SYSTEM WITH A RUNNING SHAFT FOR A GAS TURBINE WITH A SHAFT FOOT PROTECTION PLATE FEATURING A SEALING SECTION

Description

[0001] The present invention relates to a system with a rotor blade for a gas turbine, in particular an aircraft gas turbine, with a blade root, a blade neck adjoining the blade root in the radial direction, an airfoil adjoining the blade neck in the radial direction, a radially outer bulkhead which forms a radially inner boundary section of an annular space of a gas turbine, an axially front bulkhead and an axially rear bulkhead which are connected to the radially outer bulkhead such that the bulkheads surround the blade neck from three sides, the bulkheads projecting circumferentially beyond the blade neck, and with a blade root protection plate provided for arrangement on the blade root.

[0002] Directional terms such as "axial", "radial" and "circumferential" are generally to be understood as referring to the machine axis of the gas turbine, unless the context explicitly or implicitly indicates otherwise.

[0003] Rotor blades constructed in this way do not have a radially inner bulkhead, as is known from previous rotor blades. In the known rotor blades, a radially outer bulkhead, a radially inner bulkhead, and the axially leading and trailing bulkheads form a one-piece (integral) box shape that surrounds the blade neck, in particular protruding beyond it in the circumferential direction. For weight reasons and due to the difficulty of tool design for rotor blades with a contoured annular space, it is advantageous to omit the radially inner bulkhead. However, this gives rise to the problem that hot gas can be drawn in in the area of ​​the missing radially inner bulkhead, which can lead to undesirable heating of the rotor blade disk.

[0004] Blade root guards are known from documents FR2951494A1, US20170145841A1, and CH526716A. US20160153303A1 discloses a damper for placement in an area beneath the platforms of two adjacent blades.

[0005] The object underlying the invention is to provide a system with a rotor blade in which, on the one hand, weight can be saved, but also the sealing against the annular space carrying the hot gas can be improved.

[0006] To solve this problem, a system with a rotor blade having the features of claim 1 is proposed. Further optional and advantageous features are specified in the dependent claims.

[0007] What is proposed is a system with a rotor blade for a gas turbine, in particular an aircraft gas turbine, having a blade root, a blade neck adjoining the blade root in the radial direction, an airfoil adjoining the blade neck in the radial direction, a radially outer bulkhead which forms a radially inner boundary section of an annular space of a gas turbine, an axially front bulkhead and an axially rear bulkhead which are connected to the radially outer bulkhead so that the bulkheads surround the blade neck from three sides, wherein the bulkheads project beyond the blade neck in the circumferential direction, and having a blade root protection plate provided for arrangement on the blade root.It is provided that the blade root guard plate has at least one sealing section which extends in the axial direction from the front bulkhead to the rear bulkhead and whose radial outer side is arranged opposite the radially outer bulkhead when the blade guard plate is arranged on the blade root.

[0008] By providing a sealing section on the blade root guard, a sealing effect can be achieved that counteracts the ingress of hot gas. Since blade root guards are already commonly used, the weight increase of the blade root guard due to the additional sealing section is only slight. In any case, the mass of a sealing section on the blade root guard is significantly lower than the mass of a radially inner bulkhead.

[0009] The bulkheads and the blade throat form a pocket that is open radially downwards and the sealing section, when the blade root guard is arranged at the blade root, closes the pocket completely radially downwards.

[0010] In the assembled state of the system, the sealing section can bridge a gap formed between a projecting section of the axially forward bulkhead and a projecting section of the axially rear bulkhead.

[0011] Accordingly, the sealing section of the blade root guard covers exactly the area left free by the omitted radially inner bulkhead.

[0012] The radially outer bulkhead, the axially forward bulkhead, the axially rear bulkhead, and the sealing section of the blade root guard can form a box-like profile that surrounds the blade throat. The sealing section can be positioned with its radial outer side against the axially forward and rear bulkheads, or the distance to them can be very small to achieve the desired sealing effect.

[0013] In order to achieve an optimal sealing effect, the sealing section can have essentially the same length in the axial direction as the blade root.

[0014] The sealing section can have at least one bead, which is formed in particular along the axial direction or along the circumferential direction. The formation of at least one bead leads to a stiffening of the generally rather thin sealing section of the blade root guard plate. Thus, the stability of the sealing section can be improved by providing at least one bead. Furthermore, a bead can also be designed in such a way that an improved sealing effect is achieved.

[0015] The above-mentioned object is also achieved by a rotor blade disk with a plurality of circumferentially arranged adjacent rotor blade receptacles, into which a blade root of a respective rotor blade of the system is inserted, as described above, and with a plurality of disk lobes formed between the rotor blade receptacles. The sealing section of the blade root guard plate is arranged with its radial inner side opposite a radial outer side of a respective disk lobe. Thus, the sealing section can effectively prevent the penetration or induction of hot gas to the disk lobes.

[0016] Finally, the above object is also achieved by a gas turbine, in particular an aircraft gas turbine, with at least one such rotor blade disk. The rotor blade disk can, in particular, be part of a turbine stage of the gas turbine.

[0017] The invention is described below by way of example and not by way of limitation with reference to the accompanying figures. Fig. 1 shows a simplified schematic diagram of an aircraft gas turbine. Fig. 2 shows a simplified and schematic perspective view of a rotor blade with a blade root guard. Fig. 3 shows a sectional view approximately along section line III-III of the Fig. 2 . Fig. 4 shows a Fig. 3 similar sectional view, wherein a bead is formed in a sealing section of the blade root guard.

[0018] Fig. 1 shows a schematic and simplified representation of an aircraft gas turbine 10, which is illustrated purely by way of example as a bypass engine. The gas turbine 10 comprises a fan 12 surrounded by an indicated casing 14. In the axial direction AR of the gas turbine 10, the fan 12 is followed by a compressor 16, which is accommodated in an indicated inner casing 18 and can be of single-stage or multi-stage design. The combustion chamber 20 is connected to the compressor 16. Hot exhaust gas flowing out of the combustion chamber then flows through the adjoining turbine 22, which can be of single-stage or multi-stage design. In the present example, the turbine 22 comprises a high-pressure turbine 24 and a low-pressure turbine 26. A hollow shaft 28 connects the high-pressure turbine 24 to the compressor 16, in particular a high-pressure compressor 29, so that they are driven or rotated together.A further internal shaft 30 in the radial direction RR of the turbine connects the low-pressure turbine 26 to the fan 12 and to a low-pressure compressor 32, so that they are jointly driven and rotated. A thrust nozzle 33, only indicated here, is connected to the turbine 22.

[0019] In the illustrated example of an aircraft gas turbine 10, a turbine intermediate casing 34 is arranged between the high-pressure turbine 24 and the low-pressure turbine 26, which is arranged around the shafts 28, 30. Hot exhaust gases from the high-pressure turbine 24 flow through the turbine intermediate casing 34 in its radially outer region 36. The hot exhaust gases then enter an annular space 38 of the low-pressure turbine 26. Rotor blade rings 27 of the compressors 29, 32 and the turbines 24, 26 are shown as examples. For reasons of clarity, conventionally present guide vane rings 31 are shown as examples only for the compressor 32.

[0020] The following description of an embodiment of the invention relates in particular to the rotor blades that can be used in a rotor blade ring 27 of the compressor 16 or the turbine 22.

[0021] Fig. 2 shows a simplified and schematic perspective view of a rotor blade 40 for a system according to the invention. The rotor blade 40 comprises a blade root 42. The blade root 42 is designed here, for example, with a so-called fir-tree profile. In the radial direction RR, a blade neck 44 adjoins the blade root 42. The blade neck 44 merges into the blade airfoil 46.

[0022] The rotor blade 40 further comprises a radially outer bulkhead 48, which is arranged between the blade airfoil 46 and the blade neck 44. The radial outer side 50 of the bulkhead 48 forms part of an annular space of a gas turbine when the rotor blade 40 is installed as intended in a gas turbine. The rotor blade 40 further comprises an axially forward bulkhead 52 and an axially rearward bulkhead 54. The axially forward bulkhead 52 and the axially rearward bulkhead 54 are connected to the radially outer bulkhead 48, in particular are formed integrally. As can be seen from the Fig. 2 As can be seen, the bulkheads 48, 52, 54 surround the blade neck 44 on three sides. A forward shroud section 56 or a rear shroud section 58 can be connected to the respective bulkhead 52, 54.

[0023] A blade root guard 60 is arranged along the blade root 42, in particular along its outer contour. The blade root guard 60 comprises a sealing section 62 on the radial outside. The sealing section 62 extends in the axial direction AR from the front bulkhead 52 to the rear bulkhead 54. In particular, the sealing section 62 bridges an intermediate space ZR formed between the front bulkhead 52 and the rear bulkhead 54. In particular, the sealing section is dimensioned such that it bridges the intermediate space ZR formed between a projecting section 52a of the axially front bulkhead 52 and a projecting section 54a of the axially rear bulkhead 54. The sections 52a, 52 protrude beyond the blade neck 44 in the circumferential direction UR. A radial outer side 62a of the sealing section 62 is arranged opposite the radially outer bulkhead 48 in the radial direction RR.

[0024] Fig. 3 shows a simplified and schematic sectional view, which corresponds approximately to the section line III-III of the Fig. 2 corresponds to the blade root 42, which is received in a blade root receptacle 64 of a rotor blade disk 66. The rotor blade disk 66 typically comprises a plurality of rotor blades 40 arranged next to one another in the circumferential direction UR. A respective blade root 42 is received between two adjacent disk humps 68 of the rotor blade disk 66.

[0025] From the Fig. 3 Also visible is the blade root guard 60, which is shown in simplified form as a thick black line. The blade root guard 60 encompasses the sealing section 62 radially outward. The sealing section 62 is arranged opposite a respective radial outer surface 70 of a respective disk hump 68. In particular, the sealing section 62 at least partially covers the respective disk hump 68. A portion of the rear bulkhead 54 is also visible in the axial direction.

[0026] From the overview of the Fig. 2 and 3It can be seen that the bulkheads 48, 52, 56, together with the sealing section 62, form a type of box-shaped profile that surrounds or encloses the blade neck 44. The sealing section 62 can have an axial length that essentially corresponds to the axial length of the blade root 42. In other words, it can also be said that the bulkheads (48, 52, 54) and the blade neck (44) form a pocket that is open radially downwards, and the sealing section (62), when the blade root guard (60) is arranged on the blade root (42), completely closes the pocket radially downwards.

[0027] Fig. 4 shows a Fig. 3 similar sectional view. Therefore, Fig. 4 also the same reference numerals as in Fig. 3 presented, even if these are related to the Fig. 4 not be written again. Fig. 4 shows an exemplary embodiment in which a bead 72 running along the axial direction is formed in the sealing section 62. Not just one bead 72 can be formed in the sealing section 62. It is also conceivable that, for example, several beads running parallel or transverse to one another are formed. In particular, several beads running in the circumferential direction UR can also be provided, which are arranged essentially parallel to one another along the axial direction and adjacent to one another. The formation of one or more bead(s) 72 serves in particular to stiffen and stabilize the sealing section 62, which, as part of the blade root guard plate 60, is made of a relatively thin sheet material. Bezugszeichenliste

[0028] 10 Aircraft gas turbine 12 Fan 14 Shroud 16 Compressor 18 Inner casing 20 Combustion chamber 22 Turbine 24 High-pressure turbine 26 Low-pressure turbine 27 Blade ring 28 Hollow shaft 29 High-pressure compressor 30 Shaft 31 Guide vane ring 32 Low-pressure compressor 33 Exhaust nozzle 34 Turbine center casing 36 Radial outer area 38 Annulus 40 Blade 42 Blade root 44 Blade throat 46 Blade 48 Radial outer bulkhead 50 Radial outer side of the bulkhead 52 Axial forward bulkhead 52a Projecting section 54 Axial rear bulkhead 54a Projecting section 56 Forward shroud section 58 Rear shroud section 60 Blade root guard 62 Sealing section 62a Radial outer side 64Blade root support 66Blade disc 68Disc hump 70Radial outer surface of the disc hump 72Bead

Claims

1. System comprising a rotor blade (40) for a gas turbine (10), in particular an aircraft gas turbine, comprising a blade root (42), a blade neck (44) adjoining the blade root (42) in the radial direction (RR), an airfoil (46) adjoining the blade neck (44) in the radial direction (RR), a radially outer bulkhead wall (48) for forming a radially inner delimitation portion (50) of an annular space of a gas turbine (10), an axially leading bulkhead wall (52) and an axially trailing bulkhead wall (54) which are connected to the radially outer bulkhead wall (48) such that the bulkhead walls (48, 52, 54) enclose the blade neck (44) from three sides, wherein the bulkhead walls (48, 52, 54) project beyond the blade neck (44) in the circumferential direction (UR), and comprising a blade root protective plate (60) provided for arrangement on the blade root (42), wherein the blade root protective plate (60) has at least one sealing portion (62) which extends in the axial direction (AR) from the leading bulkhead wall (52) to the trailing bulkhead wall (54) and the radially outer side (62a) thereof is arranged opposite the radially outer bulkhead wall (48) when the blade root protective plate (60) is arranged on the blade root (42), wherein the bulkhead walls (48, 52, 54) and the blade neck (44) form a pocket which is open radially at the bottom, i.e. radially inwards, characterized in that the sealing portion (62) completely closes the pocket radially at the bottom when the blade root protective plate (60) is arranged on the blade root (42).

2. System according to claim 1, characterized in that, in the assembled state of the system, the sealing portion (62) bridges a gap (ZR) which is formed between a projecting portion (52a) of the axially leading bulkhead wall (52) and a projecting portion (54a) of the axially trailing bulkhead wall (54).

3. System according to any of the preceding claims, characterized in that the radially outer bulkhead wall (48), the axially leading bulkhead wall (52), the axially trailing bulkhead wall (54) and the sealing portion (62) of the blade root protective plate (60) form a box-like profile which encloses the blade neck (44).

4. System according to any of the preceding claims, characterized in that, in the axial direction (AR), the sealing portion (62) is substantially the same length as the blade root (42).

5. System according to any of the preceding claims, characterized in that the sealing portion (62) has at least one bead (72) which is formed in particular in the axial direction (AR) or in the circumferential direction (UR).

6. Rotor blade disk (66) comprising a plurality of systems according to any of the preceding claims, comprising a plurality of rotor blade receptacles (64) arranged next to one another in the circumferential direction, into which a blade root (42) of a corresponding rotor blade (40) of the system according to any of the preceding claims is inserted, and comprising a plurality of disk humps (68) formed between the rotor blade receptacles (64), wherein the sealing portion (62) of the blade root protective plate (60) is arranged with its radially inner side opposite a radially outer side (70) of a corresponding disk hump (68).

7. Gas turbine, in particular aircraft gas turbine (10) comprising at least one rotor blade disk (66) according to claim 6, wherein the rotor blade disk is in particular part of a turbine stage of the gas turbine.