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洞、渠组合的长距离泄流系统受大变幅水流条件的影响和局部边界约束,沿程流态十分复杂,因此泄流安全的研究十分必要.本文借助水力模拟与理论分析,以某抽水蓄能电站水库的明流泄洪洞、渠系统为例,研究了复杂运用条件的水力学特性.研究发现泄流过程中因边界约束出现的洞内水跃使跃后缓流段过流能力剧减,引发洞内壅塞与明渠局部漫溢,出现水深随流量改变呈驼峰曲线变化的泄流特异性.这一特异性与洞内水跃的发生及当地的流态转换密切相关,表现为无量纲水深与水流Fr的波状函数关系,相应的特征水深则随Fr呈幂函数规律变化.针对洞内水跃引发的洞内壅塞与明渠漫溢等泄流安全问题,基于多目标、多约束条件的水力优化分析,提出了“抑制洞内水跃强度、控制流量与流态协调性”的泄流运行原则,并据此对泄流系统进行了体型优化.试验研究表明通过调整泄流系统的纵横剖面,协调各段的泄流能力与流态,控制特殊部位的水流能量关系,可以有效削弱、控制局部边界约束引发的泄流特异性,消除洞内壅塞,满足复杂水流条件下的泄流安全要求.
The long-distance drainage system of tunnel and canal combination is greatly influenced by the large fluctuating water flow conditions and the local boundaries, and the flow pattern along the road is very complicated, so it is very necessary to study the safety of discharges.In this paper, with hydraulic simulation and theoretical analysis, The Mingliu flood discharge tunnel and canal system of reservoir are taken as an example to study the hydraulics characteristics of complex operation conditions.It is found that due to the boundary constraints in the discharge process, Reduce and cause the congestion and the open channels in the tunnel to overflow partially, the water depth changes with the change of the flow characteristics of the hump curve.The specificity is closely related to the occurrence of hydrodynamic and local flow regime transformation in the cave, The relationship between water depth and water flow Fr, and the corresponding characteristic depth changes with the power function law Fr.Aiming at the problem of discharge safety such as tunnel congestion and open channel overflow caused by water jump in a cave, a multi-objective and multi-constraint hydraulic Optimization analysis, the paper put forward the principle of discharging operation that suppresses the hydro-tempering intensity in the cave, controlling the flow and the coordination of the flow pattern, and according to the result, the body shape of the discharge system is optimized.Experimental results show that The vertical and horizontal profiles of the whole discharge system can coordinate the discharge capacity and flow pattern of each segment and control the flow energy relation of special parts so as to effectively weaken and control the discharge leakage specificity caused by the local boundary constraints and eliminate the congestion in the tunnel to meet the complicated water flow Discharge safety requirements under conditions.