Pressurized sudden expansion sudden drop circular jet energy dissipator

Abstract

The invention discloses a pressure sudden expansion and sudden fall circular jet flow energy dissipater, which comprises a first transition section, a rectangular sluice chamber section and a stilling pool which are jointed with a pressure flood discharging tunnel, and is structurally characterized by comprising a second transition section and an equal hole diameter circular pipe section; the first transition section, the rectangular sluice chamber section, the second transition section, the equal hole diameter circular pipe section and the stilling pool are jointed and connected in sequence; the hole diameter of the equal hole diameter circular pipe section meets the inequation that 0.2B is smaller than d and d is smaller than 0.9B, wherein d is the hole diameter of the equal hole diameter circular pipe section, and B is the minimum width of the bottom of the stilling pool; the backward step height S after the equal hole diameter circular pipe section is jointed with the stilling pool meets the inequation that 0.6d is smaller than S and S is smaller than 3.3d; the relationship between the backward step height S and the downstream water depth ht of the stilling pool is that 2 is smaller than ht / S and ht / S is smaller than 5. The maximum bottom flow speed of the stilling pool can be reduced by more than 50% in comparison with the rectangular outlet, the air entrainment concentration can be greatly improved, and the possibility that flow is subjected to cavitation and cavitation erosion can be effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of flood discharge and energy dissipation in water conservancy and hydropower projects, in particular to an energy dissipation device for flood discharge and energy dissipation at the outlet of a pressurized flood discharge tunnel with high water head. Background technique [0002] In the construction of high-head power stations, it is common to use flood discharge tunnels for flood discharge. Stilling tanks are usually installed after the flood discharge tunnels. The energy dissipation type of the water outlet at the junction of the pressurized flood discharge tunnel and the stilling tank is particularly important, because it is related to the stilling tank. Safety and stability of floor and side walls. A commonly used pressurized flood discharge tunnel is provided with a rectangular sluice section and a connecting section between it and the stilling basin. Rectangular outlet (referred to as rectangular ou...

AI Technical Summary

Problems solved by technology

A commonly used pressurized flood discharge tunnel is provided with a rectangular sluice section and a connecting section between it and the stilling basin. Rectangular outlet (referred to as rectangular outlet energy dissipator), when the outlet flow velocity of this rectangular outlet energy dissipator is large (especially the outlet flow velocity exceeds 20m / s), it is easy to cause the flow velocity at the bottom of the stilling pool and the side wall to be too large, resulting in the dissipator The bottom plate of the stilling pool is unstable and damaged. Moreover, the cavitation number of the water flow on the side wall of the stilling pool is small, and the concentration of aeration is low, so cavitation and cavitation damage are very likely to occur in the stilling pool

Even if the rectangular outlet with sudden expansion and sudden drop is adopted, it cannot fundamentally solve the problems of high flow velocity at the bottom of the stilling tank and small cavitation number of water flow at the side wall of the stilling tank

In addition, in the rectangular exit energy dissipator, the stilling basin is usually a symmetrical stilling basin, and its use is limited by the terrain

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