多弯段溢洪道糙条和导流墩联合消能工消能机理及布置型式研究

Affected by the terrain geological conditions, construction conditions and other factors, part spillways were designed to curving. There are as many as five bending sections in the 635 reservoir spillway in Xinjiang, when the flow disorder, the curve of ultra-high water, uneven horizontal velocity distribution, water shock wave and downstream erosion and other issues are caused by disordered flow. In the discharge chute, using roughness section and diversion piers combined energy dissipator, the project has run for many years better. At present, the research on how to arrange and shape the roughness section and the diversion piers still be at the initial stage, especially for the mechanism research about the energy dissipation by the roughness section was rarely reported. This project will aim at the combination of the roughness section and the diversion pier of the spillway section for the research object, using the PIV velocity measuring technology and FLUENT fluid simulation technology, through the theory analysis, model test and numerial simulation method combining the prototype observation, major research the hydraulic characteristics by adding the roughness section and the diversion pier in the spillway discharge chute, the energy decline rule and the layout method for the roughness section and the diversion piers, expound the mechanism of energy dissipation by the roughness section and the diversion piers in the discharge chute, reveal the effect regular by the parameters as the different arrangement type of the roughness section and the diversion pier to the energy dissipation rate and steady flow, establish the calculation method of the roughness section and the diversion piers in carved spillway. These can provide the theoretical basis for designing the similar project of the carved spillway.

受地形地质条件、施工条件等因素影响，部分溢洪道设计成弯曲溢洪道。新疆635水库溢洪道多达五个弯曲段，水流下泄时造成流态紊乱、弯道水面超高、横向速度分布不均、水流冲击波和下游冲刷等问题，在泄槽弯段内采用了糙条和导流墩联合消能工，工程运行多年效果较好。目前关于糙条和导流墩如何布置以及体型确定的研究尚处于起步阶段，尤其对糙条消能机理研究鲜有报道。本项目以溢洪道弯段设置的糙条和导流墩联合消能工为对象，采用PIV流速测量技术和FLUENT流体模拟技术，通过理论分析、模型试验和数值模拟方法并结合原型工程观测，重点研究溢洪道泄槽加设糙条和导流墩后的水力特性、水流能量削减规律以及高消能率时糙条和导流墩的布置型式，阐明糙条和导流墩在溢洪道弯段的消能机理，揭示不同布置型式的糙条和导流墩对其消能和稳流效率的影响规律，建立多弯段溢洪道糙条和导流墩联合消能工的计算方法，为类似多弯段溢洪道消能工设计提供理论依据。

受地形地质条件、工程特点、施工条件以及经济指标等因素约束，目前在我国实际工程中也出现了一些弯曲溢洪道，其中还有少数溢洪道甚至布置了两个及其以上弯道，如鲁布革水电站溢洪道。水流在流经弯道时，由于惯性离心力和坡降的共同作用，产生了弯道水面超高、横向速度分布不均、水流冲击波等问题，恶化了溢洪道流态；如何在保证其有充足泄洪能力的前提下，使其水流流态满足泄洪建筑物安全泄洪的要求是设计的难点重点。新疆“635”水库溢洪道是典型的多弯段溢洪道，为了解决上述的水流弯道飞溅紊乱问题，采用了糙条和导流墩联合运用的组合方式，导流墩通过介入水体控导水流，调整水流的流向与动量分布，能够使泄槽扩散段水流达到均匀扩散的效果，同时糙条消能作用明显，工程量相对较小，产生的水头损失一般不大，有效解决了陡坡急流弯曲溢洪道消能和导流难题。.基于此，课题以溢洪道弯段底部设置的糙条和导流墩联合消能工位研究对象，采用理论分析、模型试验、数值计算方法结合原型工程观测等研究方法，重点研究溢洪道泄槽加设糙条和导流墩后的水力特性、水流能量削减规律以及高消能率时糙条和导流墩布置型式，阐明糙条和导流墩在溢洪道弯段的消能机理，揭示糙条和导流墩不同布置型式对其消能和稳流效率的影响规律，建立多弯段溢洪道糙条和导流墩联合消能工的计算方法，为类似多弯段溢洪道消能工设计提供理论依据。.研究结果表明：糙条和导流墩联合消能工能够很好的起到消能导流作用，特别是在弯道宽深比B•H-1>10时，联合消能工在导流方面有传统消能工无法取代的优势。糙条和导流墩联合消能工可将表面旋涡转换成淹没状态，有效增加底流与表流之间的剪切和掺混作用，加快能量的转移与耗散。糙条消能工相对高度为0.4H（H为入弯前断面水深）、角度为30°、布置率为25%时，对弯道水流冲击波改善效果较好。糙条消能工高度、消能率多因素影响模型等半理论半经验公式，可为糙条和导流墩消能工的广泛推广提供理论依据。