扩散段长度对侧式进/出水口水力特性的影响

以某上水库无调整段侧式进/出水口为研究对象，采用雷诺应力湍流模型探究了扩散段长度对进/出水口水力特性的影响规律，并从水力学的角度给出了扩散段长度建议值。结果表明：扩散段长度对侧式进/出水口水流运动存在显著影响，扩散段不宜过长或过短；对于进/出水口沿程流速分布，只有在抽水工况下扩散段长度才会对其产生影响，发电工况下基本不存在影响；对于水头损失、各孔口流量配比等其他水力指标，扩散段长度在双向过流时均会对其产生较大影响，随着扩散段长度的增加，各水力指标均先变好再变差；对于无调整段侧式进/出水口体型，当扩散段长度为隧洞直径的5.7～6.0倍时，各水力指标满足规范要求；当扩散段长度为隧洞直径的5.8倍时，进/出水口水力特性得到较大改善，且具有较好的水流流态。

Effects of diffusion section length on hydraulic characteristics of side inlet/outlet

Taking the side inlet/outlet of an upper reservoir without adjustment section as the research object, the Reynolds stress model was used to explore the influence of diffusion section length on the hydraulic characteristics of the inlet/outlet, and the recommended value of diffusion section length was given from the perspective of hydraulics. The results show that the length of the diffusion section has a significant influence on the water flow movement of the side inlet/outlet, and the diffusion section should not be too long or too short. The flow velocity distribution along the inlet/outlet can only be affected by the length of the diffusion section under the pumping condition, and there is basically no influence under the power generation condition. For other hydraulic indicators such as head loss and flow distribution at each orifice, the length of the diffusion section will have a greater impact on it when the flow is in both directions, and with the increase of the length of the diffusion section, the hydraulic indicators will first become better and then worse. For the body type of side inlet/outlet without adjustment section, when the length of the diffusion section is 5.7 to 6.0 times the tunnel diameter, the hydraulic indicators meet the requirements of the specification. When the length of the diffusion section is 5.8 times the tunnel diameter, the hydraulic characteristics of the inlet/outlet are greatly improved, and the water flow pattern is better.