某水电站泄洪洞挑流试验研究

Experimental Study on Deflecting Flow of Flood Discharging Tunnel of a Hydropower Station

针对某水电站泄洪洞出口原设计方案中存在明显的淘刷及较高的堆积体的情况,笔者采用水工模型动床试验,对比分析两种不同修改方案下的水舌入水流态及下游河道冲淤情况,对出口挑坎体形及布置方案进行调整优化。试验结果表明,采用斜切扩散坎,左侧挑坎底长10.1 m、出口挑角为15°,右侧挑坎底长12.0 m、出口挑角为17°,出口两侧扩散角为19.1°的布置方案有利于分散水流冲击力,河道沿程冲刷明显减轻,水舌横向扩散良好,仅有部分表面余能波及对岸山体。因此,推荐采用此方案进行泄洪洞出口挑坎体形设计和布置。

In view of the obvious scouring and high accumulation in the original design scheme of the outlet of the flood discharging tunnel of a hydropower station, the author uses the hydraulic model dynamic bed test to compare and analyze the flow pattern of the water tongue and the scouring and silting of the downstream channel under two different modification schemes, and adjust and optimize the shape and layout scheme of the outlet flip bucket. The test results show that the arrangement scheme of oblique diffusion bucket with the bottom length of10.1 m on the left side, the outlet flip angle of 15°, the bottom length of 12.0 m on the right side, the outlet flip angle of 17°and the diffusion angle of 19.1°on both sides of the outlet is conducive to dispersing the flow impact, significantly reducing the scouring along the river, good lateral diffusion of the water tongue, and only some surface residual energy waves and mountains on the opposite bank. Therefore, this scheme is recommended for the shape design and layout of the flip bucket of the flood discharging tunnel outlet.