V型掺气坎在龙抬头式泄洪洞中的应用

本文通过试验研究,从掺气坎后空腔区的三维形态考虑,提出了一种新型V型槽式掺气坎(简称V型坎),其主要特点是:坎后射流水舌的流速、挑角和高程沿中心向两侧保持连续变化,其水舌落水点范围即空腔长度成为一连续变化的曲线,且沿曲线水流流速亦呈连续变化,很好地减弱或消除了龙抬头式泄洪洞掺气坎后水流落水处产生的回水.在V型坎出口断面处,水流的三维扩散充分,水舌与空腔的接触面明显增大,对底空腔长度、通气量等掺气特性指标都有明显改善.

Experimental study on V-type aerator for spillway tunnel with inlet raised

A new type of aerator for spillway tunnel with inlet raised was studied in model test.The bucket angle and elevation of the aerator are linearly varies in the crosswise direction so that the velocity distribution,water depth and angle of the trajectory of the jet nappe are linearly vary from the center to both sides. It is found that the backwater in the air chamber beneath the nappe is eliminated.The strong turbulence takes place at the bilateral edges of the nappe contributing more aeration to the flow.The 3-D diffusion of the jet flow formed by this type of aerator is stronger than the traditional aerators and much more air will be entrained into the flow.