The 24th IAHR-APD Congress (24th IAHR-APD Congress)

591 / 2024-09-13 10:27:36

Influence of horizontal curved water conveyance tunnel on hydraulic characteristics of side inlet/outlet

Side inlet/outlet; Planar turning tunnel; Hydraulic characteristics; Numerical simulation

Subtheme 1: Water-related Hazard and Risk Reduction > Topic 6: Safety Risk Prevention and Control of Water Engineering

Limited to geological conditions or comprehensive costs, a planar turning section in the water conveyance tunnel may be used to connect the side inlet/outlet with the generator unit of pumped storage power stations. However, due to the curvature effect, Dean vortices are likely to be generated in the curved tunnel, which

will affect the flow distribution at the inlet/outlet and the velocity distribution at the cross-section of the trash rack. In this paper, the influence of the layout of the planar turning tunnel(the Length of straight tunnel after turning, the tunnel slope, and the position of the slope change )on the hydraulic characteristics of side inlet/outlet was studied using numerical simulation method. The results show that, compared with the straight tunnel, the planar turning section will cause uneven flow distribution at the inlet/outlet. Longer straight section can lead to a more uniform distribution of the flow ratio of each orifice. Larger tunnel slope  could improve the flow velocity distribution in the trash rack section. And setting the location of the slope change of the pressurized tunnel to the exit of the transition section can improve both the orifices' flow distribution and the flow velocity distribution in the trash rack section.