TURBINE BLADE HAVING AN INNER MODULE AND METHOD FOR PRODUCING A TURBINE BLADE

Abstract

A turbine blade having a casing and having an inner module, wherein a cooling medium can flow through the inner module both in a longitudinal direction and in a radial direction, and the inner module is attached to the casing by fixed bearings and floating bearings. A method for producing a turbine blade having an inner module and having a casing is produced by selective laser melting.

Claims

1.-15. (canceled)

16. A turbine rotor blade, comprising: a casing and an inner module adapted to the shape of the casing, wherein the inner module comprises an interior space, through which flow can pass in a longitudinal direction and which has an inflow opening, and a wall, which has a number of ducts through which flow can pass in a radial direction and which connect an inner side to an outer side of the wall of the inner module, wherein in the turbine rotor blade a peripheral intermediate space is provided between the outer side of the wall of the inner module and an inner side of the casing, and a number of perforations is provided between the inner side and an outer side of the casing at a certain angle of inclination relative to the outer side of the casing, wherein the outer side of the inner module is connected by at least one fixed bearing and at least one floating bearing to the inner side of the casing.

17. The turbine rotor blade as claimed in claim 16, further comprising: supporting profiles on the outer side of the wall of the inner module.

18. The turbine rotor blade as claimed in claim 16, wherein the material of the inner module is a metal.

19. The turbine rotor blade as claimed in claim 16, wherein the inner module and casing are metallurgically connected.

20. The turbine rotor blade as claimed in claim 16, wherein the inner module and casing are connected in positively locking fashion by the fixed bearing.

21. The turbine rotor blade as claimed in claim 16, wherein the angles of inclination of the perforations in the casing relative to the outer side of the casing are configured such that a film is formable on the outer side of the casing by the air flowing out via the perforations.

22. The turbine rotor blade as claimed in claim 16, wherein the interior space of the inner module is divided into at least two chambers which are connected to one another by, in each case, at least one opening through which flow can pass.

23. The turbine rotor blade as claimed in claim 16, wherein ducts through which flow can pass in the longitudinal direction of the inner module are additionally arranged in the distal wall of the inner module.

24. The turbine rotor blade as claimed in claim 16, wherein the inner module is generated by selective laser melting.

25. A method for producing a turbine rotor blade as claimed in claim 16, wherein the steps for generating an inner module comprise: S1) providing a building platform in a powder bed, S2) applying a powder material in a certain quantity, S3) distributing the material over the building platform, S4) locally melting powder particles by means of the action of a laser beam, S5) lowering the platform, wherein steps S2-S5 are repeated as many times as necessary to complete the manufacture of the inner module, and wherein the method subsequently additionally comprises: S6) applying a ceramic casting core around the inner module, wherein the supporting and free flanks at at least one supporting profile provided for a fixed bearing are not encased by a ceramic core material, S7) embedding the ceramic casting core, which comprises the inner module, into a wax model of the blade, S8) producing a casting mold for the casing from the wax model, S9) stabilizing the casting core in the casting mold by fixing by means of ceramic and/or metallic pins, and S10) casting the casing mold.

26. The method as claimed in claim 25, wherein the powder material has a metal.

27. The method as claimed in claim 25, wherein supporting profiles are generated in the outer side of the inner module.

28. The method as claimed in claim 25, wherein the outer side of the inner module is connected to the inner side of the casing in the region of the fixed bearing by mechanical positive locking.

29. The method as claimed in claim 25, wherein the outer side of the inner module is metallurgically connected to the inner side of the casing in the region of the fixed bearing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The invention will be discussed in more detail on the basis of the figures, in which:

[0047] FIG. 1 shows a longitudinal section through an exemplary embodiment of a turbine blade, with an illustration of the inner geometry of an inner module and of a casing of the turbine blade.

[0048] FIG. 2 shows a longitudinal section through a section of the turbine blade as per FIG. 1.

[0049] FIG. 3 shows a longitudinal section through a section of the turbine blade as per FIG. 1.

[0050] FIG. 4 shows a longitudinal section through a section of the turbine blade as per FIG. 1.

[0051] FIG. 5 shows a longitudinal section through a device for producing the inner module of the turbine blade as per FIG. 1.

[0052] FIG. 6 shows a longitudinal section through the inner module of the turbine blade as per FIG. 1.

[0053] FIG. 7 is an illustration of a wax mold for the production of the casing of the turbine blade as per FIG. 1.

[0054] FIG. 8 shows a flow diagram of an exemplary embodiment of a method for the production of the turbine blade as per FIG. 1.

DETAILED DESCRIPTION OF INVENTION

[0055] In the embodiment illustrated by way of example in FIG. 1, the turbine blade 1 comprises a casing 2 and an inner module 3. The inner module 3 is adapted substantially to the shape of the casing 2. The inner module 3 has an interior space 4 through which flow can pass in a longitudinal direction 17 of the inner module 3 and which has an inflow opening 5 and a wall 6 with a number of ducts 7, through which ducts flow can pass in a radial direction 18 and which ducts connect an inner side 61 to an outer side 62 of the wall 6 of the inner module 3. Furthermore, the illustrated inner module 3 has, in the distal region of the wall 6, a number of ducts 8 through which flow can pass in the longitudinal direction 17, which ducts are in this case arranged in addition to the ducts 7, through which flow can pass in the radial direction, in the lateral region of the wall 6.

[0056] Between the inner module 3 and casing 2 there is provided a peripheral intermediate space 9 which is delimited by the outer side 62 of the inner module 3 and the inner side 21 of the casing 2. Through the ducts 7 and 8, cooling air can flow out of the inner space 4 into the peripheral intermediate space 9, where it can impinge on the inner side 21 of the casing 2 and thereby impart the effect of impingement cooling. In the casing 2 there is arranged a number of perforations 10 through which the cooling air can flow out of the intermediate space 9 to the outer side 22 of the casing 2, where said cooling air can form a cooling film.

[0057] The inner module 3 is connected to the casing 2 by means of fixed bearings 11 and floating bearings 12. Here, in each case at least one bearing is provided, though it is advantageous for multiple fixed bearings 11 and multiple floating bearings 12 to be provided for the connection of inner module 3 and casing 2. For the connection by means of fixed bearings 11, the inner module 3 has at least one supporting profile 15, and for the connection by means of floating bearings 12, the inner module has at least one supporting profile 16, wherein the number of supporting profiles 15 and 16 is configured in accordance with the length of the turbine blade 1 and accordingly of the inner module 3. At the locations of the fixed bearings 11 that are provided, the casing 2 has recesses 19 corresponding to the supporting profiles 15, and at the locations of the floating bearings 12 that are provided, the casing has recesses 20 corresponding to the supporting profiles 16.

[0058] The supporting profiles 15 and 16 and the recesses 19 and 20 advantageously run in ring-shaped fashion around an entire region around the outer side 62 of the inner module 3 or the inner side 21 of the casing 2, though may also be arranged only at individual locations. The fixed bearings 11 and floating bearings 12 accordingly advantageously run in closed ring-shaped form, though may also be arranged only at individual locations.

[0059] The fixed bearings 11 interrupt the peripheral intermediate space 9 as they run around the entire outer side 62 of the inner module 3 and, here, are impermeable to cooling air owing to positive locking or metallurgical connection to the inner side 21 of the casing 2. The floating bearings 12 interrupt the peripheral intermediate space 9 if they run in a region around the outer side 62 of the inner module 3 and, here, abut firmly against a region of the inner side 21 of the casing 2.

[0060] The interior space 4 of the inner module 3 is composed of multiple chambers 14 which are separated by the material of the inner module 3 and which are connected to one another by means of openings 13 through which flow can pass in a longitudinal direction. Here, the inner module 3 advantageously has 2 chambers 14, likewise advantageously 3, likewise advantageously 4, and likewise advantageously 5 and more.

[0061] At the root end, the turbine blade 1 has a fir-tree-shaped structure 31 which serves for the stable connection to the turbine rotor (not shown) by means of a correspondingly designed structure.

[0062] The peripheral intermediate space 9 essential for the cooling of the turbine blade 1 is formed between the outer side 61 of the wall 6 of the inner module 3 and the inner side 21 of the casing 2, as illustrated in FIG. 2. Here, the ducts 7 are formed such that, from the interior space 4, cooling air can flow in a radial direction 18 through the ducts 7 into the peripheral intermediate space 9, where said cooling air impinges on the inner side 21 of the casing 2. The perforations 10 in the casing 2 are configured, in terms of number and angle of inclination, such that cooling air flowing through the perforations from the peripheral intermediate space 9 to the outer side 22 of the casing 2 can form a cooling film there. The angle of inclination of the perforations relative to the outer side 22 is between 10 and 80 degrees, advantageously between 20 and 70 degrees, more advantageously between 30 and 60 degrees, even more advantageously between 40 and 50 degrees, and is even more advantageously 45 degrees.

[0063] The connection of the inner module 3 to the casing 2 by means of fixed bearings 11 is illustrated in detail in FIG. 3. The supporting profile 15 of the inner module 3 and the corresponding recess 19 in the casing 2 are dimensionally coordinated with one another so as to fit with one another in positively locking fashion. Owing to the complete positive locking thereby effected, the inner module 3 is not movable in any direction at the location of the fixed bearing 11.

[0064] The connection of the inner module 3 to the casing 2 by means of floating bearings 12 is illustrated in detail in FIG. 4. The supporting profile 16 of the inner module 3 and the corresponding recess 20 in the casing 2 are dimensionally coordinated with one another, but allow degrees of freedom, that is to say a certain mobility or a certain clearance of the supporting profile 16 within the recess 20.

[0065] The production of the inner module 3 of the turbine blade 1 is performed, as per the steps of the flow diagram in FIG. 8, in a melt bath 100. In step S1, as per FIG. 5, a building platform 101 is provided. In step S2, a powder material 102, advantageously composed of a metal or of a metal alloy, for example composed of the same material as the turbine blade, but optionally also composed of a different material, is applied in a certain quantity to the building platform 101 by means of the filling device 103. In step S3, the applied material 102 is distributed on the building platform 101, for example by means of a slide or a wiper, so as to form a layer of a thickness which can be easily melted, correspondingly to the desired structure, by means of laser beams 105. Advantageous layer thicknesses are in this case 20-100 μm.

[0066] In step S4, local melting of the powder particles 103 is effected by means of the action of a laser beam 105 which is generated by means of a laser 104 and which, by means of a rotating mirror 106, is guided over the building platform 101 in software-controlled fashion such that the desired solid structures are realized, for example the supporting profiles 15 and 16. The powder material 102 is fully re-melted at the locations of the laser radiation, and after solidifying, forms a solid material layer.

[0067] After step S4, it is checked whether the manufacture of the inner module is complete. If it is incomplete, then in step S5, the building platform 101 is lowered by the height corresponding to a layer thickness, and the process is started again from step S2. The cycle of steps S2-S5 is repeated until the manufacture of the inner module 3 in the desired structure is complete.

[0068] If, in step S4, it is identified that the manufacture of the inner module is complete, then following this step, in step S6, a ceramic casting core 110 is generated around the inner module 3. Here, conventional ceramic material is used for the casting core. Here, as can be seen in FIG. 6, the supporting profiles 15 provided for forming fixed bearings 11 are not encased by ceramic. By contrast, the supporting profiles 16 provided for forming floating bearings 12 are encased by ceramic.

[0069] In step S7, the ceramic casting core 110 containing the inner module 3 is embedded into a wax model 120 of the turbine blade 1, in which said casting core is surrounded by wax 121, as illustrated in FIG. 7. Then, in step S8, a casting mold, the so-called casting shell, for the casing 2 is produced. In step S9, the ceramic core 110 with inner module 3 is stabilized in the casting shell by means of ceramic and/or metallic pins.

[0070] In step S10, the mold of the casing 2 is cast. Here, a region of the ceramic casting core 110 forms the peripheral intermediate space 9 between inner module 3 and casing 2. As material of the casing 2, use is made for example of metals, advantageously alloys and superalloys. By means of the positively locking configuration of the supporting profiles 15 and the corresponding recesses 19, the outer side 62 of the inner module 3 is connected to the inner side 21 of the casing 2 in the region of the fixed bearings 11 advantageously by mechanical positive locking.

[0071] Owing to the positively locking configuration of the supporting profiles 15 and of the corresponding recesses 19 and owing to the advantageous metal of the powder material 102, the outer side 62 of the inner module 3 is connected to the inner side 21 of the casing 2 in the region of the fixed bearings 11 likewise advantageously by means of a metallurgical connection. The metallurgical connection is in this case made possible by the high temperatures of the liquid metal of the casing 2, which effect melting of exposed regions of the inner module.

[0072] Modifications and alterations to the invention that are obvious to a person skilled in the art fall within the scope of protection of the patent claims.