Method for inhibiting back cavitation of blade of mixed-flow water turbine

Abstract

The invention relates to a method for inhibiting back cavitation of a blade of a mixed-flow water turbine. Pressure distribution analysis is carried out for calculation results, the location of the point with the lowest pressure on the back face of the blade can be obtained, that is, the point most prone to cavitation can be obtained, a small hole with the diameter being 0.003D1 is drilled at the point with the lowest pressure on the back face of the blade, the front face and the back face of the blade are connected, and high-pressure water flow on the front face can be compensated into the low-pressure center of the back face due to pressure difference between the front face and the back face, so that the pressure on the back face cannot reach the environmental vapor pressure, and thus the cavitation can be undermined. By adopting the method, when the mixed-flow water turbine operates under all normal conditions in a power station, no cavitation can easily occur to the blades of the water turbine, and the safe and stable operation of the water turbine can be ensured.

Description

Technical field: [0001] The invention relates to a method for suppressing cavitation on the back side of blades of a Francis water turbine. Background technique: [0002] Cavitation is a liquid phenomenon. When the temperature of the liquid is constant and the pressure is reduced to a certain critical pressure, the liquid will vaporize or the air dissolved in the liquid will develop to form cavities. This phenomenon is called cavitation, which includes The whole process of acupoint birth, development and growth to collapse. The cavitation process can occur inside a liquid as well as at a solid boundary. When the cavitation on the solid boundary collapses, the shock pressure wave will be radiated from the collapse center, and when this high-frequency shock pressure wave acts on the solid side wall, it will damage the solid side wall, which is cavitation formed. [0003] The cavitation and cavitation erosion phenomena in hydraulic turbines are customarily defined according ...

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Problems solved by technology

[0012] Among the above methods, the cavitation performance of a pair of existing runners cannot be changed, the second method requires the installation of an air supply device, and the third method is difficult to

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