反坡段对侧式进/出水口水力特性影响研究

对于抽水蓄能电站侧式进/出水口,因进/出水口底高程低于库底高程,进/出水口与库区设反坡明渠连接,反坡坡比的大小将影响进出水口水力特性.目前缺乏反坡坡比建议值指导进/出水口设计,本文通过数值模拟研究了6种不同坡比1∶1～1∶6对进出水口水力特性的影响.结果 表明,对于进/出水口水头损失系数、拦污栅断面流速分布只有在进流工...

Study on the influences of reverse slope section on hydraulic characteristics of side inlet/outlet

For the side inlet/outlet of a pumped storage power station, because its bottom elevation is lower than that of the reservoir, it is connected to the reservoir via an open channel with a reverse slope, and the reverse slope ratio usually affects flow characteristics. In the previous designs of such inlets/outlets, no recommended values of the reverse slope ratio have been available. This paper presents a numerical simulation study on the influence of different reverse slope ratios in the range of 1:1 - 1:6 on the hydraulic characteristics of the inlet and outlet. The results show that the head loss coefficient of the inlet/outlet and the velocity distribution at the trashrack cross-section are affected by this slope ratio only when operating in inflow mode. In this case, typical inlet flow patterns are featured with a recirculation zone with a significant depth forming in the upper layer of the flow in the internal adjustment section of the inlet, and a smaller slope ratio leads to a smaller area ratio of this zone; when the slope ratio is less than 1:3, no backflow occurs in the reverse slope section of the open channel. In outflow mode of different slope ratios, such backflows appear in the reverse slope section of the middle and side passages of the outlet; the recirculation zone length ratio (relative to tunnel height) in the side passage is larger than that in the middle passage, and a smaller slope ratio leads to a larger length ratio. As the slope ratio of the outlet decreases from 1:1 to 1:6, flow in its platform section diffuses more evenly into the reservoir water body; when the ratio is 1:3 - 1:4, the inlet/outlet is best in hydraulics.