Experimental investigation of the diameter and length effects of the dendritic, bottomless, extended structure on reservoir sediment removal efficiency by flushing
Experimental investigation of the diameter and length effects of the dendritic, bottomless, extended structure on reservoir sediment removal efficiency by flushing
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DOI：
10.1016/j.jher.2022.09.002
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发表时间：
2022-10-03
影响因子：
2.8
通讯作者：
Beiramipour, Sepideh
中科院分区：
文献类型：
--
作者：
Haghjouei, Hadi;Rahimpour, Majid;Beiramipour, Sepideh
坝前泥沙淤积是水库可持续发展的主要障碍。由于合适的新坝址的可获得性有限，低效的泥沙管理的后果与社会经济关切和环境问题有关。现有的大多数泥沙管理技术对于干旱和半干旱地区来说是不可接受的，因为它们对可用水的储存和发电有影响。因此，压力冲洗是一种经济的排沙方法，因为它通过底部出水口释放的水很少。然而，加压冲洗的主要缺点之一是底孔附近的泥沙清除有限。本文研究了树枝状无底延伸(DBE)结构对冲刷锥体向更广区域发展的影响。进行了四种不同直径(125、160、200和250 mm)、四种不同长度(30、50、80和110 cm)和三种放电速率(12.5、15和18 L/S)的几个实验，以确定最有效操作的扩展结构的尺寸。结果表明，长度无量纲指数为LDBE/DO=10，直径无量纲指数DDBE/DO=1.14，出水流量无量纲指数Fro=1.82的DBE结构与参考试验相比，冲沙锥尺寸和泥沙去除效率提高了36.55倍。最后，通过对计算结果的统计分析，提出了泥沙冲刷锥度的无量纲计算公式。文中给出了两张示意图，以说明冲刷距离、建筑物长度和直径与出水口流量之间的关系。
Sedimentation in front of a dam is the main obstacle against reservoir sustainability. Due to the limited avail-ability of suitable new dam sites, the ramifications of inefficient sediment management are associated with socio-economic concerns and environmental issues. Most of the existing sediment management techniques are unfa-vorable for arid and semi-arid regions due to their impacts on available water storage and power generation. Therefore, pressure flushing is an economical desilting method as it releases little water through the bottom outlet. However, one of the main disadvantages of pressurized flushing is limited sediment removal near the bottom outlet. In this paper, the impacts of a dendritic, bottomless, and extended (DBE) structure were inves-tigated to develop the scour cone to a broader area. Several experiments were carried out with four different diameters (125, 160, 200, and 250 mm), four different lengths (30, 50, 80, and 110 cm), and three discharge rates (12.5, 15, and 18 L/s), to identify the dimensions of the extended structure with the most efficient oper-ation. The results indicated that the DBE structure with a length dimensionless index of LDBE/Do = 10, a diameter dimensionless index of DDBE/Do = 1.14, and an outflow discharge dimensionless index of Fro = 1.82, yielded a 36.55-fold increase in the sediment flushing cone dimensions and sediment removal efficiency compared to a reference test. Finally, a dimensionless equation is presented for calculating the sediment flushing cone di-mensions, according to a statistical analysis of the results. Two diagrams are provided to illustrate the interre-lationship between the distance limits of scour, length, and diameter of the structure and outlet discharges.