Rotor blade assembly comprising a ring segment shaped or disc segment shaped blade carrier and a radially inner reinforcement structure

Abstract

A rotor blade assembly group for an engine with at least one blade carrier having at least one rotor blade that is provided with multiple rotor blades along a circle line about a central axis of the rotor blade assembly group, wherein the blade carrier has a carrier section that extends radially inwards in the direction of the central axis with respect to the rotor blade, the carrier section comprises a connection area at which a stiffening structure with at least two, first and second, stiffening elements is fixedly attached, and the stiffening element is arranged at a first face side of the blade carrier, and the second stiffening element is arranged at a second face side that is facing away from the first face side. The blade carrier is formed in a ring-segment-shaped or disc-segment-shaped-manner.

Claims

1. A rotor blade assembly group for an engine, comprising: a blade carrier including a plurality of rotor blades that are provided along a first circle line about a central axis of the rotor blade assembly group, the blade carrier including a carrier section that extends radially inward in a direction toward the central axis with respect to the plurality of rotor blades, the carrier section comprising a connection area positioned at a radially innermost portion of the carrier section farthest from the plurality of rotor blades, at least one stiffening ring fixedly attached at the connection area of the carrier section, the at least one stiffening ring being arranged at a first or a second face side of the blade carrier, the blade carrier being formed in a ring-segment-shaped or a disc-segment-shaped manner, the connection area of the carrier section including a profile that includes at least one axial projection, with the profile having a T-shaped, I-shaped, or fir tree shaped cross-section, the at least one stiffening ring engaging around the profile in a form-fit manner, such that the at least one axial projection is received at least partially between a radially outer section and a radially inner section of the at least one stiffening ring, and a sleeve-shaped connection component for connecting the blade carrier to at least one other adjacent blade carrier via a bolt connection element, and such that the bolt connection element connects the sleeve-shaped connection component and an extension of the at least one stiffening ring to the blade carrier, wherein the blade carrier includes a passage hole that extends axially with respect to the central axis and that is radially delimited by a radially innermost edge of the carrier section, and a portion of the radially inner section of the at least one stiffening ring axially extends radially inwardly of the radially innermost edge of the carrier section and is positioned directly radially between the central axis and the radially innermost edge of the carrier section.

2. The rotor blade assembly group according to claim 1, wherein: the at least one stiffening ring includes a first stiffening ring and a second stiffening ring, the first stiffening ring and the second stiffening ring fixedly attached at the connection area of the carrier section, the first stiffening ring is arranged at the first face side of the blade carrier and the second stiffening ring is arranged at the second face side of the blade carrier, such that the second face side is facing away from the first face side, and the first and second stiffening rings are connected to the connection area of the carrier section and in addition are connected to each other.

3. The rotor blade assembly group according to claim 2, wherein at least one of the first stiffening ring and the second stiffening ring is made of a metal matrix composite.

4. The rotor blade assembly group according to claim 2, wherein at least one of the first stiffening ring and the second stiffening ring includes an internal core made of a metal matrix composite.

5. The rotor blade assembly group according to claim 4, wherein the at least one stiffening ring that includes the internal core made of the metal matrix composite is configured such that the internal core made of the metal matrix composite axially extends radially inwardly of the radially innermost edge of the carrier section and is positioned directly radially between the central axis and the radially innermost edge of the carrier section.

6. The rotor blade assembly group according to claim 1, wherein the profile of the connection area of the carrier section that has the T-shaped, I-shaped, or fir tree shaped cross-section extends along a second circle line about the central axis of the rotor blade assembly group at least in certain sections.

7. A gas turbine engine with at least one rotor blade assembly group according to claim 5.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying Figures illustrate possible embodiment variants of the invention by way of example.

(2) FIG. 1 shows, by sections and in a sectional rendering, a part of a turbine of a gas turbine engine with two embodiment variants of a rotor blade assembly group according to the invention.

(3) FIG. 2 shows an enlarged detailed view of a connection area of a blade carrier of the rotor blade assembly group with a stiffening structure fixated thereat as well as a connection to two front and rear rotor blade assembly groups that are respectively arranged in an axially offset manner.

(4) FIG. 3 shows a schematic front view of the rotor blade assembly group.

(5) FIGS. 4A-4D show, in enlarged rendering and by sections, a connection area of a blade carrier with different variants of stiffening structures with MMC stiffening rings that are arranged thereat.

(6) FIGS. 5A-5B show, by sections and in a sectioned perspective view, embodiment variants of a blade carrier of a rotor blade assembly group according to the invention with a firtree-shaped profile of the connection area, wherein, on the one hand, the blade carrier has rotor blades formed integrally therewith (FIG. 5A) and, on the other hand, is provided for separately manufactured rotor blades which are to be fixated thereat (FIG. 5B).

(7) FIG. 6 shows, in a sectioned and enlarged view, a variant on a connection area of the blade carrier with a firtree-shaped profile.

(8) FIG. 7 shows, by sections and in sectioned rendering, an embodiment of rotor blade rows of a turbine of a gas turbine engine as it is known from the state of the art.

(9) FIG. 8 shows a cross sectional view of a turbine engine in which one embodiment variant of a rotor blade assembly group according to the invention is used in the area of a compressor and/or in the area of a turbine.

DETAILED DESCRIPTION

(10) FIG. 8 schematically illustrates, in a sectional rendering, a gas turbine engine T in which the individual engine components are arranged in succession along a rotational axis or central axis M, and in which the engine T is formed as a turbofan engine. By means of a fan F, air is suctioned in along an entry direction E at an inlet or an intake E of the engine T. This fan F, which is arranged inside a fan housing, is driven via a rotor shaft S that is set into rotation by a turbine TT of the engine T. Here, the turbine TT connects to a compressor V, which for example has a low-pressure compressor 11 and a high-pressure compressor 12, and where necessary also a medium-pressure compressor. The fan F supplies air to the compressor V, on the one hand, and, on the other hand, to a secondary flow channel or bypass channel B for generating the thrust. Here, the bypass channel B extends about a core engine that comprises the compressor V and the turbine TT, and also comprises a primary flow channel for the air that is supplied to the core engine by the fan F.

(11) The air that is conveyed via the compressor V into the primary flow channel is transported into the combustion chamber section BK of the core engine where the driving power for driving the turbine TT is generated. For this purpose, the turbine TT has a high-pressure turbine 13, a medium-pressure turbine 14, and a low-pressure turbine 15. The turbine TT drives the rotor shaft S and thus the fan F by means of the energy that is released during combustion in order to generate the necessary thrust by means of the air that is conveyed into the bypass channel B. The air from the bypass channel B as well as the exhaust gases from the primary flow channel of the core engine are discharged via an outlet A at the end of the engine T. Here, the outlet A usually has a thrust nozzle with a centrally arranged outlet cone C.

(12) As is known, rotor blade assembly groups which rotate about the central axis M and respectively have one rotor blade row and in which the rotor blades are provided at a ring-shaped or disc-shaped blade carrier, are used in the area of the (axial) compressor with its low-pressure compressor 11 and its high-pressure compressor 12 as well as in the area of the turbine TT. In principle, the ring-shaped or disc-shaped blade carrier can be integrally bladed, and can thus be manufactured in Bling or Blisk design. Alternatively, it is possible to fixate individual rotor blades at a ring-shaped or disc-shaped blade carrier via their respective blade roots. For this purpose, a blade root may for example be axially inserted into a fastening groove of the blade carrier and axially secured at the respective blade carrier.

(13) By way of example, FIG. 7 illustrates multiple rotor blade assembly groups 2a, 2b and 2c of the turbine TT arranged behind each other along the central axis M. Here, the section that is shown in FIG. 5 depicts only a part above the central axis M in the area of the medium-pressure turbine 14 or the low-pressure turbine 15. The individual rotor blade assembly groups 2a, 2b and 2c are connected to each other in a torque-proof manner via flange connections 4.1 and 4.2. Further, each rotor blade assembly group 2a, 2b and 2c has respectively one ring-shaped or disc-shaped blade carrier 23, 24 or 25, at which individual rotor blades 20, 21 or 22 of a blade row are arranged behind each other along a circle line about the central axis M, and are fixated at the respective blade carrier 23, 24 or 25 via a blade root 200, 210 or 220 of a rotor blade 20, 21 or 22. In the axial direction along the central axis M, rotor blade rows of the rotor blade assembly groups 2a, 2b and 2c alternate with stationary guide vane rows. The guide vane rows respectively have guide vanes 30 or 31 that are also arranged along the entire circumference on a circle line extending about the central axis M.

(14) Due to the rotational speeds and the resulting loads, each blade carrier 23, 24 or 25 of a rotor blade assembly group 2a, 2b or 2c of the state of the art has a radially inwardly extending carrier section 230, 240 or 250. A disc-shaped carrier section 250 of the rear rotor blade assembly group 2c for example serves for the rotatable mounting of the rotor blade assembly groups 2a, 2b and 2c that are connected to one another in a torque-proof manner. In the carrier section 230, 240 of two (with respect to the flow direction through the engine T) frontal rotor blade assembly groups 2a and 2b, a central passage hole O1 or O2 is provided mainly for the purpose of weight reduction, for example in the form of a bore. With view to the necessary installation space of the rotor blade assembly groups 2a and 2b as well as their weight, it is primarily important which radial extension the blade carriers 23 and 24 have in order to be able to withstand the loads that occur during operation.

(15) In the different variants of a solution according to the invention, which are for example illustrated in FIG. 1 by way of example based on two rotor blade assembly groups 2a and 2b of the turbine TT, a considerable size reduction of the radially extending carrier sections 230 or 240 is achieved by providing a stiffening structure 5a or 5b. Each of the stiffening structures 5a or 5b has two ring-shaped stiffening elements in the form of (MMC) stiffening rings 50 and 51 that are arranged opposite each other at the face sides of the respective blade carrier 23 or 24. On the one hand, the stiffening rings 50 and 51 are directly connected to each other, preferably by means of at least one additional connection element. On the other hand, both stiffening rings 50, 51 respectively enclose one connection area 231 or 241 of the respective carrier section 230 or 240 in a form-fit manner at least in certain sections, with the carrier section 230 or 240 having a continuous profile in the circumferential direction that comprises at least two projections axially extending in opposite directions. Here, the connection area 231, 241 is respectively provided a firtree-shaped (cross sectional) profile. FIGS. 4C and 4D respectively show I-shaped and T-shaped cross-sectional profiles.

(16) The two stiffening rings 50 and 51 of a rotor blade assembly group 2a or 2b that are arranged on face sides of a blade carrier 23 or 24 that are facing away from each other are connected to each other by means of respectively one connection appliance 6a or 6b and in the present case are fixated at each other as well as at the carrier section 230 or 240. At that, the respective connection appliance 6a or 6b comprises at least one separate connection element in the form of a stud bolt 60. This stud bolt 60 is provided, among other positions, above the respective connection area 231, 241 for the stiffening structure 5a or 5b. A nut 61 is screwed onto the stud bolt 60 for axial fixation. At that, the stud bolt 60 extends above the respective connection area 231, 241, among other positions respectively through a connection opening that is formed in an edge-side, radially protruding connecting web 50a or 50b of a stiffening ring 50 or 51, as well as through a connection opening 233 or 243 in the carrier section 230, 240.

(17) Further, also a fixation of at least one connection components 7a, 7b at a blade carrier 23, 24 is realized by means of a stud bolt 60. In this manner, the individual rotor blade assembly groups 2a, 2b and 2c are connected to each other in a torque-proof manner via multiple sleeve-shaped connection components 7a, 7b. The rotor blade assembly groups 2a and 2b that are provided according to the invention with respectively one stiffening structure 5a, 5b are connected to each other in a torque-proof manner via a first sleeve-shaped connection component 7a, while the rotor blade assembly group 2b is connected in a torque-proof manner to the rear rotor blade assembly group 2c via a further, second sleeve-shaped connection component 7b. At their face sides, each of the sleeve-shaped connection components 7a, 7b has a ring-shaped flange section 70a, 70b. In the circumferential direction, this flange section 70a or 70b has multiple connection openings for fixation at the rotor blade assembly groups 2a, 2b and 2c which are arranged next to each other.

(18) In the present case, it is provided with a view to a simplified mounting process and additional weight reduction as well as a more compact structure, that the connection components 7a and 7b at a rotor blade assembly group 2a or 2b are additionally fixated at the blade carriers 23 and 24 by means of a connection appliance 6a and 6b, via which the stiffening rings 5a and 5b are also fixated at each other and at the respective blade carrier 23 or 24. A single stud bolt 60 thus extends through the connection openings of the flange sections 70a, 70b and the stiffening rings 50, 51 as well as through a connection opening 233 or 243 of the respective blade carrier 23 or 24.

(19) As can also be seen in the enlarged rendering of FIG. 2, the connecting webs 50a and 50b of the stiffening rings 50 and 51 are thus fixated in a sandwiched manner between the flange sections 70a and 70b. Likewise, a part of the carrier section of the respective blade carriershown as the carrier 240 of the blade carrier 24 in FIG. 2 by way of exampleis arranged in a sandwiched manner between the connecting webs 50a and 50b.

(20) At the circumferential side, the stiffening rings 50 and 51 are fixated at multiple positions by means of respectively one connection appliance 6a or 6b to at least one stud bolt 60 at blade carriers 23, 24 of different, respectively ring-segment-shaped or disc-segment-shaped design, wherein at least one sleeve-shaped connection component 7a, 7b is in turn fixated at these stiffening rings 50, 51 by means of the same stud bolt 60. This is schematically illustrated particularly in the front view of FIG. 3.

(21) The rotor blade assembly group 2b, which is illustrated only schematically and by way of example in FIG. 3, has multiple respectively ring-segment-shaped or disc-segment-shaped blade carriers 24 with at least one rotor blade 21, in the present case three rotor blades 21 along a circumferential direction about the central axis M, so that the individual blade carriers 24 defined a circumferentially extending rotor blade row. In that case, the individual ring-segment-shaped or disc-segment-shaped blade carriers 24 are stiffened through respectively two stiffening rings 50 and 51 that are arranged at different face sides, and fixated relative to each other by means of the stud bolts 60 as well as in addition at the same time connected to at least one connection component 7a or 7b, via which in turn a torque-proof connection to a further rotor blade assembly group 2a or 2c is realized.

(22) As is illustrated based on FIGS. 4A and 4B for different variants of the stiffening structures 5a, 5b, each stiffening ring 50, 51 of the respective stiffening structure 5a or 5b has a coated MMC core 500, for example a TiMMC core. By manufacturing the stiffening rings 50 and 51 in MMC design, a considerably increased stiffness of the blade carriers 23 or 24 is achieved, while at the same time they have a comparatively low weight. Here, a stiffening ring 50 or 51 extends with a enclosing section 50.1 or 51.2 axially below an edge of the connection area 231 or 241 that is facing towards the respective passage hole O1 or O2 in the direction of the other face side. Thus, each stiffening ring 50 or 51 at least partially encloses a radially internal edge of the respective blade carrier 23 or 24 in an L-shaped manner. In this manner, in particular the radial securing of the respective stiffening ring 50, 51 at the carrier section 230 or 240 is facilitated, and also a support of the blade carrier 23, 24 below of the connection area 231, 241 is achieved.

(23) In the present case, both stiffening rings 50 and 51 extend so far axially below the inner edge of the carrier section 231 or 241 of the blade carrier 23 or 24 with respectively one enclosing section 50.1 or 51.2, that the stiffening rings 50 and 51 directly adjoin each other with their enclosing sections 50.1 and 51.2. Consequently, the stiffening rings 50 and 51 that are provided on both sides of the connection area 231 or 241 and that are respectively supported at the respective connection area 231 or 241 in a form-fit manner directly abut each other, and the stiffening structure 5a or 5b thus created extends completely through the passage hole O1 or O2.

(24) The stiffening structure 5a or 5b with the stiffening rings 50 and 51, which are arranged at face sides of the blade carrier 23 or 24 that are facing away from each other, mainly receives radially acting forces. But at the same time, a simpler mounting as well as a simpler radial securing of the stiffening rings 50 and 51 to be mounted at the blade carrier 23 or 24 is facilitated as a result of the circumferentially extending profile of the connection area 231 or 241.

(25) In a firtree-shaped cross sectional profile according to the variants of FIGS. 4A and 4B, the connection area 231, which is shown here by way of example, forms pairs of projections 2410.1/2410.2, 2411.1/2411.2 and 2412.1/2412.2 which axially extend in opposite directions. Each of these axial projections 2410.1 to 2412.2 protrudes in a ring-shaped manner at a face side of the carrier section 240. For forming the firtree-shaped profile, the axial length of the individual axial projections 2410.1 to 2412.1 or 2410.2 to 2412.2 decreases on each face side in the radial direction, in the present case radially inwards. Accordingly, a pair of axial projections 2412.1/2412.2, that is located closest to the passage hole O1, has the smallest axial extension, and the pairs of axial projections 2411.1/2411.2 and 2410.1/2410.2 that are arranged further radially outwardly respectively protrude further axially.

(26) Provided at the individual stiffening rings 50 and 51 are grooves corresponding to the projections 2410.1 to 2312.1 or 2410.2 to 2412.2 of a face side, so that the stiffening ring 50 or 51 that is respectively attached at a face side encloses each projection 2410.1 to 2412.1 or 2410.2 to 2412.2 at the respective face side in a form-fit manner, and accordingly each projection 2410.1 to 2412.2 is respectively received between a radially further internally and a radially further externally positioned section of the respective stiffening ring 50 or 51. Through a form-fit connection between the blade carrier 24 and the stiffening rings 50 and 51 that is thus formed, radial loads as they occur during operation of the engine T are introduced into the stiffening structure 5a in a manner distributed across the firtree-shaped profile. In addition, the stiffening structure 5a is thus radially fixated at the carrier section 240 of the blade carrier 24 already by plugging on the stiffening rings 50, 51, without any additional fastening means.

(27) In the embodiment variant of FIG. 4B, it is further provided that the MMC core 500 of a stiffening ring 50 or 51 extends below the inner edge of the carrier section 240 with at least one section 500.1 or 500.2 made of the metal matrix composite. Here, the MMC core has a substantially L-shaped cross section. In the variant of FIG. 2A, the MMC core 500 is thus arranged only axially next to the connection area 241 and in particular next to the projections 2410.1 to 2412.2. In contrast to that, in the variant of FIG. 2B, the MMC core 500 is arranged axially next to the connection area 241 and at least partially below the connection area 241, and accordingly in particular next to the projections 2410.1 to 2412.2 and at least partially below the projections 2410.1 to 2412.2.

(28) In FIGS. 5A and 5B, two different variants of the blade carrier 23, 24 of the rotor blade assembly group 2a or 2b are illustrated. In both variants, the blade carrier 23, 24 has a firtree-shaped cross sectional profile extending in the circumferential direction at the connection area 231 or 243 for the stiffening structure 5a or 5b and its stiffening rings 50 and 51 that are to be attached thereto. While in the variant of FIG. 5A, the ring segment-shaped or disc-segment-shaped blade carrier 23, 24 is embodied with rotor blades 20, 21 that are formed integrally thereat, the blade carrier 23, 24 of FIG. 5B has multiple fastening grooves 232, 242 arranged circumferentially next to each other for blade roots 200, 210 of the rotor blades 20, 21 that are to be fixated thereat.

(29) Regarding a firtree-shaped profile of the connection area 241 of a blade carrier 24, it is further illustrated by way of example based on the cross sectional rendering of FIG. 6 which constructional parameters can be used, where necessary, to influence the connection between the blade carrier 24 and the stiffening rings 50, 51, and thus the force transmission into the stiffening structure 5b. For instance, in the present case, a radius Ra for a transitional area between a radially extending face surface of the carrier section 240 and a radially outermost projection 2410.1 of a face side is shown, based on the size of which the degree of concavity of the transitional area is influenced.

(30) A geometry of the firtree-shaped profile can further be characterized by an angle taken by two tangents with respect to each other, which are respectively applied in across the sectional view along the central axis M at the ends of the axial projections 2410.1 to 2412.1 or 2410.2 to 2412.2 of a face side. The larger the angle , the larger the axial extension of the firtree-shaped profile and/or the larger the gradation in the axial extension between the projections 2410.1 to 2412.1 or 2410.2 to 2412.2 that are provided at a face side.

PARTS LIST

(31) 11 low-pressure compressor 12 high-pressure compressor 13 high-pressure turbine 14 medium-pressure turbine 15 low-pressure turbine 20, 21, 22 rotor blade 200, 210, 220 blade root 23, 24, 25 blade carrier 230, 240, 250 carrier section 231 connection area 232, 242 connection groove 233, 243 connection opening 241 connection area 2410.1, 2410.2, axial projection 2411.1, 2411.2, 2412.1, 2412.2 2a, 2b, 2c rotor blade assembly group 30, 31 guide vane 4.1, 4.2 flange connection 50, 51 stiffening ring (stiffening element) 50.1, 51.2 enclosing section 500 MMC core 500.1, 500.2, MMC section 50a, 50b connecting web 5a, 5b stiffening structure 60 stud bolt 61 nut 6a, 6b connection appliance 70a, 70b flange section 7a, 7b connection component (sleeve-shaped/sleeve-segment-shaped) A outlet B bypass channel BK combustion chamber section C outlet cone E inlet/intake F fan FC fan housing M central axis/rotational axis O1, O2 passage hole R entry direction Ra radius S rotor shaft T turbine engine (gas turbine engine) TT turbine V compressor angle