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Crack treatment method for outlet edge of mixed flow type runner blade

A runner blade and treatment method technology, applied in welding equipment, metal processing equipment, manufacturing tools, etc., can solve the problems that the regular cracks on the water outlet edge of the runner blade of a Francis turbine cannot be eliminated, and the dynamic stress level of the blade cannot be effectively reduced. , to achieve the effects of eliminating regular cracks, reducing the amplitude of stress level changes, and reasonable structure

Inactive Publication Date: 2019-02-15
DONGFANG ELECTRIC MACHINERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The method disclosed in this patent document for alleviating the pressure pulsation hazard in the vaneless zone of the Francis pump turbine is proposed on the basis of the cause of the pressure pulsation in the vaneless zone. Effectively reduce the dynamic stress level of the blades, and thus cannot eliminate the regular cracks on the outlet edge of the blades of the Francis turbine runner

Method used

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  • Crack treatment method for outlet edge of mixed flow type runner blade
  • Crack treatment method for outlet edge of mixed flow type runner blade
  • Crack treatment method for outlet edge of mixed flow type runner blade

Examples

Experimental program
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Effect test

Embodiment 1

[0031] A method for treating cracks on the water outlet edge of a Francis runner blade includes the following steps:

[0032] a. Restorative repair, repair and restore the original shape of the blade 3 at the cracked part;

[0033] b. Reinforce the triangle block 2. Weld the triangle block 2 at the water outlet edge of the blade 3 near the upper crown 1 to change the angle between the blade 3 and the upper crown 1 from an acute angle to an obtuse angle;

[0034] c. Profile optimization. The blade 3 is welded along the thickness direction in the transition area between the triangular block 2 and the blade 3, so that the thickness change of the transition area between the triangular block 2 and the blade 3 is a smooth transition in any direction in space.

[0035] This example is the most basic implementation, "a. Restorative repair, repairing and restoring the cracked part according to the original shape of the blade; b. Triangular block reinforcement, welding the triangular block at th...

Embodiment 2

[0037] A method for treating cracks on the water outlet edge of a Francis runner blade includes the following steps:

[0038] a. Restorative repair, repair and restore the original shape of the blade 3 at the cracked part;

[0039] b. Reinforce the triangle block 2. Weld the triangle block 2 at the water outlet edge of the blade 3 near the upper crown 1 to change the angle between the blade 3 and the upper crown 1 from an acute angle to an obtuse angle;

[0040] c. Profile optimization. The blade 3 is welded along the thickness direction in the transition area between the triangular block 2 and the blade 3, so that the thickness change of the transition area between the triangular block 2 and the blade 3 is a smooth transition in any direction in space.

[0041] In the step b, the geometric size of the triangle block 2 is determined according to the spatial shape of the water outlet edge of the blade 3.

[0042] This embodiment is a preferred embodiment. In step b, the geometric size of...

Embodiment 3

[0044] A method for treating cracks on the water outlet edge of a Francis runner blade includes the following steps:

[0045] a. Restorative repair, repair and restore the original shape of the blade 3 at the cracked part;

[0046] b. Reinforce the triangle block 2. Weld the triangle block 2 at the water outlet edge of the blade 3 near the upper crown 1 to change the angle between the blade 3 and the upper crown 1 from an acute angle to an obtuse angle;

[0047] c. Profile optimization. The blade 3 is welded along the thickness direction in the transition area between the triangular block 2 and the blade 3, so that the thickness change of the transition area between the triangular block 2 and the blade 3 is a smooth transition in any direction in space.

[0048] In the step b, the geometric size of the triangle block 2 is determined according to the spatial shape of the water outlet edge of the blade 3.

[0049] In the step b, the thickness of the triangular block 2 is 6 times the thick...

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Abstract

The invention discloses a crack treatment method for an outlet edge of a mixed flow type runner blade, and belongs to the field of water turbines. The crack treatment method comprises the steps that firstly, restorative repair, specifically, repair welding and recovering is carried out at a crack portion in accordance with the original shape of the blade; secondly, triangular block reinforcement,specifically, a triangular block is welded to the position, close to the upper crown, of the outer edge of the blade so that the angle between the blade and the upper crown can be changed from an acute angle to an obtuse angle; and thirdly, molded line optimization, specifically, the blade is subjected to surfacing in the thickness direction in a connection transition zone between the triangular block and the blade so that the thickness variation of the connection transition zone between the triangular block and the blade can be a smooth transition in any direction of a space. By adding the triangular block reinforcement of the outlet edge of the mixed flow type water turbine runner blade and optimizing local molded lines of the blade, the dynamic stress level of the blade can be greatly reduced, and regular cracks of the outlet edge of the mixed flow type water turbine runner blade are eliminated, so that the problem of cracks, close to the upper crown, of the runner blade is completely solved.

Description

Technical field [0001] The invention relates to the field of hydraulic turbines, in particular to a method for treating water-outlet edge cracks of a Francis runner blade. Background technique [0002] Among all the flow-induced vibration problems of Francis turbines, the resonance induced by the Karman vortex street at the exit of the runner blade is a kind of hydraulic elastic vibration with strong destructive force. Once this kind of resonance occurs, whistling will occur when the turbine is running, and cause large-area cracks in the runner blades in a short time. The resonance induced by the Karman vortex street at the exit of the Francis turbine runner blade usually occurs in the runner's operation zone with high flow velocity, that is, it usually appears in the Francis turbine's high load operation zone. In addition, the frequency of howling is high, and the frequency of howling increases as the load of the turbine increases. The fundamental cause of resonance is that th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K31/02
CPCB23K31/02
Inventor 石清华冯涛张彬王平
Owner DONGFANG ELECTRIC MACHINERY