DE102017209421A1 - Blade with blade tip cooling - Google Patents

Abstract

The invention relates to a rotor blade for a gas turbine, in particular an aircraft gas turbine, having a main portion (12) and a radial end portion (14) connected to the main portion (12), the end portion (14) projecting at least one radially beyond the main portion (12) Endwandung (16), which is circumferentially formed relative to a flow-around profile cross-section of the blade (10), such that a recess (18) is bounded by the end wall (16) in the radial end portion (14), wherein in the region of the end wall (16 ) and / or in a base portion (20) of the recess (18) at least one cooling channel (30) is provided to cool the end portion (14) of the blade (10) by means of cooling air (34). According to the invention, it is proposed that the end wall (16) has an inner wall section (16b) delimiting the recess (18) and an outer wall section (16a) between which the at least one cooling channel (30) is formed, wherein the cooling channel (30) Portion of the radial ends of the inner wall portion (16b) and the outer wall portion (16a) has an opening (32) through which cooling air (34) can emerge substantially in the radial direction.

Description

The present invention relates to a rotor blade for a gas turbine, in particular an aircraft gas turbine, having a main portion and a radial end portion connected to the main portion, wherein the end portion has at least one radially extending over the main portion end wall, which is circumferentially formed with respect to a flow-around profile cross-section of the blade in that a recess is delimited by the end wall in the radial end section, wherein at least one cooling channel is provided in the region of the end wall and / or in a base section of the recess in order to cool the end section of the blade by means of cooling air.

Directional information such as "axial" or "axial", "radial" or "radial" and "circumferential" are basically based on the machine axis of the gas turbine to understand, unless the context explicitly or implicitly otherwise results.

The term Endabschnitt used here is referred to in the jargon as a blade tip. The term end wall used here can also be referred to as a blade crown.

From the US 2016/0265366 A1 a vane tip cooling is known in which in the end wall, a circumferential cooling channel is provided which has a plurality of openings to the recess. In the radial direction, the end wall has a radial end which forms a continuous surface, wherein the radial end delimits the cooling channel in the radial direction.

In such an embodiment of the blade tip cooling, there is a risk that the radial end, in particular the continuous, the cooling channel final end surface, is removed or damaged during operation of the gas turbines by the brushing of the blade tip, whereby the cooling of the blade tip is impaired. To counteract this danger, such an end surface has a relatively large radial thickness, so that the complete removal of the radial end surface does not occur during the usual lifetime of a blade. However, this embodiment has the disadvantage that at a radially far outer portion, in particular radially to extremely on the blade much material is present, which has an adverse effect on the entire blade under the action of centrifugal forces.

The object of the invention is to provide a blade in which the known disadvantages can be reduced or even avoided.

According to a first aspect of the invention it is proposed that the end wall has a recess bounding the inner wall portion and an outer wall portion, between which the at least one cooling channel is formed, wherein the cooling channel in the region of the radial ends of the inner wall portion and the outer wall portion an opening can escape through the cooling air substantially in the radial direction.

The two wall sections are preferably formed substantially parallel to one another, wherein along the circumferential direction of the wall sections at least one cooling channel is provided. The cooling channel may be formed as a circumferential, substantially continuous channel, which is bounded by the two wall sections. However, the two wall sections can also be connected to each other in sections, so that along the circulation direction a plurality of cooling channels are formed, which are separated by partitions, wherein the partitions extend substantially transverse to the course of the two wall sections. Such a configuration of channels which are open in the radial direction can save material, in particular in the radially outer regions, that is to say in particular in the end section of the rotor blade, so that less strong centrifugal forces act. In the case of the brushing of the blade during operation, both wall sections are usually removed or shortened in the radial direction, as a result of which the at least one cooling channel in the radial direction is also reduced. However, this has little or no influence on the basic mode of operation of the cooling of the end portion of the blade because the basic structure of the end portion is not damaged.

According to a second aspect of the invention is proposed to achieve the object that in the recess air-permeable filler means are arranged, which are connected to the end wall and the base portion of the recess. Such fillers allow the passage of cooling air in the region of the recess. Further, the material surface can be increased by the fillers, so that heat generated by friction, for example, in the case of brushing the blade, can be well distributed and the blade tip (end portion) can be efficiently cooled.

The air-permeable filler can also be arranged in a cooling channel.

It is proposed that the air-permeable fillers are formed by a porous material arrangement. In this case, the porous material arrangement may be a grid-like or matrix-like or net-like or sponge-like material arrangement. It results in particular a structure with interconnected material bridges, are limited by the cavities or open spaces. Cooling air can flow through these cavities or free spaces and cool the material bridges in the event of the rotor blade brushing on. Incidentally, such material arrangements also have a stabilizing effect on the end section of the moving blade. With regard to the term sponge-like it should also be noted that this merely refers to the structural structure of a sponge, without it being concluded that the spongy material arrangement referred to here is reversibly deformable or that its strength changes depending on fluid intake.

The fillers may be formed as a strut-like material arrangement. In this case, for example, in the recess or in a cooling channel some material struts may be formed, which also have a stabilizing function, for example, to support the end wall and the inner and outer wall sections against each other.

In particular, the fillers are selected so that, on the one hand, sufficient material is present in the area of the end section or the blade tip to enable stability of the blade tip and optimum cooling, and on the other hand material can be saved in the region of the blade tip in order to control the centrifugal forces acting to reduce.

The blade can be produced by an additive manufacturing method, in particular selective laser melting, wherein in particular the main portion and the radial end portion are integrally formed. Furthermore, the fillers can also be produced by the additive manufacturing method, wherein the fillers are formed integrally with the end section, in particular the end wall or the wall sections and the base section.

An additive manufacturing method allows targeted production of the end portion with fillers, which can be easily and reliably produced by the additive manufacturing process in particular also the above-mentioned reticulated or latticed or sponge-like or stringenartigen material arrangements.

In the main portion of the blade, at least one further cooling channel may be formed, which is in fluid communication with the at least one cooling channel in the region of the end wall and / or in the base portion of the recess. As a result, cooling air can flow through the blade and be transported to the end portion or in the region of the blade tip. The blade is cooled as a whole.

Further, the blade may have a radially inner coupling portion through which the blade is connectable or connected to a rotor. The coupling portion may be formed, for example, as a blade root, such as with a known fir tree shape. The coupling portion may also be formed as a material connection of a blade with the rotor.

The invention also relates to a gas turbine, in particular an aircraft gas turbine, with a compressor region, a combustion chamber region and a turbine region, the turbine region having a high-pressure turbine with at least one rotor, on which a plurality of rotor blades described above are arranged along the circumferential direction.

• 1 zeigt in einer vereinfachten und schematischen Perspektivdarstellung eine Laufschaufel einer Gasturbine.
• 2 zeigt in einer vereinfachten und schematischen Darstellung eine Draufsicht auf den radialen Endabschnitt bzw. eine Schaufelspitze der Laufschaufel der 1.
• 3 zeigt in einer vereinfachten und schematischen Darstellung eine Draufsicht auf den radialen Endabschnitt eine Laufschaufel entsprechend einer Ausführungsform.
• 4 zeigt in einer Schnittdarstellung, die etwa einer Schnittlinie IV-IV der 3 entspricht den Endabschnitt der Laufschaufel mit einem Kühlkanal in einer Endwandung.
• 5 zeigt in einer Schnittdarstellung, die etwa einer Schnittlinie III-III der 2 entspricht den Endabschnitt der Laufschaufel, wobei in einer Aufnahme des Endabschnitts Füllmittel angeordnet sind.
• 6 zeigt in einer zur 4 ähnlichen Darstellung Füllmittel in Kühlkanälen.
• 7 zeigt in einer zur 5 ähnlichen Darstellung ein anderes Füllmittel.
• 8 zeigt in einer zur 5 und 7 ähnlichen Darstellung Füllmittel mit variabler Höhe.

The invention will be described below by way of example and not limitation with reference to the attached figures.

• 1 shows in a simplified and schematic perspective view of a rotor blade of a gas turbine.
• 2 shows in a simplified and schematic representation of a plan view of the radial end portion and a blade tip of the blade of the 1 ,
• 3 shows in a simplified and schematic representation of a plan view of the radial end portion of a blade according to an embodiment.
• 4 shows in a sectional view, approximately along a section line IV-IV of 3 corresponds to the end portion of the blade with a cooling channel in an end wall.
• 5 shows in a sectional view, about a section line III-III of 2 corresponds to the end portion of the blade, wherein in a receptacle of the end portion fillers are arranged.
• 6 shows in a to 4 similar representation fillers in cooling channels.
• 7 shows in a to 5 similar representation another filler.
• 8th shows in a to 5 and 7 similar representation filler with variable height.

In 1 is schematic and simplifies a blade 10 shown in a perspective view. The blade 10 includes a main section 12 and radially outside an end portion 14 , The end section 14 has at least one end wall 16 on, in the radial direction over the main section 12 protrudes. The end wall 16 limited inside a recess 18 , From this recess 18 is a basic section 20 or floor visible.

From the schematic plan view of 2 it can be seen that the end wall 16 a circumferential inside 22 and a circumferential outside 24 having. The inside 22 and the outside 24 essentially follow the profile shape of the blade 10 , The end wall does not extend in the example shown up to a rear edge 26 the blade. Accordingly, in the end section 14 trained recess 18 , in particular its basic section 20 a smaller area than the cross-sectional area of the entire blade in the plane of the base portion 20 ,

In the area of the end section 14 , which can also be referred to as a blade tip, the run schaufei 10 during operation of the gas turbines on radially outer, not shown here parts of the gas rub rub rubbing. In particular, the rubbing takes place on sealing bodies, not shown here, which for example have a honeycomb-shaped or porous structure. The end section 14 is thus subject to high loads due to the centrifugal force acting and the rubbing friction. Accordingly, it is necessary that in particular the end portion 14 can be cooled efficiently.

In the 3 and 4 is an embodiment of a blade 10 represented according to the first aspect of the invention. Here is the end wall 16 through an outer wall section 16a and an inner wall section 16b educated. Through the outer wall section 16a and the inner wall section 16b becomes at least one cooling channel 30 educated. The cooling channel 30 has an outlet opening 32 on, which is designed so that cooling air 34 can emerge in a substantially radial direction. Usually along the peripheral wall sections 16a . 16b several cooling channels 30 provided, as shown in the illustration of 3 is apparent. To these cooling channels 30 separate from each other and around the wall sections 16a . 16b to give sufficient stability, between adjacent cooling channels respective connecting portions 36 provided by which the wall sections 16a . 16b connected to each other. It should be noted that the cooling channels 30 not necessarily parallel to the cutting plane of the 4 , in particular must run parallel to the radial direction. Rather, the cooling channels 30 also inclined.

5 shows an embodiment in which the end wall 16 compared with known Endwandungen a very small thickness WD having. Preferably, the wall thickness WD the end wall 16 from about 0.1 mm to 2.0 mm, in particular from about 0.2 mm to 1.5 mm. Such a wall thickness WD is incidentally also for the in 3 and 4 illustrated, inner and outer wall sections 16a . 16b applicable. The reduction of the wall thickness WD the end wall 16 leads to a significant material reduction in the radial end section 14 compared with known blade tips. So that in the radial end section 14 (Blade tip) sufficient stability can be maintained are in the recess 18 air-permeable fillers 40 arranged. The fillers 40 are in the example of 5 as a net-like or latticed material arrangement 42 executed. It should be noted that the mesh-like or lattice-like structure is represented by the illustrated cross hatching only representative, without the illustrated cross hatching an actual configuration of the filler 40 should show. In other words, it can also be said that the fillers 40 have a porous structure. In this case, the material arrangement is designed such that interconnected cavities 44 are formed by material bridges 46 are limited. This allows for cooling air 34 through the fillers 40 can flow and can escape radially outward.

In the 6 is one to 4 similar embodiment shown with cooling channels 30 , In terms of drawing is in a left cooling channel 30 a filler 40 shown having a similar or the same structure (material arrangement 42 ), like that with reference to FIGS 5 described filler 40 in the recess 18 , In the in 6 left illustrated cooling channel 30 is the filler 40 designed like a strut. The material arrangement is thus chosen so that between the outer wall section 16a and the inner wall section 16b several aspirations 48 are formed.

7 shows one to 5 similar representation, wherein as filler 40 a spongy material arrangement 50 is shown schematically and simplified.

8th shows one to the 5 and 7 similar representation, wherein filler 40 are arranged so that the material arrangement is designed in the radial direction of different heights or thick. By such a change in the height of the material arrangement, in particular the sealing effect of the blade crown against hot gas overflow can be improved.

The in the 3 to 8th illustrated blades are in particular by an additive manufacturing process, such as selective Laser melting made. Accordingly, at least the main section 12 and the end section 14 with the end wall 16 or the wall sections 16a . 16b integrally formed. The in the 5 to 8th illustrated filler 40 or the corresponding grid-like or net-like or sponge-like or strip-like material arrangement 42 . 48 . 50 may also be made by the additive manufacturing method. Accordingly, porous or air-permeable filler 40 in the manufacture of the blade 10 be built at the same time. Due to the additive manufacturing process, the fillers 40 especially with the end wall 16 or the inner and outer wall sections 16a . 16b and with the basic section 20 the recess 18 integral or integrally connected. Accordingly, by the filler 40 a possible loss of stability due to material reduction, in particular in the wall thickness WD the end wall can be compensated. The fillers 40 Not only do they serve to ensure efficient cooling due to their porous structure, but they also allow stabilization of the end wall 16 or the wall sections 16a . 16b so that they can be made as thin as possible.

Allen embodiments shown here is also common that when a rubbing of the blade 10 with its end section 14 the basic structure of the cooling channels or the air-permeable filler 40 not destroyed. Rather, even with a material removal of usually a few tenths of a millimeter to a few millimeters during the life of a blade, the cooling function and the leadership of cooling air is substantially retained. The fillers 40 Incidentally, due to the selected air permeable structure also have a low weight, so that the effect of the centrifugal force is positively influenced.

Like from the 4 to 8th can be seen, are the cooling channels 30 with at least one cooling channel 60 in the main section 12 the blade 10 connected, through which the cooling air 34 usually the end section 14 or the blade tip is supplied. Such a connection can be made by means of connecting sections 35 (see eg 3 ) can be achieved. In this case, the connection sections 35 be configured or dimensioned so that in this way the amount of cooling air, which supplies or reaches the various regions of the blade crown, can be set or controlled.

With reference to the 5 to 8th and the fillers shown there 40 or material arrangements 42 . 50 It should also be noted that in the material arrangements also substantially radially extending channels or holes 41 can be provided. Exemplary and representative is such a channel or such a hole 41 schematic and simplified in 5 shown. By such regular or irregular in the material arrangement 42 . 50 arranged channels or holes 41 can escape in the cooling air contained solid particles, so that the risk of blockages in the flow of cooling air can be reduced. Such channels or holes 41 may have any cross-sectional area; they do not necessarily have to have a circular cross-sectional area. Furthermore, such channels or holes 41 be released immediately in an additive manufacturing or they can be formed by the fact that the structure of the material arrangement in such a region has a coarser structure or larger interconnected cavities.

LIST OF REFERENCE NUMBERS

10

blade

12

main section

14

end

16

end wall

16a

outer wall section

16b

inner wall section

18

recess

20

base portion

22

inside

24

outside

26

end edge

30

cooling channel

32

outlet opening

34

cooling air

35

connecting portion

36

connecting portion

40

fillers

41

Channel / bore

42

Mesh-like / grid-like material arrangement

44

cavity

46

material bridge

48

strut

50

spongy material arrangement

60

cooling channel

WD

wall thickness

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2016/0265366 A1 [0004]

Claims (11)

Blade for a gas turbine, in particular an aircraft gas turbine, having a main portion (12) and a radial end portion (14) connected to the main portion (12), the end portion (14) having at least one end wall (16) projecting radially beyond the main portion (12). has, with respect to a flow-around profile cross-section of the blade (10) is formed circumferentially, such that by the end wall (16) in the radial end portion (14) has a recess (18) is limited, wherein in the region of the end wall (16) and / or in a base portion (20) of the recess (18) at least one cooling channel (30) is provided to cool the end portion (14) of the blade (10) by means of cooling air (34), characterized in that the end wall (16) has a Recess (18) delimiting inner wall portion (16b) and an outer wall portion (16a) between which the at least one cooling channel (30) is formed, wherein the cooling channel (30) in the region the radial ends of the inner wall section (16b) and the outer wall section (16a) have an opening (32) through which cooling air (34) can exit in a substantially radial direction. Blade for a gas turbine, in particular an aircraft gas turbine, having a main portion (12) and a radial end portion (14) connected to the main portion (12), the end portion (14) having at least one end wall (16) projecting radially beyond the main portion (12). has, with respect to a flow-around profile cross-section of the blade (10) is formed circumferentially, such that by the end wall (16) in the radial end portion (14) has a recess (18) is limited, wherein in the region of the end wall (16) and / or in a base portion (20) of the recess (18) at least one cooling channel (30) is provided to cool the end portion (14) of the blade (10) by means of cooling air (34), characterized in that in the recess (18) permeable to air Fillers (40) are arranged, which are connected to the end wall (16) and the base portion (20) of the recess (18). Blade after Claim 1 or 2 , characterized in that in the at least one cooling channel (30) air-permeable filling means (40) are arranged. Blade after Claim 2 or 3 , characterized in that the air-permeable filling means (40) are formed by a porous material arrangement. Blade after Claim 4 , characterized in that the porous material arrangement is a grid-like or matrix-like or net-like or sponge-like material arrangement (42, 50). Blade after Claim 3 , characterized in that the filling means are designed as a strut-like material arrangement (48). Blade according to one of the preceding claims, characterized in that it is produced by an additive manufacturing method, in particular selective laser melting, wherein in particular the main portion (12) and the radial end portion (14) are integrally formed. Blade after Claim 2 and 7 or after Claim 3 and 7 characterized in that the fillers (40) are made by the additive manufacturing method, wherein the fillers (40) are integral with the end portion (14), particularly the end wall (16) or the wall portions (16a, 16b) and the base portion (20 ) are formed. Blade according to one of the preceding claims, characterized in that in the main portion of the blade at least one further cooling channel is formed, which is in fluid communication with the at least one cooling channel in the region of the end wall and / or in the base portion of the recess. Blade according to one of the preceding claims, characterized in that it comprises a radially inner coupling portion through which the blade (10) is connectable or connected to a rotor. A gas turbine, in particular an aircraft gas turbine, with a compressor area, a combustion chamber area and a turbine area, the turbine area having a high-pressure turbine with at least one rotor, along which a plurality of rotor blades (10) according to one of the preceding claims are arranged along the circumferential direction.

Images