JP2012510582A - Guide vane array structure for axial turbomachinery - Google Patents

Abstract

  The present invention relates to a guide blade arrangement structure (12) for an axial turbomachine, the structure (12) being arranged concentrically with respect to at least one annular guide blade carrier (14) and this carrier (14). A plurality of guide blades (20) arranged in a radial pattern between the guide blade carrier (14) and the inner ring (22). In order to achieve a wear-resistant and particularly durable attachment of the guide blade (20) supported by the guide blade carrier (14) to the inner ring (22), the guide blade (20) is connected to the inner ring (22). It is proposed to be elastically attached to. The attachment is realized by a spring element (52). Ensuring uniform contact pressure of the guide blade head (30) to the inner ring (22) or, if appropriate, to the further spring element (52) so that the stress and wear caused by the spring element (52) can be reduced Is possible.

Description

  The present invention relates to a stator blade arrangement for an axial turbomachine, which comprises an annular stator blade carrier and an inner ring arranged concentrically with respect to the stator blade carrier. A number of stator blades with blade airfoils are arranged radially, and each stator blade is fixed on a stator blade carrier.

  The stator blade array structure described at the beginning is well known from the prior art. This is known, for example, in the case of stationary gas turbine compressors, in which the stator blades of the compressor are mounted on a stator blade carrier or on a compressor casing. For this purpose, known stator blade carriers (especially usually formed with a cylindrical shape) have a retaining slot with an undercut, which in the circumferential direction has its inner generating surface. The stator blades or outer ring are inserted and secured therein. The stator blades, in this example, can be formed on the one hand as self-supporting stator blades, whereby the blade airfoil tip is present facing the inner boundary wall of the compressor flow path and forms a gap. For example, it is also known from Patent Document 1 that the inner boundary wall of the flow path is part of the stator blade or can be held by the stator blade itself. In this example, the known stator blade has in each case a shroud arranged on the tip side (which forms part of the boundary wall), or the stator blade has an inner ring (its outer generating surface) on the tip side. In this case constitutes the inner boundary for the flow path). The attachment of the inner ring on the stator blade of the stator blade arrangement can in this example be carried out via suitable bolt connections, by welding or by caulking.

  In the case of a known type of inner ring attachment on the stator blades of the stator blade array structure, the connection between the inner ring and the stator blades may become worn or cracked during operation of the compressor. The wear phenomenon occurs due to the rotation of the inner ring as a result of aerodynamic blade loading and / or due to the heat-induced expansion resulting from the heat generated during compression within the compressor. Periodic blade load changes or vibrations can also lead to wear phenomena.

  Furthermore, radial inner spring coupling of the blade airfoil is known from US Pat.

US Patent Application Publication No. 2007/0177973 UK Patent Application Publication No. 2 400 415 US Patent 2,914,300

  The object of the present invention is therefore to provide a stator blade arrangement (described at the beginning) for an axial turbomachine, which is particularly simple, has expansion tolerance, is not easily worn out, and Reliable stator blade fixing on the inner ring.

  The above object on which the present invention is based is achieved by a stator blade arrangement according to the features of claim 1.

  According to the invention, in the case of the stator blade arrangement described at the outset, the stator blade comprises a stator blade tip comprising a web section and a tip section extending so as to intersect with the web. The blade tip projects into the encircling slit of the inner ring, and the slot is in each case isolated by a shroud in the section between two adjacent stator blades, and the adjacent shrouds are spaced apart from each other. Forming a recess for accommodating the web, and at least one stator blade tip of the stator blade is spring-coupled onto the inner ring by at least one spring element disposed in the side of the recess facing the web ing.

  The present invention is based on the finding that the rigid coupling of the stator blades on the inner ring is disadvantageous. It therefore proposes a connection in a manner that allows a small range of relative movement of the stator blade relative to the inner ring in a wear-free manner without damage to the connection. Thus, the present invention differs from previous approaches that provided a rigid fixed connection between the stator blade and the inner ring.

  In the context of the present invention, a simple spring element will be used to secure the stator blade on the inner ring. Utilizing stator blade springing on the inner ring allows uniform crimping of the stator blade on the inner ring, resulting in thermal expansion and / or the consequences of static and / or dynamic stress Stress can be effectively minimized. At the same time, assembly tolerances (which are essential for easy assembly) can be compensated particularly easily as a result of springing.

  By reducing wear and avoiding cracks, the overall plant operating rate can be increased. This is because the check and repair of worn components (which was essential until now) is eliminated when the present invention is applied. Furthermore, repair costs can be saved and intermediate inspections can probably be omitted. Furthermore, the above approach can be easily combined with some of the previously known solutions, but this improves the repairability of existing turbomachines.

  Each stator blade is provided with a stator blade tip on the inner ring side, which is hidden in the inner ring, i.e. protrudes into a slot provided for it, and with it, the stator blade is Spring-loaded on the inner ring. In order to allow the stator blade to spring on the inner ring, it comprises at least one structural element, i.e. a stator blade tip, which can be joined to the inner ring and suitable for carrying out it. Is.

  According to a simple development, the stator blade tip of each stator blade comprises a web arranged in each case in an outwardly open recess arranged on the inner ring, wherein the spring element is attached to the web. The spring element is disposed in at least one of the side surfaces of the facing recess and abuts in a pretensioned state against the inner ring and against the web of the stator blade. Thus, for springing of the stator blade on the inner ring, provision is made for a further structural element, i.e. a spring element, which is supported on one side on the inner ring and on the other side Is supported on the web of the stator blade. In this example, the stator blade arrangement has a spring element that is preferably pre-tensioned, thereby indirectly or directly to the inner ring, in particular to one of the two sides of the recess. It is designed to press the web of the stator blades against.

  The stator blade tip is formed in an inverted T shape by a web and a tip section that extends across the web, where the web connects the tip section to the aerodynamically curved blade airfoil of the stator blade And the inner ring has an enclosed slot (which is formed to accommodate the stator blade tip) for receiving the stator blade tip, which slot is in the section between two adjacent stator blades. I.e. facing the blade airfoil and isolated in each case by the shroud. Stator blade shape mating connection to the inner ring by an inverted T-shaped stator blade tip or stator blade hook disposed on the stator blade and a slot formed on the inner ring and corresponding to the shape of the stator blade tip As a result, it is possible to provide a stator blade arrangement structure in which the inner ring is particularly reliably supported by the stator blades. This deployment is such that the stator blade array structure itself, the inner ring and / or the annular stator blade carrier are not integrally formed in each case, but from each other ring segment in a manageable manner during installation and / or removal. It is particularly advantageous when formed by at least two arc-shaped ring segments that are separated in some cases. The shroud on the one hand suppresses the displacement of the inner ring with respect to the stator blades along the circumferential direction. This is because, in each case, the shroud is arranged between the two stator blades and thus blocks the displacement path along the slot. On the other hand, the shroud also ensures a boundary surface with no step in the flow path. In general, the components of the structure and the structure itself can therefore be easily manufactured.

  Advantageous developments are as described in the dependent claims.

  According to an advantageous development, two spring elements, which are arranged on the sides of the recesses that are opposite to each other, are provided for each stator blade. As a result, each stator blade thus provided indirectly, i.e. via a spring element, is arranged on the inner ring in a pretensioned state. The spring force of each spring element is conveniently directed in this example in the circumferential direction of the inner ring. When a tension sleeve is used as a spring element, there is only a linear abutment between the web of each stator blade and the tension sleeve, so that the static load of the stator blade on the connection point is , Lower than in the case of two-dimensionally fixed stator blades. Since static loading is primarily the result of the displacement of the inner ring in the circumferential direction caused by an aerodynamic blade load, displacement tolerance mounting in the form of a circumferential spring mount avoids wear and cracking and crack propagation. Is necessary to do.

  It is advantageous for simple production of the stator blade arrangement structure that the inner ring consists of two ring sections that can be installed after its assembly to form an integral inner ring.

  The stator blades may be provided with two or more ring segments, i.e. the inner ring and / or the annular stator blade carrier is arcuate, i.e. when the array structure is used in particular in stationary turbomachines. Advantageously formed as a shaped ring segment. Since the stator blade array structure and its components are part of a component part fixed in the rotational direction of the turbomachine (this has a separating surface when used in a stationary region, so that in the rotational direction The stator component arrangement divided into two ring segments (each 180 °) is particularly suitable for stationary turbomachines, where the fixed component parts are divided for the upper and lower halves. Simple installation of the individual components thus forming a complete annular stator blade array structure is thus possible. The stator blade arrangement is preferably used in turbomachines which can be formed in particular as axial compressors or axial turbines. Furthermore, the stator blade carrier can be arranged in a separate casing, or it can even be formed as a casing itself.

  The present invention will be described with reference to the drawings. Further advantages and features are apparent from the illustration in this example.

It is a perspective view which shows the segment 10 of the stator blade arrangement | sequence structure 12 of an axial-flow turbomachine. FIG. 2 is an exploded view of FIG. 1. FIG. 3 is a longitudinal section through a joint according to the invention of a stator blade and an inner ring. It is an enlarged view of an inner ring in a state where a stator blade is omitted. It is a side view in section VV. FIG. 6 is a schematic diagram showing the twist of the stator blade as a result of the load reaction force and the support reaction force for a stator blade fixed according to the prior art. FIG. 6 is a schematic diagram illustrating the twisting of the stator blade as a result of the load reaction force and the support reaction force for a stator blade fixed in accordance with the present invention.

  FIG. 1 is a perspective view showing a segment 10 of a stator blade arrangement structure 12 of an axial-flow turbomachine. The segment 10 is formed in an arc shape and extends over a 180 ° arc. Two segments 10 shown in FIG. 1 can be combined to form a stator blade array structure 12 according to the invention, which in this case is formed as an annular form. A slot 18 is provided on the inner surface 16 of the stator blade carrier 14 that extends in the axial direction and accommodates the stator blade 20. In FIG. 2, the stator blade 20 to be inserted into the slot 18 is shown separated from the stator blade carrier 14 for exploded view. The radially outer portion of the stator blade 20 is in this example referred to in each case as the stator blade root, and the radially inner portion of the stator blade 20 is referred to as the stator blade tip. Between the stator blade root and the stator blade tip, the stator blade 20 has an aerodynamically curved blade airfoil. The inner ring 22 (only its 180 ° segment is shown in FIG. 2) is disposed on the stator blade 20 on the tip side. The inner ring 22 or segment thereof is assembled from two ring sections 36, 38 or ring section segments in this example.

  The stator blade array structure 12 assembled from two segments 10 thus comprises a ring of stator blades 20, also known as stator blade rings, which are part of the compressor stage or turbine stage. Also good.

  The stator blade carrier 14 is fixed on a casing (not shown) of an axial-flow turbomachine, for example a compressor, or is itself formed as a casing. The stator blade carrier 14 supports the stator blade 20, which is fixed on it on the inside and that in turn supports the inner ring 22 on the inside on the tip side. The outer formed surface of the inner ring 22 and the inner surface 16 of the stator blade carrier 14 in this example form radial inner and outer boundaries for the medium flowing through the axial turbomachine. When an axial turbomachine is formed as a compressor, the medium is compressed air or air to be compressed.

  FIG. 3 is a longitudinal section through the joint according to the invention of the stator blade 20 to the inner ring 22 (relative to the direction of the axial turbomachine). A blade airfoil 28 that is part of the stator blade 20 is partially shown. A stator blade tip 30 (which has a web 32 and a tip section 34 extending across it) is provided on the blade airfoil 28 in the tip side section of the stator blade 20. By the web 32 and the tip section 34, the stator blade tip 30 has an inverted T-shape as a whole as can be seen from the cross section.

  The inner ring 22 includes an outwardly opening slot 44, whose longitudinal cross-sectional profile is formed corresponding to the stator blade tip 30. The inner ring 22 comprises two ring sections 36, 38, which in turn are formed according to FIG. 2 as 180 ° arc-shaped segments. The ring sections 36, 38 or their segments are interconnected in a fixed manner by welds 40. The ring sections 36, 38 in each case have protrusions 42, 43 in order to form an undercut that can be used in each case to radially secure the inverted T-shaped stator blade tip 30. Are arranged facing each other.

  FIG. 4 is a perspective view of a section of the inner ring 22, where the ring sections 36, 38 are shown in a separated state, rather than in their final structural state, for clarity. In the final structural state, the two protrusions 42 and 43 are in contact with each other so that a gap is not generated as much as possible. Recesses 46 (two of which are shown in FIG. 4) are provided in the protrusions 43 of the ring section 36 for each stator blade 20. The recess 46 serves to accommodate the web 32 of the stator blade tip 30 of the stator blade 20. The protrusion 43 thus forms a shroud 47 between the recesses that isolate the slot 44 between the two stator blades 20 to provide a flow path without misalignment. Between the two adjacent shrouds 47, therefore, a recess 46 is provided in each case, in which the web 32 is accommodated (FIG. 3). For the sake of overview, the stator blade 20 shown in FIG. 3 is not shown in FIG. Each recess 46 has two side surfaces 48 that face each other. At least one of the two sides 48 of each recess 46 is provided with a further pocket 50 in which a spring element (which is formed as a tension ring) is a stator blade on the inner ring 22. Provided for 20 spring connections. In FIG. 4, the spring element 52 is shown roughly in a recess 46 shown far from the left side. FIG. 5 is a side view of a portion of the ring section 36, which is shown farther to the right side in FIG. The recess 46 is delimited by two side surfaces 48, which are each provided with a pocket 50. The pocket 50 is essentially formed in the shape of a circular segment and extends over the entire axial length of the recess 46. In this example, the pocket 50 can be formed, for example, by drilling or erosion before the recess 46 is introduced. The pocket 50, in this example, has a diameter (which exists in the radial plane of the axial turbomachine) within the protrusion 43 so that only a relatively small cross-section of the hole circle is covered by the recess 46. Or it arrange | positions so that it may arrange | position in the shroud 47. The tension sleeve in this case has a diameter slightly smaller than the diameter of the pocket 50. As a result of the selected position of the pocket 50, the spring element 52 formed as a tension ring can still protrude into the recess 46 by such a distance and the web 32 positioned there (this is shown in FIG. 5). Is not seated by spring action on the inner ring 22 via the spring element 52. Due to the selected arrangement of the recess 46, the pocket 50 and the spring element 52, the last-mentioned direction of force acts in the circumferential direction.

  The fall of the spring element 52 from the pocket 50 into the recess 46 can be avoided by the position of the pocket 50. This facilitates assembly of the stator blade array structure 12.

  Of course, the spring element 52 could also be provided in a pocket located on the web 32 rather than on the side 48 of the recess 46.

  FIGS. 6 and 7 are the result of load and support reaction forces for a stator blade fixed according to the prior art (FIG. 6) and for a stator blade fixed according to the invention (FIG. 7). The twist of the stator blade 20 is roughly shown.

  The stator blades 20 fixed on the tip side according to the prior art are particularly twisted so that high loads and wear (which can lead to cracking and crack propagation depending on the load) It can occur especially at the weakest point, i.e. at the stator blade tip 32 or at the inner ring. In accordance with the present invention, a spring connection of the stator blade tip 30 and thus a connection referred to as a flexible bearing is provided, which results in significantly less twisting of the stator blade 20 as a result of additional and support reaction forces. Does not occur. As a result, the load on the stator blade tip 32 can be reduced, which delays or prevents the occurrence of cracks and wear. In particular, the displacement of the inner ring in the circumferential direction as a result of the aerodynamic blade load creates a static load on the blade, which is more than the stator blade fixed according to the prior art by the connection according to the invention. Can be compensated well.

  In general, the present invention relates to a stator blade array structure 12 for an axial turbomachine, comprising at least one annular stator blade carrier 14 and an inner ring 22 disposed concentrically with respect to the stator blade carrier 14. In the meantime, a large number of stator blades 20 are arranged radially between them. In order to disclose a wear-resistant and particularly durable attachment of the stator blade 20 on the inner ring 22 (which is supported by the stator blade carrier 14), the stator blade 20 is spring-coupled on the inner ring 22 Proposed to do. The coupling is realized in this example by a spring element 52. The spring element 52 can ensure a uniform crimping of the stator blade tip 30 to the inner ring 22 or possibly to the further spring element 52, so that the stress and the resulting wear can be reduced.

10 segment 12 stator blade arrangement structure 14 stator blade carrier 16 inner surface 18 slot 20 stator blade 22 inner ring 28 blade airfoil 30 stator blade tip 32 web 34 tip section 36, 38 ring section 40 welded portion 42, 43 protruding portion 44 slot 46 Recess 47 Shroud 48 Side 50 Pocket 52 Spring element

Claims (11)

A stator blade arrangement (12) for an axial-flow turbomachine, comprising an annular stator blade carrier (14) and an inner ring (22) concentrically arranged with respect to the stator blade carrier (14), In between, a plurality of stator blades (20) with blade air foils (28) are arranged radially,
Each stator blade (20) is fixed on the stator blade carrier (14),
The stator blade (20) includes a web (32) and a tip section (34) extending so as to intersect with the stator blade tip (30) protruding into an enclosing slit 44 of the inner ring (22). And the slot (44) is in each case isolated by a shroud (47) in the section between two adjacent stator blades (20),
Adjacent shrouds (47) are spaced apart from each other to form a recess (46) for accommodating the web (32); and
At least one of the stator blade tips of the stator blade (20) is formed by the at least one spring element (52) disposed in a side surface (48) of the recess (46) facing the web (32). Stator blade array structure (12) characterized in that it is spring-coupled onto ring (22).   The spring element (52) is in a pre-tensioned condition, abutting against the inner ring (22) and against the web (32) of the stator blade (20). Item 12. The stator blade array structure (12) according to Item 1.   Two spring elements (52), which are arranged on the side surfaces (48) of the recesses (46) that face each other, are provided for each stator blade (20). The stator blade array structure (12) according to claim 1 or 2, wherein the stator blade array structure (12) is provided.   The stator blade array structure (12) according to any one of claims 1 to 3, wherein the spring (52) is formed as a tension sleeve.   A pocket (50) for receiving the spring element (52), from which the spring element (52) partially projects, is provided on the side surface (48). The stator blade arrangement structure (12) according to any one of claims 1 to 4, characterized in that:   The stator blade array structure (12) according to any one of claims 1 to 5, wherein the spring force is directed in a circumferential direction of the inner ring (22).   The stator blade arrangement (12) according to any one of the preceding claims, wherein the inner ring (22) comprises two ring sections (36, 38).   The stator according to any one of the preceding claims, wherein the inner ring (22) and / or the annular stator blade carrier (14) comprises at least two ring segments. Blade array structure (12).   The stator blade arrangement (12) according to any one of claims 1 to 8, characterized in that the stator blade carrier (14) is formed as a casing.   A turbomachine provided with the stator blade arrangement structure (12) according to any one of claims 1 to 9.   The turbomachine according to claim 10, wherein the turbomachine is formed as an axial compressor or an axial turbine.

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