CN210660413U

CN210660413U - Crown structure capable of reducing water pressure between rotating wheel and top cover

Info

Publication number: CN210660413U
Application number: CN201921466283.3U
Authority: CN
Inventors: 李浩亮; 常喜兵; 刘辉; 赵威
Original assignee: Dongfang Electric Machinery Co Ltd DEC
Current assignee: Dongfang Electric Machinery Co Ltd DEC
Priority date: 2019-09-05
Filing date: 2019-09-05
Publication date: 2020-06-02
Anticipated expiration: 2029-09-05

Abstract

The utility model discloses a can reduce last crown structure of water pressure between runner and top cap belongs to hydraulic engineering technical field. The upper surface of the upper crown is provided with a plurality of spoke-shaped bosses which are arranged along the radial direction of the upper crown. The utility model discloses under the condition that does not change other current structures, through the runner crown upside at the mixed-flow turbine increase a plurality of spoke-like boss structure to increase the rotation rate of water between top cap and runner, thereby make the water of crown upside increase along the pressure gradient of radial direction, reach and reduce between top cap and the runner and the water pressure before the main shaft seal, reduce the effect of crown axial thrust.

Description

Crown structure capable of reducing water pressure between rotating wheel and top cover

Technical Field

The utility model relates to a crown structure of mixed-flow water turbine, concretely relates to crown structure of water pressure between reducible runner and top cap.

Background

In the mixed flow machine set, upstream water flow enters a bladeless area through movable guide vanes, most of water enters a downstream flow channel through a runner inner flow channel, and a small part of water finally enters the downstream flow channel through the outer sides of an upper crown and a lower ring. The water body entering the outer side of the crown enters a cavity between the rotating wheel and the top cover, namely a crown cavity, through a leakage stopping ring between the rotating wheel and the top cover.

For reducing the water pressure between top cap and runner crown among the prior art, generally realize through designing the decompression drain pipe, for example the publication number is CN202900515U, and the publication date is 24 days 04 months in 2013, the chinese utility model patent of the name "mixed flow turbine top cap decompression drainage structures", its technical scheme is: the utility model provides a structure of hydraulic turbine top cap decompression drainage, through set up the decompression drain pipe on the top cap, introduces the main shaft seal department through this decompression pipe with leaking of runner leak-stopping ring department on top cap upper portion, discharges through the outlet of runner wash-out awl department, reaches the reduction, reduces the purpose of the water thrust of unit.

And in the conventional mixed flow unit hydraulic turbine transformation process, because the application of partly transformation unit lack outer concora crush pipeline and novel runner, often can cause the pressure between runner and the top cap too high, the top cap load is on the large side, and it is on the large side that the axial water thrust of crown is gone up, and the main shaft seal is exceeded design value scheduling problem by sealed water pressure, influences the safety and stability operation of unit.

Disclosure of Invention

The utility model discloses aim at solving the above-mentioned problem among the prior art, provide a simple structure, preparation convenience, safe and reliable's crown structure of going up that can reduce water pressure between runner and top cap.

In order to achieve the above purpose, the technical solution of the present invention is as follows:

the utility model provides a can reduce water pressure's between runner and top cap crown structure, includes crown, its characterized in that: the upper surface of the upper crown is provided with a plurality of spoke-shaped bosses which are arranged along the radial direction of the upper crown.

Furthermore, the spoke-shaped bosses are uniformly distributed on the top of the upper crown, and the included angles formed by the connecting lines of the adjacent two spoke-shaped bosses and the center of the upper crown are the same.

Furthermore, the spoke-shaped bosses and the upper crown are of an integrally formed structure.

Furthermore, the section of the spoke-shaped boss is in the shape of a multi-section arc, ellipse, circle, triangle, arch or rectangle.

The utility model has the advantages that:

1. the utility model increases the rotation speed of the water body between the top cover and the runner by adding a plurality of spoke-shaped boss structures on the upper side of the runner crown of the mixed-flow turbine without changing other existing structures, thereby increasing the pressure gradient of the water body on the upper side of the crown along the radial direction, reducing the water pressure between the top cover and the runner and before the main shaft sealing, and reducing the effect of thrust of the crown to water;

2. the utility model discloses reduced the welding volume of decompression board and destroyed cracked risk, structural style is simple, safe and reliable.

Drawings

FIG. 1 is a sectional view of the structure of the present invention;

fig. 2 is a top view of the structure of the present invention;

FIG. 3 is a schematic view of the cross-sectional shape of the spoke-shaped boss according to the present invention;

FIG. 4 is a pressure profile of a body of water between a stationary disk and a rotating disk;

wherein the content of the first and second substances,

1. crown 2, spoke boss 3, runner 4, multi-section arc, 5, ellipse, 6, circle, 7, triangle, 8, arch, 9, rectangle.

Detailed Description

The present invention will be described in further detail with reference to examples, but the present invention is not limited thereto.

Example 1

This embodiment is the most basic embodiment.

FIG. 4 is a pressure distribution diagram of a water body between a stationary disk and a rotating disk, where ω is the rotation speed of the rotating structure and P is the rotation speed of the rotating structure_EAnd P₁Water pressure values, R, of the distal end and the proximal end, respectively_EAnd R₁The rotating radiuses of the far end and the near end are respectively, rho is the liquid density, and mu is a correlation coefficient (mu is more than 0 and less than or equal to 1). The pressure distribution of the final water body between the static disc and the rotating disc can be expressed as:

and for the structure with smooth upper and lower side surfaces of the water body, mu is 0.5-0.7.

The existing runner crown structure of the mixed-flow water turbine is produced by adopting a casting forming process, the roughness of a non-machined surface on the upper side of the crown except part of machined surfaces is 6.3, the surface curved surface on the upper side of the crown is smooth, and other accessory structures are not provided.

The water pressure distribution in the annular cavity between the crown and the top cover is mainly determined by the rotation speed of water flow in the annular cavity, the upper surface of the crown of the rotating wheel rotates to drive the water flow to rotate, the peripheral speed generated by the rotation wheel is in direct proportion to the radius, the peripheral speed is large near the outer edge of the rotating wheel and is reduced along with the reduction of the radius, and the centrifugal force generated by the rotation causes a pressure gradient along the radial direction.

The embodiment provides a crown structure capable of reducing water pressure between a runner and a top cover as shown in figure 1, other existing structures are not changed, a plurality of spoke-shaped bosses 2 are additionally arranged on the upper side of the crown 1 of the runner of the mixed-flow water turbine, and the length, the width and the height of the spoke-shaped bosses 2 are determined according to the sizes of structures of the crown 1 of different units. Preferably, as shown in fig. 2, the spoke-shaped bosses 2 are uniformly distributed on the top of the crown, and the included angles formed by the connecting lines of the two adjacent spoke-shaped bosses 2 and the center of the crown 1 are the same.

When the proper radial rib plates are arranged on the upper side of the rotating body, the rotating speed of the water body on the rotating body is considered to be almost equivalent to that of the rotating member, and according to a formula,

in this case, μ is 0.8 to 1.0

The spoke-shaped boss 2 structure is added on the upper part of the crown 1, and the rotating speed of the water body between the top cover (not shown in the figure) and the rotating wheel 3 is increased, so that the pressure drop gradient of the water body on the upper side of the crown 1 along the radial direction is increased, and the purposes of reducing the water pressure between the top cover and the rotating wheel 3 and before the main shaft is sealed and reducing the axial water thrust of the crown 1 are achieved.

Example 2

The content of this embodiment is based on the entire content of embodiment 1, with the following differences:

preferably, as shown in fig. 3, the section of the spoke-shaped boss 2 has a shape of a plurality of segments of arc 4, ellipse 5, circle 6, triangle 7, arch 8 or rectangle 9.

Example 3

The content of this embodiment is based on the entire content of embodiment 2, with the difference that:

preferably, the spoke-shaped boss and the upper crown can be cast together, so that the welding amount and the risk of breakage of the pressure reducing plate are reduced, and the spoke-shaped boss can also be fixed on the surface of the upper crown by welding or other connection modes.

The above is only the preferred embodiment of the present invention, not to the limitation of the present invention in any form, all the technical matters of the present invention all fall into the protection scope of the present invention to any simple modification and equivalent change of the above embodiments.

Claims

1. The utility model provides a can reduce water pressure's between runner and top cap crown structure, includes crown (1), its characterized in that: the upper surface of the upper crown (1) is provided with a plurality of spoke-shaped bosses (2), and the spoke-shaped bosses (2) are arranged along the radial direction of the upper crown (1).

2. The crown structure of claim 1, wherein the crown structure is adapted to reduce the pressure of water between the runner and the crown, and further comprises: the spoke-shaped bosses (2) are uniformly distributed on the top of the upper crown (1), and the included angles formed by the connecting lines of the two adjacent spoke-shaped bosses (2) and the center of the upper crown (1) are the same.

3. The crown structure of claim 1 or 2, wherein the water pressure between the runner and the top cover is reduced by: the spoke-shaped bosses (2) and the upper crown (1) are of an integrated structure.

4. The crown structure of claim 3, wherein the water pressure between the runner and the top cover is reduced by: the section of the spoke-shaped boss (2) is in the shape of a multi-section arc (4), an ellipse (5), a circle (6), a triangle (7), an arch (8) or a rectangle (9).