A straight tapered draft tube with elliptical and regular hexagonal grids

Abstract

The invention discloses a conical draft tube provided with an oval and regular hexagon grid. The outmost part of the conical draft tube is a straight cone cylinder with a conical axial section, the upper end of the straight cone cylinder is a conical small end, the lower end of the straight cone cylinder is a conical big end, a flow dividing cylinder with a conical axial section is arranged inside the straight cone cylinder, and the upper end of the flow dividing cylinder is a conical small end, the lower end of the flow dividing cylinder is a conical large end, a flow dividing piece with a conical axial section is fixedly embedded between the outer side wall of the flow dividing cylinder and the inner side wall of the straight cone cylinder, the upper end of the flowing dividing piece is a conical large end, the lower end of the flowing dividing piece is a conical small end, and a plurality of oval grid pieces are uniformly embedded in the flowing dividing piece in the circumferential direction. The middle of each oval grid piece is continuously connected regular hexagon grid holes, the edges of the periphery of each oval grid piece is irregular polygonal grid holes, and the oval grid pieces are used for reducing the eccentric distance of a vortex strip; when a fluid passes through the oval grid pieces, the separation of boundary layers of the fluid is small, so that the pressure difference between the periphery and the center of the interior of the draft tube is reduced, the radial pulsation of the vortex strip is weakened, and the service life of the draft tube is prolonged.

Description

technical field [0001] The invention relates to the field of fluid machinery and engineering equipment, in particular to a straight tapered draft tube structure installed in a water turbine of a hydropower station. Background technique [0002] The water turbine is installed in the hydropower station and converts the potential energy of water into kinetic energy through the potential difference of water level. When the water flow leaves the runner of the turbine, the velocity of the water flow gradually decreases, and the pressure increases accordingly. When the water flow enters the draft tube below the runner, the central pressure inside the draft tube is high due to the high surrounding pressure, resulting in The pressure difference between the surrounding and the center becomes larger, the flow rate of the water flow decreases and the pressure increases, causing the breakage and eccentricity of the vortex belt, resulting in serious radial pressure fluctuations, and also ...

AI Technical Summary

Problems solved by technology

[0007] The present invention aims to solve the pressure pulsation problem caused by the offset and breakage of the vortex belt in the draft tube of the existing water turbine, and proposes a straight conical structure with ellipse and regular hexagonal grids that can reduce the pressure pulsation and improve the smooth operation of the water turbine. draft tube

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