TURBINE SHELL TIP, TURBINE SHELL AND METHOD

Description

[0001] The invention relates to an improved design of a turbine blade tip and manufacturing methods for it.

[0002] Turbine blades of gas turbines or turbines that are subject to high temperature stress have cooling structures inside and, if necessary, cooling holes on the outer wall of the blade, from which cooling air flows out from the inside of the turbine blade.

[0003] These blade tips often have a circumferential wall at their radial end, which runs along the outer contour of the blade and thus forms a depression in between.

[0004] US 2019 / 170000 A1 discloses a turbine blade tip comprising at least: a wall circumferentially on a surface along an outer contour of a blade, forming a recess in between the wall, wherein a channel is provided in the wall, wherein the channel within the wall can be supplied with cooling air via at least one air supply channel of the turbine blade, wherein several cooling air holes are provided which are arranged in the wall and are fluidically connected to the channel and allow the cooling air to flow out of the radial end of the wall.

[0005] Documents EP 3 428 397 A1, US 2019 / 153873 A1, WO 2019 / 177600 A1 and US 9 816 389 B2 also show cooling of turbine blade tips.

[0006] The purpose of the invention is to improve the cooling of such a turbine blade tip.

[0007] The problem is solved by a blade tip according to claim 1, a turbine blade according to claim 5 and a method according to claim 7.

[0008] The dependent claims list further advantageous measures which can be combined arbitrarily to achieve further advantages.

[0009] The show Figures 1 to 6 The invention is shown schematically.

[0010] The description and figures represent only exemplary embodiments of the invention, which can also be combined with each other as desired to achieve further advantages.

[0011] Figure 1 shows a top view of a turbine blade tip 3 of a turbine blade 1.

[0012] Visible are a leading edge 7 and a trailing edge 10 of a blade 4 of the turbine blade 1.

[0013] The tip of the shovel 3 has a wall 19 that runs along the outer contour of the blade 4.

[0014] The wall 19 runs on a preferably flat or level surface 28 of the turbine blade 1.

[0015] Viewed in the radial direction 14 (installation direction of the turbine blade 1 in the turbine), the wall 19 preferably has the same thickness at every point.

[0016] Preferably, the wall 19 has the same height everywhere when viewed from the surface 28.

[0017] Such profiles and geometries of wall 19 are known from the prior art.

[0018] Within a recess 20 formed by the wall 19, preferably at least one, and in particular at least two, cooling air holes 18 are provided in the base body of the turbine blade 1, from which cooling air flows out of the surface 28. Preferably, there are two or three cooling air holes 18. The cooling air holes 18 are preferably arranged near the leading edge 7 and in the longitudinal direction (i.e., from the leading edge 7 towards the trailing edge 10) or flow direction around the turbine blade 1, preferably in front of an inlet housing 22 when viewed in operation.

[0019] In the case of multiple cooling air holes 18, these are preferably arranged one behind the other in the longitudinal direction of the turbine blade 1.

[0020] Within the recess 20 there is an inlet housing 22, which supplies air channels 32 ( Fig. 4 , 5 ) from the interior 35 of the turbine blade 1, so that cooling air can be introduced into a channel 40 of the wall 19 ( Figure 5 ).

[0021] In particular, there are at least three supply air ducts 32. Preferably, there is only one duct 40 in the wall 19. The inlet housing 22 is arranged on the surface 28 within the recess 20 and is directly adjacent to the wall 19.

[0022] This inlet housing 22 is preferably formed on the suction side 13, which is opposite the pressure side 16. The inlet housing 22 is not as high as the wall 19. The inlet housing 22 is designed to be just long enough to cover the supply air ducts 32 ( Fig. 5 ).

[0023] Viewed longitudinally, the inlet housing 22 is preferably located behind the last cooling air hole 18.

[0024] Figure 2 shows a top view of the turbine blade tip 3. The wall 19 has, on the suction side 13, on its outermost surface 21, outlets of several cooling holes 25, in particular ten, from which cooling air from the channel 40 ( Fig. 5, 6) of wall 19 flows outwards through wall 19.

[0025] The cooling holes 25 are arranged one behind the other in the longitudinal direction of the turbine blade tip 3 and preferably offset from each other.

[0026] There are preferably at least three of these cooling holes (25), and more preferably at least five.

[0027] The cooling air supply to the cooling holes 25 is provided via a cooling air duct 40 ( Fig. 5, 6 ), in particular only through the single cooling air duct 40.

[0028] On the printed side 16, there are preferably no holes formed in the wall 19.

[0029] Figure 3 shows an exemplary starting situation in the manufacture of such a turbine blade tip 3.

[0030] The turbine blade 1 is manufactured with a preferably flat or planar surface 28, or is provided or reconditioned after use, which preferably already has the cooling air holes 18 arranged within the area of ​​the recess 20, as well as further, in particular five, air supply channels 32, from which cooling air from the interior 35 ( Fig. 4 , 5 ) the turbine blade 1 can flow into the channel 40 inside the wall 19.

[0031] Such a turbine blade 1 can already be manufactured or repaired according to Figure 3 The cooling air holes 18 are newly introduced, are already present, or are partially closed because the cooling of the blade tip 3 has been improved. This applies in particular to the last cooling air hole 18 viewed in the direction of airflow.

[0032] Likewise, the entire turbine blade 1 with blade tip 3 can be completely manufactured together in an additive manufacturing process.

[0033] Likewise, the blade tip 3 can be applied to the surface 28 using SLM, SLS, cladding or any other additive manufacturing process.

[0034] It is also possible to manufacture the shovel tip 3 separately ( Fig. 6 ) and with the turbine blade 1 according to Figure 3 to connect.

[0035] Figure 4 shows a section according to Figure 3 with the surface 28 and the supply air channels 32, which are supplied via the interior 35, in particular from a deflection channel (the interior 35), within the turbine blade 1.

[0036] The supply air ducts 32 preferably run at an angle α of 90° > α > 0°, in particular 80° ≥ α ≥ 5° to the radial direction 14.

[0037] Figure 5shows a section through a structure according to the invention of a shovel tip 3.

[0038] The shovel tip 3 can include part of the interior 35 or may only be formed from surface 28 onwards ( Fig. 6 ).

[0039] The suction side 13 and pressure side 16 and an inner 35 or deflection channel 35 of an internal cooling structure of the turbine blade 1 in the blade 4 can be identified.

[0040] The wall 19 has a channel 40 in its cross-section on the inside, into which cooling air from the supply air channels 32 flows. The channel 40 then distributes the cooling air to the outside via the preferably ten cooling air holes 25.

[0041] Preferably, all the cooling air for the wall 19 flows from preferably all supply air ducts 32 into the preferably single duct 40 and then preferably through all cooling holes 25 through the wall 19 to the outside.

[0042] Channel 40 has a triangular cross-section, which is rounded at the upper end. As a result, channel 40 has a greater width at the level of surface 28 than at its radial end in the radial direction 14.

[0043] The channel 40 is preferably wider than the diameter of the supply air channels at the level of the surface 28.

[0044] The channel 40 is therefore limited in cross-section by the surface 28 of the turbine blade 1 and the wall 19 and is also formed by the inlet casing 22.

[0045] The opposite part of the wall 19 on the pressure side 16 preferably has no channel in the wall and no cooling air holes.

[0046] Different materials can be used for the shovel tip 3 and shovel blade 4.

[0047] Likewise, preferably there are no holes emerging on the blade side 13, 16 near the blade tip.

[0048] Such structures can be manufactured using additive manufacturing processes, particularly selective laser melting. This can be done during new production or repair.

Claims

1. A blade tip (3) of a turbine blade (1), having at least: a wall (19) circumferential along an outer contour of a blade aerofoil (4) on a surface (28), thereby forming a recess (20) between the wall (19), wherein a duct (40) is present in the wall (19), in particular only one duct (40) is present, wherein via multiple, in particular at least three, supply air ducts (32) of the turbine blade (1), the duct (40) within the wall (19) can be supplied with cooling air, wherein multiple cooling air holes (25) are present, which are arranged in the wall (19) and are or can be fluidically connected to the duct (40) and allow the cooling air to flow out of the radial end (21) of the wall (19), in particular all of the cooling air holes (25) are connected to the duct (40), wherein an air-intake casing (22) is present on the wall (19) and within the recess (20), wherein the air-intake casing (22) is not as high as the wall (19), wherein the air-intake casing (22) covers supply air ducts (32) in the surface (28), which open into the duct (40) of the wall (19), wherein the air-intake casing (22) forms a part of the duct (40).

2. The blade tip according to claim 1, wherein within the recess (20), in particular in the region in proximity of a leading edge (7), cooling air holes (18), in particular two cooling air holes (18), are present, from which cooling air flows out of the interior (35) of the turbine blade (1) to the outside.

3. The blade tip according to claim 1, in which the duct (40) is formed on the suction side (13) in the wall (19).

4. The blade tip according to any one or more of claims 1, 2 or 3, in which the supply air ducts (32) are at an angle α of 90° > α > 0°, in particular 80° ≥ α ≥ 5°, with respect to the radial direction (14).

5. A turbine blade (1), either having been refurbished or constituting a new part and having a blade tip (3) with a wall (19) circumferential along an outer contour of the blade aerofoil (4) on a surface (28) according to any one or more of claims 1 to 4.

6. The turbine blade according to claim 5, having different materials for the blade tip (3) and the blade aerofoil (4).

7. A method of producing a blade tip (3) according to any one or more of claims 1, 2, 3 or 4 and a turbine blade (1) according to claim 5 or 6, within the framework of a repair or of new part production, in which an additive manufacturing method, in particular selective laser melting, is used.

8. The method according to claim 7, in which a cooling air hole (18) present is closed.