CN101333941A

CN101333941A - Domed tip cap and related method

Info

Publication number: CN101333941A
Application number: CNA2008101293803A
Authority: CN
Inventors: L·维尔特尔; W·S·泽米蒂斯; G·C·利奥塔
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 2007-06-25
Filing date: 2008-06-25
Publication date: 2008-12-31
Also published as: JP2009002339A; US20080317597A1; DE102008002906A1

Abstract

The invention relates to a dome-shaped tip cap and a related method. A bucket for a turbine includes a dovetail mounting portion, a shank portion defined at a radially outer end thereof by a platform, and an airfoil portion extending radially outward of the platform. The airfoil portion has a radially outer end closed by a tip cap having a non-planar shape that reduces stress in the tip cap during use. A related method of reducing stress in a tip cap of a turbine bucket includes providing an airfoil portion of the turbine bucket with a radially outer end; and closing the radially outer end with a tip cap having a non-planar shape that reduces stress in the tip cap during use.

Description

The tip cap and the correlation technique of dome shape

Technical field

The present invention relates to turbine technology, more particularly, relate to the cap that is used for turbine vane (bucket) or blade.

Background technique

Traditionally, use tip cap (tip cap) to cover the tip of turbine vane aerofoil profile (airfoil) part, wherein, turbine vane has the cooling circuit of inner complications.These tip caps are made by flat plate stock, and typically or be welded on the radial outer end of airfoil section of wheel blade, perhaps with the airfoil section castingin together.Under arbitrary situation, straight tip cap all suffers heavily stressed when operation.

Summary of the invention

In an exemplary and nonrestrictive embodiment, tip cap insert is suitable for being welded on the radial outer end of wheel blade airfoil section.According to this embodiment, the tip cap that is to say for the dome shape of upset, the direction recessed (just as what seen from the wheel blade outside) that the tip cap is radially inside substantially.

The tip cap also is formed with channel portion, and it is suitable for being placed on the interior inner circular bead of tip cap welding airfoil section thereon.

In another exemplary and nonrestrictive embodiment, the tip cap of dome shape and the airfoil section of wheel blade and other aerofoil profile feature are cast integratedly.

Therefore, in one aspect, the wheel blade that is used for turbine is provided, this wheel blade comprises the dovetail mounting portion, the shank part that is limited by platform at its radial outer end and the airfoil section that extends on this platform outer radial ground, this airfoil section has the radial outer end by the tip cap closure, wherein, in the internal surface of this tip cap and the outer surface or both are configured as and have the nonplanar shape that reduces the stress in the tip cap when using.

In yet another aspect, the wheel blade that is used for turbine is provided, the shank part that this wheel blade comprises the dovetail mounting portion, limited by platform at its radial outer end and at the airfoil section of this platform outer radial ground extension, this airfoil section has the radial outer end by the tip cap closure, wherein, the internal surface of this tip cap is the dome shape of radially inside direction at least; And wherein the tip cap is configured as and has one or more internal ribs (internal rib).

In yet another aspect, provide the method for the stress in the tip cap that reduces turbine vane, this method comprises that the airfoil section of turbine vane has radial outer end; And with tip cap closure radial outer end, this tip cap has the nonplanar shape that reduces the stress in the tip cap when using.

To provide more detailed description in conjunction with the accompanying drawing of following sign now.

Description of drawings

Fig. 1 is the perspective view of traditional turbine vane;

Fig. 2 is the detailed drawing of the tip cap portion of aerofoil profile shown in Fig. 1, and it shows with slightly different angle, so that the tip cap on plane as seen;

Fig. 3 is the planimetric map of the airfoil section shown in Fig. 1 and Fig. 2; The cross section that Fig. 4 is intercepted for the line 4-4 along Fig. 3;

Fig. 5 is the plan view of wheel blade airfoil section, and according to the exemplary and nonrestrictive embodiment of technology disclosed herein, this wheel blade has the tip cap of dome shape;

The partial cross section that Fig. 6 is intercepted for the line 6-6 along Fig. 5;

Fig. 7 is similar to the cross section of Fig. 6 for according to another exemplary and nonrestrictive embodiment, but shows the tip cap with the airfoil section castingin dome shape together of wheel blade; With

Fig. 8 be have to Fig. 6 and Fig. 7 in similar orientation but illustrate cross section according to another kind of tip cap shaped of the present invention.

Component list

Wheel blade 10,110

Dovetail 12

Shank or shank part 14

Platform 16

Aerofoil profile 18,118,218

Tip cap 20,120,220,320

Flange 22,122

Rib 24,123,124

Outer surface 321

Internal surface 323

Embodiment

Referring to Fig. 1-4, the conventional inner-cooled wheel blade 10 that is used for turbogenerator comprises installs dovetail 12, shank or shank part 14, the platform 16 on the shank top and the airfoil section or the aerofoil profile 18 of extending radially outwardly from platform.Aerofoil profile 18 ends at tip cap 20 in its outermost end.Illustrated tip cap comprises the flat board that is welded on the airfoil section in Fig. 1-4.More particularly, and as finding best among Fig. 4, straight tip cap 20 is placed on the inner peripheral land or flange 22, and welds thereon according to traditional welding technique.Should understand, straight tip cap can also with this aerofoil profile castingin together, eliminated necessity of welding.Can adopt internal rib 24 (being shown in broken lines) to strengthen the tip cap when needing.

Turn to Fig. 5 and Fig. 6 now, illustrate tip cap according to the exemplary and nonrestrictive embodiment of this invention.For simplicity, in Fig. 5 and Fig. 6, use and refer to common means, prefix 1 is arranged but increase corresponding to label used among Fig. 1 to Fig. 4.Therefore, wheel blade 110 comprises the aerofoil profile 118 that has tip cap 120, and wherein, this tip cap 120 is fastened on the radially outermost end place of aerofoil profile.Tip cap 120 can be described as the dome shape with upset, that is to say, the radially inner direction of tip shade is recessed into (or as seeing from the wheel blade outside).In other words, the tip cap is radially given prominence to into wheel interlobar part.Tip cap 120 forms flange or the edge 26 with periphery, and this flange or edge 26 are placed on the inner circular bead or flange 122 of aerofoil profile 118, and again, weld thereon according to traditional welding technique.

In Fig. 7 among the illustrated exemplary and nonrestrictive embodiment, the tip cap 220 of aerofoil profile 218 and airfoil section castingin together, and the tip cap in the image pattern 6 has the dome of upset or the shape that inwardly concaves like that.

By giving the dome shape of upset for (being the plane) tip cap, can reduce typically relevant flexural stress with straight tip cap.In some situation, the benefit that the stress of dome cap reduces can suffice to show that eliminates the correct of rib welding, and wherein, the rib welding is used for the tip cap is fastened on their aerofoil profiles separately traditionally.Should understand that the curvature of tip cap dome is optimized to regardless of the span that is covered provides the stress to tip cap Zone Full to reduce.In addition, the tip cap of dome shape can be provided with known surface characteristics (as swirler) and strengthens convection current (for example seeing internal rib 122 among Fig. 3 and the internal rib 124 among Fig. 5).

Fig. 8 illustrates another exemplary, nonrestrictive mode of execution, and the tip cap 320 of wheel blade 318 keeps straight on the surface 323 within it curving inwardly on its outer surface 321 herein.Shape also provides required stress to reduce.Therefore, should understand, term " dome shape " intention comprises of being used for wheel blade tip cap internal surface and outer surface or both many shapes (no matter be welded on the airfoil section of wheel blade or with this airfoil section castingin and be in the same place), and these shapes can comprise circle, parabola or be different from traditional flat plate stock and reduce other complicated shape of stress.

The dome shape of tip cap also makes it possible to reduce essential material property and/or material thickness, and perhaps need not to change material composition and the running temperature of the tip cap that can raise.In addition, compare, can cover the opening of broad with the straight design of same material and thickness.

Although the present invention has combined and has currently thought that the most practical and preferred embodiment are described, but should be appreciated that, the invention is not restricted to the disclosed embodiments, and just the opposite, this invention is intended to contain the essence and interior various modifications and the equivalent arrangements of scope that are included in appended claims.

Claims

1. wheel blade (110) that is used for turbine, the shank part (14) that it comprises dovetail mounting portion (12), limited by platform at its radial outer end and at the airfoil section (118) of described platform outer radial ground extension, described airfoil section has the radial outer end by tip cap (120) sealing, wherein, in the internal surface of described tip cap and the outer surface or both are configured as and have the nonplanar shape that reduces the stress in the described tip cap when using.

2. wheel blade according to claim 1 is characterized in that, described nonplanar shape is the shape of the dome shape of radially inside direction.

3. wheel blade according to claim 2 is characterized in that, described tip cap and described airfoil section castingin are together.

4. wheel blade according to claim 1 is characterized in that, described tip cap is welded on the described airfoil section.

5. wheel blade according to claim 4 is characterized in that, described tip cap is configured as and has the channel portion (122) that is placed on the shoulder, and described shoulder is formed in the described airfoil section.

6. wheel blade according to claim 1 is characterized in that, described tip cap is configured as and has one or more internal ribs (123).

7. the method for the stress in the tip cap that reduces turbine vane comprises that the airfoil section (118) to described turbine vane provides radial outer end; With

With the described radial outer end of tip cap closure, described tip cap has the nonplanar shape that reduces the stress in the described tip cap (120) when using.

8. method according to claim 7 is characterized in that, described tip cap (120) is configured as and has one or more internal ribs (123).

9. method according to claim 7 is characterized in that, the internal surface of described tip cap (120) and outer surface are the shapes of the dome shape of radially inside direction.

10. method according to claim 7 is characterized in that, the outer surface of described tip cap (120) is the shape of the dome shape of radially inside direction.