龙抬头水电站泄洪洞水力特性研究

针对青海省某大型水电站龙抬头泄洪洞工程,采用计算流体力学软件Flow-3D,应用RNG k-ε紊流模型、VOF方法,对泄洪洞整体水力特性进行三维数值模拟研究,得到泄洪洞闸室、龙抬头段、挑坎等部位水流流态、壁面压强、水流流速等水力参数。将部分数值模拟结果同整体水工模型试验实测结果进行比较,两者吻合良好。数值模拟及试验成果显示,泄洪洞闸室合理设置突扩突跌设施可有效掺气、利于减蚀,龙抬头段水流流态平稳无突变、壁面无负压;而且,扭曲斜切挑坎有利于挑射水流归槽,可避免水流冲刷对向河岸,泄洪洞体型设计合理。研究表明,数值模拟与理论研究结果接近,可靠度较高,可为类似工程设计提供参考。

Study on hydraulic characteristics of ogee spillway tunnel of hydropower station

Aiming at the ogee spillway tunnel of a large-scaled hydropower station in Qinghai Province，the computational fluid dynamics software Flow － 3D，ＲNG k － ε turbulence model and VOF method are adopted for the 3 － D numerical simulative study on the overall hydraulic characteristics of the spillway tunnel，and then the hydraulic parameters such as flow regime，wall pressure，flow rate，etc. at the locations of the gate chamber of the tunnel，ogee section，flip bucket，etc. are obtained. A part of the results from the numerical simulation are compared with the measured result from the experiment of the overall hydraulic model，from which both of them are better coincided. The results from the numerical simulation and the experiment show that effective aeration can be realized by reasonably arranging sudden lateral enlargement and sudden drop facilities for the gate chamber of the spillway tunnel，which is favorable to erosion reduction，while the flow regime at the ogee section is stable without sudden change and no negative pressure is there on the wall. Moreover，the distorted and beveled flip bucket is favorable for the jet flow to return into the channel，and then avoids flow erosion toward the opposite bank，thus the design of the shape of the spillway tunnel is reasonable. The study indicated that the numerical simulation is close to the theoretical study result，which can provide reference for the design of the similar project.