高坝明流泄洪洞掺气减蚀三维数值模拟分析

Numerical simulation of aeration and cavitation in high dam spillway tunnels

高坝明流泄洪洞的掺气减蚀问题倍受关注。以溪洛渡水电站3#泄洪洞为研究对象,结合大比尺单体模型试验成果,应用分段计算方法对泄洪洞掺气减蚀问题进行了三维紊流数值模拟分析。结果表明:泄洪洞各道掺气坎布置合理且有稳定掺气空腔,掺气坎体型基本合理,明流段洞顶余幅足够。泄洪洞反弧段及末端一段区域水力特性复杂,应重点关注此部位的设计及施工问题。对于高流速、大梯度泄洪洞水力学问题,采用分段计算能提高计算速度。

The aeration problem in spillway tunnels has attracted much attention in hydropower projects.A hydrodynamic model study of aeration devices is conducted for the 3# spillway tunnel of Xiluodu Power Station.The study uses a 3-D numerical model and a segmentation algorithm to simulate the flow field in the tunnel.The result shows that the simulation agrees well with the experimental data from a large-scale physical model test.The layout and design of spillway aeration devices,and the clearance between the water surface and the top of the tunnel are proven to be reasonably arranged for the 3# spillway tunnel according to the model simulations.The simulation proves the complicate nature of hydraulic regime in the ogee section.The emphasis should be on the design of the ogee section and its construction.The use of segmentation algorithms can improve the computational efficiency of high-speed flow simulation with presence of large velocity gradients.