CN212985304U

CN212985304U - Reduce gland sealing device that steam leaked at stationary blade top of steam turbine

Info

Publication number: CN212985304U
Application number: CN202021049413.6U
Authority: CN
Inventors: 崔传涛; 王学栋; 蒋叶辉; 张东兴; 王彬; 刘金亮; 郑惠
Original assignee: Huadian Electric Power Research Institute Co Ltd
Current assignee: Huadian Electric Power Research Institute Co Ltd
Priority date: 2020-06-09
Filing date: 2020-06-09
Publication date: 2021-04-16
Anticipated expiration: 2030-06-09

Abstract

The utility model relates to a reduce gland sealing device that steam leakage at quiet leaf blade top of steam turbine. The utility model discloses a can carry out gland clearance adjustment, in order to reduce the gland tooth that quiet leaf top leaked vapour, the gland tooth is inlayed on quiet leaf top steam side, the quantity of gland tooth is twice, and the height of twice gland tooth is the same, and the twice gland tooth is taken parallel, face-to-face mode to arrange. Reduce the gland sealing device of steam turbine stationary blade top steam leakage, break through above-mentioned thinking restriction, no longer choose novel gland at stationary blade top department for use, but change stationary blade top gland sealing structure, reduce the stationary blade top loss of leaking steam, have the breakthrough in the design theory, can play good sealed effect.

Description

Reduce gland sealing device that steam leaked at stationary blade top of steam turbine

Technical Field

The utility model relates to a reduce gland sealing device that steam leakage at quiet leaf blade top of steam turbine.

Background

In recent years, with the development of society and economy of China entering a new normal state, the nation pays more and more attention to efficient and clean development of coal-fired thermal power units, and various indexes of energy conservation and emission reduction of the coal-fired thermal power units are continuously refined, so that power generation enterprises are guided and standardized to develop towards high efficiency and cleanness. The steam turbine is important equipment of a coal-fired generating set, the operation economy of the steam turbine has important influence on the economy of a power generation enterprise, one of measures for reducing the steam leakage loss of the steam turbine and improving the operation efficiency of the steam turbine is favorable for developing the energy-saving and consumption-reducing work of the power generation enterprise.

When the steam turbine runs at high speed, a proper gap needs to be left between the rotating part and the static part to ensure that the rotating part and the static part cannot be rubbed, and although the gap reduces the probability of collision and abrasion of moving and static parts, the flow of steam in the gap is also caused, and steam leakage loss is generated. In the loss of each stage of the steam turbine, steam leakage loss is an important component, and the adverse effect of the leakage of steam on a unit is mainly reflected in two aspects: on one hand, the steam quantity passing through the movable and fixed blades is reduced, so that the steam quantity participating in effective work is reduced, and the efficiency of a steam turbine cylinder is reduced; on the other hand, the axial thrust at the position is increased, and the running economy and the safety of the unit are both adversely affected.

The reduction of the steam leakage loss of each stage of the steam turbine is an important measure for improving the efficiency of a steam turbine cylinder, and the steam sealing device has an obvious effect on the reduction of the steam leakage and is widely adopted. The steam sealing device can ensure that the movable part and the static part have proper gaps, and can prevent steam from leaking from the gaps of the movable part and the static part, thereby preventing the steam from leaking into the atmosphere from the shaft end or air from leaking into the vacuum part of the cylinder from the shaft end. How to improve the efficiency of the cylinder and reduce the steam leakage loss of the steam turbine becomes the subject of extensive research, and with the continuous progress of scientific technology, advanced steam seals are continuously applied to obtain certain energy-saving effect, but the control measures of the steam leakage loss of the steam turbine have many defects and still have certain energy-saving potential.

Steam turbine steam seals are of various types, and can be divided into stationary blade top steam seals, moving blade top steam seals, balance disc steam seals, end steam seals and the like according to different installation positions. Steam in the steam turbine flows between the movable blades and the fixed blades, when working steam enters the fixed blades from the outlets of the movable blades, the working steam flows along the direction of the main channel, and leakage steam leaks to the tops of the fixed blades from the steam outlet sides of the roots of the movable blades; when steam enters the stationary blade from the stationary blade outlet, acting steam flows along the direction of the main channel, and leakage steam enters the tops of the movable blades along the steam outlet side of the root part of the stationary blade; the amount of the steam leakage depends on the clearance at the top of the blade and the sealing effect of the steam seal.

With the continuous development of the steam seal technology, adjustable steam seals, side tooth steam seals, honeycomb steam seals, contact steam seals and other types of steam seals are widely applied, the novel steam seal is applied to the positions of a fixed blade top, a movable blade top and the like, a certain effect is achieved in the aspect of reducing steam leakage, but in the view of actual effect operation, leakage prevention measures are not enough to reduce steam leakage to the maximum extent by adopting the positions of the blade tops alone. At present, measures for reducing steam leakage between stages of a steam turbine mainly focus on reducing steam leakage loss of movable blade tops and static blade tops of the steam turbine, namely, the steam leakage loss is reduced by adopting a novel steam seal, the steam leakage loss reduction of the steam turbine is a system project, and the steam turbine is limited by only adopting the novel steam seal. There are generally three methods for reducing the loss of steam leakage from a gland seal: the steam seal structure is changed, the steam seal gap is reduced, the number of steam seal teeth is increased, and the effect of reducing steam leakage loss is obvious by changing the steam seal structure and reducing the steam seal gap.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the above-mentioned not enough that exists among the prior art, and provide a steam seal device of the quiet leaf blade top steam leakage of reduction steam turbine that structural design is reasonable, break through above-mentioned thinking restriction, no longer choose for use novel steam seal in quiet leaf top department, but change quiet leaf top steam seal structure, reduce the loss of quiet leaf top steam leakage, have breakthroughs in the design theory, can play good sealed effect.

The utility model provides a technical scheme that above-mentioned problem adopted is: this reduce gland sealing device of steam turbine stationary blade top steam leakage, its structural feature lies in: the steam seal tooth is embedded on the side face of the steam outlet side of the fixed blade tops, the number of the steam seal teeth is two, the heights of the two steam seal teeth are the same, and the two steam seal teeth are arranged in a parallel and face-to-face mode.

Further, the stationary blade ejection steam side surface is arranged on the stationary blade top.

Furthermore, the two steam seal teeth and the steam side surface of the ejection steam side of the stationary blade form a U-shaped sealing cavity.

Further, turbulence is created as the steam flows through the U-shaped sealed chamber to reduce steam leakage.

Further, the steam inlet side surface of the blade root of the movable blade is arranged on the blade root of the movable blade.

Further, the clearance between the tooth tip of the steam seal tooth and the blade root of the movable blade is 0.75 +/-0.10 mm.

Compared with the prior art, the utility model has the advantages of it is following:

1. the steam sealing device optimizes the steam sealing structure at the top of the stationary blade, a U-shaped sealing cavity is added on the side surface of the steam edge at the top of the stationary blade of the steam turbine, the steam sealing structure is changed from the steam sealing structure at the top of the stationary blade into the steam sealing structure at the top of the stationary blade and the steam sealing structure at the side surface of the steam edge at the top of the stationary blade, and the steam leakage can be reduced to the maximum extent by double sealing;

2. the steam sealing device changes the side surface of the steam edge ejected by the stationary blade from non-steam-seal sealing to embedded steam-seal sealing by adding the steam-seal teeth, increases steam flow disturbance and can effectively reduce steam leakage loss;

3. the steam sealing device comprehensively considers factors such as steam sealing gaps, radial gaps, cylinder expansion and differential expansion in the design process, reduces steam leakage loss, improves the efficiency of a cylinder, and does not affect the operation safety of a unit.

The steam sealing device has wide application prospect to the following units:

1. for a new production unit, the steam sealing device can be adopted in the model selection design stage of the unit for design and manufacture;

2. for the in-service unit, the synchronous implementation can be carried out in the process of flow-through transformation of the unit;

3. for the unit with obvious problems of high temperature at a certain position, large steam leakage and the like in the operation of the unit, the practical problem of the unit can be solved by taking the practical situation as one of the processing measures.

Drawings

FIG. 1 is a schematic view of a prior art steam seal assembly.

Fig. 2 is a schematic structural diagram of a steam seal device according to an embodiment of the present invention.

Fig. 3 is a partially enlarged schematic view of fig. 2.

In the figure: the steam turbine comprises a steam seal tooth 1, a stationary blade ejection steam side surface 2, a movable blade root steam inlet side surface 3, a U-shaped seal chamber 4, a stationary blade top 5, a movable blade root 6 and a steam turbine rotor 7.

Detailed Description

The present invention will be described in further detail by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not intended to limit the present invention.

Examples

Referring to fig. 2 to 3, it should be understood that the structures, ratios, sizes, etc. shown in the drawings attached to the present specification are only used for matching with the contents disclosed in the specification, so as to be known and read by those skilled in the art, and are not used for limiting the limit conditions that the present invention can be implemented, so that the present invention has no technical essence, and any modification of the structures, changes of the ratio relationship, or adjustment of the sizes should still fall within the scope that the technical contents disclosed in the present invention can cover without affecting the efficacy and the achievable purpose of the present invention. Meanwhile, in the present specification, if there are terms such as "upper", "lower", "left", "right", "middle" and "one", they are used for clarity of description only, and are not intended to limit the scope of the present invention, and changes or adjustments of the relative relationship thereof are considered as the scope of the present invention without substantial changes in the technical content.

The steam sealing device for reducing steam leakage at the top of the stationary blade of the steam turbine in the embodiment comprises steam sealing teeth 1 capable of adjusting steam sealing gaps to reduce steam leakage at the top 5 of the stationary blade, wherein the steam sealing teeth 1 are embedded on the steam side surface 2 at the top of the stationary blade, the number of the steam sealing teeth 1 is two, the heights of the two steam sealing teeth 1 are the same, and the two steam sealing teeth 1 are arranged in a parallel and face-to-face mode.

The fixed blade top 5 in the embodiment is provided with a fixed blade top steam side surface 2, and two steam seal teeth 1 are embedded in the fixed blade top steam side surface 2; the two steam seal teeth 1 and the steam side surface 2 of the stationary blade ejection form a U-shaped seal chamber 4.

In the embodiment, when steam flows through the U-shaped sealing chamber 4, turbulent flow is formed so as to reduce steam leakage; the steam inlet side surface 3 of the blade root of the movable blade is arranged on the blade root 6 of the movable blade; the clearance between the tooth tip of the steam seal tooth 1 and the blade root 6 of the movable blade is 0.75 +/-0.10 mm.

Specifically, the technical scheme that the steam sealing device reduces steam leakage of the stationary blade top 5 is as follows: a steam sealing device is additionally arranged on the side face 2 of the steam outlet side of the top of the stationary blade, the steam sealing device consists of two embedded steam sealing teeth 1 which are respectively a lower steam sealing tooth on the side portion of the steam outlet side of the top of the stationary blade and an upper steam sealing tooth on the side portion of the steam outlet side of the top of the stationary blade, and the two steam sealing teeth 1 are arranged face to face and in equal height and are combined with the side face 2 of the steam outlet side of the top of the stationary blade to form a U-shaped sealing cavity 4. The steam seal structure of the stationary blade top 5 of the steam turbine is changed after the steam seal device is additionally arranged, the original steam seal structure of the stationary blade top 5 is changed into two parts of the stationary blade top 5 steam seal and the stationary blade top steam side surface 2 steam seal, and the steam leakage can be reduced to the maximum degree through double sealing.

The steam sealing device is structurally shown in fig. 2, and structurally comprises a U-shaped sealing chamber 4, wherein the U-shaped sealing chamber 4 comprises lower steam sealing teeth of the stationary blade ejecting steam side surface 2, upper steam sealing teeth of the stationary blade ejecting steam side surface 2 and the stationary blade ejecting steam side surface 2. The leakage steam flows out from the steam outlet side of the blade root of the upper-stage movable blade, flows along the blade root of the upper-stage movable blade, changes in flow direction after encountering a steam turbine rotor 7, passes through the top gland seal teeth of the fixed blade top 5 in the direction of the steam turbine rotor 7, reduces in flow rate after passing through the fixed blade top 5, the leakage steam continues to flow forwards, changes in flow direction after encountering the movable blade root 6, flows upwards along the movable blade root 6, enters the U-shaped sealing chamber 4, the steam forms the rotary flow in the U-shaped sealing chamber 4, the space of the U-shaped sealing chamber 4 is relatively narrow and small, the relative damping effect is obvious, the rotor gland seal gap is small, vortex disturbance is easily formed, the flow path resistance and the local resistance of the steam are obviously increased, and therefore a good sealing effect is achieved.

This gland sealing device makes the through-flow of leaking steam change into U type seal chamber 4 by the straight way, and it is sealed to change into embedded gland tooth 1 by original nothing gland, and the gland clearance obtains reasonable control, and this design is through the method that changes the gland structure and reduce the gland clearance, and the effectual steam leakage that has reduced is controlled the minimum with leaking the vapour loss, can effectively improve cylinder efficiency.

The steam seal device relates to a steam seal tooth 1 of a stationary blade ejecting steam side surface 2, a ferrite material with low hardness is selected, the thickness of a steam seal tooth tip is small, even if the steam seal tooth tip contacts with a movable blade root 6, the rotor cannot be damaged, and the operation safety of a unit cannot be influenced.

The value of the gland seal clearance has important influence on the economic efficiency and the safety of the unit operation, and the clearance is too small, so that the collision and abrasion probability of the movable blade and the fixed blade is increased, and the safe operation of the unit is influenced; too many clearances can increase steam leakage loss, the sealing effect of the steam seal teeth 1 becomes poor, and the value principle of the steam seal clearances of the steam seal device is to reduce the steam leakage loss to the maximum extent on the premise of not influencing the safe operation of the unit. The clearance between the tooth tip of the steam seal tooth 1 and the blade root 6 of the movable blade is preferably 0.75 +/-0.10 mm, and is required to be higher than the design upper limit of the unit differential expansion value so as to ensure that the unit cannot be subjected to dynamic and static rubbing during operation. The clearance adjustment work can be carried out on site during the unit construction, along with the increase of unit operating time, can measure the gland clearance that the quiet leaf pushed out steam side 2 during the maintenance, if the gland clearance exceeds standard, can adjust or inlay again the clearance of gland tooth 1, control within standard clearance scope. The analysis shows that the steam sealing device improves the economic efficiency of unit operation and does not have negative influence on the unit operation safety.

The steam sealing device mainly has the control effect on steam leakage in two aspects: on one hand, a U-shaped sealing chamber 4 is added on the steam side surface 2 of the stationary blade top of the steam turbine, the steam sealing structure is changed from a stationary blade top 5 steam sealing structure to a stationary blade top 5 steam sealing structure and a stationary blade top steam side surface 2 steam sealing structure, and the double sealing can reduce steam leakage to the maximum extent; on the other hand, by adding the steam seal teeth 1, the original non-steam seal is changed into the embedded steam seal, and the steam seal gap is reasonably controlled; the design effectively reduces steam leakage by changing the steam seal structure and reducing the steam seal clearance, controls the steam leakage loss to the minimum and can effectively improve the efficiency of the cylinder.

In addition, it should be noted that the specific embodiments described in the present specification may be different in the components, the shapes of the components, the names of the components, and the like, and the above description is only an example of the structure of the present invention. All the equivalent changes or simple changes made according to the structure, characteristics and principle of the utility model are included in the protection scope of the utility model. Various modifications, additions and substitutions may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.

Claims

1. The utility model provides a reduce gland sealing device that steam leaked at quiet leaf blade top of steam turbine which characterized in that: including can carry out the gland clearance adjustment, in order to reduce gland tooth (1) of quiet leaf top (5) steam leakage, gland tooth (1) are inlayed on quiet leaf top steam side face (2), the quantity of gland tooth (1) is twice, and the height of twice gland tooth (1) is the same, and twice gland tooth (1) are taken parallel, face-to-face mode and are arranged.

2. The gland sealing device for reducing steam leakage at the tip of a turbine stator blade according to claim 1, wherein: the fixed blade ejection steam side surface (2) is arranged on the fixed blade top (5).

3. The gland sealing device for reducing steam leakage at the tip of a turbine stator blade according to claim 1, wherein: the two steam seal teeth (1) and the steam side surface (2) of the stationary blade ejection form a U-shaped sealing chamber (4).

4. The gland sealing device for reducing steam leakage at the tip of a turbine stator blade according to claim 3, wherein: when steam flows through the U-shaped sealing chamber (4), turbulent flow is formed so as to reduce steam leakage.

5. The gland sealing device for reducing steam leakage at the tip of a turbine stator blade according to claim 1, wherein: the movable blade root (6) is provided with a movable blade root steam inlet side surface (3).

6. The gland sealing device for reducing steam leakage at the tip of a turbine stator blade according to claim 5, wherein: the clearance between the tooth tip of the steam seal tooth (1) and the blade root (6) of the movable blade is 0.75 +/-0.10 mm.