CN212716773U

CN212716773U - Turbulent flow type steam seal structure of steam turbine

Info

Publication number: CN212716773U
Application number: CN202021188990.3U
Authority: CN
Inventors: 黄建球
Original assignee: Alstom Beizhong Power Beijing Co Ltd
Current assignee: Alstom Beizhong Power Beijing Co Ltd
Priority date: 2020-06-24
Filing date: 2020-06-24
Publication date: 2021-03-16
Anticipated expiration: 2030-06-24

Abstract

The utility model relates to a steam turbine field of making, especially a steam turbine vortex formula vapor seal structure, including the rotor with install the shaft seal body on the rotor, a plurality of steam extraction passageways have in the shaft seal body, still be provided with the vortex tooth on the rotor, the vortex tooth is located the position that last stage steam extraction passageway among a plurality of steam extraction passageways corresponds. The utility model discloses an on the rotor that the steam extraction passageway corresponds, reasonable position, set up the vortex tooth, lead to the steam extraction passageway with the high-temperature steam in the cylinder, increase the steam extraction volume in shaft seal body middle section, avoid high-temperature steam to reveal outward to the cylinder along the clearance, reach the sealed effect of strengthening the bearing seal. And, adopt the utility model discloses with low costs, it is high to receive the effect, no matter purchase in earlier stage and still later maintenance, all very economical and practical.

Description

Turbulent flow type steam seal structure of steam turbine

Technical Field

The utility model relates to a steam turbine field of making, especially a steam turbine spoiler type vapor seal structure.

Background

When the steam turbine set is in operation, the pressure in the high and medium pressure cylinders is different from several to dozens of atmospheric pressures, and one atmospheric pressure is outside the cylinder; and because the rotor is a high-speed rotating component and can not be in direct contact with components such as a cylinder, the high-medium pressure shaft seal has the function of isolating steam in the cylinder from air outside the cylinder and avoiding the steam in the cylinder from leaking to the outside of the cylinder under the condition of not directly contacting the rotor.

In the operation process of a plurality of existing steam turbines in a power plant, the problem of steam leakage of shaft seals of high and medium pressure cylinders often occurs due to various reasons, and the steam loss is caused as a result, so that the efficiency of a unit is reduced; secondly, the bearing box can be directly heated by steam leakage, and lubricating oil and the bearing can be indirectly heated, so that high risk is brought to the safe operation of the unit; and thirdly, the leaked steam can enter the bearing box to emulsify the lubricating oil.

As shown in fig. 1, which is a schematic view of a rotor shaft seal structure in the prior art, in a cylinder 1, because a plurality of steam seal blocks 4 and steam seal teeth 5 are arranged between a rotor 3 and a shaft seal body 2, high-temperature steam in the cylinder leaks step by step along a labyrinth-like path between the steam seal blocks 4 and the steam seal teeth 5, and the step by step leakage also has the functions of reducing pressure step by step and reducing leakage amount step by step. In the gradual leakage process, the shaft seal body 2 is also provided with a plurality of steam extraction channels in the middle section (three times for the high pressure cylinder and two times for the medium pressure cylinder), so that the steam extraction function is provided, most of leaked steam is extracted, and a part of atmosphere flowing from the outside of the cylinder is even sucked at the outermost side, so that the steam in the cylinder is prevented from leaking to the outside of the cylinder, and the purpose of sealing is achieved.

The existing shaft seal structure adopts labyrinth type, honeycomb type, brush type, reinforced labyrinth type and other various steam seal teeth, and can realize long-time sealing effect under the condition of qualified design, processing, installation and operation. However, after long-term operation, the rotor vibration value is too large, which causes the rotor to rub against the steam seal teeth, so that the gap between the steam seal teeth 5 and the steam seal blocks 4 on the rotor 3 is too large, the steam amount flowing out of the cylinder is increased, increased steam leakage cannot be completely removed by several times of steam extraction, high-temperature steam in the cylinder flows out from the gap between the steam seal blocks at the outermost side along the direction of a dotted line, and the problem of steam leakage of the shaft seal is caused. Although the structure of the prior gland sealing teeth is improved, the prior gland sealing teeth can not solve the problem of steam leakage caused by long-term operation and other unexpected reasons.

SUMMERY OF THE UTILITY MODEL

The utility model overcomes above-mentioned shortcoming provides a sealed effectual, the long steam turbine spoiler formula vapor seal structure of ageing.

The utility model provides a technical scheme that its technical problem adopted is: the utility model provides a steam turbine vortex formula steam seal structure, includes the rotor and installs the shaft seal body on the rotor, a plurality of steam extraction channels have in the shaft seal body, still be provided with the vortex tooth on the rotor, the vortex tooth is located the position that last stage steam extraction channel among a plurality of steam extraction channels corresponds.

Furthermore, turbulence teeth can be arranged on the rotors corresponding to other steam extraction channels except the final steam extraction channel.

Further, a plurality of shaft side steam seal teeth are arranged between the shaft seal body and the rotor, and when the height of the shaft side steam seal teeth is C, the height C of the turbulence teeth can be selected as follows: c is more than or equal to C and less than or equal to 2C.

Further, when the height of the turbulence teeth is the same as that of the shaft-side gland teeth, the turbulence teeth and the shaft-side gland teeth can have the same structure.

The utility model discloses an on the rotor that the steam extraction passageway corresponds, reasonable position, set up the vortex tooth, lead to the steam extraction passageway with the high-temperature steam in the cylinder, increase the steam extraction volume in shaft seal body middle section, avoid high-temperature steam to reveal outward to the cylinder along the clearance, reach the sealed effect of strengthening the bearing seal. And, adopt the utility model discloses with low costs, it is high to receive the effect, no matter purchase in earlier stage and still later maintenance, all very economical and practical.

Drawings

FIG. 1 is a schematic view of a prior art rotor shaft seal configuration;

fig. 2 is a schematic structural diagram according to a first embodiment of the present invention;

FIG. 3 is an enlarged partial view of the position of the last extraction passage of FIG. 2;

FIG. 4 is a comparison diagram of the 3D flow field before and after the turbulator teeth are arranged.

Detailed Description

The utility model discloses a turbine vortex formula vapor seal structure, it is right to combine specific embodiment below the utility model discloses the content describes in detail.

The first embodiment is as follows:

as shown in fig. 2, which is a schematic structural diagram of the present embodiment, in the present embodiment, a high-pressure steam turbine cylinder is taken as an example, a shaft seal body 2 is installed on a rotor 3 of the steam turbine, three

steam extraction channels

21, 22, and 23 in the shaft seal body 2, a plurality of shaft side steam seal teeth 5 and a plurality of steam seal blocks 4 are provided between the shaft seal body 2 and the rotor 3, and spoiler teeth 6 are provided on the rotor 3 and between two adjacent steam seal blocks 4 corresponding to each

steam extraction channel

21, 22, and 23.

As shown in fig. 3, which is a partial enlarged view of the position of the last stage steam extraction channel 23, turbulence teeth 6 are arranged on the rotor 3 corresponding to the last stage steam extraction channel 23 and between two adjacent steam seal blocks 4. When meeting the turbulence teeth 6, the high-temperature steam flowing out of the cylinder (from right to left in the figure) changes the flow direction, prevents the high-temperature steam from flowing directly to the outer side of the flowing cylinder, but is guided to the direction of the steam extraction channel by the turbulence teeth 6 and guided to the direction beneficial to being extracted, so that the risk of steam leakage of the shaft seal can be effectively reduced.

As shown in fig. 4, in order to set the 3D flow field contrast diagram before and after the spoiler tooth, the deeper the gray level in the diagram, the larger the air pressure. The upper diagram in fig. 4 is a 3D flow field diagram without turbulator teeth in the prior art, when the steam in the cylinder is too much, the air pressure at the position of the steam extraction channel is greater than the air pressure outside the cylinder, i.e. p1 < p2, and the shaft seal is caused to leak steam; the lower drawing in fig. 4 is a 3D flow field diagram provided with the spoiler teeth 6 in the present embodiment, and the added spoiler teeth 6 improve the flow of steam, and can ensure that p1 is not less than p2, effectively prevent steam from flowing out, and effectively prevent steam leakage of the shaft seal.

In this embodiment, the height of the spoiler tooth 6 may be equal to the height of the shaft-side gland seal tooth 5, and more preferably, the spoiler tooth 6 may adopt a structural form completely the same as the shaft-side gland seal tooth 5, so that the production and processing may be simplified, and the improvement cost is extremely low. The turbulence teeth are arranged at a reasonable position between two adjacent steam seal blocks 4, so that the turbulence teeth 6 are prevented from being in collision and abrasion with the steam seal blocks 4 on two sides, 3D simulation calculation is carried out on steam flowing in the shaft seal according to different turbine types and different operation parameters, and the installation position of the shaft seal is corrected according to a calculation result, so that a better installation scheme is achieved.

Example two:

the present embodiment is basically similar to the first embodiment, except that the height of the disturbing flow teeth 6 is twice the height of the shaft-side gland sealing teeth 5, and the increased tooth height enhances the disturbing flow effect, and is more favorable for guiding high-temperature steam to the steam extraction channel.

Compared with the two preferred embodiments, if the height of the turbulence teeth 6 is too small, the shaft seal effect can be reduced, if the height of the turbulence teeth 6 is too high, the turbulence teeth 6 are impacted by high-temperature steam for a long time, and the fracture risk is easy to occur, so that as a preferred embodiment, when the height of the shaft side steam seal teeth is C, the value of the height C of the turbulence teeth is as follows: c is more than or equal to C and less than or equal to 2C.

The turbulent flow type steam seal structure of the steam turbine provided by the utility model is introduced in detail, and a specific example is applied in the text to explain the principle and the implementation mode of the utility model, and the description of the above embodiment is only used for helping to understand the method and the core idea of the utility model; meanwhile, for the general technical personnel in the field, according to the idea of the present invention, there are changes in the specific implementation and application scope, to sum up, the content of the present specification should not be understood as the limitation of the present invention.

Claims

1. The utility model provides a steam turbine vortex formula steam seal structure, includes the rotor and installs the shaft seal body on the rotor, have a plurality of steam extraction passageways in the shaft seal body which characterized in that: and the rotor is also provided with turbulence teeth which are positioned at the positions corresponding to the final stage steam extraction channels in the plurality of steam extraction channels.

2. The turbine spoiler seal configuration according to claim 1, wherein: and turbulence teeth are also arranged on the rotors corresponding to other steam extraction channels except the final steam extraction channel.

3. The turbulent flow type gland seal structure of a steam turbine according to claim 1 or 2, wherein: between the shaft seal body and the rotor, a plurality of shaft side gland seal teeth are arranged, and when the height of the shaft side gland seal teeth is C, the value of the height C of the turbulence teeth is as follows: c is more than or equal to C and less than or equal to 2C.

4. The turbine spoiler seal configuration according to claim 3, wherein: when the heights of the turbulence teeth and the shaft side steam seal teeth are the same, the turbulence teeth and the shaft side steam seal teeth have the same structure.