跌坎消力池体型优化数值模拟

Numerical simulation study on shape optimization of stilling basin with drop sill

以某高水头大单宽流量的水电站为例,对不同体型参数的跌坎型消力池进行了一系列的数值模拟计算。在原体型设计的基础上,顺次改变出口反坡坡度、池长、进口跌坎坡度及高度,通过数值计算得出了各影响因素的变化对消力池内水力特性的影响,以此来确定最优消力池体型。由数值计算结果可得:消力池出口反坡不宜垂直;缩短消力池池长,冲击区时均压强略微减小,临底流速开始变化不大,当消力池池长缩短到一定程度时,临底流速明显增大;减小跌坎坡度,冲击区正向临底流速减小,但反向临底流速增大;降低消力池前半段高程,可使进口临底流速降低,但反坡段临底流速会有明显增大,建议不进行挖深工作;提高底板高程,时均压强减小,临底流速变化不大,考虑到挖方量,建议不降低底板高程。此研究成果可为类似工程设计提供参考和依据。

In this paper,based on a high head and large unit-width discharge hydropower station,a series of numerical simulations on stilling basin with drop sill were conducted to reduce the stilling basin bottom hydraulics indexes.Based on the original body design,export reverse slope gradient,pool length,import fell ridge slope and height were sequentially changed,the impact of changes in various factors on stilling pool hydraulic characteristics was obtained by numerical simulation,and ultimately the optimal size of stilling basin was determined.The main results and conclusions were as follows:the export slope of stilling basin should not vertical;with stilling pool length shortening,pressure were slightly reduced at impact zone,and the velocity near the bottom changed little at first and increased significantly when stilling pool length was shortened to a certain length;when the drop sill slope decreased,the forward velocity became smaller at impact zone,but the reverse velocity became greater;lowering the first half of the stilling basin elevation could reduce the velocity at the import,but the velocity of the reverse slope section increased significantly.It is recommended not to deepen the work.When the bottom elevation was increased,the pressure decreased and the velocity changed little,so taking the amount of excavation into account,it is recommended not to lower the floor elevation.The results can provide reference and basis for similar projects design.