Blade tip of a turbine blade, turbine blade, and method for producing a turbine blade with a blade tip
Patent Information
- Application Number
- EP2023820875
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-01-20
- Filing Date
- 2023-12-07
- Publication Date
- 2025-09-10
AI Technical Summary
Gas turbine blade tips face challenges in cooling due to material oxidation, leading to performance loss and mechanical integrity issues, as convective cooling holes can be blocked by friction and contamination, reducing their effectiveness.
The design incorporates radially extending cooling channels with half-open channels that drain contamination away from the pressure side, preventing material accumulation and maintaining cooling functionality even during rubbing, allowing for a stable gap size and reduced material degradation without significant aerodynamic losses.
This design ensures the turbine blade tip maintains cooling efficiency and mechanical integrity by preventing contamination from blocking cooling channels, thus addressing the issue of material oxidation and performance loss while avoiding compromises between gap size and material stability.
Smart Images
Figure EP2023084692_25072024_PF_FP_ABST
Abstract
Description
[0001] Blade tip of a turbine blade, turbine blade and method for producing a turbine blade with a blade tip
[0002] The invention relates to a blade tip of a turbine blade and a method for producing it.
[0003] Gas turbine blades operate at high temperatures. The blade tip, in particular, is difficult to cool, which frequently leads to material oxidation and thus often to material loss. This degradation enlarges the gap to the stationary component, such as the ring segment, which directly correlates with power loss.
[0004] On the other hand, degradation can also endanger the mechanical integrity of the component.
[0005] Convective cooling holes in the blade tip counteract this damage phenomenon in the thermally highly stressed areas. Cooling of these tip walls is achieved by a coolant flow in radially extending cooling channels.
[0006] However, as the distance from the stationary parts decreases, the tip increasingly rubs against the opposing parts. This friction can temporarily block a cooling hole. Additionally, contaminants from the opposing turbine component are "scooped up" and block a cooling opening (Fig. 1, 2). This directly negates the benefit of these cooling holes at this point.
[0007] It is therefore the object of the invention to solve this problem.
[0008] The object is achieved by a turbine blade with an improved blade tip according to claim 1, a turbine blade according to claim 6, and a method according to claim 7. The subclaims list further advantageous measures which can be combined with one another as desired to achieve further advantages.
[0009] It shows
[0010] Figures 1 , 2 show the state of the art,
[0011] Figures 3, 4, 5 schematically show the invention.
[0012] Figure 1 shows an arrangement 1 ' with a stator 4 such as a ring segment and a blade tip 7 ' according to the prior art.
[0013] The accumulation of dirt 8 in front of a side wall 13 of a turbine blade is indicated.
[0014] The side walls 13 form or have a cooling channel 16T.
[0015] The arrow 11 shows the movement or direction of rotation of the blade tip 7 ' or of a turbine blade.
[0016] Figure 2 shows an overall overview with the details from Figure 1 .
[0017] Also visible is a blade tip 7 ' with its surrounding blade wall 13 , in which cooling channels 16T are present.
[0018] The cooling channels 16T, 16 extend largely or entirely in the radial direction 3 within the blade wall 13, 14 and terminate on an end face 20 with an opening 22 in the end face 20, so that cooling air can flow out of the plane of the end face 20. The cooling channels 16T, 16 can also extend in a curved manner within the blade wall 13. This also applies to Figures 3, 4, 5.
[0019] In the figures, the course of the cooling channels 16T is only indicated schematically.
[0020] This also applies to Figures 3 , 4 , 5 .
[0021] Figure 3 shows, starting from Figure 1, an inventively enlarged gap 19 between a blade wall 14 '' according to the invention and the stator 4 .
[0022] The pressure side of a turbine blade 2 is formed in Figure 3 to the right of the blade wall 14 '' on the blade airfoil.
[0023] The blade walls 14 extend in the radial direction 3 .
[0024] Figure 4 shows a view according to Figure 2, but according to the invention or starting from Figure 3.
[0025] It can be seen that the rear blade wall 14 '' in the direction of rotation 11 has the gap 19 .
[0026] The gap 19 is formed by an open, in particular semi-open channel 18.
[0027] The channel 18 extends toward the pressure side. Thus, one channel 18 of the blade wall 14' ends on the pressure side, and one channel 18 of the opposite blade wall 14' ends in the cavity above a crown base 15.
[0028] To better illustrate the invention, reference is made to Figure 5 with a plan view of the blade tip 7 according to the invention, since Figures 1 to 4 are only sectional views.
[0029] In addition to the top view of the blade tip 7 of the turbine blade 2 with its suction and pressure sides, the two walls 17, 14 of the blade tip 7 extend from the leading edge 6 and surround and delimit the crown base 15.
[0030] On the front side 20 of the walls 17, 14, several cooling channels 16 with their opening 22 each open.
[0031] The number and distance between the cooling channels 16 is determined by thermodynamic considerations.
[0032] It can be seen that starting from a cooling channel 16 for cooling air or from its opening 22, a channel 18 is present in the front side 20 of the walls 14, 17.
[0033] Contaminants 8 are drained away through this channel 18. Preferably, a channel 18 is provided for each cooling channel 16.
[0034] The channels 18 preferably run parallel to one another. Figure 5 shows that the channels 18 are of different lengths due to the curvature of the blade walls 13, 14.
[0035] The channel 18 can be designed and optimized in different ways in its geometry or can be .
[0036] The width of the channel 18 preferably corresponds to the diameter of the cooling hole 16 at the level of the front side 20 .
[0037] However, the width of the channel 18 can also be wider or narrower than the diameter of the cooling hole 16 at the level of the front side 20.
[0038] The channel 18 may preferably have a constant width over its length.
[0039] Likewise preferably, the channel 18 can also widen at least partially, in particular completely, over its length starting from the cooling channel 16, so that it is V-shaped.
[0040] The basic idea is the introduction of shapes that are not aligned in the flow direction, as with conventional blade / platform / disk tip cooling, but rather counter to the "friction direction." The friction of a blade 2 against a stationary part is directly linked to rotation (relative motion between the two friction partners). As can be seen in Figures 3 and 4, this prevents abraded material from a stationary part (stator) from accumulating in the cooling channel. This preserves the cooling function of the cooling channels 16 in the event of friction.
[0041] This design of the blade tip 7 has the advantage that there is no need to compromise between gap size and material loss for a stable design. Both requirements are met simultaneously, resulting in a time-stable design without high degradation and without significant aerodynamic losses.
[0042] The turbine blade 2 with the blade tip 7, walls 14, 17 and channels 18 can be cast or, during new production or during a repair process by a manufacturing process other than casting, in particular by an additive process such as build-up welding or three-dimensional printing, the blade tip 7 is applied to the crown base 15 of a turbine blade 2 to be manufactured or repaired.
[0043] The blade tip 7 can also be manufactured separately and applied to one end of a turbine blade, such as by soldering, particularly in the case of repairs.
[0044] The channels 18 can also be added later.
Claims
Patent claims 1. Blade tip (7) of a turbine blade (2), which has blade walls (14, 17) and a blade a pressure side and a suction side, wherein in a blade wall (14, 17) of the blade tip (7) Cooling channels (16) for cooling air are provided, wherein the cooling channels (16) run within the blade wall (14, 17) and open onto the end face (20) of the blade wall (13, 14), characterized in that starting from the opening (22) of the at least one cooling channel (16) on the end face (20), a channel (18) on the end face (20) runs transversely to the longitudinal direction of the turbine blade (2) and in the direction towards the pressure side.
2. Blade tip according to claim 1, wherein only one channel (18) is provided for each cooling channel (16).
3. Blade tip according to one or both of claims 1 or 2, in which some, in particular all, cooling channels (18) run parallel to one another.
4. Blade tip according to one or more of claims 1, 2 or 3, wherein the cooling channels (18) are of different lengths.
5. Blade tip according to one or more of claims 1, 2, 3 or 4, wherein the channel (18) has a constant width over its length.
6. Turbine blade comprising a blade tip according to one or more of claims 1 to 5, 7. Method for producing a turbine blade (2) with a blade tip (7) according to one or more of the preceding claims, in which the turbine blade (2) with the blade tip (7) and walls (14, 17) and channels (18), or during new production or during a repair process by a manufacturing process other than casting, in particular by an additive process such as build-up welding or three-dimensional printing, the blade tip (7) is applied to the crown base (15) of a turbine blade (2) to be manufactured or repaired.