci Rep. 2023 Jan 30;13(1):1679. doi: 10.1038/s41598-023-28762-2.
In urban wastewater collection and drainage networks, vortex structures are recruited to transfer fluid between two conduits with significant level differences. During the drop shaft, in addition to preventing the fluid from falling due to vortex flow formation, a significant amount of the fluid energy is dissipated due to wall friction of vertical shaft. In the present study, by constructing a physical model with a scale of 1:10 made of Plexiglas, the energy dissipation efficiency in the vertical shaft has been investigated. In this way, the performance of dimensional analysis indicates that the flow Froude number (Fr) and the ratio of drop total height to shaft diameter (L⁄D) are parameters affecting the efficiency of flow energy dissipation in the vertical shaft (η). This research considers four levels of Fr factor (1.77, 2.01, 2.18, and 2.32) and three levels of L⁄D factor (10, 13, and 16). Additionally, four replications for 12 possible combinations allow us to carry out 48 experiments and the full factorial method. The results demonstrated that the energy dissipation efficiency in the vertical shaft changes varies from 10.80 to 62.29%. Moreover, η values decrease with an increase in Fr whereas the efficiency increases with increasing L⁄D ratio. Furthermore, the regression analysis gave a second-order polynomial equation which is a function of Fr and L⁄D to accurately estimate the flow energy dissipation efficiency in the vertical shaft.
在城市污水收集和排水管网中，涡旋结构被用来在具有显著高差的两个管道之间传输流体。在下降井中，除了防止由于涡旋流动形成而导致流体下降之外，大量的流体能量由于垂直井筒的壁面摩擦而耗散。在本研究中，通过构建一个比例为 1:10 的有机玻璃物理模型，研究了垂直井筒中的能量耗散效率。这样，量纲分析的性能表明，流弗劳德数 (Fr) 和下降总高度与井筒直径比 (L⁄D) 是影响垂直井筒中流动能量耗散效率 (η) 的参数。本研究考虑了 Fr 因子的四个水平 (1.77、2.01、2.18 和 2.32) 和 L⁄D 因子的三个水平 (10、13 和 16)。此外，四个复制为 12 个可能的组合允许我们进行 48 个实验和完全析因法。结果表明，垂直井筒中的能量耗散效率变化范围为 10.80%至 62.29%。此外，η 值随 Fr 的增加而减小，而效率随 L⁄D 比的增加而增加。此外，回归分析给出了一个二次多项式方程，它是 Fr 和 L⁄D 的函数，可准确估计垂直井筒中的流动能量耗散效率。
