掺气坎与过渡阶梯联合作用对阶梯面掺气特性的影响研究

阶梯溢流坝面的掺气特性是联合消能工发展的桎梏,而掺气坎与过渡阶梯对阶梯面掺气特性有积极的影响,通过水工模型的方法,结合阿海水电站进行12组试验。研究掺气坎高度11.67、16.67 mm和角度8°、10°以及4种组合过渡阶梯联合作用下,对阶梯面掺气特性的影响。结果表明:掺气坎角度10°、高度16.67 mm这种体型比其他7组掺气坎体型更优,故掺气坎角度与高度适当增加可使水流下缘接触阶梯面的位置后移,掺气空腔长度、掺气面积以及掺气浓度亦随之增大;并且在此掺气坎体型的基础上,过渡阶梯设置为25 mm×33.33 mm(宽×高)的大阶梯,阶梯面掺气特性相对其他3种体型更优,故过渡阶梯体型适度增加,更有利于过渡阶梯进行掺气。通过12组试验的结果分析得出,前置掺气坎角度为10°、高度为16.67 mm、过渡阶梯设置为25 mm×33.33 mm(宽×高)的大阶梯时,阶梯溢流坝面的掺气特性为12种方案中相对最优。

The Influence of the Combined Action of Aerator and Transition Steps on the Aeration Characteristics of Stepped Surface

The aeration characteristics of stepped spillway dam face are the fetter of combined energy dissipators development,and the aerator and transition steps have a positive effect on the aeration characteristics of stepped surface.This paper adopts the method of hydraulic model,twelve groups of experiments are carried out in combination with the Ahai hydropower station.The aerator of height 11.67 mm and 16.67 mm and Angle 8°and 10°and four groups transition steps,the impact on the aeration characteristics of stepped surface.The results show that the aerator angle of 10°and height of 16.67 mm better than seven other group of aerator.Therefore,with the aerator of angle and height increase properly,the position of the lower edge of the flow in contact with the step surface moves backward,the aerator of nappe length and area and concentration accompanies growth.On the basis of the shape of the aerator,the transition step is set as a large 25 mm 33.33 mm(width height)steps.The aeration characteristics of the step surface are better than those of the other three types of transition steps.Therefore,the moderate increase in the shape of the transition steps is more conducive to the aeration of the transition steps.Through an analysis of the results of 12 groups of experiments,the aerator angle of 10°and the aerator height of 16.67 mm and transition steps are set to 25 mm×33.33 mm(width x height)of the steps,the stepped spillway dam face of aeration characteristics will be relatively optimal for 12 schemes.