引黄灌区首部枢纽泥沙输移特性与流速试验研究

Experimental study on sediment transport characteristics and velocity of first hub in Yellow River Diversion Irrigation District

为了探究引黄灌溉枢纽挟沙水流沿程含沙量变化规律和悬移质泥沙的垂向分布规律,推求首部枢纽有害泥沙悬浮的临界不淤流速,阐明减少有害泥沙引入的措施与方法,以提高输配水利用效率.以山西尊村灌区为主要研究对象,通过对一级站首部枢纽2019年5—7月取黄河水样及工况、断面流速、水深、水面宽度数据监测,分析了泥沙含量、沉起流速,采用马尔文Mastersizer 3000仪器处理分析了粒径级配,修正了适用于尊村灌区首部枢纽的挟沙力、扬动流速公式.结果表明:干渠黄河水泥沙含量与来水工况呈正相关;尊村灌区所引黄河泥沙粒径以0.006~0.200 mm为主;尊村灌区淤积与黄河口流速及粒径大小密切相关.建议增长泵前黄河口输水距离,流速控制在0.30 m/s左右,同时对引水口清淤;干渠以大于2.06 m/s流速定时冲刷.实际运行中单机组工况应控制在7.50 m^(3)/s左右以减少有害泥沙引入,干渠流速控制在0.42 m/s左右,输配水效率最高.

In order to explore the variation law of sediment content and vertical distribution law of suspended sediment along the sand-carrying flow of the Yellow River Diversion Irrigation Project,deduce the critical non silting velocity of harmful sediment suspension in the first project was calculated.The measures and methods to reduce the introduction of harmful sediment were elucidated,so as to improve the utilization efficiency of water transportation and distribution.Taking Zuncun Irrigation District in Shanxi Province as the main research object,the sediment content and settling velocity were analyzed by monitoring the water samples of the Yellow River which taken from May to July 2019,the data of working conditions,section velocity,water depth and water surface width.The particle size gradation was analyzed by using the Malvern Mastersizer 3000 instrument.The formulas of sand-carrying capacity and uplifting velocity applied to the first junction of Zuncun Irrigation District were modified.The results show that there is a positive correlation between sediment content and inflow conditions.The sediment particle size of the Yellow River sediment in Zuncun Irrigation District is mainly 0.006-0.200 mm.The siltation in Zuncun Irrigation District is closely related to the velocity and particle size of the Yellow River estuary.It is suggested to increase the water delivery distance of the Yellow River estuary before the pump,control the flow rate at about 0.30 m/s,and clear the silt at the inlet.The main channel is scoured regularly at a flow velocity that larger than 2.06 m/s.In actual operation,the wor-king condition of single unit should be controlled at about 7.50 m^(3)/s to reduce the introduction of harmful sediment.The flow velocity in the main channel should be controlled at about 0.42 m/s to achieve the highest water delivery and distribution efficiency.