JP2015517048A - Turbine blade and method for manufacturing the turbine blade - Google Patents

Abstract

The present invention is a turbine blade (10) comprising a stationary part (14), a platform (16) and a blade (18), comprising a stationary part (14), a platform (16) and a blade blade (18). Are arranged one after the other along the longitudinal axis (12) of the turbine blade (10), the platform (16) in the radial direction with respect to the longitudinal direction (12), the inner platform portion (22) and the outer A turbine blade (24) comprising a platform portion (24), wherein the outer platform portion (24) is formed as a continuous platform frame (28) surrounding the outer edge (26) of the inner platform portion (22). 10). The invention further relates to a method for manufacturing a turbine blade.

Description

  The invention relates to a turbine blade comprising a stationary part, a platform for forming a flow duct, and a blade blade, the stationary part, the platform and the blade blade being continuous along the longitudinal axis of the turbine blade. It is related with the turbine blade arrange | positioned. The invention further relates to a method for manufacturing a turbine blade, comprising the step of manufacturing a unitary blade body comprising a blade blade, a platform for forming a flow duct and a stationary part.

  Various forms of turbine blades based on various prior arts and methods of manufacturing the same are known. For example, turbine blades for gas turbines may be manufactured by a molding technique. During molding, this type of turbine blade is a monolithic structure because the blade legs, platform, and blade blades are simultaneously formed from the molding material. Surfaces exposed to the hot gas of the turbine, i.e. the platform and blade blades, are provided with a corrosion protection layer and a thermal protection layer to extend the useful life of the turbine blade. Since most of the molded turbine blades are hollow structures, means for cooling the blade material can be circulated therein. The majority of steam engine turbine blades are milled or cast from the solid.

  Turbine blades utilized in stationary turbomachines are subject to various loads during their operation, so that the turbine blades deteriorate and wear in an anticipated and unexpected manner.

  Specifically, both high cycle fatigue load, low cycle fatigue load, thermal load and mechanical load are generated. There is also a need to protect the turbine blades from oxidation and creep. The aforementioned loads are particularly associated with turbine blade surfaces and components that are directly exposed to hot gases or steam. Furthermore, loads known as “bearing loads” and “friction loads” act on the turbine blade on the fixed side. In view of these differing loads and requirements, monolithic turbine blade materials, if possible, if not all, without premature aging or premature end of the turbine blade, A number of loads need to be chosen so that they are absorbed by the material. With regard to loads due to heat and corrosion, it is known to provide a gas turbine turbine blade with a layer structure that protects its material from both corrosion and excessive heat conduction, for example.

  Nevertheless, wear phenomena such as cracks may occur in various regions of the turbine blade, which exposes the turbomachine to a dangerous condition. To this end, after a predetermined period of use, turbine blades are inspected for such defects, and if any such defect is found, the turbine blade in which the defect is found is replaced or reprocessed. It is known.

  It is also known to make turbine blades modular, and to produce corresponding modules from materials that meet the local requirements of the modules. However, the connection may not be realized with persistence and reliability.

  In this regard, for example, Patent Document 1 discloses a movable blade having two platform halves arranged on both sides of a blade blade. In order to prevent the platform halves from moving along the blade wings, a secure connection is achieved by the two platform halves being locked together. However, it has been determined that fixing such a platform is dangerous. U.S. Pat. Nos. 5,099,086 and 5,037,086 similarly disclose splitting the platform into two halves.

  As an alternative to the platform halves disclosed in US Pat. No. 6,057,049, US Pat. No. 5,057,089 discloses a single platform element disposed between two directly adjacent mobile blades of a mobile blade ring. ing. However, it is considered disadvantageous to attach the components to the rotor.

  U.S. Pat. Nos. 5,099,086 and 6,037,059 disclose various additional assembled turbine blades. In both patent documents, it is proposed to utilize a monolithic platform for the turbine blade with a recess that fits the blade blade profile. In both patent documents, each blade blade without a platform is inserted into the platform and secured via an intermediate piece to complete the turbine blade.

US Pat. No. 4,650,399 European Patent Application No. 1905950 US Patent No. 4019832 International Publication No. 2000/057032 US Pat. No. 3,451,654 US Pat. No. 7,762,781

  An object of the present invention is a turbine blade comprising a stationary part, a platform for forming a flow duct and a blade blade, the stationary part, the platform and the blade blade being along the longitudinal axis of the turbine blade. It is to provide a turbine blade which is arranged in series with each other and allows the turbine blade to be regenerated especially at low cost. It is a further object of the present invention to provide a method for manufacturing the turbine blade.

  The object directed to the turbine blade is achieved by a turbine blade according to the features of claim 1. The object directed to a method for manufacturing a turbine blade is achieved by a method step as defined in claim 9. Advantageous variants are specified in the respective dependent claims. In this case, the features of each dependent claim can be easily combined with the features of the other dependent claims.

  The present invention is based on the recognition that defects caused by oxidation can occur even at the outer edge of the platform, especially in the case of turbine blades that are subjected to operational loads. In particular, such a problem of oxidation occurs when the heat insulating layer applied to the outer edge is locally peeled off. As a result, there is an increased risk of operation in the turbine blade, so that the turbine blade with delamination is replaced or processed. However, conventional turbine blade reprocessing has been relatively complex. At the same time, the regeneration rate, i.e. the proportion at which the reprocessed turbine blades are still suitable for use in a turbomachine after reprocessing, may be quite low. In order to counteract these effects, in the present invention, the platform comprises an inner platform portion and an outer platform portion in a radial direction with respect to the longitudinal direction, and the outer platform portion surrounds the outer edge of the inner platform portion. It is formed as a simple platform frame. Therefore, the periphery of the platform frame has a continuous and integral structure and is configured to be closed.

  In this case, the present invention is not intended to have a modular turbine blade configuration, preferably the surface of the inner platform portion through which the hot gas flows is the surface of the platform frame through which the hot gas flows. Is substantially larger.

  As long as the turbine blades under operation are reproducible in the region of the outer edge of the platform, it is necessary to remove the above mentioned defects in the vicinity of the outer edge of the platform, for example by retreating the outer edge of the platform, for example by milling or grinding There is. In this case, the present invention does not remove only local defects when the outer edge of the platform is retracted.

  Conversely, the outer edge of the platform is retracted along the entire perimeter to produce a monolithic blade body. The platform of the blade body is provided with a support surface for the platform frame as the inner platform portion of the turbine blade to be manufactured. After the continuous platform frame is attached to the inner platform portion, the turbine blade thus produced has a platform having dimensions corresponding to the original turbine blade.

  Obviously, the method also removes blade material that is not degraded or damaged. However, this is advantageous in that the reprocessing does not need to be performed individually, in other words, according to the defect, and the reprocessing can be automatically executed. This can reduce the cost due to reprocessing and the defective product rate.

  Needless to say, a new component, i.e. a turbine blade that is not subjected to operational loads, can also be realized as an integral construction of a so-called blade body comprising blade blades, a platform and a fixed part. The unitary blade body can be manufactured by a conventional molding method, and can be solidified by, for example, single crystal solidification or directional solidification. After the blade body has been manufactured, in order to form a precisely dimensioned support surface for the platform frame on the inner platform portion of the turbine blade, the edge of the blade body platform is suitably applied by some grinding or milling. Need to be of a predetermined exact dimension along the entire circumference. Before, during or after this, the platform frame needs to be manufactured as a generally rectangular structure. After securing or attaching the platform frame to the precisely sized edge of the inner platform portion, the turbine blade is manufactured as a new component. The cross section of the platform frame can take various forms. Preferably, however, these configurations are positively connected to the edge of the inner platform portion. For example, the cross-sectional shape is a diamond shape or a C shape. In this case, the edge of the inner platform portion is always formed to match the cross-sectional shape.

  A particular advantage for the turbine blade and the method of manufacturing the turbine blade in the present invention is that, in particular, two different materials are made available for the blade body and the platform frame. Thus, additional consideration can be given to various local stresses, and, if appropriate, can extend the useful life of the turbine blade.

  A further advantage of the turbine blade in the present invention is that the accuracy of the platform outer dimensions can be further increased. This is because it can be more easily implemented during the manufacture of the platform frame than when a fully integrated turbine blade is molded.

  Various methods can be implemented to permanently connect the platform frame to the blade body. Since the platform frame is configured as a continuous frame, it is preferred that the platform frame be suitably contracted to fit the periphery of the inner platform portion. Prior to shrinking, the platform frame is heated and / or the blade body is cooled. After the platform frame and blade body are assembled and the temperature is equilibrated, the platform frame is firmly seated on the periphery of the inner platform portion. It is also possible to solder and weld in spots along the connecting lines between the inner platform portion and the edges of the platform frame.

  In a first advantageous development, the platform frame supports the inner platform portion in surface contact, and the contact area is at least inclined at an angle greater than 0 degrees and less than 90 degrees with respect to the longitudinal axis. It is partially formed. Such an arrangement is advantageous when the present invention is utilized in mobile turbine blades because it prevents parallel displacement of the platform in at least one direction along the longitudinal axis. In this case, the centrifugal force acting on the platform frame during operation of the turbomachine is transmitted to the inner platform part by a secure connection. This is because the contact area is inclined with respect to the longitudinal axis. Thereby, the loss of the platform frame due to the centrifugal force can be surely prevented.

  Preferably, the angle is 15 ° to 35 °, for example 20 °.

  In a second advantageous development, the platform frame has a slot for receiving a sealing element on at least one surface facing laterally outward. With such an improvement, the present invention is of this type under load from operation when the slot at the edge of the platform is worn due to a sheet-like sealing element placed in the slot. This is advantageous in that the turbine blade can be easily and reliably regenerated. Furthermore, such a slot can be manufactured more cost-effectively than a fully monolithic turbine blade.

  Advantageously, the turbine blade may be configured as a guide blade or a movable blade.

The inner platform portion and the platform are coated by a coating operation so that a turbine blade comprising an inner platform portion and an outer platform portion in the form of a continuous platform frame surrounding the inner platform portion is made available in a high temperature environment. It is advantageous if the frame is coated. Thus, a seamless protective layer may be applied to the inner platform portion and the outer platform portion.

  Further advantages of the features of the present invention are identified in the description of the drawings.

It is a perspective view of the turbine blade in this invention. It is a perspective view of a platform frame. It is sectional drawing of the turbine blade represented to FIG. FIG. 2 is a detailed view of a corner portion of the platform of the turbine blade illustrated in FIG. 1 when the blade body and the platform frame are assembled.

  The same features are denoted by the same reference symbols in all drawings.

  FIG. 1 is a perspective view of the turbine blade 10. The turbine blade 10 can be configured as a movable blade. However, the turbine blade 10 is also configured as a guide blade. The turbine blade 10 includes a stationary portion 14, a platform 16, and a blade blade 18 that are disposed directly and continuously along the longitudinal axis 12 of the turbine blade 10. The outer shape of the fixed portion 14 is formed in the shape of a pine tree, which is a typical embodiment of a movable blade. The guide blade for the turbine has a plurality of hooks that are pushed into the guide blade carrier of the turbomachine, not shown, instead of the generally pine wood-like fixed portion 14.

  The fixed portion 14 is integrated with the platform 16. As shown in FIG. 1, the platform 16 has a platform top surface 20 on which blade blades 18 are mounted. In the exemplary embodiment shown, the platform 16 includes an inner platform portion 22 and an outer platform portion 24 in a radial direction with respect to the longitudinal axis 12. The outer platform 24 is configured as a continuous platform frame 28 that surrounds the outer edge 26 of the inner platform 22. In the exemplary embodiment shown, the fixed portion 14, the inner platform portion 22 and the blade wing 18 are integrally formed together, which is a one-piece structure. In addition, such a unit having an integral structure may be configured as a blade body 19. The platform top surfaces 20 of the inner platform 22 and the outer platform 24 are directed toward the blade wings 18 as shown and are arranged without being offset from each other. Thus, when the turbine blade 10 is utilized in a turbomachine, the inner platform 22 and the outer platform 24 can provide a boundary without steps and corners for the working medium flowing in the turbomachine.

  In this case, the surface of the inner platform portion 22 through which the hot gas flows is larger than the surface of the platform frame 28 through which the hot gas flows.

  The turbine blade 10 is configured to be internally cooled by a cooling medium at least. There may be a film cooling port and a trailing edge port for the coolant. Needless to say, the turbine blades are not cooled.

  FIG. 2 is a perspective view of the platform frame 28. The platform frame 28 comprises two longitudinal struts 30 arranged parallel to each other and two lateral struts 32 arranged parallel to each other. The platform frame 28 may be made of a material different from the material of the blade body 19 shown in FIG. However, the platform frame 28 may be made from the same material. Platform frame 28 may be made by welding longitudinal struts 30 to lateral struts 32. The platform frame 28 may be made by molding or may be made by machining from an ingot. FIG. 3 is a cross-sectional view of the turbine blade 10 along the longitudinal axis 12. In contrast to the turbine blade shown in FIG. 1, the fixed part shown in FIG. 3 is not in the form of a pine tree but in the form of a dovetail. Further, FIG. 3 shows the platform frame 28 being attached to the blade body 19 just before the platform frame 28 reaches the final attachment position. In the exemplary embodiment shown, the cross section of the platform frame 28 is diamond-shaped. However, other shapes are possible.

  Each of the longitudinal struts 30 and the lateral struts 32 of the platform frame 28 has a first support surface 34 and a second support surface 36 that face inward. Similarly, the outer edge 26 of the inner platform portion 22 has a first support surface 38 and a second support surface 40 facing laterally outward. After the platform frame 28 is attached, the first support surface 34 of the platform frame 28 supports the first support surface 38 of the inner platform portion 22 in surface contact with the second support frame 38 of the platform frame 28. The support surface 36 supports the second support surface 40 of the inner platform portion 22 in surface contact. The first contact region and the second contact region thus formed are inclined at different angles with respect to the longitudinal axis 12. The first contact area is a cross section oriented parallel to the longitudinal axis 12. However, the second contact area is a cross section that is inclined at an acute angle α with respect to the longitudinal axis 12. Further, the embodiment prevents the platform frame 28 from being detached from the blade body 19 when the centrifugal force is acting on the turbine blade 10 by a reliable connection.

  FIG. 4 is a perspective view of the inner platform portion 22 and the flat foam frame 28 in the installed state. In addition to the features described above, FIG. 4 represents a slot 44 for receiving a sheet-like sealing element formed in the laterally outward surface 42 of the platform frame 28.

  Accordingly, in general, the present invention is a turbine blade 10 comprising a stationary portion 14, a platform 16 for forming a flow duct, and a blade vane 18, wherein the stationary portion 14, the platform 16 and the blade vane 18 comprise The turbine blade 10 is arranged in direct succession along the longitudinal axis 12 of the turbine blade. In order to provide a turbine blade 10 having a particularly long service life, the present application provides that the platform 16 comprises an inner platform portion 22 and an outer platform portion 24 in a radial direction with respect to the longitudinal direction 12, and the outer platform It is proposed that the portion 24 is configured as a continuous platform frame 28 that surrounds the outer edge 26 of the inner platform portion 22. In a method aspect, the present application utilizes a blade body 19 manufactured in a unitary structure, or applies or retracts a turbine blade 10 subjected to operational loads along the entire outer edge of the platform, and It is proposed to produce a continuous platform frame 28 that can then be attached to the outer edge 26 of the platform, so that the turbine blade 10 can be produced in full or planned dimensions.

10 turbine blade 12 longitudinal axis (of turbine blade 10) 14 fixed portion 16 platform 18 blade wing 20 platform top surface 22 inner platform portion 24 outer platform portion 26 outer edge 28 of inner platform portion 22 platform frame 30 longitudinal strut 32 lateral Directional strut 34 First support surface 36 (of longitudinal strut 30 or lateral strut 32) Second support surface 38 (of longitudinal strut 30 or lateral strut 32) First support surface 40 (of outer edge 26) Second support surface 42 (of outer edge 26) Laterally outward surface (of platform frame 28) 44 Slot

Claims (13)

A turbine blade (10) comprising a stationary part (14), a platform (16) for forming a flow duct, and a blade blade (18),
The turbine blade, wherein the stationary part (14), the platform (16) and the blade blade (18) are arranged in series with each other along the longitudinal axis (12) of the turbine blade (10) In (10),
The platform (16) comprises an inner platform portion (22) and an outer platform portion (24) in a radial direction relative to the longitudinal direction (12), wherein the outer platform portion (24) Turbine blade (10) characterized in that it is formed as a continuous platform frame (28) surrounding the outer edge (26) of 22). The platform frame (28) supports the inner platform portion (22) in surface contact;
A turbine blade (1) according to claim 1, characterized in that the contact area is at least partly formed with an inclination with respect to the longitudinal axis (12) at an angle greater than 0 ° and less than 90 °. 10).   The turbine blade (10) according to claim 2, wherein the angle is 10 ° to 35 °.   The inner platform portion (22) and the fixed portion (14) and / or the inner platform portion (22) and the blade wing (18) are unitary. The turbine blade (10) according to any one of the preceding claims.   The platform frame (28) according to any of the preceding claims, characterized in that it has a slot (44) in the at least one laterally outward surface (42) for receiving a sealing element. The turbine blade (10) of claim 1.   The platform frame (28) is in contracted contact with the inner platform portion (22) and / or is soldered and / or welded to the inner platform portion (22). The turbine blade (10) according to any one of claims 1 to 5.   The turbine blade (10) according to any one of the preceding claims, characterized in that the turbine blade (10) is configured as a guide blade or a movable blade.   The surface of the inner platform portion (22) through which hot gas flows is substantially larger than the surface of the platform frame (28) through which hot gas flows. Turbine blade (10). In a method for manufacturing a turbine blade (10),
Manufacturing a monolithic blade body (19) comprising a blade (18) and a platform (16) as an inner platform portion (22) for forming a flow duct and a stationary portion (14); ,
Manufacturing a continuous platform frame (28);
Attaching the continuous platform frame (28) to the outer edge (26) of the platform (16);
A method characterized by comprising:   In order to produce the blade body (19), the outer edge of the platform of the turbine blade, which has been subjected to operational loads, is retracted along the entire circumference of the platform, so that the continuous platform 10. A method according to claim 9, characterized in that a support surface (36, 38) for a frame (28) is formed and the platform (16) is converted to the inner platform portion (22). The blade body (19) comprising the fixed part (14), the platform (16) and the blade wing (18) is manufactured by molding;
The method according to claim 9, characterized in that the outer edge (26) of the platform is formed as a support surface (36, 38) for the continuous platform frame (28).   Contracting the platform frame (28) in contact with the inner platform portion (22) and / or soldering and / or welding to the blade body (19). The method according to any one of claims 9 to 11.   13. A method according to any one of claims 9 to 12, characterized in that it comprises the step of coating the inner platform part (22) and the platform frame (28) in a coating operation.

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