Guide vane arrangement, rotary machine with such guide vane arrangement and method for mounting a rotary machine

Abstract

Guide vane arrangement (100) comprising: at least one stationary guide vane (120); an outer ring (110) having a predefined shape, wherein the outer ring (110) has at least one defined groove (114) therein, the at least one groove (114) of the outer ring (110) being configured to receive at least one first end section (122) of the at least one stationary guide vane (120); and a fastening element (152) coupled between the at least one stationary guide vane (120) and the outer ring (110), wherein the fastening element (152) has a first configuration at a first operating temperature of the guide vane arrangement (100) and a second configuration at a second operating temperature of the guide vane arrangement (100);wherein the fastening element (152) is configured to radially pre-tension the at least one stationary guide vane (120) at a distance from the outer ring (110) when it is in the first configuration; and wherein the fastening element (152) creates a gap between the at least one stationary guide vane (120) and the outer ring (110) when it is in the first configuration; characterized in that the fastening element (152) is configured such that the at least one stationary guide vane (120) comes into contact with the outer ring (110) and the gap is thereby closed when the fastening element (152) transforms into the second configuration at the second operating temperature of the guide vane assembly (100), which is higher than the first operating temperature of the guide vane assembly (100).

Description

BACKGROUND TO THE INVENTION The present invention relates generally to turbines and in particular to systems and methods for securing turbine guide vanes within a turbine support groove. At least some well-known turbines, such as gas turbines and steam turbines, feature a support for axially spaced circumferential arrangements of guide vanes. The support typically has support halves that extend in an arc of 180° and are joined together at a horizontal interface to form a 360° arrangement of guide vanes at each axial stage position. Typically, the guide vanes include a blade with a dovetail-shaped base that fits into a corresponding dovetail-shaped groove in the support. When the guide vanes are installed in each support half-slot, the guide vane bases are stacked against each other within the slots, forming a semicircular arrangement of guide vanes. A common method for securing guide vanes within their grooves involves using spacers to hold them in the correct position. However, these spacers must be precisely cut and fitted to fit each guide vane. If the spacers are not cut accurately, the guide vane can jam when installed over them, resulting in reduced operating efficiency. Furthermore, using spacers is a time-consuming and labor-intensive process that can increase manufacturing costs. Another known method for retaining guide vanes within the grooves involves the use of radial turnbuckles to secure each guide vane. In such a method, a turnbuckle is positioned between the base of the guide vane and the base of the groove to preload the guide vane radially inward. The turnbuckles are typically made of steel to exhibit high strength under room-temperature assembly conditions and high strength under high-temperature operating conditions. Due to the turnbuckle material and the dovetail geometry of known guide vanes, high stresses are present in the guide vane dovetail hook and an upstream band of the outer ring that retains the guide vane. DE 10 2004 057 025 A1 , DE 15 51 180 A and US 7 445 426 B1 each disclose a guide vane arrangement with the features of the preamble of claim 1, a rotary machine with such a guide vane arrangement and a method for assembling a rotary machine with the features of the preamble of dependent claim 8. Based on this, it is an object of the present invention to provide a guide vane arrangement, a rotary machine and a method for assembling a rotary machine that makes it possible to reduce the loads introduced into the guide vane arrangement and other components. SHORT DESCRIPTION To solve the above problem, a guide vane arrangement with the features of claim 1 has been created in one aspect. The fastening element of the guide vane assembly can be made of brass. The fastening element of the aforementioned guide vane assembly can be made of a copper material. The at least one stationary guide vane of any guide vane arrangement mentioned above may have the first end section having a substantially arcuate groove defined therein, the groove being configured to accommodate the fastening element therein. The at least one groove of the outer ring of any guide vane arrangement mentioned above can define a substantially arcuate groove, wherein the arcuate groove can be configured to accommodate the fastening element. The fastening element of any of the aforementioned guide vane arrangements may include a tension pin extending between the at least one stationary guide vane and the outer ring. The first end section of at least one stationary guide vane of any guide vane arrangement mentioned above may have a dovetail-shaped end section. To solve the above problem, a rotary machine with the features of dependent claim 7 is provided in a further aspect. The rotary machine comprises a rotor and at least one guide vane arrangement, which is designed as described above and encloses the rotor. To solve the above problem, a method for assembling a rotary machine with the features of dependent claim 8 has been created in a further aspect. The aforementioned method for mounting a rotary machine may include coupling a fastening element which contains a spring pin made of either a brass material or a copper material. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of an exemplary steam turbine; Fig. 2 is a schematic cross-sectional view of a high-pressure (HP) section of the steam turbine shown in Fig. 1; Fig. 3 is a schematic cross-sectional view of a section of an exemplary guide vane assembly that may be used in the HP section shown in Fig. 2; Fig. 4 is a side view of an exemplary fastening element that may be used in the guide vane assembly shown in Fig. 3. DETAILED DESCRIPTION As used herein, the terms "axial" and "axial" refer to directions and orientations that extend substantially parallel to a longitudinal axis of a turbine. Furthermore, the terms "radial" and "radial" refer to directions and orientations that extend substantially perpendicular to the longitudinal axis of the turbine. Additionally, the terms "circumferential" and "circumferential" refer to directions and orientations that extend in an arc around the longitudinal axis of the turbine. Fig. 1 shows a schematic view of an exemplary steam turbine 10. Although Fig. 1 describes an exemplary steam turbine, it should be noted that the guide vane mounting element, systems, and methods described herein are not limited to any particular type of turbine. A person skilled in the art will recognize that the guide vane mounting element, systems, and methods described herein can be used in any rotating machine, including a gas turbine, in any suitable configuration that enables such a device, system, and method to function in the manner further described herein. In the exemplary embodiment, the steam turbine 10 is a single-flow steam turbine. Alternatively, the steam turbine 10 can be of any steam turbine design, such as a low-pressure turbine, a counterflow high-pressure and intermediate-pressure steam turbine combination, a double-flow steam turbine, and / or other steam turbine designs, but is not limited to such designs. Furthermore, as explained above, the present invention is not limited to use in steam turbines and can be used in other turbine systems, such as gas turbines. In the exemplary embodiment shown in Fig. 1, the steam turbine 10 comprises several turbine stages 12 coupled to a rotor. A casing 16 is axially divided into an upper half-section 18 and a lower half-section (not shown). The upper casing half 18 has a high-pressure (HP) steam inlet 20 on a high-pressure (HP) section 21 and a low-pressure (LP) steam outlet 22. The rotor 14 extends along a central axis 24 through the casing 16. The rotor 14 is supported in the casing 16 by shaft bearings 26 and 28, respectively, which are coupled to opposite end sections 30 of the rotor 14. Several sealing elements 31, 34 and 36 are coupled between the end sections 30 and the housing 16 to enable the sealing of the housing 16 around the rotor 14. In the exemplary embodiment, the steam turbine 10 further comprises a stator component 42, which is coupled to an inner shell 44 of the housing 16. Several sealing elements 34 are coupled to the stator component 42. The housing 16, the inner shell 44, and the stator component 42 each extend circumferentially around the rotor 14 and the sealing elements 34. In the exemplary embodiment, the sealing elements 34 form a coiled sealing path between the stator component 42 and the rotor 14. The rotor 14 has several turbine stages 12 through which high-pressure, high-temperature steam, or steam 40 for short, is passed via the steam channel 46. The turbine stages 12 have several inlet guide vanes 48. The steam turbine 10 can have any number of inlet guide vanes 48 that enable the steam turbine 10 to function in the manner described herein.The steam turbine 10 can, for example, have more or fewer inlet guide vanes 48 than shown in Fig. 1. The turbine stages 12 also have several turbine blades or rotor blades, generally designated by 38. The steam turbine 10 can have any number of rotor blades 38 that enables the steam turbine 10 to operate in the manner described herein. The steam turbine 10 can, for example, have more or fewer rotor blades 38 than shown in Fig. 1. The steam passage 46 typically passes through the casing 16. The steam 40 flows into the steam passage 46 through the high-pressure steam inlet 20 and flows down the length of the rotor 14 through the turbine stages 12. During operation, high-pressure, high-temperature steam from a steam source, such as a boiler (not shown), is directed to the turbine stages 12, where the thermal energy is converted into mechanical rotational energy. Specifically, the steam 40 is directed from the high-pressure steam inlet 20 through the casing 16, where it impacts the multiple rotor blades 38, which are coupled to the rotor 14, causing the rotor 14 to rotate around the central axis 24. The steam 40 exits the casing 16 at the low-pressure steam outlet. The steam 40 can then be directed to the boiler (not shown), where it can be reheated, or to other components of the system, such as a condenser (not shown). Fig. 2 shows a schematic cross-sectional view of the HD section 21 of the steam turbine (shown in Fig. 1). Fig. 3 shows a schematic cross-sectional view of a section of an exemplary guide vane assembly 100 that can be used in the HD section 21 of the steam turbine 10, cut along the area 3 (shown in Fig. 2). In the exemplary embodiment, the HD section 21 has an upper casing half 18 (as shown in Fig. 1) coupled to a lower casing half (not shown) when the steam turbine 10 is fully assembled. The HD section 21 has at least one guide vane assembly 100 having a substantially annular outer ring 110 or blinglet ring that substantially surrounds the rotor 14 (shown in Fig. 1).Furthermore, in the exemplary embodiment, an upper ring half 112 of the outer ring 110 is coupled to radially inner surfaces of the upper housing half 18, so that the upper ring half 112 of the ring serves as a radially inner extension of the housing 16. Such a coupling makes it possible to hold the upper ring half 112 of the outer ring 110 in a substantially fixed position with respect to the rotor 14. The upper ring half 112 of the outer ring 110 also has at least one groove 114 defined within it. In the exemplary embodiment, the guide vane assembly 100 further comprises at least one stationary guide vane 120. The groove 114 is dimensioned and oriented to accommodate at least one section of the guide vane 120. In particular, in the exemplary embodiment, the guide vane assembly 100 has grooves 114 defined within the upper ring half 112, and each groove 114 is dimensioned and oriented to accommodate a guide vane 120. In the exemplary embodiment, each guide vane 120 has a first end section 122 and a second end section 124 opposite the first end section 122. In the exemplary embodiment, each first end section 122 is dovetail-shaped and comprises a first upstream hook section 128, a second upstream hook section 129, a first downstream hook section 130, and a second downstream hook section 131.A lower half of the outer ring 110 (not shown) is coupled to the lower housing half and accommodates guide vanes 120 in a similar manner to the upper ring half 112. The HD section 21 also has several rotatable impeller blades 132 which are securely coupled to the rotor 14. In the exemplary embodiment, a coupling section 140 extends from each first end section 122 of the guide vane. More specifically, in the exemplary embodiment, each coupling section 140 is integrally formed with the respective first end section 122 of the guide vane, so that the guide vane 120 and the coupling section 140 form a single component. The coupling section 140 can be produced with the guide vane 120 by various conventional manufacturing processes known in the field, such as casting, drawing, or machining.One or more material types can be used to manufacture the coupling section 140 and / or the guide vane 120, with materials selected based on suitability for one or more manufacturing techniques, dimensional stability, cost, castability, machinability, stiffness, and / or other material properties. The coupling section 140 and / or the guide vane 120 can, for example, be made of a metal, such as a steel alloy, and / or a nickel-based material. In the exemplary embodiment, the coupling section 140 is integrally formed with the first end section 122 of the guide vane and positioned adjacent to it. The coupling section 140 is arranged adjacent to the groove 114. In the exemplary embodiment, the first end of the coupling section has a defined arcuate groove 150. The arcuate groove 150 is dimensioned and oriented to accommodate a fastening element 152. In the exemplary embodiment, a single fastening element 152 is arranged within each arcuate groove 150. In the exemplary embodiment, the fastening element 152 is a pin or a bolt that couples at least one section of the first end section 122 of the guide vane to at least one section of the groove 114, so that the guide vane 120 and the outer ring 110 are securely coupled to each other. Furthermore, in the exemplary embodiment, the rotor 14 has a rotor surface 180 which includes several substantially annular rotor grooves 182 formed therein. At least one substantially arc-shaped sealing strip 184 is securely coupled in each rotor groove 182. In the exemplary embodiment, the second end section 124 of the guide vane is arranged adjacent to the sealing strips 184. In the exemplary embodiment, the sealing strips 184 significantly reduce the amount of fluid flow path leakage that can occur between the rotor 14 and the housing 16. Fig. 4 shows a side view of an exemplary fastening element 152 (shown in Fig. 3) that can be used in the guide vane assembly 100 (shown in Fig. 3). In the exemplary embodiment, the fastening element 152 is substantially wedge-shaped, having a partially cylindrical cross-sectional shape (as shown in Fig. 3) and a rising, i.e., inclined or stepped, wall section 200. The fastening element 152 has a wall section 200 that is substantially continuously inclined from a first insert end 202 to a second proximal end 204 to define a substantially tapered or wedge-shaped fastening element 152. A height H2 of the fastening element 152 at the insert end 202 is lower than a height H1 of the fastening element 152 at the proximal end 204.Furthermore, the (not shown) cross-sectional area of ​​the fastener 152 at the insertion end 202 is smaller than a (not shown) cross-sectional area of ​​the fastener 152 at the proximal end 204. Although the wall section 200 is illustrated as a continuously tapered surface, a wall section having multiple steps to define an effectively continuously inclined surface would be functionally equivalent. The fastener 152 is inserted into the arcuate groove 150 between the outer ring 110 and the guide vane 120. The fastener 152 creates a wedge-like contact to clamp the guide vane 120 radially inward against the first and second hook sections 128 and 130 with sufficient force to maintain a designed pre-twist of the blade. In the exemplary embodiment, the fastening element 152 is manufactured using a material that, during assembly at room temperature, exhibits sufficient tensile strength to hold the guide vanes 120 in position, and whose tensile strength decreases under operating conditions with high temperatures (e.g., above approximately 400°C). More specifically, in the exemplary embodiment, the fastening element 152 is manufactured using brass, brass alloy, copper, copper alloy, and / or any other material known in the trade that enables the fastening element to function in the manner described herein. In the exemplary embodiment, the fastening element 152 has a first configuration at a first operating temperature of the guide vane assembly and a second configuration at a second operating temperature of the guide vane assembly. The fastening element 152 is configured to radially preload the guide vane 120 at a distance from the outer ring 110 when it is in the first configuration. When in the first configuration, the fastening element 152 creates a gap between the guide vane 120 and the outer ring 110. At the second operating temperature of the guide vane assembly, which is higher than the first operating temperature, the fastening element 152 transforms into the second configuration. When the fastening element 152 transforms into the second configuration, the guide vane 120 moves and comes into contact with the outer ring 110, thereby closing the gap.During operation, steam enters the high-pressure section 21 through the high-pressure steam inlet 20 of the high-pressure section (shown in Fig. 1) and is guided through the high-pressure section 21. The inlet guide vane assembly 48 (shown in Fig. 1) and the guide vanes 120 direct the steam to the rotor blades 132. As the steam is directed to the guide vanes 120 and the rotor blades 132, the pressure of the steam exerts forces on the guide vanes 120 and the rotor blades 132. Specifically, the pressure drops within the high-pressure section 21, and various forces, such as radial forces, are exerted on the guide vanes 120 and the rotor blades 132. For example, the steam exerts a first radial force F1 on the first hook section 128 on the upstream side of the guide vane 120. The fastening element 152 loses tensile strength and deforms with increasing operating temperature.When the fastening element 152 deforms, the guide vane 120 slightly changes its position within the groove 114. The hook sections 128 and 130 make contact with the outer ring 110. The second downstream hook section 131 makes contact with a lower radial outer groove surface 115 of the outer ring 110. When contact is made, at least part of the first radial force F1 is transferred to the contact point between the second downstream hook section 131 and the lower radial outer groove surface 115 as a second radial force F2. The second radial force F2 is directed in the opposite direction to the first radial force F1. As a result, the load path supporting the guide vane 120 changes, reducing load forces on the upstream hook section 128 and load forces on the outer ring 110.When the radial load path transitions from the passage through the pin as a fastening element 152 to the loading of the lower radial outer groove surface 115, the upstream reaction force F1 is reduced by approximately half, thereby reducing the load in the upstream hook section 128 and an upstream band section of the outer ring 110 by approximately half. A technical effect of the systems and methods described herein comprises at least one of the following: (a) coupling at least one stationary guide vane to a rotor, such that the at least one stationary guide vane extends radially outward from the rotor; (b) coupling an outer ring having a predefined shape to the rotor, such that the outer ring substantially surrounds the rotor, the outer ring having at least one defined groove therein, the at least one groove being configured to receive at least one section of the at least one stationary guide vane; and (c) coupling a fastening element between the at least one stationary guide vane and the outer ring, the fastening element having a first configuration at a first operating temperature of the guide vane assembly and a second configuration at a second operating temperature of the guide vane assembly. The systems and methods described herein enable an improvement in turbine performance by providing a fastening element for a guide vane assembly that significantly reduces operational loads introduced into the turbine. Specifically, a fastening element is described that exhibits a first configuration at a first operating temperature of the guide vane assembly and a second configuration at a second operating temperature. The fastening element radially pre-tensions a guide vane relative to a turbine casing when in the first configuration and transforms into a second configuration at a higher operating temperature to transfer operational loads away from the fastening element and the casing to a contact surface where a guide vane hook contacts the casing.In contrast to known turbines that use spacers to reduce operational loads, the devices, systems and methods described herein therefore enable a reduction in the time and difficulty of assembling guide vane assemblies, and they enable a reduction in the operational loads and costs associated with the guide vane assemblies, and allow coupling at the guide vane base to reduce dynamic loads in the dovetail. A guide vane assembly comprises at least one stationary guide vane and an outer ring having a predefined shape. The outer ring includes at least one defined groove configured to receive at least one section of the at least one stationary guide vane. The guide vane assembly further comprises a fastening element coupled between the stationary guide vane and the outer ring. The fastening element has a first configuration at a first operating temperature of the guide vane assembly and a second configuration at a second operating temperature of the guide vane assembly. PARTS LIST: 10 Steam turbine 12 Turbine stage 14 Rotor 16 Casing 18 Upper casing half 20 High-pressure steam inlet 21 High-pressure section 22 Low-pressure steam outlet 24 Central shaft 26 Shaft bearing 28 Shaft bearing 30 End sections 31 Sealing element 34 Sealing element 36 Sealing element 38 Rotor blade 40 Steam 42 Stator component 44 Inner casing 46 Steam channel 48 Inlet guide vanes 100 Guide vane assembly 110 Outer ring 112 Upper ring half 114 Groove 115 Lower radial outer groove surface 120 Guide vane 122 First end section 124 Second end section 128 First upstream hook section 129 Second upstream hook section 130 First downstream hook section 131 Second downstream hook section 132 Rotor blade 140 Coupling section 150 Arc-shaped groove 152 Fastening element 180 Rotor surface 182 Rotor groove 184 Sealing strip 200 Wall section 202 Insert end 204 Proximal end

Claims

Guide vane arrangement (100) comprising: at least one stationary guide vane (120); an outer ring (110) having a predefined shape, wherein the outer ring (110) has at least one defined groove (114) therein, the at least one groove (114) of the outer ring (110) being configured to receive at least one first end section (122) of the at least one stationary guide vane (120); and a fastening element (152) coupled between the at least one stationary guide vane (120) and the outer ring (110), wherein the fastening element (152) has a first configuration at a first operating temperature of the guide vane arrangement (100) and a second configuration at a second operating temperature of the guide vane arrangement (100);wherein the fastening element (152) is configured to radially pre-tension the at least one stationary guide vane (120) at a distance from the outer ring (110) when it is in the first configuration; and wherein the fastening element (152) creates a gap between the at least one stationary guide vane (120) and the outer ring (110) when it is in the first configuration; characterized in that the fastening element (152) is configured such that the at least one stationary guide vane (120) comes into contact with the outer ring (110) and the gap is thereby closed when the fastening element (152) transforms into the second configuration at the second operating temperature of the guide vane assembly (100), which is higher than the first operating temperature of the guide vane assembly (100). Guide vane arrangement (100) according to claim 1, wherein the fastening element (152) is made of a brass material or a copper material. Guide vane arrangement (100) according to claim 1, wherein the first end section (122) of the at least one stationary guide vane (120) has an arc-shaped groove (150) defined therein, wherein the arc-shaped groove (150) is configured to receive the fastening element (152) therein. Guide vane arrangement (100) according to claim 1, wherein the at least one groove (114) of the outer ring (110) defines an arc-shaped groove, wherein the arc-shaped groove is configured to accommodate the fastening element (152) therein. Guide vane arrangement (100) according to claim 1, wherein the fastening element (152) has a tension pin extending between the at least one stationary guide vane (120) and the outer ring (110). Guide vane arrangement (100) according to claim 1, wherein the first end section (122) has a dovetail-shaped end section. Rotary machine comprising: a rotor (14); and at least one guide vane arrangement (100) according to one of the preceding claims, wherein the at least one guide vane arrangement (100) surrounds the rotor (14). A method for assembling a rotary machine, the method comprising: arranging at least one guide vane assembly (100) having at least one stationary guide vane (120) in such a way that the at least one guide vane assembly (100) encloses a rotor (14), wherein the at least one stationary guide vane (120) extends radially outward from the rotor (14); arranging an outer ring (110) of the at least one guide vane assembly (100) having a predefined shape, such that the outer ring (110) encloses the rotor (14), wherein the outer ring (110) has at least one defined groove (114) therein, wherein the at least one groove (114) receives at least one first end section (122) of the at least one stationary guide vane (120) therein;and coupling a fastening element (152) between the at least one stationary guide vane (120) and the outer ring (110), wherein the fastening element (152) has a first configuration at a first operating temperature of the at least one guide vane arrangement (100) and has a second configuration at a second operating temperature of the at least one guide vane arrangement (100); wherein the fastening element (152) is coupled such that it radially preloads the at least one stationary guide vane (120) at a distance from the outer ring (110) when it is in the first configuration; and wherein the fastening element (152) creates a gap between the at least one stationary guide vane (120) and the outer ring (110) when it is in the first configuration;characterized in that the fastening element (152) is arranged such that the at least one stationary guide vane (120) comes into contact with the outer ring (110) and the gap is thereby closed when the fastening element (152) transforms into the second configuration at the second operating temperature of the at least one guide vane arrangement (100), which is higher than the first operating temperature of the at least one guide vane arrangement (100).

Images