公明水库进库闸环形溢流消力池水力特性研究

底流消能型式在水利工程中被广泛应用,但随着现代工程技术的发展,现有的矩形消力池、梯形消力池已不能完全满足工程需要,根据重力相似准则设计几何比尺为1∶10的水工模型,采用模型试验与Flow-3D数值模拟相结合的研究方法,以公明水库进库闸消力池为例,对环形溢流消力池的流态、泄流能力、流速、压强与消能率等水力特性进行研究。研究表明,溢流竖井内水流呈漩涡上升,溢流跌水呈贴壁流,消力池内无法形成完全水跃;环形溢流竖井泄流能力较等宽度等堰高的宽顶堰略小;溢流跌水在约11.80m的落差内迅速增大至12.60m/s,但水流跌入消力池后流速迅速减小,出池流速在1.70m/s内;消力池底板脉动压强最大值不会超过水流自身水位落差;环形溢流消力池综合消能率可达80.38%。由此可见,环形溢流消力池虽然在流态、流速分布、压强分布上不同于常规消力池,但同样能达到较好的消能效果,可供类似工程参考。

Study on Hydraulic Characteristics of Ring Overflow Stilling Basin of Inlet Gate for Gongming Reservoir

Energy dissipation by hydraulic jump is widely used in hydraulic engineering. With the development of engineering technology, current stilling basin which is rectangular section or trapezoidal section cannot fully meet engineering needs. Taking the stilling basin of inlet gate of Gongming reservoir as an example, hydraulic characteristics of ring overflow stilling basin, such as flow pattern, discharge capacity, velocity, pressure and energy dissipation ratio were studied. Designing a hydraulic model whose geometric scale equals 1∶10 based on Froude criterion of gravitational similarity, the study used the methods of model test and numerical simulation by Flow3D. The results show that the vortex of water flow in overflow shaft rises, the overflow water falls into a wall pressing weir flow, and the hydraulic jump cannot be formed in the stilling basin;The discharge capacity of overflow shaft is slightly smaller than the broad crest weir which is the same width and height;The velocity of drop rapidly increases to 12.60 m/s within a height of about 11.80 m and then reduces in stilling basin to less than 1.70 m/s;Maximal pressure on the floor of stilling basin does not exceed the water level drop;Comprehensive energy dissipation ratio of ring overflow stilling basin achieves at 80.38%. The above results indicate that although the ring overflow stilling basin is different from the conventional stilling basin in the flow pattern, velocity distribution and pressure distribution, it can also achieve good energy dissipation effect, which can be used for similar engineering reference.