摘要
旋流排沙渠道是基于旋转水流的特点提出的一种水沙分离新技术,为明确不同来流条件对旋流排沙渠道排沙特性的影响,该研究通过物理模型试验探究了来流流量、来流流速、泥沙级配及下游渠道水力条件下旋流排沙渠道的排沙、余沙及淤沙特性,分析了其截沙率变化规律。结果表明,当来流条件改变时,旋流排沙渠道的排沙特性发生规律性变化,在来流流量增加或流速增加或来沙中值粒径减小情况下,旋流排沙渠道的排沙量减小,余沙量增加,其中改变来流流量对截沙率的影响最为明显,最大变幅为16.3%。不同水沙条件下0.075~0.315 mm细颗粒泥沙的排沙量及余沙量均存在较大差异,且下游渠道余沙均以该粒径区间的泥沙为主,而粒径>0.315~3.0 mm泥沙的排除效果受水沙条件改变的影响极小。排沙洞内泥沙淤沙量随来流量和泥沙中值粒径的增加而增加,而随流速的增加而减少,但各水沙条件下最大淤沙量仅为来沙量的2.6%。在渠道下游设置挡水板后,旋流排沙渠道的排沙性能得到进一步提升,提高了粒径>0.16~0.315 mm泥沙的排除效果,与不设挡水板相比截沙率增加了4.6个百分点,改善了排沙洞内的泥沙淤积问题。旋流排沙渠道具有良好的泥沙分选效果,能有效排除高含沙水流中的粗颗粒泥沙(在不同水沙条件下最小截沙率为76.9%),从而减少了泥沙对渠道下游设施的影响,因此工程中可通过优化流量、流速、下游水力条件等提升旋流排沙渠道的排沙特性。该研究明确了不同水沙条件下旋流排沙渠道的适用性,成果可为其在工程中的设计和应用提供参考。
The desilting channel with a swirling flow is an alternative novel technology for the water–sediment separation. The reason is that the swirling flow can be used to effectively separate the water and sediment. The obstruction of water diversion channels and abrasion of hydraulic machinery can also be reduced when diverting the water from sediment-laden rivers. This study aims to clarify the impact of different water and sediment conditions on the sediment characteristics in the desilting channel with a swirling flow. The physical tests were carried out to determine the expelled, the residual, and the deposited sediment along the downstream of the channel. In addition, the sediment trapping efficiency was evaluated under the incoming flow rate, the incoming flow velocity, the sediment gradation, and the hydraulic conditions. The results indicated that there was a regular variation in the sediment characteristics in the desilting channel with a swirling flow under the incoming flow.Specifically, the mass of expelled sediment decreased, when the incoming flow rates or the velocity increased, or the median particle size of incoming sediment decreased during this time. By contrast, the residual sediment mass increased to change the inflow rate during the sediment trapping, where the maximum variation amplitude was 16.3%. There was a great difference in the expelled sediment mass and the residual sediment mass of fine sediment with a particle size of 0.075-0.315 mm under various water and sediment conditions. The residual sediment was dominated in the downstream channel in the particle size range. Nevertheless, there was little difference in the removal of the sediment with the particle size >0.315-3.0 mm, as the water and sediment conditions changed. The mass of the deposited sediment in the sediment transport pipe increased with the increase of the incoming flow rate and the median particle size of sediment but decreased with the increase of the incoming flow velocity in the upstream channel. The maximum mass of th
作者
南军虎
汪超群
李伟
高欢
陈垚
代江龙
陶然
马康宁
Nan Junhu;Wang Chaoqun;Li Wei;Gao Huan;Chen Yao;Dai Jianglong;Tao Ran;Ma Kangning(School of Energy and Power Engineering,Lanzhou University of Technology,Lanzhou 730050,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2022年第14期127-135,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金资助项目(52069011)
甘肃省教育厅产业支撑计划项目(2021CYZC-27)。
关键词
泥沙
试验
旋流排沙渠道
截沙率
排沙
余沙
淤沙
sediments
experiments
desilting channel with a swirling flow
sediment trapping efficiency
expelled sediment
residual sediment
deposited sediment
