AU2005201225A1

AU2005201225A1 - Turbomachine component having a cooling arrangement

Info

Publication number: AU2005201225A1
Application number: AU2005201225A
Authority: AU
Inventors: Ulrich Rathmann; Ingolf Schulz
Original assignee: Alstom Technology AG
Current assignee: General Electric Technology GmbH
Priority date: 2004-03-23
Filing date: 2005-03-22
Publication date: 2005-10-13
Anticipated expiration: 2025-03-22
Also published as: MY147657A; CN1769653A; EP1580414A3; EP1580414A2; CN100425812C; AU2005201225B2; DE102004014117A1

Description

AUSTRALIA

Patents Act 1990 ALSTOM TECHNOLOGY LTD COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Turbomachine component having a cooling arrangement The following statement is a full description of this invention including the best method of performing it known to us:- -1

A-

Technical field of use The present invention relates to a component of a turbomachine, in particular of a gas turbine, said component having a cooling arrangement which has at least one cooling duct for the leadthrough of a cooling medium at or in the component.

When turbomachines, in particular gas turbines, are in operation, high temperatures occur which subject individual components of the turbines to severe load.

With the development of gas turbines of ever-increasing performance, temperatures are reached which even exceed the melting point of the material of individual turbine components. To prevent damage to these components on account of the high operating temperatures, these have to be constantly cooled during operation. For this purpose, cooling ducts within these turbine components are provided, via which a cooling medium, as a rule sucked-in compressor air, is led past the locations to be cooled. In addition to convective cooling, in which cooling ducts run directly by the regions to be cooled, for example in cooling ducts within a blade leaf, impact cooling and film cooling are also adopted. In impact cooling, the cooling air impacts approximately perpendicularly onto the surface to be cooled, while, in film cooling, it brushes approximately tangentially over the surface and forms a thin cooling air film there.

The cooling arrangements formed by the cooling ducts constitute, as a rule, open systems in which the medium flows via bores or orifices from one cavity to another cavity of the same or of another component. This may, however, lead to high leakage rates of the cooling medium owing to the extensive boundary surfaces.

2 One example of components to be cooled is heat shield segments which protect the outer carrier structure of the turbine, for example the carrier for the turbine guide blades, from direct contact with the hot gas.

Depending on the alloy material of the heat shield, on the temperatures occurring during operation and on the design, it may or may not be necessary to cool the heat shield. For cooling such a component of the gas turbine, known systems employ the already mentioned cooling arrangements in which the cooling air flows via cavities and connecting orifices, in particular cooling air bores, formed by the components or as a result of the interaction of -the components of the turbine plant.

In this case, because of the cooling air flowing through, the boundary surfaces of the cavities are also cooled, even if this is not desirable or not desirable in the entire region of the component.

Presentation of the invention The object of the present invention is to provide a component of a turbomachine, in particular of a gas turbine, said component having a cooling arrangement which allows a more controlled cooling, along with a lower leakage rate.

The object is achieved by means of a turbomachine component according to patent claim i. Advantageous refinements of the component are the subject matter of the subclaims or can be gathered from the following description and the exemplary embodiments.

The proposed turbomachine component having a cooling arrangement which has at least one cooling duct for the leadthrough of a cooling medium at or in the component is distinguished in that the cooling duct is formed by a tube having an inside diameter of 4 mm and fastened 3 to the component.

In contrast to known solutions in which cooling ducts are formed as a result of the shaping of the component itself, in particular by means of cavities formed in the component or in interaction with an adjacent component, if appropriate with a corresponding arrangement of webs, the present component comprises separately produced and shaped tubes which are fastened to or in the component. Fastening may in this case take place, for example, by hard soldering, welding or adhesive bonding or by any other suitable mechanical connection. The component itself may, for example, constitute a heat shield segment, but also any other rotating or static turbomachine component to be cooled, in which only a local limited region is to be cooled or the cooling medium is to be lead merely through the component to the cooling arrangement of another component to be cooled, that is to say is to issue into a secondary cooling system.

With the present component, the controlled cooling of only part of this component or the transport of the cooling medium, without the cooling of the component, into a secondary cooling system becomes possible.

Extensive boundary surfaces for leading the cooling medium are in this case avoided, thus resulting in a leakage rate which is reduced, as compared with known solutions. It is precisely heat shield segments, additionally possessing mechanical functions, for example for fastening the guide blades, which also have an appreciable radial extent. The temperature gradients caused due to large-area contact with the cooling medium are very high and lead to undesirably pronounced thermal deformations of this part. Owing to the configuration of such a heat shield according to the present invention, it is possible to lead the cooling medium solely to those surfaces to be cooled which are -4near the hot gas path, without the regions of the heat shield which lie further outward radially being cooled appreciably.

In a preferred refinement, the one or more tubes of the cooling arrangement are designed to be at least partially flexible or elastic, so that thermally induced fluctuations in expansion of the component can be followed or compensated. Several possibilities are appropriate for this purpose. Thus, the tubes may have a multiply curved or coiled shape, in particular also run helically or spirally. Furthermore, individual portions of the tubes may form bellows, so that flexibility in a predominantly axial direction of the tubes is achieved. In a further refinement, locations of connection of the tubes to the component may be connected to sliding joints, in particular at locations where the tubes are led through a wall of the component. Such a leadthrough may also be provided with an additional seal. Furthermore, it is possible to assemble the tubes in a component from a plurality of tube parts. In this case, it is also possible for sliding joints to be used as a connection between individual tube parts.

The component on one side and the tube or tubes of the cooling arrangement on the other side may be produced independently of one another by means of different techniques, for example by casting, by cutting shaping, by semicold or coldforming or by similar known techniques. In the case of tubes composed of individual sections, these can likewise be connected to one another via conventional techniques, such as, for example, hard soldering, welding or other mechanical connection techniques.

Individual tubes may in this case vary in their inside diameter over the tube length, depending on 5 requirements. The cross-sectional shape of the inside diameter may also be suitably optimized. Thus, the tubes may have a circular inner cross section, for example, in rectilinear portions, while they have an elliptical or ellipse-like design in curved regions.

A secondary cooling system to which the tubes lead the cooling medium may, of course, employ the most diverse possible known cooling techniques, that is to say convective cooling, impact cooling or film cooling. It may be formed in the component itself in a known way or else in or on an adjacent component.

Brief description of the drawings The present invention is explained once again in more detail below by means of exemplary embodiments, in conjunction with the drawings in which: fig. 1 shows a first example of an' embodiment of the component having the cooling arrangement; fig. 2 shows an alternative embodiment of the component for the purpose of cooling the blade cover band; fig. 3 shows a second example of an embodiment of the component having the cooling arrangement; fig. 4 shows an example of the shape of a cooling tube used; fig. 5 shows the tube of fig. 4 in three different views; fig. 6 shows an example of the cross section of the tube in a curve.

6 Ways of implementing the invention Figure 1 shows a first example of an embodiment of the present components having the cooling arrangement. The cooling arrangement is composed, in this example, of a multiply bent tube 2 which is fastened at its first end to an inlet orifice 4 of the component, a heat shield i, and which conducts the cooling air to a region of the component 1 which lies on the hot gas path of the turbine. The path of the cooling air is indicated by the arrows illustrated in the figure. The cooling air emerges via the orifices 3 in the component 1 into the hot gas path and cools this region of the component on the outside. In a conventional construction of a turbine, of course, a plurality of these tubes are arranged in the heat shield 1 so as to be distributed over the circumference of the hot gas path.

Owing to the closed routing of the cooling air in the tube 2, the remaining parts of the component 1 are not cooled, so that markedly lower temperature gradients occur in the component in the radial direction. Since the cooling air also does not occupy the entire inner space of the components 1, the leakage rates are markedly reduced, as compared with an embodiment of this type. In the present example, the tube 2 is connected to the component.l via a hard-soldered sleeve 9 in the inlet orifice 4. The seals 5, into which blade leaf tips of the turbine engage during operation, can also be seen at that region of the component 1 which lies on the hot gas path.

This is illustrated in figure 2 which shows part of a blade leaf 6 for the turbine in engagement with the seals 5. In this example, the heat shield 1 is not cooled or is only insignificantly cooled. Instead, the tube 2 is utilized in order to employ the cooling air directly for cooling the tip of the blade leaf 6. This 7 is illustrated by the arrow which can be seen in the figure which indicates the cooling air which emerges from the tube 2 and impinges onto the tip of the blade leaf 6.

Figure 3 shows a further example of an embodiment of the present component, in which the tube 2 has, in the upper region, a portion which is designed as a bellows 7 and which allows an axial expansion of the tube 2.

This axial expansion may be necessary in order to follow or compensate a different expansion of the component 1 caused in the same direction on account of temperature fluctuations. The figure also illustrates, furthermore, a possibility of expansion in the radial direction, which is implemented by means of a sliding joint 8 (slip joint), by means of which the outlet end of the tube 2 is connected to the component 1. In this embodiment, a reduction in the cross section of the tube 2 brought about by the sliding joint 8 can be seen, this reduction leading to higher outflow velocities of the cooling air from the tube 2.

In the present examples, the tube 2 has a doubly curved shape, as can be seen in figure 4. As a result of this doubly curved shape, in which, in this example, the curves lie in two planes perpendicular to one another, some flexibility of the tube 2 is likewise achieved.

The basic possibilities for the configuration of a doubly curved shape of this type are illustrated by means of figure 5 which shows a tube 2 of the type with corresponding dimensions in three different views. The following ranges can be selected, as a function of the outside diameter D, for the dimensions which can be seen in figure 5: Xl 0.2 50D, X2 0.2 70D, Y1 0.2 90D, R1 0.5 10D, R2 0.5 10D, al 1700, c 20 1700 and c3 100. These dimensions are in this case selected according to the shape of the component 1 and to the desired routing of the cooling -8air in the component. The inside diameter of the tube in this case moves in an order to magnitude of 4 mm to preferably a maximum of 70 mm. The wall thickness may in this case be selected as desired.

Finally, figure 6 shows, by way of example, a cross section of the tube 2, such as may be selected in a curve. In principle, the ratio between the diameter D2 and the diameter D1 of the tube 2 can be varied within the ranges D1/D2 0.4 1.6 as a 'function of the respective tube portion.

I

9 List of reference symbols 1 Heat shield 2 Tube 3 Orifices 4 Inlet orifice Seals 6 Blade leaf 7 Bellows 8 Sliding coupling 9 Sleeve

Claims

2. The component as claimed in claim 1, characterized in that the tube is soldered, welded or adhesively bonded to the component
3. The component as claimed in claim 1, characterized in that at least individual tube portions are designed to be flexible, in order to compensate operationally induced deformations of the component
4. The component as claimed in claim 3, characterized in that the tube runs helically or spirally in order to compensate operationally induced deformations of the component
5. The component as claimed in claim 3, characterized in that one or more tube portions form a bellows in order to compensate operationally induced deformations of the component
6. The component as claimed in claim i, characterized in that one or more tube portions are connected to one another or to the component via a sliding joint in order to compensate operationally induced deformations of the component
7. The component as claimed in claim i, characterized in that curved tube portions have a predominantly elliptical inner cross section and straight tube 11 portions have a predominantly circular inner cross section.
8. The components claimed in claim 1, characterized in that the tube has at least two curved tube portions, of which a first tube portion lies in a first plane and a second tube portion lies in a second plane, the two planes forming an angle of between 20 and 1700°.
9. The component as claimed in claim 8, characterized in that the two planes form an angle of between 800 and 1000 The component as claimed in claim 8 or 9, characterized in that the first tube portion has a curvature of 170° to 190° and the second tube portion has a curvature of 800 to 1000.
11. The component as claimed in claim 1, characterized in that a plurality of the tubes are fastened to the component
12. The component as claimed in claim 1 or 11, characterized in that the tube or tubes lead into a secondary cooling system.
13. .A use of the component as claimed in one or more of claims 1 to 12 has a heat shield segment for a gas turbine. DATED THIS 22 DAY OF MARCH 2005 ALSTOM TECHNOLOGY LTD Patent Attorneys for the Applicant:- F.B.RICE CO