Method for eliminating bow-shaped cyclotron self-excited vibration of main shaft of mixed-flow water turbine generator

A hydroelectric generator and self-excited vibration technology, which is applied in the field of hydraulic machinery, can solve problems such as the failure of the unit to operate normally, endanger the safety of the power station, and severe vibration swings, and achieve the effects of clear plans, elimination of hazards, and strong pertinence

Inactive Publication Date: 2019-11-12
CHINA INST OF WATER RESOURCES & HYDROPOWER RES +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the operation of a hydropower station, the self-excited vibration developed by the bow-like rotation of the main shaft is the most common. If the self-excited vibration developed by the bow-like ro

Method used

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  • Method for eliminating bow-shaped cyclotron self-excited vibration of main shaft of mixed-flow water turbine generator
  • Method for eliminating bow-shaped cyclotron self-excited vibration of main shaft of mixed-flow water turbine generator
  • Method for eliminating bow-shaped cyclotron self-excited vibration of main shaft of mixed-flow water turbine generator

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0015] Example 1

[0016] Embodiment 1 provides a Francis hydroelectric generator with a suspended structure, and its structure is described in detail below.

[0017] reference figure 1 , The Francis turbine generator includes a rotating part 3 and a thrust bearing 1. The rotating part 3 includes a generator rotor 31, a turbine runner 32 and a main shaft 33. The unit arrangement adopts a hanging arrangement, that is, the generator rotor 31 and The water turbine runner 32 is arranged under the thrust bearing 1.

[0018] Specifically, the generator rotor 31 and the water turbine runner 32 are respectively arranged at the upper and lower parts of the main shaft 33, and the main shaft 33 and the generator rotor 31 and the water turbine runner 32 disposed on the main shaft together constitute the rotating part 3. The top of the main shaft 33 is provided with a thrust bearing 1 and an upper guide bearing 2 for connecting the top of the unit, and the rotating part 3 is located below the th...

Example Embodiment

[0022] Example 2

[0023] Embodiment 2 provides a half-umbrella structure Francis hydroelectric generator, the structure of which will be described in detail below.

[0024] reference Figure 4 , The semi-umbrella hydro-generator is also composed of thrust bearing 1, upper guide bearing 2, rotating part 3, lower guide bearing 4, water guide bearing 5 and runner chamber 6. The most obvious difference between it and the Francis hydro-generator with a suspended structure is that its thrust bearing 1 is arranged under the generator rotor 31.

[0025] Compared with the overhanging type, the semi-umbrella arrangement has two advantages in preventing the arc-shaped cyclotron self-excited vibration:

[0026] (1) The self-excited vibration occurs in the runner chamber 6. The semi-umbrella-arranged runner chamber 6 is close to the thrust bearing 1. Under the same centrifugal force and cavitation suction conditions, the main shaft 33 produces little deformation, and the self-excited vibration m...

Example Embodiment

[0028] Example 3

[0029] Embodiment 3 provides a method for eliminating the arcuate cyclotron self-excited vibration of the main shaft of a Francis hydroelectric generator, and the method includes the following contents:

[0030] (1) Unit structure design: When selecting or designing the structure of a Francis turbine generator unit, it is preferable to choose such Figure 4 The thrust bearing 1 shown is arranged under the generator rotor 31 of the semi-umbrella Francis hydro-generator. Avoid using as much as possible figure 1 The thrust bearing shown is arranged on the suspended Francis turbine generator on the top of the unit.

[0031] The reason for this choice is because figure 1 The thrust bearing 1 of the suspension type unit shown is arranged on the upper part of the generator rotor 31, at the highest point of the unit. The turbine runner 32 is the farthest away from the thrust bearing 1, which may cause the geometric center O'of the runner 31 to deviate further from the cen...

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Abstract

The invention discloses a method for eliminating bow-shaped cyclotron self-excited vibration of a main shaft of a mixed-flow water turbine generator. The method comprises the following steps that whena unit structure is designed, a semi-umbrella mixed-flow water turbine generator with thrust bearings arranged below a generator rotor is preferred; and if a suspension type water turbine generator is selected, four or more air supplement pipes need to be uniformly arranged in the gap of a rotary wheel chamber, and compressed air can be supplemented into the labyrinth gap through the air supplement pipes in case of self-excited bow-shaped rotation so as to change the pressure condition of the gap and eliminate self-excited vibration. The design and operation maintenance method is clear in scheme, simple to operate, targeted, high in pertinence, comprehensive and effective.

Description

technical field [0001] The invention relates to the technical field of hydraulic machinery, in particular to a method for eliminating arcuate self-excited vibration of a main shaft of a mixed-flow hydroelectric generator. Background technique [0002] Francis turbines can be divided into horizontal and vertical according to the layout. Horizontal turbine generators are suitable for small and medium-sized, inertial and impact turbines. Generally, large and medium-sized units with low and medium speeds use vertical generators. During the operation of a power station installed with a Francis turbine vertical unit, it often encounters problems that affect the safety and stability of the power station due to the large vibration swing of the unit. When the main shaft swing of the unit in the power station suddenly increases, the unit vibrates violently, and the swing frequency reaches the critical speed frequency of the main shaft, resulting in self-excited vibration of the unit. ...

Claims

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Application Information

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IPC IPC(8): F03B13/00F03B11/04F03B11/06H02K7/18
CPCF03B11/04F03B11/06F03B13/00H02K7/1823Y02E10/20
Inventor 徐洪泉孟龙李铁友廖翠林陆力王万鹏赵立策王武昌何磊易艳林瞿军刘莎宫衍斌
Owner CHINA INST OF WATER RESOURCES & HYDROPOWER RES
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