跌坎型底流消能流态转捩及控制研究

跌坎型底流消能工是一种建立在常规底流消能工基础上的新型消能工。通过理论分析得出,跌坎型底流消能工消能率随着跌坎高度与上下游水深的变化而发生变化,且不同入池Fr下,满足消能率所需坎高与水深不同。结合某大型水电工程进行验证,针对上游相对水位120.0~140.0 m、下游相对水位40.0~50.0 m,跌坎型消力池内水流流态特征进行分析。研究结果表明,跌坎型消力池内水位波动最大值发生在跌坎下游50~100 m范围内;随着跌坎型消力池跌坎高度的变化,消力池内水流可呈现出三种不同流态特征;当跌坎断面采用收缩体型后,跌坎高度可得到提升,有效地保障消力池内水流流态稳定和消能效率,改善消力池内临底水力学指标。

Study on flow regime transition of falling-sill bottom-flow energy dissipation and its control

Falling-sill bottom-flow energy dissipater is a new type of energy dissipater is developed on the basis of the conventional bottom flow energy dissipater. It is obtained through the relevant theoretical analysis that the energy dissipation ratio of the falling-sill bottom-flow energy dissipater changes along with the changes of both height of the falling-sill and the upstream and downstream water depths,furthermore,the necessary height of sill and water depth to meet the energy dissipation ratio are different under different inflow rates（Fr）. It is verified in combination with a large-sized hydropower project,i.e. the characteristics of the flow regime inside of the falling-sill stilling pool is analyzed for the upstream relative water level of 120.0~140.0 m and the downstream relative water level of 40.0~50.0 m. The study result shows that the maximum value of the fluctuation of the water level inside of the falling-sill stilling pool occurs in the scope of the 50~100 m downstream of the falling-sill. Following with the variation of the falling-sill of the stilling pool,the water flow inside of the stilling pool can present three kinds of different flow regime characteristcs. When a shrinked shape is adopted for the cross-section of the falling-sill,the height of the falling-sill can be rised to effectively ensure the stability and energy dissipation efficiency of the flow regime in side of the stilling pool and then improve the underflow hydraulic indexes concerned.