Mixed-flow water turbine draft tube with inclined bent cone

Abstract

The invention discloses a mixed-flow water turbine draft tube with an inclined bent cone. The draft tube is sequentially composed of an inclined bent cone section unit, an elbow section unit and a diffusion section unit, wherein the central axes of the inclined bent cone section unit, the elbow section unit and the diffusion section unit, the upstream side contour line and the downstream side contour line of the inclined bent cone section unit, the upstream side contour line and the downstream side contour line of the elbow section unit and the top contour line and the bottom contour line of the diffusion section unit conform to an exponential curve y = a + b * e (cx), wherein a, b and c are all undetermined constants, and the values a, b and c of different lines of different units are different, so that the fluid flow state in the draft tube is the best, and the vortex strip is the minimum. The spiral symmetrical structure or the cylindrical symmetrical structure of the vortex strip of the draft tube is destroyed through the asymmetric design of the inclined bent cone, generation of the vortex strip of the draft tube is effectively simulated, then pressure pulsation is reduced, and the operation and output stability of the water turbine is improved.

Description

technical field [0001] The invention belongs to the field of water conservancy and hydropower engineering, and in particular relates to a draft pipe of a Francis water turbine with an obliquely curved cone. Background technique [0002] As the largest renewable energy and clean energy, hydropower energy will be continuously developed and utilized. The outstanding advantage of the Francis turbine is that it can operate in a wider range with higher efficiency. The disadvantage is that when the flow rate is higher or lower than the design flow, the internal flow instability of the turbine is obvious, and it will form a spiral or Cylindrical vortex, accompanied by severe output fluctuations. [0003] In order to solve the flow stability problem inside the existing Francis turbine, the current treatment measures include aeration or water injection that require additional energy, and optimized design of the shape of the discharge cone of the runner and the cross-sectional shape o...

AI Technical Summary

Problems solved by technology

Due to the complexity of the internal flow of the Francis turbine, the current engineering measures have not solved the instability of the internal flow of the Francis turbine and the problem of output fluctuations.

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