改进直线型沉沙池在农业微灌中的运行效果

针对传统直线型沉沙池存在的泥沙去除率低、适应性弱和占地面积大等缺点,基于泥沙沉淀特性、水流特性和泥沙在池内的分布特征,对引流段和溢流堰进行改进;结合涡流排沙原理,在溢流堰后部设置涡流管,实现双重沉沙.通过搭建物理模型,测试沉沙池不同点位水流流速、泥沙粒径及质量分数,研究双重沉沙池泥沙沿程变化规律及沉沙率.结果表明:一重沉沙主要为推移质泥沙;二重沉沙主要为悬移质泥沙,相对于无溢流槽和涡管其沉沙率分别提高了12.70%和18.80%;系统总的沉沙率可达到96.88%以上,极大提高了池内泥沙的沉沙率,充分说明改进后的沉沙池对改善泥沙沉降效果的作用显著.研究结果可为微灌工程的大规模推广应用提供一定的技术支撑.

Operation effect of improved straight-line desilting basin in agricultural micro-irrigation

Aiming at the disadvantages of traditional straight-line desilting basin, such as low sediment removal rate, weak adaptability and large footprint area, based on sediment deposition cha-racteristics, flow characteristics and sediment distribution characteristics in the tank, the drainage section and overflow weir were improved. Combined with the principle of eddy current sediment ejection, vortex tubes were set at the back of overflow weir to achieve double desilting. A physical model was built to test the flow velocity, sediment grain size and concentration at different points of the desilting basin, and to study the sediment variation law by distance and the underflow rate of the double desil-ting basin. The results show that single trial sediment is mainly bed load sediment, and the quantity of precipitate is more than 95%. The second trial sediment is mainly suspended sediment load, which is increased by 12.70% and 18.80% compared with the desilting basin without spillway trough and vortex tube. The total bed cleaning efficiency of the system can reach more than 96.88%, which greatly improves the underflow rate of sediment in the pool. It fully shows that the improved desilting basin can significantly improve the sediment settling effect, and the research results can provide some technical support for the large-scale application of micro-irrigation engineering.