泄水闸堰前冲刷机理及减淤措施研究

摘要

The bulkhead gate of low-head navigation-power junction could not open and close normally because of sediment deposition in the upstream of weir,affecting the inspection and maintenance of sluice gate.In view of this,we established movable-bed physical model and 3D mathematical model of sluice gate to analyze the three di-mensional flow field and turbulent kinetic energy distribution in the upstream of the gate.We also observed the scouring effect in the presence of different operation modes of the gate.Results suggest that sediment’s incipient motion is not only related with the flow velocity at gate bottom,but also affected by the flow pattern and turbulence intensity in front of the gate.It is also affected by the increase of turbulent kinetic energy.When the outlets of gate were opened in intervals,vortexes were formed near the gate wall,and complex three-dimensional flow patterns oc-curred in front of the gate.In this case better scouring effect can be achieved than that when sluice gate is opened continuously.%低水头航电枢纽堰前泥沙淤积将导致检修闸门无法正常启闭，影响到泄水闸的检修、维护工作。针对此问题，建立了用于研究闸前三元流的泄水闸物理模型及数学模型，运用动床物理模型试验和三维数学模型计算研究了闸前的三维流场及紊动能分布，并观测了闸门不同调度方式下的堰前冲沙效果。结果表明：泄水闸堰前泥沙启动不仅与闸底水流流速有关，也与闸前的水流流态及紊动强度有关，紊动能的增强对泥沙启动的影响作用明显；闸门隔孔开启时水流受挡水闸阻水作用，在闸前近壁区水流下潜形成漩涡，闸前呈现复杂的三元流流态；复流态下的紊动能显著增加，强烈的紊动造成闸前床面泥沙大量启动，比连续开启泄水闸更有利于泥沙的起动，达到较好冲刷效果。