Patent Application
20190078446
This claims the benefit of German Patent Application DE102017215940.5, filed Sep. 11, 2017 and hereby incorporated by reference herein.
The present invention relates to a blade of a turbomachine, for example a stationary gas turbine or an aircraft engine, and in particular a turbine blade, preferably a turbine blade of a high-pressure turbine, the blade including at least one cooling channel in the interior of the blade for cooling the blade with the aid of a fluid flowing through the cooling channel The present invention furthermore relates to a method for manufacturing a blade of this type.
In turbomachines, such as stationary gas turbines or aircraft engines, it is known to provide blades, in particular blades for the area of the high-pressure turbine, with cooling channels to be able to conduct a cooling fluid through the at least one cooling channel of the blade for the purpose of reducing the temperature load of the blade. In this way, a preferably high operating temperature of the turbomachine may be implemented for a blade made from a given material, or more alternatives for a possible material for manufacturing the blade are available for a certain operating temperature of the turbomachine, without damage to the blade or the material of the blade occurring during operation due to the temperature load.
Examples of turbine blades of this type are described, for example in US 2016/0312617 A1 or DE 10 2015 213 090 A1. Although high operating temperatures of the turbomachines may already be effectuated with the aid of the known turbine blades, there remains a need to improve the cooling of blades in turbomachines either to be able to further increase the operating temperature of the turbomachine or to be able to use other materials for the blades. To operate the turbomachines efficiently, it is also advantageous if a low demand exists for cooling fluid, for example cooling air.
The described aspects of the importance of the cooling of blades are all the more applicable if blades are designed to be integral with a rotor disk as a so-called blisk, since this limits the material selection for the blades, and the cooling of the blade and the vane becomes correspondingly more important.
It is an object of the present invention to provide a blade or blisk for a turbomachine, which facilitates a better and, in particular more efficient, cooling of the blade and the vane during the operation of the turbomachine. At the same time, the blade should be reliably operable and easy to manufacture.
The present invention provides a blade or blisk as well as a method for manufacturing a blade of a turbomachine.
For the sake of simplicity, only blades are mentioned below, this term, however, also covering so-called blisks, i.e. blades designed to be integral with rotor disks.
According to the present invention, it is proposed, in a blade for a turbomachine, which includes at least one cooling channel in the interior of the blade for cooling the blade with the aid of a fluid flowing through the cooling channel, to situate at least one displacement body in the cooling channel, so that an annular or tubular gap between the displacement body and the wall of the cooling channel results in the area of the one or more displacement bodies, which is available for the through-flow of the fluid. This achieves the fact that the cooling fluid comes into better contact with the wall of the cooling channel to be cooled or the adjacent material of the blade which is to be cooled by the cooling fluid, for example cooling air. As a result, the heat transfer to the cooling fluid may be improved, and a more effective and more efficient cooling of the blade takes place, so that the temperature load of the blade and/or the consumption of the cooling fluid may be reduced.
As an alternative to forming an annular or tubular gap between the displacement body and the wall of the cooling channel, the displacement body/bodies may also be formed in the cooling channel in such a way that at least two or more subchannels are formed, which also cause the cooling fluid flowing through the cooling channel to be provided efficiently to the areas of the blade to be cooled.
The displacement body or multiple displacement bodies may be situated in the cooling channel of a blade of a turbomachine in different ways to achieve a better heat transfer from the wall of the cooling channel to the through-flowing cooling fluid.
For example, the at least one displacement body may be situated in the area of the axial and/or radial center of the cooling channel The axial direction is understood to be the longitudinal extension of the cooling channel along the flow direction of the cooling fluid, while the radial direction represents a direction transverse to the axial direction or longitudinal direction of the cooling channel Accordingly, the at least one displacement body may thus be situated in the middle of the cooling channel with respect to the longitudinal direction or the axial direction and/or with respect to the center axis of the cooling channel, i.e. the radial direction.
The displacement body may extend along the center axis of the cooling channel, in particular coaxially to the center axis of the cooling channel This results in a uniform distribution of the through-flowing cooling fluid along the circumference of the cooling channel.
The displacement body may be situated entirely inside the cooling channel It may not touch, in particular, the wall of the cooling channel and/or it may be held via one or multiple webs, which in this case are not part of the displacement body.
The gap width of the gap formed between the displacement body and the wall of the cooling channel and the maximum diameter or the flow cross section of a subchannel formed through the displacement body may be constant along the longitudinal axis of the cooling channel or be varied along the longitudinal axis of the cooling channel Moreover, combinations are also conceivable, so that the gap width of the gap and the maximum diameter or the flow cross section of a subchannel may be different in subareas, while the gap width of the gap and the maximum diameter or the flow cross section of the subchannel remain constant over the longitudinal axis. The gap width of the gap and the maximum diameter or the flow cross section of a subchannel may remain constant over the entire length of the cooling channel or at least over a large subarea of the cooling channel, for example over at least 90% of the cooling channel.
In addition to a variation of the gap width of the gap between the displacement body and the wall of the cooling channel along the longitudinal axis of the cooling channel, the gap width may also be designed to be varied or remain constant around the longitudinal axis along the circumference of the cooling channel A variation of the gap width along the circumference of the cooling channel may be used to allow more or less cooling fluid to flow along the wall of the cooling channel in certain areas of the cooling channel, for example depending on the proximity to the surface of the vane.
The displacement body may be designed and situated in the cooling channel in such a way that the flow cross section of the cooling channel is reduced in the area of the displacement body.
The displacement body may be enclosed or trapped in the blade, it being able to be, in particular, unremovably, i.e. nondestructively removably, enclosed or trapped in the blade.
The displacement body itself may, in turn, have cooling channels, so-called displacement body channels, which may also be connected via overflow openings to the cooling channel in which the displacement body is situated.
The displacement body may furthermore be formed by a honeycomb, matrix or lattice structure, so that both the use of materials and the weight of the blade may be kept low. In the design of the displacement body having a honeycomb, matrix or lattice structure, the cavities of the honeycomb, matrix or lattice structure may be filled with a filling material which has, for example, a low density. Alternatively or additionally, the displacement body may be provided with a closed shell, for example with a metal shell, to prevent the penetration of cooling fluid. The closed shell may be completely tightly sealed by manufacturing material after the cavities have been filled with filling material or after the cavities have been emptied. Alternatively, the formation of a partial shell or a partially open shell is also conceivable.
The closed shell may define an inner volume which encompasses or is a cavity and/or which has a lower density compared to the blade material.
The closed shell and/or the inner volume may be situated entirely inside the cooling channel.
The cross-sectional shapes of the cooling channel and/or one of the subchannels and/or the displacement body may be implemented in different ways, for example, as round, circular, oval, angular, quadrangular, hexagonal shapes or arbitrary free shapes. The cross-sectional shapes of the cooling channel and the displacement body may be identical or different.
The arrangement of a displacement body in a cooling channel may be characterized in that a shared cooling inlet is provided for all cooling fluid paths through the cooling channel, i.e. for an annular or tubular gap and/or multiple subchannels. Accordingly, if multiple subchannels are formed, they may open into a shared cooling channel.
If subchannels are formed, the at least one displacement body may be shaped and/or situated in the cooling channel in such a way that the subchannels are formed on the sides of the cooling channel which are situated closer to a surface of the blade than one of the other sides of the cooling channel In particular, the subchannels may be situated in such a way that at least a larger portion of their surface is situated on the side(s) of the cooling channel which is/are closer to a surface of the blade than the sides of the cooling channel without or having a smaller surface portion of one of the subchannels.
The cooling channel and/or the subchannels of the cooling channel may be designed in such a way that the maximum diameter of the cooling channel or of a subchannel is smaller than the longitudinal extension of the cooling channel and/or the subchannel
The cooling channel may extend through the blade, in particular in a meandering manner, so that large areas of the blade may be cooled by the cooling fluid flowing through the cooling channel
In this or in other specific embodiments, the displacement body may be bent according to a bent course of the channel.
The manufacture of a corresponding blade may take place, in particular using a generative or additive manufacturing method, in which the blade is built up layer by layer from a powder material. In this way, it is easily possible to form the displacement body in a cooling channel.
Selective laser beam melting or selective electron beam melting may preferably be used as the generative or additive manufacturing method.
The attached drawings show the following in a purely schematic way:
Additional advantages, characteristics and features of the present invention are apparent from the following detailed description of the exemplary embodiments. However, the present invention is not limited to these exemplary embodiments.
As is apparent from the sectional view in
Cooling channel 5 initially runs in a meandering manner from cooling channel inlet 6 in the area of blade root 3 to the upper end of vane 2 and, after a 180° deflection, it runs from the upper end of vane 2 back to blade root 3, where, after another 180° deflection, cooling channel 5 again runs in the direction of the upper end of vane 2. In the area of the upper end of vane 2, at the blade tip, cooling channel 5 has multiple cooling channel outlets 7, through which a fluid, which is used to cool turbine blade 1, for example cooling air, may exit cooling channel 5.
To achieve the fact that the cooling fluid or the cooling air preferably passes along the wall of cooling channel 5 radially delimiting cooling channel 5, for the purpose of facilitating a corresponding heat transfer there with the aid of the material of vane 2 heated during operation, a displacement body 8 is provided in cooling channel 5, which, in the illustrated exemplary embodiment in
As is apparent in
In the example in
Displacement body 8, which, in the illustrated exemplary embodiment, has a cylindrical basic shape with an oval cross section (see
Displacement body 8 is thus situated spaced apart from the wall of cooling channel 5 in such a way that an annular gap 10 results, which surrounds displacement body 8 and is formed between displacement body 8 and the wall of cooling channel 5. Annular gap 10 extends in a tubular manner along the longitudinal direction of displacement body 8 and cooling channel 5. The cooling fluid flowing through the cooling channel may flow through cooling channel 5 only in the area of annular gap 10, due to displacement body 8, so that a large portion of the through-flowing cooling fluid flows in the direct vicinity of the wall of cooling channel 5, where it is able to effectuate a corresponding heat transfer.
In the illustrated exemplary embodiment in
Moreover, it is also possible that gap width S of gap 10 between displacement body 8 and the wall of cooling channel 5 varies along the longitudinal axis of cooling channel 5.
In a cross-sectional view comparable to the cross-sectional view in
In a cross-sectional view comparable to the cross-sectional view in
Although the present invention was described in detail on the basis of exemplary embodiments, it is as a matter of course to those skilled in the art that the present invention is not limited to these exemplary embodiments, but instead modifications are possible in such a way that individual features may be omitted or different combinations of features may be implemented, without departing from the scope of protection of the attached claims. In particular, the above description includes all combinations of the individual features shown in the different exemplary embodiments, so that individual features described only in connection with one exemplary embodiment may also be used in other exemplary embodiments or in combinations of individual features not explicitly illustrated.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102017215940.5 | Sep 2017 | DE | national |
