节制闸调控下明渠输水系统水力特性研究

Research on Hydraulic Characteristics of Open Channel Water Diversion System under the Control of Regulating Gates

长距离明渠输水工程的水力控制问题直接关系到工程的安全运行。以南水北调中线某一渠段为典型算例,建立非恒定流数学模型,通过数值模拟,对节制闸调控下的明渠输水系统水力特性进行了研究。结果表明:当流量变化相同时,水位波动范围、流量变化速率与闸门的启闭速率呈正相关。闸门的启闭速率越大,水位波动出现的时间越早,但明渠恢复到新的恒定流状态所需的时间越少。渠段水力震荡及渠道的漫溢现象主要受闸门关闭速度影响,应尽量降低闸门的关闭速率,从而减少水力振荡的影响,延长渠道出现漫溢的时间。综合比较不同节制闸间距下的渠道响应时间、闸前水位壅高、事故排空时间、建闸投资比,建议南水北调中线某明渠段节制闸间距取在2535 km之间最优。

The hydraulic control problem is very important for the safe operation of open channels in the long-distance water diversion project. Taking one section of middle route of south- to-north water transfer project as example in this paper, the hydraulic characteristics of open channel water diversion system under control of regulating gates are studied by establishing unsteady mathematic model and making numerical simulation. The results show that ： under the same flow conditions, the fluctuations of the water level and the flow change rate of the different sections of the canal were positively correlated with the regulation speed of the gate. The greater the regulation speed of the gate, the earlier the fluctuations of the water level, but the final setting time of the water level of the open channel is shorter. The hydraulic oscillation and o- verflow of the canal is mainly affected by gate closing velocity, so the gate closing velocity should be reduced to alleviate the influence of hy- draulic oscillation and prolong the time of overflow. After comparing the channel response time, backup water level in front of the gate, eliminating accident time of different gate interval,it is advised that the optimal regulating gate interval is 25 -35 km.