中文摘要：

某水电站尾水渠扩散段在工程设计时为提高过流能力,实现尾水洞出口断面低水位运行,采取较大扩散角的布置形式.模型试验表明：设计方案下扩散段流态紊乱,过流能力较低.先后采取在扩散段设置控导流设施、减小扩散段的扩散角、调整闸室位置与修改闸室及上、下游连接段体型等3种修改方案进行试验研究.其中第3种修改方案较好地顺应了水流的流动特性,尾水渠各流段流态平顺,过流能力相对较强,实现了尾水洞出口断面较低水位运行;同时节省工程量,基本达到预期效果.该水力优化措施已应用于工程设计.

英文摘要：

In order to improve the flow capacity,and make the outlet section of tailrace tunnel operating with low water level,the diffusion section of tailrace in a hydropower station was arranged the layout with large diffusion angle. The results from model experiments show that the diffusion section has disordered flow regime and low flow capacity. Then we designed three modified schemes,namely setting up control and diversion facilities and reducing the diffusion angle in the diffusion section,changing the location and shape of the lock chamber and modifying the figure of the connected section between upstream and downstream,and researched the flow capacity under three modified schemes by experiments. The experimental results show that the third scheme better conforms to the characteristics of water flow,the flow regime remains steady in every sections of the tailrace,the flow capacity is relatively strong,the outlet section of tailrace tunnel is realized to operate with lower water level. In addition,this scheme reduces the workload and basically achieves the expected results. This hydraulic optimized measures have already been applied to practical engineering design.