Abstract:The tunnel of Xiaowan Hydropower Station with high head water and large discharge has complex hydraulic conditions. The model test has scale effect. By using RNG k-ε turbulence model, and unique FAVOR grid technology of Flow 3D, 3D numerical simulation was conducted for nine wor-king conditions of the tunnel of Xiaowan Hydropower Station. We obtained the discharge capacity, flow pattern, dynamic pressure, water surface, velocity of flow and compared them to those of the model test and prototype observation. The results show that the discharge capacity simulated is a littler greater than that of the model test. There is no gasbag in the pressure section, and the flow regime is smooth in the non-pressure section, there is no water and water-wing to attack the cave roof, and stable cavity is formed behind the aerator. The simulation results are consistent with those of the model test and prototype observation. The velocity of flow and water depth of the model test and the simulation are almost the same and in accord with the characteristics of rapids. The distribution law of dynamic pressure at the inlet of tunnel, turning section, ogee surface and arc segment is the same with that of the model test, showing that the hydraulic parameters of the numerical simulation have a certain accuracy and are more systematic than those of the model test and prototype observation.
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