WO2018153529A1

WO2018153529A1 - Rotor blade module for a steam turbine and method for producing same

Info

Publication number: WO2018153529A1
Application number: PCT/EP2017/082014
Authority: WO
Inventors: Inka Beyer; Martin Schubert
Original assignee: Siemens Aktiengesellschaft
Priority date: 2017-02-21
Filing date: 2017-12-08
Publication date: 2018-08-30
Also published as: DE102017202784A1; EP3568573B1; EP3568573A1; PL3568573T3

Abstract

What is described is a rotor blade module (11) for securing to a rotor part in order to form a rotor blade ring in a steam turbine. The rotor blade module (11) has (a) a root plate (13), (b) a blade airfoil (12) that extends from one side of the root plate (13), and (c) a securing means which extends from the other side of the root plate (13), wherein a projection of the blade airfoil (12) onto a plane containing the root plate (13) is completely covered by the root plate (13). Also described is a steam turbine having such a rotor blade module (11) and a method for producing such a rotor blade module (11).

Description

description

Of the same blade module for steam turbine and method for the manufacture ^¬ lung

The present invention relates to the technical field of steam turbines. The present invention relates insbesonde re ^¬ a blade module for attachment to a drive acting ^¬ felkranz a steam turbine, a steam turbine with several such blade modules and a method for manufacturing such a blade module.

A steam turbine generally has a series of rotor blades which are mounted side by side on an axis of rotation. Each blade ring has a plurality of rotor blades, which have a shape optimized in terms of fluid dynamics. The rotor blades may be modular, with each module having a base plate, an airfoil and a fastener. The foot plates and fasteners for the blades must i.a. be designed so that the design default number of blades on the blade ring fit next to each other and so that a predetermined maximum distance to an adjacent blade ring can be maintained. Due to these restrictions with regard to the shape and size of the individual parts, undesired stress concentrations can arise, in particular in the transition region between the blade and the foot plate / fastening means. The object of the present invention is to reduce or avoid such stress concentrations.

This object is achieved by the subjects of inde ^¬ Gigen claims. Advantageous embodiments of the present invention are described in the dependent claims. According to a first aspect of the invention, a blade module for mounting on a rotor part for forming a blade ring in a steam turbine is described. The blade module described comprises: (a) a base plate, (b) an airfoil that extends from one side of the base plate, and (c) a Befestigungsmit ^¬ tel which extends from the other side of the base plate, wherein a projection the airfoil to the foot plate ^{¬-containing} layer is completely covered by the base plate.

The described blade module is based on the finding that stress concentrations can be significantly reduced or completely avoided if the projection of the blade onto the soleplate plane is completely covered by the soleplate, that is to say that the profile of the airfoil does not overlap the edge of the base plate protrudes. This property is to be achieved in particular by the form ^¬ gebung the footplate, in particular the edge of the base plate, as the shape of the airfoil is CARDINAL ^¬ Lich fluid dynamic conditions.

According to one embodiment of the invention, the

Base plate a quadrangular shape with pairwise parallel

Edges up.

According to a further embodiment of the invention, the base plate is rhomboid-shaped or diamond-shaped. In this embodiment, two opposing edges of the foot plate, for example, perpendicular to the axis of rotation of the rotor while the two other opposing edges are not parallel to the axis of rotation. In other words, the foot plate has no angle which is 90 °. According to a further embodiment of the invention, the fastening means has a plurality of tabs, which for Attach the blade module to the rotor section

Forming of the blade ring are set up.

The tabs may in particular have a quadrilateral shape and parallel to each other and perpendicular to the rotational axis ^¬ net angeord. The tabs fit into corresponding grooves in the rotor member and can be secured therein.

According to a further embodiment of the invention, the tabs on a through hole for receiving a tapered pin. The bevel pin is used to attach the Laufschaufelmo ^¬ module.

Comparable According to a further embodiment of the invention, the through hole running through the center of each link plate and parallel to an edge of the foot plate that is neither parallel nor perpendicular ^¬ right to a rotational axis of the rotor blade ring.

The central through bore results in a stable as possible struc- ture when the blade module is attached (for example by means troduction ^¬ proceedings of a tapered pin into the through hole) on the rotor ^¬ part because the stressed cross section of the flaps (the level of the hole) on both sides of the same is great. According to a further embodiment of the invention, the foot plate, the blade and the fastening means are integrally formed.

According to a second aspect of the invention, a steam turbine is described. The steam turbine described comprises (a) at least one rotor part and (b) a plurality of rolling show ^¬ felmodulen according to the first aspect or any one of the above embodiments, wherein the blade modules are attached to form a blade ring on the rotor part. Due to the use of the advantageous blade modules, this steam turbine benefits from the advantages described above. In particular, results in comparison with other steam turbines a longer life and a lower risk of failure.

According to a third aspect of the invention, a method of manufacturing a blade module for mounting on a rotor part to form a blade ring in a steam turbine is described. The described method comprises: (a) providing a base plate, (b) providing an airfoil that extends from one side of the base plate, and (c) providing a Fixed To ^¬ supply means extending from the other side of the base plate, wherein a projection of the airfoil on a footplate-containing plane is completely covered by the foot plate ^¬ dig.

This aspect basically relates to a method of manufacturing a blade module according to the first aspect.

According to one embodiment of the invention, the

Base plate a quadrangular shape with pairwise parallel

Edges up. The footplate may in particular be rhomboidal.

According to a further embodiment of the invention, the attachment means comprises a plurality of tabs adapted to secure the blade module to the rotor member, and the method further comprises forming a throughbore through the tabs to receive a bevel pin.

According to a further embodiment of the invention, the method further comprises forming a recess in one

Surface of the rotor part, which is inclined so that the formation of the through hole perpendicular to the surface of the Recess may occur when the blade module is mounted on the rotor part, in particular when the tabs are mounted in corresponding grooves in the rotor part. The recess facilitates the piercing of the rotor part and of the flaps and in particular allows that the Durchboh ^¬ tion can be created with high precision.

It should be noted that embodiments of the invention have been described with reference to different subject matter of the invention. In particular, some embodiments of the invention are described with method claims and other embodiments of the invention with apparatus claims. However, it will be readily apparent to those skilled in the art upon reading this application that, unless explicitly stated otherwise, in addition to a combination of features belonging to a type of subject matter, any combination of features that may result in different types of features is also possible Subject matters belong.

Further advantages and features of the present invention will become apparent from the following exemplary description of a preferred embodiment.

Figure 1A shows a first side view of a conventional blade module.

Figure 1B shows a second side view of the conventional blade module.

Figure IC shows a plan view of the conventional Laufschau ^¬ felmoduls. Figure 2 shows another view of the conventional run ^¬ shovel module. FIG. 3 shows a partial view of a rotor part with three conventional moving blade modules.

Figure 4 shows a plan view of a blade module according to the present invention.

Figure 5 is a sectional view of a foot strap of a blade module according to the present invention.

It should be noted that as described hereinafter ^¬ NEN embodiments represents only a limited selection of possible embodiments of the invention. 1A to 1C show various views of a conventional blade module 1. More specifically, FIG. 1A shows a first side view of the blade module 1 with airfoil 2 and base plate 3. FIG. 1B shows a second side view of the blade module 1 relative to the first side view in FIG 1A is turned 90 °. In Figure 1B tabs 4 can be seen. The lugs 4 represent a fastening means for mounting the blade module 1 on a rotor part with corresponding grooves. FIG. IC shows a plan view of the blade module 1. As can be seen from this view, the projection of the blade 2 lies on the plane of the base plate 3 In other words, a part of the profile of the airfoil 2 protrudes beyond the edge of the base plate 3. The arrow 6 shows the direction of the incoming steam.

The overhang of the airfoil 2 shown in FIG. 1C arises due to the predetermined pitch of a rotor blade rim and the profile shape in the hub section, but is not ideal for structural mechanical reasons because it leads to stress concentration in the corresponding region 5. This fact is also shown in Figure 2 and may affect the life and lead to failure by blade loss. FIG. 3 shows a partial view of a rotor part 7 with three conventional running blade modules 1 mounted side by side. More specifically, the tabs 4 of each run ^¬ scoop module 1 are inserted into corresponding grooves 8 of the rotor part 7 and two fasteners, in particular conical pins 9 (per module) pass through corresponding holes in the tabs 4 and thus hold the modules 1 on the rotor part 7 fixed ,

FIG. 4 shows a plan view of a blade module 11 according to the present invention. The blade module 11 has an airfoil 12 and a base plate 13. Rectangular base plate 3 deviate ^¬ accordingly shown by in FIG IC (and in Figure 4 also in phantom), the foot ^¬ plate 13 of the rotor blade module of the invention 11 designed so that the projection of the airfoil 12 on the plane completely inside the edge of the Foot plate 13 is located. In the illustration shown, this is achieved in that the foot plate is rhomboid-shaped or diamond-shaped. In other words, although the shape of the foot plate is quadrangular and the opposing edges 13a and 13b are pairwise parallel, the shape is not at right angles. Figure 4 further shows the outer surfaces 7a, 7b of the rotor 7. The rotor blade part module 11 is Zvi ^¬ rule the outer surfaces 7a, 7b mounted.

The rotor blade module 11 also has tabs (not visible in FIG. 4) with a through bore whose axis 14 is shown schematically. This axis 14 extends parallel to and in the middle between (in this embodiment) longer edges 13a of the footplate 13. To facilitate the corresponding drilling operation, a recess 15 may be provided in one of the outer side surfaces 7a, 7b of the rotor member 7 which forms a surface perpendicular to the direction of the axis 14. The arrow 16 shows the turbine longitudinal axis.

FIG. 5 shows a sectional view of a foot strap 17 of the blade module 11 shown in FIG. 4 according to the present invention. The foot-plate 17 as shown has a cross sectional shape corresponding to the shape of the foot plate 13 and has a central through bore 18 into which a buildin ^¬ actuating element, for example a tapered pin can be inserted. This is done according to the same principle that in

3, whereby the fastening elements do not run parallel to the turbine axis 16 but to the edges 13a (see FIG. With reference to Figure 1B, which shows four plates 4, it should be mentioned that the invention run ^¬ vane module 11 also comprises a plurality of tabs 17th These are mounted so that they follow the shape of the foot plate, and so that the respective central through holes 18 are aligned with the axis 14.

Reference sign list

1 blade module

2 airfoil

3 foot plate

4 tab

5 area

6 arrow

7 rotor part

7a surface

7b surface

8 groove

9 fastener

11 blade module

12 airfoil

13 foot plate

13a edge

13b edge

14 axis

15 recess

16 arrow

17 tab

18 hole

Claims

claims

1. Blade module (11) for attachment to a rotor ^¬ part to form a running blade ring in a steam turbine, the blade module having

a foot plate (13),

an airfoil (12) extending from one side of the foot plate (13), and

a fastener extending from the other side of the foot plate (13),

wherein a projection of the airfoil (12) on a footplate (13) containing plane of the footplate (13) is completely covered.

2. Blade module according to the preceding claim, wherein the base plate (13) has a quadrangular shape with pairwise parallel edges (13a, 13b).

3. Blade module according to one of the preceding claims, wherein the base plate (13) is rhomboidal.

4. Blade module according to one of the preceding Ansprü ^¬ che, wherein the fastening means comprises a plurality of tabs (17), which are for attaching the blade module (11) on the rotor part to the formation of the blade ring ^¬ set.

5. Blade module according to the preceding claim, wherein the tabs (17) have a through bore (18) for receiving a tapered pin.

6. Blade module according to the preceding claim, wherein the through bore (18) extends centrally through each tab (17) and parallel to an edge (13 a) of the base plate, which is neither parallel nor perpendicular to a rotation axis of the running ^¬ blade ring.

7. Blade module according to one of the preceding Ansprü ^¬ che, wherein the base plate (13), the blade (12) and the fastening means are integrally formed.

8. Steam turbine having

at least one rotor part and

a plurality of running vane modules (11) according to one of the preceding claims,

wherein the blade modules are mounted on the rotor part to form a rotor blade ring.

9. A method of making a blade module (11) for mounting on a rotor part to form a blade ring in a steam turbine having the method

Providing a foot plate (13),

Providing an airfoil (12) extending from one side of the footplate (13), and

Providing a fastener extending from the other side of the foot plate (13),

10. The method according to the preceding claim, wherein the base plate (13) has a quadrangular shape with pairs of parallel edges (13a, 13b), wherein the base plate (13) is in particular ^¬ special rhomboid.

11. The method according to claim 9 or 10, wherein the Fixed To ^¬ supply means comprises a plurality of tabs (17) that are for securing the blade module (11) arranged on the rotor part, the method further comprising

Forming a throughbore (18) through the tabs to receive a bevel pin.

12. The method according to the preceding claim, further comprising

Forming a recess (15) in a surface of the rotor part, which runs obliquely so that the formation of the throughbore (18) perpendicular to the surface of the recess (15) can take place when the blade ^{module is} mounted on the rotor ^¬ part.