JP2015512486A - Modular turbine blade with platform - Google Patents

Abstract

The present invention relates to a turbine blade (10) comprising a blade blade (12) continuous along the longitudinal axis (11) of the turbine blade (10) and a modular platform (13). In order to show a modular turbine blade (10) which, on the one hand, is particularly easy and simple to construct, and on the other hand ensures particularly reliable and long-lasting and continuous joining of the individual parts together. It is proposed that the wing blade (12) comprises an extension (26) and the platform (17) is radial with respect to the longitudinal axis (11) consisting of an outer platform part (15) and at least two parts. With the inner platform parts (13), these platform parts (13, 15) abutting laterally against the extension (26) of the wing blade (12) and the outer platform parts (15) It is formed as an endless platform frame (18) surrounding the outer edge of (13). It is.

Description

  The present invention relates to a turbine blade having a platform and blade blades that are directly continuous along the longitudinal axis of the turbine blade.

  The turbine blades and the manufacturing method of the turbine blades are known in various ways from widely existing prior art. For example, turbine blades for gas turbines are often manufactured by a casting process. In the case of casting, such turbine blades are integral because at the same time the blade root, platform and blade blades are molded from the cast material. Subsequently, the surface exposed to the hot gas of the turbine further includes a corrosion protection layer and a thermal protection layer in order to increase the durability of the turbine blade. Cast turbine blades are often also hollow so that a medium that cools the blade material can flow therethrough. Steam engine turbine blades are often milled or forged from solids.

  Turbine blades used in stationary turbomachines are subject to many loads that cause the turbine blades to age and wear out in both predictable and unpredictable ways when driving the turbomachine.

  Specifically, both low and high cycle fatigue loads and thermomechanical loads occur. Turbine blades must also be protected from oxidation and creep. The aforementioned loads relate in particular to turbine blade surfaces and components that are directly exposed to hot gases or steam. Moreover, on the fixed side, the turbine blades are exposed to so-called “bearing loads” and “friction loads”. In light of these different loads and requirements, an integral turbine blade material will carry as much as possible, if not all, of the turbine blades without aging earlier than expected or end of service life earlier than planned. It must be chosen so that the material is acceptable. With regard to heat and corrosion loads, for example, it is known to equip turbine blades of gas turbines with a layer system that protects the material from corrosion and excessive heat input.

  Nevertheless, wear phenomena such as cracks can occur in various areas of the turbine blade that compromise the drive of the turbomachine. For this reason, it is known to investigate such defects in turbine blades after a pre-determined time of use and to replace or repair the relevant turbine blades if such investigation results are available. Yes.

  Furthermore, modular turbine blades are known from the prior art, where the blade blades and the platform are manufactured separately, the members being assembled into one turbine blade by a completely different configuration or joint connection. ing.

  The disadvantages are, for example, that they have a shorter service life than possibly monolithic turbine blades, and this short service life is caused by the configuration or joining of the individual parts, which is only conditionally reliable. Similarly, modular turbine blades are often very expensive to construct and manufacture.

  The object of the present invention is to provide a modular turbine blade that is constructed and joined in a particularly easy but extremely reliable manner.

  This problem directed to the turbine blade is solved by a turbine blade according to the features of claim 1.

  According to the invention, the turbine blade comprises at least one platform and a blade blade which are directly continuous along the longitudinal axis of the turbine blade corresponding to the radial direction of the turbomachine, the blade blade comprising an extension in the longitudinal direction. And the platform includes an outer platform part and an at least two-part inner platform part, radially with respect to the longitudinal axis, the inner platform part laterally abutting the extension of the wing blade, and the outer platform part Is formed as an endless platform frame surrounding the outer edge of the inner platform part. The main members of the inner platform parts are each referred to herein as platform elements.

  The basis of the present invention is that the platform elements manufactured separately from the turbine blades are in contact with the long side of the blade blade, that is, the so-called extension, using clips. The recognition is that if both platform elements are pressed against the extension of the wing blade, they can be fastened to the separately manufactured wing blade in a particularly easy manner. For example, a first platform element may be provided on the suction side of the extension of the wing blade and a second platform element may be provided on the compression side. The clip is configured as a platform frame that circulates endlessly. Due to the annular and endless shape of the platform frame, the platform frame can hold the platform elements with an interference fit, so that further measures to protect the platform frame from possible damage are no longer necessary.

  The extension part of the blade blade is retracted through the stepped portion with respect to the blade blade surface on the compression side and the blade blade surface on the suction side. It is impossible to shift parallel to the axis.

  The platform frame may have a shape with a different cross section. However, a shape that provides a shape connection with the edge of the inner platform part is preferred. For example, the cross-sectional shape may be formed in a diamond shape or a C shape. In that case, the edge part of the inner platform part is always implemented corresponding to the cross-sectional shape.

  A particular advantage of the turbine blade according to the invention is that, in particular, two different materials can also be used for the platform elements, blade blades and platform frame. Thus, additionally, different local loads can be taken into account, which in some cases extends the service life of the turbine blades.

  A further advantage of the turbine blade according to the invention is that it is more precise with respect to the outer dimensions of the platform. This is because the outer dimensions of the platform can be provided more easily when manufacturing the platform frame than when casting purely monolithic turbine blades.

  Different methods can be used to join the platform frame with the platform elements over time. Since the platform frame is configured as an endless frame, it may be conceivable to preferably fit the platform frame to the circumferential edge of the inner platform part. Prior to the interference fit, the platform frame may be heated and / or the platform elements may be cooled. After assembling the platform frame and platform elements and subsequently equalizing the temperature, the platform frame is secured to the circumferential edge of the inner platform part. Dots brazing or welding along the joint line between the edge of the inner platform part and the platform frame is also possible.

  Particularly advantageous is the fact that a collar is formed at the free end of the extension of the wing blade, which, along with the stepped portion, forms an endless groove in the circumferential direction of the profile of the wing blade, and inside the groove The platform elements of the platform parts are fitted in a shape connection. The platform element is then provided with a wall thickness in the vicinity of the extension approximately corresponding to the groove width.

  What is special about the proposed turbine blade is that the platform element is abutted against the extension by movement perpendicular to the longitudinal axis, and its safety element against return movement, in the shape of the platform frame, against that movement. In other words, it is placed over the platform element in a sideways or parallel movement with respect to the longitudinal axis. Only then should it be guaranteed that only the platform frame is protected from being removed. The deviation parallel to the longitudinal axis of the platform comprising the platform element and the platform frame is likewise blocked by the step between the original wing blade and the extension and the collar of the extension.

  Reasonably, the inner platform part comprises two platform elements, but more platform elements may be provided.

  The arrangement according to the invention makes it possible to use different materials for different members of the turbine blade. Thereby, for example, the wing blades and the platform elements can be manufactured from different materials that are adapted to the respective local requirements and loads as described at the outset. The platform frame may also be made from a material most suitable for that purpose. Thereby, different alloys and casting materials may be used inside the turbine blade.

  The turbine blade includes an inner platform part having a plurality of platform elements at both a first blade blade end and a second end facing the first end, and an outer platform part formed from a platform frame. It may be equipped with the aforementioned platform. In this case, the wing blade is provided with one of the aforementioned extensions on both ends.

  According to a further advantageous embodiment, the plurality of platform elements are connected to each other in an overlapping manner and / or one platform element or a plurality of platform elements having wing blades or all the platform elements are connected to each other via bolts May have been. For example, if there are only two platform elements surrounding the extension of the wing blade, both platform elements may have oppositely aligned holes in which bolts are fitted. This improves the mechanical connection between the two platform elements and increases the strength of the turbine blades assembled from the individual parts.

  Further, the platform element may comprise a through hole and / or a blind hole that extends parallel to the longitudinal axis, and a bolt that is also in an opening extending through the collar of the extension, It is inserted inside. Bolting the wing blade extension with the platform element in this way prevents the platform element from detaching from the wing blade without the platform frame. Besides being easy to assemble, this procedure increases the strength of the turbine blade and the driving safety of the turbine blade, even if the platform frame is not likely to rip or even tear.

  In order to prevent the platform frame from shifting from the inner platform part, the inner platform part and the outer platform part may be connected via a groove-spring connection.

  According to a first advantageous embodiment, the platform frame abuts the inner platform part in a plane and the contact surface forms at least partly with the longitudinal axis at an angle greater than 0 degrees and less than 90 degrees. Such an arrangement prevents the platform frame from shifting parallel along the longitudinal axis in at least one direction, which is particularly advantageous when the present invention is used with turbine blades. In this case, the centrifugal force acting on the platform frame during driving of the turbomachine is transmitted to the inner platform part by a geometric connection by means of a contact surface inclined with respect to the longitudinal axis. This ensures that the platform frame is not damaged by centrifugal force.

  Preferably, this angle is between 15 and 35 degrees, for example, this angle is 20 degrees.

  According to a further advantageous embodiment, the platform frame comprises a slit for receiving a sealing element on at least one side whose side faces outwards. The advantage provided by such a structure is that such a turbine blade that has been overworked by the drive according to the invention provided herein when the slits at the platform edge are worn by the plate-like sealing elements therein. There is an easy and reliable possibility that it can be maintained again. Moreover, such slits can be manufactured less expensive than in the case of purely monolithic turbine blades.

  Reasonably, the turbine blades may be formed as either stationary blades or moving blades.

  To enable a turbine blade having an inner platform part and an outer platform part in the shape of an endless platform frame surrounding the inner platform part to be used even at high temperatures, the inner platform part and the platform It is advantageous if the frame is coated in a coating process. Thereby, a seamless protective layer can be applied to both platform parts.

  The foregoing invention is further explained below based on the description of the figures. Further advantages and features of the present invention result from the examples represented. The following is shown in the figure.

1 is an exploded view of a turbine blade comprising a blade blade having an extension, a two-part inner platform part and an outer platform part. FIG. It is sectional drawing of the turbine blade of FIG. 1 in the assembled state. It is the perspective view which looked at the turbine blade of Drawing 2 from the upper surface. 2 is the turbine blade of FIG. 1 with a modular platform on the head side.

  In all the figures, the same features have the same reference numerals.

  In FIG. 1, a part of the turbine blade 10 is shown in an exploded view. The turbine blade 10 is configured in a modular manner so that, according to this embodiment, the blade blade 12, the two platform elements 14, 16, the platform frame 18, and these members are manufactured as separate members. And a plurality of bolts 20 joined to each other. Further, the turbine blade 10 includes a virtual longitudinal axis 11.

  The wing blade 12 is aerodynamically curved and includes a compression side 22 and a suction side 24 according to known techniques. The compression side 22 and the suction side 24 are joined to each other at the front edge portion 23 and the rear edge portion 25. In normal use inside the turbomachine, the working medium flows from the leading edge 23 to the trailing edge 25.

  An extension 26 formed integrally with the profile of the blade blade 12 is provided at the upper end of the blade blade 12 shown in FIG. The extension 26 is aerodynamically curved on the side, similar to the compression side 22 and the suction side 24. However, because the extension 26 is formed with a profile dimension much smaller than the profile of the blade blade 12 set by the blade blade walls 22, 24, the extension passes through the step 28 and the blade blade 12. Connect to. The extension 26 includes a collar 32 at its free end 30. The collar 32 extends across the entire circumference of the profile across the longitudinal axis 11, and therefore the collar 32 together with the stepped portion 28 forms a circumferential groove 34.

  In the illustrated embodiment, the collar portion 32 of the extension 26 is provided with three through holes 36 each leading to one of the side walls of the groove 34 on both the suction side and the compression side. Two platform elements 14, 16 are located on the side of the extension 26 and may include a larger number of platform elements.

  Platform elements 14, 16 comprise a platform material thickness approximately corresponding to the width of groove 34. The platform elements 14, 16 comprise one or more blind holes 38, into which the bolts 20 are partially fitted, respectively, upstream of the leading edge 23 or downstream of the trailing edge 25. The orientation of the blind hole 38 is selected on the one hand perpendicular to the longitudinal axis 11, and on the other hand, when the bolt is fitted, until both platform elements 14, 16 fit into the groove 34 and abut the extension 26, The two platform elements 14, 16 are selected such that they can be pushed away from each other and closed. Moreover, the platform elements 14, 16 are provided with a blind hole 42 on the side facing away from the working medium, hereinafter referred to as the back side 40, which is inserted into the groove 34. After that, it is aligned with the corresponding through hole 36 of the collar portion 32. A pin-like bolt may then be inserted into the holes 36, 42 aligned with each other so that the platform elements 14, 16 are fixedly joined to the wing blade 12 for the first time.

  Subsequently, the platform frame 18 is shifted parallel to the longitudinal axis 11 of the turbine blade 10 until it holds both platform elements 14, 16. At that time, an interference fit of the platform frame 18 is preferable. By holding, both platform elements 14, 16 are pressed firmly against each other on the one hand and into the groove 34 on the other hand, so that both platform elements 14, 16 are no longer in the longitudinal axis due to the resulting shape connection. 11 can not be shifted along. Both platform elements 14, 16 then form the inner platform part 13 of the turbine blade 10 and the platform frame 18 forms the outer platform part 15 of the turbine blade 10. The inner platform part 13 and the outer platform part 15 form a platform 17 (FIG. 2).

  In order to prevent the platform frame 18 from detaching from both platform elements 14, 16, one groove / spring connection is formed in each of the two longitudinal edges 41 of the inner platform part 13 and the longitudinal support member 46 of the platform frame 18. ing. In FIG. 1, a spring 48 belonging to it is represented inside the longitudinal support member 46 and a groove 50 belonging to it is represented at the longitudinal edge of the platform element 14. Of course, in addition or alternatively, the lateral edge or the lateral support member may each be provided with a groove-spring connection.

  For inserting and securing the turbine blade 10 to the turbine vane support, the back side 40 of the platform elements 14, 16 has one or more saddles 52 on both the inflow side and the outflow side. Is equipped. Accordingly, the turbine blade 10 shown in FIG. 1 is formed as a stationary blade.

  If the turbine blade 10 is formed as a moving blade, the means of the turbine blade 10 provided for fixing is preferably monolithically formed in the extension 26, so that the means called the blade root is The extension 26 and the blade blade 12 are integrally joined. Circumferential grooves 34 for the platform elements 14, 16 are provided even in the case of a blade.

  FIG. 2 schematically shows a partial perspective sectional view of the turbine blade 10 of FIG. 1 in the final assembled state. However, in FIG. 2, neither the hole provided in the collar part 32 nor the bolt in it is represented. On the other hand, according to the perspective view of FIG. 3, it can be recognized that the inner platform part 13 is disassembled into the platform element 14 on the compression side and the platform element 16 on the suction side.

  In the turbine blade represented in FIGS. 1, 2 and 3, a platform 17 located radially outward in the driving position inside the axial turbomachine and thus on the root side of the blade blade 12 is constructed according to the invention. Has been. In contrast, FIG. 4 shows a turbine blade 10 having a head end 55 that is similar to the root end in the manner of two platform elements 14, 16 and A modular platform 17 comprising a platform frame 18 may be provided. Here, the head side end portion 55 differs from the root side end portion only with respect to the side of the platform 17 facing away from the working medium. In general, in the turbine stationary blade 10 used in the stationary gas turbine, a so-called U-ring is attached to the head side end portion 55, and the U-ring has a stationary blade provided in the ring on the head side. Connect and join together. Additionally, in FIG. 4, a slit 54 is shown in the surface 53 of the platform frame 18 with the sides facing outward. The slit 54 is used to receive a plate-like sealing element, and the sealing element may be provided between the adjacent stationary blades to seal a gap between them.

  In general, the present invention relates to a turbine blade 10 comprising a blade blade 12 that is continuous along a longitudinal axis 11 of the turbine blade 10 and a platform 17 that is modular thereto. In doing so, it has been proposed to show a modular turbine blade 10 which, on the one hand, is particularly easy and simple to construct and on the other hand is particularly reliable and ensures long-lasting and continuous joining of the individual parts together. The wing blade 12 comprises an extension 26 and the platform 17 comprises an outer platform part 15 and an at least two part inner platform part 13 radially inner to the longitudinal axis 11, This means that the platform parts 13, 15 abut against the extension 26 of the wing blade 12 on the side and the outer platform part 15 is formed as an endless platform frame 18 surrounding the outer edge of the inner platform part 13.

DESCRIPTION OF SYMBOLS 10 Turbine blade 11 Longitudinal axis 12 Blade blade 13 Inner platform part 14 Platform element 15 Outer platform part 16 Platform element 17 Platform 18 Platform frame 20 Bolt 22 Compression side 23 Front edge part 24 Suction side 25 Rear edge part 26 Extension part 28 Step shape Part 30 Free end part 32 Collar part 34 Groove 36 Through hole 38 Blind hole 40 Back side 41 Long edge part 42 Blind hole 46 Long support member 48 Spring 50 Groove 52 Saddle part 53 Surface whose side faces outward 54 Slit 55 Head side edge

  The present invention relates to a turbine blade having a platform and blade blades that are directly continuous along the longitudinal axis of the turbine blade.

  The turbine blades and the manufacturing method of the turbine blades are known in various ways from widely existing prior art. For example, turbine blades for gas turbines are often manufactured by a casting process. In the case of casting, such turbine blades are integral because at the same time the blade root, platform and blade blades are molded from the cast material. Subsequently, the surface exposed to the hot gas of the turbine further includes a corrosion protection layer and a thermal protection layer in order to increase the durability of the turbine blade. Cast turbine blades are often also hollow so that a medium that cools the blade material can flow therethrough. Steam engine turbine blades are often milled or forged from solids.

  Turbine blades used in stationary turbomachines are subject to many loads that cause the turbine blades to age and wear out in both predictable and unpredictable ways when driving the turbomachine.

  Specifically, both low and high cycle fatigue loads and thermomechanical loads occur. Turbine blades must also be protected from oxidation and creep. The aforementioned loads relate in particular to turbine blade surfaces and components that are directly exposed to hot gases or steam. Moreover, on the fixed side, the turbine blades are exposed to so-called “bearing loads” and “friction loads”. In light of these different loads and requirements, an integral turbine blade material will carry as much as possible, if not all, of the turbine blades without aging earlier than expected or end of service life earlier than planned. It must be chosen so that the material is acceptable. With regard to heat and corrosion loads, for example, it is known to equip turbine blades of gas turbines with a layer system that protects the material from corrosion and excessive heat input.

  Nevertheless, wear phenomena such as cracks can occur in various areas of the turbine blade that compromise the drive of the turbomachine. For this reason, it is known to investigate such defects in turbine blades after a pre-determined time of use and to replace or repair the relevant turbine blades if such investigation results are available. Yes.

Furthermore, modular turbine blades are known from the prior art, where the blade blades and the platform are manufactured separately, the members being assembled into one turbine blade by a completely different configuration or joint connection. ing. Examples of such modular turbine blades are disclosed in, for example, Patent Literature 1, Patent Literature 2, Patent Literature 3, Patent Literature 4, Patent Literature 5, Patent Literature 6, and Patent Literature 7. Different solutions have been described for fixing parts made of different materials. These range from tension tension anchoring (Patent Document 2) to screwing (Patent Document 1) or pinning (Patent Document 5) to brazing or welding (Patent Document 6). Thus, modular turbine blades are often very expensive to construct and manufacture.

A further disadvantage, for example, perhaps lies in service life is shorter than a monolithic turbine blades, shorter of the service life is reliable only under certain conditions, caused by the construction or bonding of the individual members.

US Patent Application Publication No. 2010/054932 JP-A-4-41902 European Patent Application No. 2213839 US Patent Application Publication No. 2011/0142639 US Pat. No. 4,650,399 German Patent Application No. 10346240 French Patent Application Publication No. 2463849

  The object of the present invention is to provide a modular turbine blade that is constructed and joined in a particularly easy but extremely reliable manner.

  This problem directed to the turbine blade is solved by a turbine blade according to the features of claim 1.

  According to the invention, the turbine blade comprises at least one platform and a blade blade which are directly continuous along the longitudinal axis of the turbine blade corresponding to the radial direction of the turbomachine, the blade blade comprising an extension in the longitudinal direction. And the platform comprises an outer platform part and an inner platform part comprising at least two parts, radially with respect to the longitudinal axis, the inner platform part abutting laterally against the extension of the wing blade, and the outer platform part is It is formed as an endless platform frame that surrounds the outer edge of the inner platform part. The main members of the inner platform parts are each referred to herein as platform elements.

  The basis of the present invention is that the platform elements manufactured separately from the turbine blades are in contact with the long side of the blade blade, that is, the so-called extension, using clips. The recognition is that if both platform elements are pressed against the extension of the wing blade, they can be fastened to the separately manufactured wing blade in a particularly easy manner. For example, a first platform element may be provided on the suction side of the extension of the wing blade and a second platform element may be provided on the compression side. The clip is configured as a platform frame that circulates endlessly. Due to the annular and endless shape of the platform frame, the platform frame can hold the platform elements with an interference fit, so that further measures to protect the platform frame from possible damage are no longer necessary.

  The extension part of the blade blade is retracted through the stepped portion with respect to the blade blade surface on the compression side and the blade blade surface on the suction side. It is impossible to shift parallel to the axis.

  The platform frame may have a shape with a different cross section. However, a shape that provides a shape connection with the edge of the inner platform part is preferred. For example, the cross-sectional shape may be formed in a diamond shape or a C shape. In that case, the edge part of the inner platform part is always implemented corresponding to the cross-sectional shape.

  A particular advantage of the turbine blade according to the invention is that, in particular, two different materials can also be used for the platform elements, blade blades and platform frame. Thus, additionally, different local loads can be taken into account, which in some cases extends the service life of the turbine blades.

  A further advantage of the turbine blade according to the invention is that it is more precise with respect to the outer dimensions of the platform. This is because the outer dimensions of the platform can be provided more easily when manufacturing the platform frame than when casting purely monolithic turbine blades.

  Different methods can be used to join the platform frame with the platform elements over time. Since the platform frame is configured as an endless frame, it may be conceivable to preferably fit the platform frame to the circumferential edge of the inner platform part. Prior to the interference fit, the platform frame may be heated and / or the platform elements may be cooled. After assembling the platform frame and platform elements and subsequently equalizing the temperature, the platform frame is secured to the circumferential edge of the inner platform part. Dots brazing or welding along the joint line between the edge of the inner platform part and the platform frame is also possible.

  Particularly advantageous is the fact that a collar is formed at the free end of the extension of the wing blade, which, along with the stepped portion, forms an endless groove in the circumferential direction of the profile of the wing blade, and inside the groove The platform elements of the platform parts are fitted in a shape connection. The platform element is then provided with a wall thickness in the vicinity of the extension approximately corresponding to the groove width.

  What is special about the proposed turbine blade is that the platform element is abutted against the extension by movement perpendicular to the longitudinal axis, and its safety element against return movement, in the shape of the platform frame, against that movement. In other words, it is placed over the platform element in a sideways or parallel movement with respect to the longitudinal axis. Only then should it be guaranteed that only the platform frame is protected from being removed. The deviation parallel to the longitudinal axis of the platform comprising the platform element and the platform frame is likewise blocked by the step between the original wing blade and the extension and the collar of the extension.

  Reasonably, the inner platform part comprises two platform elements, but more platform elements may be provided.

  The arrangement according to the invention makes it possible to use different materials for different members of the turbine blade. Thereby, for example, the wing blades and the platform elements can be manufactured from different materials that are adapted to the respective local requirements and loads as described at the outset. The platform frame may also be made from a material most suitable for that purpose. Thereby, different alloys and casting materials may be used inside the turbine blade.

  The turbine blade includes an inner platform part having a plurality of platform elements at both a first blade blade end and a second end facing the first end, and an outer platform part formed from a platform frame. It may be equipped with the aforementioned platform. In this case, the wing blade is provided with one of the aforementioned extensions on both ends.

  According to a further advantageous embodiment, the plurality of platform elements are connected to each other in an overlapping manner and / or one platform element or a plurality of platform elements having wing blades or all the platform elements are connected to each other via bolts May have been. For example, if there are only two platform elements surrounding the extension of the wing blade, both platform elements may have oppositely aligned holes in which bolts are fitted. This improves the mechanical connection between the two platform elements and increases the strength of the turbine blades assembled from the individual parts.

  Further, the platform element may comprise a through hole and / or a blind hole that extends parallel to the longitudinal axis, and a bolt that is also in an opening extending through the collar of the extension, It is inserted inside. Bolting the wing blade extension with the platform element in this way prevents the platform element from detaching from the wing blade without the platform frame. Besides being easy to assemble, this procedure increases the strength of the turbine blade and the driving safety of the turbine blade, even if the platform frame is not likely to rip or even tear.

  In order to prevent the platform frame from shifting from the inner platform part, the inner platform part and the outer platform part may be connected via a groove-spring connection.

  According to a first advantageous embodiment, the platform frame abuts the inner platform part in a plane and the contact surface forms at least partly with the longitudinal axis at an angle greater than 0 degrees and less than 90 degrees. Such an arrangement prevents the platform frame from shifting parallel along the longitudinal axis in at least one direction, which is particularly advantageous when the present invention is used with turbine blades. In this case, the centrifugal force acting on the platform frame during driving of the turbomachine is transmitted to the inner platform part by a geometric connection by means of a contact surface inclined with respect to the longitudinal axis. This ensures that the platform frame is not damaged by centrifugal force.

  Preferably, this angle is between 15 and 35 degrees, for example, this angle is 20 degrees.

  According to a further advantageous embodiment, the platform frame comprises a slit for receiving a sealing element on at least one side whose side faces outwards. The advantage provided by such a structure is that such a turbine blade that has been overworked by the drive according to the invention provided herein when the slits at the platform edge are worn by the plate-like sealing elements therein. There is an easy and reliable possibility that it can be maintained again. Moreover, such slits can be manufactured less expensive than in the case of purely monolithic turbine blades.

  Reasonably, the turbine blades may be formed as either stationary blades or moving blades.

  To enable a turbine blade having an inner platform part and an outer platform part in the shape of an endless platform frame surrounding the inner platform part to be used even at high temperatures, the inner platform part and the platform It is advantageous if the frame is coated in a coating process. Thereby, a seamless protective layer can be applied to both platform parts.

  The foregoing invention is further explained below based on the description of the figures. Further advantages and features of the present invention result from the examples represented. The following is shown in the figure.

1 is an exploded view of a turbine blade comprising a blade blade having an extension, a two-part inner platform part and an outer platform part. FIG. It is sectional drawing of the turbine blade of FIG. 1 in the assembled state. It is the perspective view which looked at the turbine blade of Drawing 2 from the upper surface. 2 is the turbine blade of FIG. 1 with a modular platform on the head side.

  In all the figures, the same features have the same reference numerals.

  In FIG. 1, a part of the turbine blade 10 is shown in an exploded view. The turbine blade 10 is configured in a modular manner so that, according to this embodiment, the blade blade 12, the two platform elements 14, 16, the platform frame 18, and these members are manufactured as separate members. And a plurality of bolts 20 joined to each other. Further, the turbine blade 10 includes a virtual longitudinal axis 11.

  The wing blade 12 is aerodynamically curved and includes a compression side 22 and a suction side 24 according to known techniques. The compression side 22 and the suction side 24 are joined to each other at the front edge portion 23 and the rear edge portion 25. In normal use inside the turbomachine, the working medium flows from the leading edge 23 to the trailing edge 25.

  An extension 26 formed integrally with the profile of the blade blade 12 is provided at the upper end of the blade blade 12 shown in FIG. The extension 26 is aerodynamically curved on the side, similar to the compression side 22 and the suction side 24. However, because the extension 26 is formed with a profile dimension much smaller than the profile of the blade blade 12 set by the blade blade walls 22, 24, the extension passes through the step 28 and the blade blade 12. Connect to. The extension 26 includes a collar 32 at its free end 30. The collar 32 extends across the entire circumference of the profile across the longitudinal axis 11, and therefore the collar 32 together with the stepped portion 28 forms a circumferential groove 34.

  In the illustrated embodiment, the collar portion 32 of the extension 26 is provided with three through holes 36 each leading to one of the side walls of the groove 34 on both the suction side and the compression side. Two platform elements 14, 16 are located on the side of the extension 26 and may include a larger number of platform elements.

  Platform elements 14, 16 comprise a platform material thickness approximately corresponding to the width of groove 34. The platform elements 14, 16 comprise one or more blind holes 38, into which the bolts 20 are partially fitted, respectively, upstream of the leading edge 23 or downstream of the trailing edge 25. The orientation of the blind hole 38 is selected on the one hand perpendicular to the longitudinal axis 11, and on the other hand, when the bolt is fitted, until both platform elements 14, 16 fit into the groove 34 and abut the extension 26, The two platform elements 14, 16 are selected such that they can be pushed away from each other and closed. Moreover, the platform elements 14, 16 are provided with a blind hole 42 on the side facing away from the working medium, hereinafter referred to as the back side 40, which is inserted into the groove 34. After that, it is aligned with the corresponding through hole 36 of the collar portion 32. A pin-like bolt may then be inserted into the holes 36, 42 aligned with each other so that the platform elements 14, 16 are fixedly joined to the wing blade 12 for the first time.

  Subsequently, the platform frame 18 is shifted parallel to the longitudinal axis 11 of the turbine blade 10 until it holds both platform elements 14, 16. At that time, an interference fit of the platform frame 18 is preferable. By holding, both platform elements 14, 16 are pressed firmly against each other on the one hand and into the groove 34 on the other hand, so that both platform elements 14, 16 are no longer in the longitudinal axis due to the resulting shape connection. 11 can not be shifted along. Both platform elements 14, 16 then form the inner platform part 13 of the turbine blade 10 and the platform frame 18 forms the outer platform part 15 of the turbine blade 10. The inner platform part 13 and the outer platform part 15 form a platform 17 (FIG. 2).

  In order to prevent the platform frame 18 from detaching from both platform elements 14, 16, one groove / spring connection is formed in each of the two longitudinal edges 41 of the inner platform part 13 and the longitudinal support member 46 of the platform frame 18. ing. In FIG. 1, a spring 48 belonging to it is represented inside the longitudinal support member 46 and a groove 50 belonging to it is represented at the longitudinal edge of the platform element 14. Of course, in addition or alternatively, the lateral edge or the lateral support member may each be provided with a groove-spring connection.

  For inserting and securing the turbine blade 10 to the turbine vane support, the back side 40 of the platform elements 14, 16 has one or more saddles 52 on both the inflow side and the outflow side. Is equipped. Accordingly, the turbine blade 10 shown in FIG. 1 is formed as a stationary blade.

  If the turbine blade 10 is formed as a moving blade, the means of the turbine blade 10 provided for fixing is preferably monolithically formed in the extension 26, so that the means called the blade root is The extension 26 and the blade blade 12 are integrally joined. Circumferential grooves 34 for the platform elements 14, 16 are provided even in the case of a blade.

  FIG. 2 schematically shows a partial perspective sectional view of the turbine blade 10 of FIG. 1 in the final assembled state. However, in FIG. 2, neither the hole provided in the collar part 32 nor the bolt in it is represented. On the other hand, according to the perspective view of FIG. 3, it can be recognized that the inner platform part 13 is disassembled into the platform element 14 on the compression side and the platform element 16 on the suction side.

  In the turbine blade represented in FIGS. 1, 2 and 3, a platform 17 located radially outward in the driving position inside the axial turbomachine and thus on the root side of the blade blade 12 is constructed according to the invention. Has been. In contrast, FIG. 4 shows a turbine blade 10 having a head end 55 that is similar to the root end in the manner of two platform elements 14, 16 and A modular platform 17 comprising a platform frame 18 may be provided. Here, the head side end portion 55 differs from the root side end portion only with respect to the side of the platform 17 facing away from the working medium. In general, in the turbine stationary blade 10 used in the stationary gas turbine, a so-called U-ring is attached to the head side end portion 55, and the U-ring has a stationary blade provided in the ring on the head side. Connect and join together. Additionally, in FIG. 4, a slit 54 is shown in the surface 53 of the platform frame 18 with the sides facing outward. The slit 54 is used to receive a plate-like sealing element, and the sealing element may be provided between the adjacent stationary blades to seal a gap between them.

  In general, the present invention relates to a turbine blade 10 comprising a blade blade 12 that is continuous along a longitudinal axis 11 of the turbine blade 10 and a platform 17 that is modular thereto. In doing so, it has been proposed to show a modular turbine blade 10 which, on the one hand, is particularly easy and simple to construct and on the other hand is particularly reliable and ensures long-lasting and continuous joining of the individual parts together. The wing blade 12 comprises an extension 26 and the platform 17 comprises an outer platform part 15 and an at least two part inner platform part 13 radially inner to the longitudinal axis 11, This means that the platform parts 13, 15 abut against the extension 26 of the wing blade 12 on the side and the outer platform part 15 is formed as an endless platform frame 18 surrounding the outer edge of the inner platform part 13.

DESCRIPTION OF SYMBOLS 10 Turbine blade 11 Longitudinal axis 12 Blade blade 13 Inner platform part 14 Platform element 15 Outer platform part 16 Platform element 17 Platform 18 Platform frame 20 Bolt 22 Compression side 23 Front edge part 24 Suction side 25 Rear edge part 26 Extension part 28 Step shape Part 30 Free end part 32 Collar part 34 Groove 36 Through hole 38 Blind hole 40 Back side 41 Long edge part 42 Blind hole 46 Long support member 48 Spring 50 Groove 52 Saddle part 53 Surface whose side faces outward 54 Slit 55 Head side edge

Claims (13)

In a turbine blade (10) having a platform (17) and blade blades (12) continuous along the longitudinal axis (11) of the turbine blade (10),
The wing blade (12) is provided with an extension (26) in the longitudinal direction;
And the platform (17) comprises an outer platform part (15) and an inner platform part (13) having at least two platform elements (14, 16) in a radial direction relative to the longitudinal axis (11). The platform element (14, 16) abuts the extension (26) of the wing blade (12) at the side and the outer platform part (15) surrounds the outer edge of the inner platform part (13). Turbine blade (10) characterized in that it is formed as an endless platform frame (18).   The platform frame (18), the inner platform part (13), and the wing blade (12) having the extension (26) are formed as separately manufactured members. The turbine blade (10) according to Item 1.   The turbine blade (10) according to claim 1 or 2, wherein the inner platform part (13) comprises two or three or four platform elements (14, 16).   The turbine blade (10) according to claim 3, wherein the platform element (14, 16) is joined to the blade blade (12) in a shape-connected manner relative to the longitudinal axis (11).   A plurality of the platform elements (14, 16) connected to one another and / or one platform element (14, 16) or a plurality of platform elements (14, 16) having the wing blade (12) or The turbine blade (10) according to claim 3 or 4, wherein all platform elements (14, 16) are connected to one another via bolts (20) fitted in holes.   The turbine blade (10) according to any one of claims 1 to 5, comprising a corresponding platform (17) on both end sides of the blade blade (12).   The turbine blade (10) according to any one of the preceding claims, wherein the inner platform part (13) and the platform frame (18) comprise at least one groove-spring connection.   The platform frame (18) abuts against a side surface of the inner platform part (13) in a plane, the abutment surface at least partially forming an angle with the longitudinal axis that is greater than 0 degrees and less than 90 degrees; The turbine blade (10) according to any one of claims 1 to 7.   The turbine blade (10) according to claim 8, wherein the magnitude of the angle is 10 to 35 degrees.   10. The platform frame (18) according to any one of the preceding claims, comprising a slit (54) for receiving a sealing element in at least one face (53) facing outwards. Turbine blade (10).   11. The platform frame (18) according to claim 1 to 10, wherein the platform frame (18) is interference-fitted to the inner platform part (13) and / or brazed and / or welded to the inner platform part (13). The turbine blade (10) according to any one of the preceding claims.   The turbine according to any one of the preceding claims, wherein the turbine is formed as a turbine vane and the fixing means are each monolithically provided on at least one of the platform elements (14, 16). Wings (10).   The turbine blade according to any one of claims 1 to 11, wherein the turbine blade is formed as a turbine blade, and the fixing means is monolithically provided on the extension (26) of the blade blade (12). (10).

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