JP5336649B2 - Seal plate and blade system - Google Patents

Description

  The present invention relates to a seal plate forming an annulus comprising a seal plate for a rotor of a gas turbine, and the seal plate is mainly formed from a plurality of metal sheets. Furthermore, the present invention particularly relates to a moving blade system of a gas turbine, wherein the moving blade system has a large number of moving blades arranged annularly on the turbine disk, and a large number of seal plates are arranged on the side of the turbine disk. ing. The invention further relates to a gas turbine having such a blade system.

  Gas turbines are used in many fields to drive generators or machines. In this case, the fuel energy is utilized to produce the rotational motion of the turbine shaft. In order to achieve this purpose, fuel is combusted in a combustion chamber and compressed air is supplied from an air compressor. The high-pressure and high-temperature operating medium produced in the combustion chamber as a result of the combustion of the fuel then expands to work towards a turbine device connected downstream of the combustion chamber.

  In order to produce the rotational movement of the turbine shaft, a large number of blades, usually collected in a blade group or cascade, are arranged on this shaft. In this case, the turbine disk to which the moving blade is fixed by the blade root is usually provided in each turbine stage. In order to guide the flow of the operating medium in the turbine device, further, stationary blades connected to the turbine case and assembled to form a stationary blade row are usually arranged between adjacent blade rows.

  The combustion chamber of the gas turbine can be configured as a so-called annular combustion chamber with a number of combustors, arranged around the circumference of the turbine shaft and sealed by a high heat-resistant peripheral wall It leads to the combustion chamber space. In order to achieve this purpose, the combustion chamber is designed entirely as an annular structure. In addition to one combustion chamber, it is also possible to provide a plurality of combustion chambers.

  Normally, the first stationary blade row of the turbine device is directly connected to the combustion chamber, and forms the first turbine stage of the turbine device together with the moving blade row immediately after viewed in the flow direction of the operating medium, and further turbines. The stage is usually connected downstream.

  In such a gas turbine design, in addition to the achievable power, a particularly high efficiency is usually a design goal. In this case, for reasons of thermodynamics, basically, the working medium is discharged from the combustion chamber, and the efficiency is improved by raising the discharge temperature at the place where it flows to the turbine device. In this case, temperatures of about 1200 ° C. to 1500 ° C. are targeted and achieved with such gas turbines.

  However, such hot operating media expose exposed components and parts to high heat loads. In order to protect the turbine disk and the turbine shaft against the penetration of the hot operating medium, the turbine disk is provided with a sealing plate known, for example, from US Pat. It is attached to the surface in a circular manner. In this case, one seal plate for each turbine blade is usually provided on each side of the turbine disk. In order to avoid the penetration of the hot operating medium in the turbine axial direction, they overlap in the form of roof plates and usually have sealing vanes each extending to the adjacent vanes.

  However, the seal plate performs an additional function. On the one hand, the corresponding clamping elements form the axial fixation of the turbine blades, on the other hand, not only seal the turbine disk against the penetration of hot gas from the outside, but also are guided inside the turbine disk, In addition, leakage of cooling air that normally passes for cooling the turbine blade itself is also avoided.

  Such seal plates with integrated seal blades are usually made by vacuum burial casting (eg lost wax burial casting process). In this case, some surplus is provided to compensate for dimensional errors caused by the process. Due to the geometry that the seal plate is wide, has a very thin area, and mass builds up elsewhere, it is inevitable that warping and numerous pores will occur in vacuum immersion casting, especially in the thin area. However, due to the required shape of the seal plates, they are often made from alloys, and a near net shape cannot be made except by the described vacuum-incorporated casting process.

  For this reason, such seal plates often have to be compressed at high temperatures and pressures by hot isostatic pressing to remove pores after casting, and finally have a contoured shape due to time-consuming machining processes. Must finish. First, the described hot isostatic pressing, the machining finishing process and the associated material losses are very time consuming and expensive, and then there is a non-uniform mass distribution even after machining finishing. May continue to exist, which can severely limit the function of the seal plate that is subsequently in operation and can be associated with loss of efficiency of the gas turbine.

  It is known from US Pat. No. 6,057,056 that the blades of a gas turbine are fixed against shaft movement by means of a rigid cover ring. In this case, an obliquely set baffle plate having an opening is fixed to the cover ring, the opening captures the cooling air provided in the space adjacent to the disk, and is cooled by the opening disposed in the cover ring. Guide air to the blade. However, this design still requires a casting cover.

European Patent Application No. 1944472 British Patent Application No. 947,553

  Accordingly, the present invention is directed to a seal plate and blade system that allows a simplified structure as well as a gas turbine that is as efficient as possible.

  This object is achieved by the present invention using a sealing plate according to the features of claim 1.

  The present invention achieves a particularly simple production of the seal plate if it can simplify the conventional habitual investment casting process with subsequent machining finish or be completely replaced by another manufacturing process. Based on that. In this case, due to the material selected for the seal plate, a casting process other than the described vacuum immersion casting is not possible. Therefore, the seal plate should not be made by a typical process such as casting, but by a molding method. In order to be able to realize the complex shape of the seal plate, the seal plate is made from a plurality of basic parts by molding. This is achieved in a particularly simple manner by the formation of a prepared metal sheet, and it can be said that the seal plate is made of a plurality of metal sheets.

  In this case, the seal plate comprises two metal sheets spaced apart and arranged parallel to the plane of the seal plate. These form the respective end faces of the seal plate and the thickness of the seal plate can be accurately selected by the distance between the two metal sheets. In this case, a gap remains between the metal sheets, which can be used for cooling air to pass through and can be used for cooling the inside of the seal plate. Thus, on the one hand, a particularly simple structure of the seal plate is possible, and on the other hand, as a result of active component cooling, the seal plate can withstand the most adverse environments during operation, so at particularly high temperatures. A gas turbine can be operated, with which a particularly high efficiency is achieved.

  In an advantageous development, an intermediate metal sheet with a number of cutouts is arranged between the metal sheets. Such an intermediate metal sheet functions as an end face, stabilizes the connection between the metal sheets of the seal plate, and allows an accurate and intentional distance selection. As a result of the cut out of the intermediate metal sheet, cooling air can pass through the interior of the seal plate while maintaining the described advantages.

  The respective metal sheet on the side facing the center of the turbine disk is in this case advantageously bent. Such a bend, which can be easily made by molding, allows the seal plate to be fixed in a groove provided on the side facing the center of the turbine disk and secures the seal plate and blades in the turbine disk. Make sure to hold. This is because there is no need to change the conventionally used clamping device for the turbine disk in spite of the change in the structure of the seal plate, and therefore it is particularly simple for the blade system and turbine disk having the seal plate. Provides the advantage that a structure is possible.

  In order to ensure a particularly simple feed and supply of cooling air to the sealing plate, each metal sheet advantageously has a number of cooling air holes.

  On the inlet side, the cooling air holes must face the turbine disk, in this case allowing cooling air to pass through the turbine disk and into the seal plate, and on the outlet side, the cooling air holes are adjacent. In the direction of the metal sheets attached to the components or seal plates, for example, active cooling of these components is also possible.

  In order to protect the function of the sealing blades for sealing the area between the two turbine disks against the penetration of hot gas from the hot gas passages of the gas turbine, the sealing plate is a metal sheet facing away from the plane of the sealing plate. Conveniently prepared. In order to protect the components provided there, it reaches the adjacent blade row and prevents hot gas penetration in the turbine axial direction.

  According to an advantageous development, the various metal sheets are welded and / or soldered together. As a result, a particularly simple structure of the sealing plate consisting of a large number of metal sheets is possible.

  The structure of the seal plate achieved in this way, in particular the three-layer design of the two metal sheets forming the end faces and the intermediate metal sheet with a cut-out for the cooling air, is for sealing a plurality of seal plates next to each other Is arranged to provide a tongue-in-groove connection. In order to achieve this purpose, grooves and / or tongues are conveniently arranged in the region of the end of each sealing plate. In the case of the three-layer design of the sealing plate of the above-mentioned style, such a groove can be easily made by shortening the end of the intermediate metal sheet, or the convex part can be made by lengthening the end of the intermediate metal sheet. . As a result, particularly good and simple circumferential sealing between a plurality of seal plates can be realized.

  A gas turbine advantageously comprises such a blade system, and a gas and steam turbine plant also comprises a gas turbine having such a blade system.

  The advantages achieved using the present invention are particularly possible as a result of a seal plate structure with a large number of metal sheets, especially of simple design and construction. In this case, manufacturing costs and material costs are low compared to other methods. As a result of the combination of flexible materials, the resulting materials used and costs can be reduced. When using pre-formed metal sheets, the machining finish of the large flat surface required for the casting process is not necessary and a particularly good sealing effect of the seal plate is still achieved during operation. The As a result of this, and as a result of active component cooling by directing cooling air into the seal plate, a lower limit for the temperature of the hot gas in the gas turbine is obtained, and overall high efficiency can be achieved. it can.

  Exemplary embodiments of the invention will be described in more detail with reference to the drawings.

A half section of a moving blade system is shown. The cross section of the seal plate after a casting process is shown. The cross section of the seal plate after machining is shown. 2 shows a cross section of a seal plate made from a plurality of metal sheets. The top view of the intermediate metal sheet of a seal plate is shown. Figure 2 shows a top view of a seal plate made from a number of metal sheets. A half section of a gas turbine is shown.

  In all the drawings, the same parts are denoted by the same reference numerals.

  FIG. 1 shows a cross section of a blade system 1 passing through the outer periphery of a turbine disk 6 attached to the turbine shaft of a blade stage of a gas turbine according to the prior art.

  In this case, the moving blade 12 is disposed in the moving blade holding groove 30 by the blade root 32. The blade root 32 of the moving blade 12 has a fir tree shape in cross section, and corresponds to the fir tree shape of the moving blade holding groove 30. A schematic view of the outer shape of the blade root 32 and a schematic view of the blade retaining groove 30 are shown rotated by 90 ° compared to the other FIG. Accordingly, the illustrated blade retaining groove 30 extends between the side surfaces 34 of the turbine disk 6.

  Although not shown in detail, the stationary blade 36 is provided adjacent to each other in any case, and is disposed upstream and downstream of the moving blade 12 as viewed from the flow direction of the operating medium of the gas turbine. In this case, the stationary blades 36 are annularly arranged in the radial direction.

  The seal plate 40 is inserted into each of the side walls 34 on both sides of the turbine disk 6 by a method of surrounding the periphery like a roof plate. These are held on the upper side by a groove 42 into which the rotor blade 12 is inserted, and the lower side is fixed by a fixing bolt not shown in more detail.

  The seal plate 40 plays a plurality of roles in this case. On the other hand, the added sealing vanes 46 extending essentially in the axial and azimuthal directions seal the gap between the turbine disk 36 and the adjacent stationary blade 36 against the penetration of the hot operating medium M from the turbine. Stop. On the other hand, the seal plate 40 also ensures axial fixation in the blade retaining groove 30 of the blade root 32 and secures them against axial movement. The axial and azimuth angle fixing is already achieved by the fir tree shape of the blade retaining groove 30. Further, the seal plate 40 prevents leakage of cooling air introduced into the blade root 32 and the rotor blade 12 through the cooling air passage 48 and the turbine disk 36.

  2 and 3 schematically show a cross section perpendicular to the plane 49 of the prior art seal plate 40 at two different stages of the manufacturing process.

  In this case, as shown in FIG. 2, the seal plate 40 is a first casting having a specific size. In this case, a vacuum buried casting process is usually used, and the seal plate 40 is compressed by a hot isostatic press to remove pores after casting. Then, the machining finish is executed so that the seal plate 40 has a finished outer shape as shown in FIG.

  Such a manufacturing process is relatively time consuming and expensive. Therefore, in order to simplify the manufacturing process of the seal plate 40, the seal plate 40 can be made from a number of metal sheets 50 as shown in FIG.

  In the case of the seal plate 40 according to FIG. 4, it is initially provided with two metal sheets 50 spaced apart in parallel to the flat surface 49 of the seal plate, between which an intermediate metal sheet 52 is introduced. Therefore, a three-layer structure of the seal plate 40 is formed as a whole. On the side facing the center of the rotor disk, the metal sheet 50 includes a bent portion 54 that simulates the conventional casting shape of the seal plate 40. The intermediate metal sheet 52 has a number of cutouts 56 shown in a top view in FIG. As a result, the cooling air K can be supplied through the cooling air hole 58, and the seal plate 40 can be actively cooled.

  Further, the seal plate 40 includes a metal sheet 50 that faces the flat surface 49 of the seal plate and forms the seal blades 46. In this case, a further supporting metal sheet 60 is provided to stabilize the sealing blades. The cooling air holes 58 are directed to the discharge side so that the cooling air K discharged from the seal plate 40 flows over the seal blades 46 and adjacent additional components and also cools them.

  The individual metal sheets 50 are welded together and allow a particularly simple structure of the seal plate 40. Alternatively, the metal sheet 50 can also be soldered at high temperatures.

  The seal plate 40 is again shown in top view in FIG. In this case, the intermediate metal sheet 52 is moved circumferentially with respect to the two metal sheets 50 oriented in parallel, so that a groove 64 is formed at one end 62 of the seal plate 40 and at the opposite end 66. A convex portion 68 is formed. As a result, the adjacent seal plates 40 can be sealed in the circumferential direction by a tongue and groove connection.

  A gas turbine 101 shown in FIG. 7 includes a compressor 102 for burning air, a combustion chamber 104, and a turbine device 106 for driving the compressor 102 and a generator or machine (not shown). To achieve this goal, the turbine device 106 and the compressor 102 are located on a common turbine shaft 108, also referred to as a turbine rotor, to which a generator or machine is also connected, the turbine rotor being rotatable about a central axis 109. Is attached. Combustion chamber 104 configured in the shape of an annular combustion chamber is equipped with a number of combustors 110 for burning liquid fuel or gas fuel.

  The turbine device 106 includes a blade system 1 having a number of rotatable blades 12 connected to a turbine shaft 108. The rotor blades 12 are annularly arranged on the turbine shaft 108 and thus form multiple blade rows. In addition, the turbine device 106 also includes a number of stationary vanes 36 that are annularly fixed on the vane carrier 110 of the turbine device 106 and form a vane row. In this case, the moving blade 12 functions to drive the turbine shaft 108 by an impact transmitted from the operating medium M flowing through the turbine device 106. On the other hand, when viewed from the flow direction of the operation medium M, the stationary blade 36 serves to guide the operation medium M to flow between two continuous blade rows or blade rings. A continuous pair consisting of a ring or vane row of stationary blades 36 and a ring or blade row of moving blades 12 is also referred to herein as a turbine stage.

  Like the blades 12, each vane 36 has a blade root 118, which is arranged to secure the respective vane 36 on the vane carrier 110 of the turbine apparatus 106 as a wall element. In this case, the blade root 118 is a thermally relatively heavy component and forms the outer boundary of the hot gas path for the operating medium M flowing through the turbine unit 106.

  Between the spaced apart platforms 118 of the two adjacent vane rows of vanes 36, annular segments 121 are each arranged on the vane carrier 110 of the turbine device 106. In this case, the outer surface of each annular segment 121 is also exposed to the hot working medium M flowing through the turbine unit 106 and is radially spaced by a gap from the outer end of the rotor blade 12 located in the opposite direction. . Annular segments 121 disposed between adjacent vane rows are in this case particularly due to the hot operating medium M flowing through the turbine 106, the case inside the vane carrier 110 or other components installed in the case. Acts as a cover element to protect against excessive heat stress.

  In the exemplary embodiment, the combustion chamber 104 is designed as a so-called annular combustion chamber, with a number of combustors 110 arranged circumferentially around the turbine shaft 108 leading to a common combustion chamber space. For this reason, the combustion chamber 104 is generally designed as an annular structure disposed around the turbine shaft 108.

  The seal plate 40 of the blade system 1 made from various metal sheets 50, on the one hand, provides a particularly simple and cheap production, on the other hand, achieving a particularly high efficiency gas turbine 101 by active component cooling. can do.

DESCRIPTION OF SYMBOLS 1 Rotating blade system 6 Turbine disk 12 Rotating blade 30 Rotating blade holding groove 32 Blade root 34 Side surface 36 Stator blade 40 Seal plate 42 Groove 49 Flat surface 50 Metal sheet 52 Intermediate metal sheet 54 Bending part 56 Cutout 58 Cooling air hole 60 Support metal sheet 62 One end 64 Groove 66 Reverse end 68 Convex portion 101 Gas turbine 102 Compressor 104 Combustion chamber 106 Turbine device 108 Turbine shaft 109 Center shaft 110 Combustor 118 Blade root 121 Annular segment K Cooling air M Operating medium

Claims (9)

A seal plate (40) forming an annulus of seal plates (40) for a rotor of a gas turbine,
The seal plate is formed of a number of metal sheets (50) and comprises two metal sheets (50) spaced apart from each other and arranged in parallel to the plane (49) of the seal plate ;
Seal plate (40), characterized in that an intermediate metal sheet (52) having a number of cutouts (56) is arranged between said metal sheets (50 ). The seal plate (4) according to claim 1 , wherein each metal sheet (50) has a bend (54) on the side facing the center of the turbine disk (6) when viewed from the operating position.
0). Seal plate (40) according to claim 1 or 2 , wherein each said metal sheet (50) has a number of cooling air holes (58). The seal plate (40) according to any one of claims 1 to 3 , comprising a metal sheet (50) inclined with respect to the flat surface (49) of the seal plate. The sealing plate (40) according to any one of claims 1 to 4, wherein a number of metal sheets (50) are welded and / or soldered together. Groove (64) and / or sealing plate according to any one of the projections (68) each of said seal plate (40) of the end (62, 66) according to claim is arranged in the region of 1-5 (40). A blade system (1), in particular for a gas turbine (101),
A number of rotor blades (12) arranged annularly on a turbine disk (6);
A number of seal plates (40) are arranged on the side (34) of the turbine disk (6),
A blade system (1), characterized in that each said seal plate (40) is designed as described in any one of claims 1-6 . A gas turbine comprising a bucket system (1) according to claim 7 . A gas and steam turbine plant comprising a gas turbine (101) according to claim 8 .

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