高水头旋流阻塞复合内消能工水力特性研究

旋流阻塞复合内消能工是适用于高坝泄洪消能的一种新型消能工，为了分析其在超高作用水头下的泄洪消能适用情况，采用模型试验与数值模拟相结合的方法，对200 m作用水头条件下该消能工的水力特性进行了研究。结果表明：泄流量为1 547 m³/s，略大于设计值，满足泄流要求；洞内形成了稳定的空腔旋流，旋流洞段空腔直径约6~7 m，旋流角约60°，壁面压强约110×9.8 kPa，最大点流速约45 m/s；起旋器与旋流洞段为0.050~0.274 Hz的低频脉动，且水流空化数均大于1.2，运行安全；阻塞扩散段末端最小瞬时负压为-3.81×9.8 kPa，且水流空化数较小，但水流掺气率较高，有利于减免发生空蚀；阻塞扩散段末脉动优势频率为46.99 Hz；总消能率达82.1%，消能率高。研究成果可为该复合消能工在高水头下的泄洪消能应用提供参考。

Hydraulic characteristics of swirling-blocking composite internal energy dissipator with high water head

The swirling-blocking composite internal energy dissipator is a novel energy dissipator which is applicable to the flood discharge and energy dissipation of high dams. In order to analyze its application to the flood discharge and energy dissipation of dams with ultra-high water head, its hydraulic characteristics under the condition of 200 m water head are studied by means of physical model test and numerical simulation. The results show that with the application of this novel dissipator, the discharge is 1 547 m³/s, which is slightly larger than the design value but can still meet the discharge requirements. There is a stable swirling flow in the cavity, and the diameter of the cavity in the swirling section is about 6-7 meters, with a swirling angle of about 60°. In the swirling section, the wall pressure is about 110×9.8 kPa, and the maximum point velocity is about 45 m/s. There is a low frequency pulsation between the swirling flow generator and the swirling section, which is 0.050 to 0.274 Hz, and the cavitation number is greater than 1.2, indicating that the discharge operation is safe. The minimum instantaneous negative pressure at the end of the blocking diffusion section is -3.81×9.8 kPa, and the cavitation number of the flow is small; however, the possibility of cavitation would be greatly reduced due to the high aeration rate of the flow. The dominant frequency of the flow at the end of the diffusion section is 46.99 Hz and the total energy dissipation rate is as high as 82.1 %. The research results can provide some reference for the application of the composite energy dissipator to the flood discharge and energy dissipation of dams with high water head.