Author(s): Niu Zhengming; Sun Jing; Li Qilong; Hou Yanping
Linked Author(s):
Keywords: Hydraulics; Rotary-flow spillway tunnel with blocking-diffuser; Numerical simulation; Hydraulic characteristics; Blocking-diffuser
Abstract: The rotary-flow spillway tunnel with blocking-diffuser was proposed for meeting the requirement of energy dissipation in high dam. Then the hydraulic characteristics of rotary and diffused flow in tunnel were analyzed by model test and numerical simulation. The results showed that the flow in rotary-flow section was rotational with cavity and high wall pressure, which transformed to air-water mixture with high turbulent and negative pressure after the diffuser. The velocity of rotary flow could be kept down below 30 m/s. Over radial direction, the tangential velocity was anti-symmetric suggesting a combined eddy, and the axial velocity was symmetrical, but the radial velocity was low. Even on the condition of submerged outlet, the good air ventilation and exhale were obtained. Cavitaion erosion did not occur in rotary-flow section, and sufficient water-air bleeding could reduce the possibility of cavitation with negative pressure after the diffuser. Because of the cavitation resistance and high energy dissipation, the rotary-flow spillway tunnel with the blocking-diffuser has a good application prospect for discharge and dissipation in high dam.
Year: 2015