DE102018202725A1 - Arrangement of blades in a blade ring based on a primary crystal orientation - Google Patents

Abstract

Disclosed is a blade ring (1) of a turbomachine, which comprises a plurality of blades (S ₁ , S ₂ , ..., S _i , S _{i + 1} , ... S _n-1 , S _n ), each completely or partially made of a monocrystalline material. The plurality comprises two adjacent blades (S ₁ , S _n ) whose primary crystal orientations (α) have an absolute difference greater than 10 times an absolute difference in the primary crystal orientations of at least one other pair of adjacent blades of the plurality.
Also disclosed is a turbomachine with a blade ring.

Description

The present invention relates to a blade ring for a turbomachine and a turbomachine with such a blade ring.

Blade rings with blades or vanes in turbomachinery such as aircraft engines and stationary gas turbines are exposed to strong thermal and mechanical loads. The vibrations occurring in the turbomachine can also trigger resonances that stress the material of a blade ring. This can lead to material fatigue and, in the worst case, to a material break.

In the EP 1 217 170 A2 is disclosed to use a monocrystalline alloy as a material for the blades and by means of their secondary orientation of the monocrystalline material (which is determined by an angle between the [100] direction of the monocrystalline material and the axial direction of a turbine), the natural vibrations of the blades suitable to influence. Thus, adverse resonances should be avoided.

From the publication EP 1 571 297 A2 It is known to radially align a crystal direction of the blade material to reduce material fatigue resulting from high rotational speeds.

In the EP 1 728 971 A1 For example, a turbine blade grid having a plurality of blades of a monocrystalline material is disclosed. Adjacent blades have a fixed deviation of their average crystal orientation: In a first embodiment, the change is 360 ° / n, in a second embodiment, the blades are combined as pairs, each with the same crystal orientation, wherein the crystal orientations of adjacent pairs by 360 ° / (n / 2) differ; n designates in each case the number of blades.

From the DE 10 2013 226 015 A1 For example, a blade grid having at least two sectors each comprising at least three blades is known. In this case, the blades have a monocrystalline material and in each case a crystal orientation value which lies above a fixed barrier in the blades of a first of the sectors below and in the blades of a second one of the sectors.

The present invention has for its object to provide a technique with which adverse resonances in a fluid machine or material fatigue can be reduced.

The object is achieved by a blade ring according to claim 1 and a turbomachine according to claim 7. Advantageous embodiments are disclosed in the subclaims, the description and the figures.

An inventive blade ring is intended for installation in a turbomachine or already installed in a turbomachine. It has a plurality of blades, each entirely or partially made of a monocrystalline material (e.g., a superalloy). The plurality comprises two adjacent blades whose magnitude difference in their respective primary crystal orientations is greater than ten times an absolute difference of the associated primary crystal orientations of at least one other pair of adjacent blades of the plurality.

In particular, therefore, the difference in magnitude of the primary crystal orientations of the two adjacent blades is different from zero, and the two adjacent blades among all the blades of the plurality are the only ones having the largest occurring absolute difference of the primary crystal orientations.

The "primary crystal orientation" is given by an angle between a [001] direction of the monocrystalline material (or its unit cells) to the radial direction of the blade ring (or to the stacking axis of the blade); the indication "[001]" is the usual Miller's index designation. The terms "radial", "axial" and "circumferential direction", in this document always refer to an (abstract) central geometric axis, which rotates around the blade ring; when installed in the turbomachine state of the blade ring this axis coincides with a designated axis of rotation of the turbomachine.

Thus, according to the invention, there is a particularly great detuning between the two adjacent blades with the greatest difference in the absolute value of the primary crystal orientations, in comparison to which the differences between the primary crystal orientations of the other respective adjacent blades are relatively small. It has been found that such a large local detuning between two adjacent blades, with at the same time relatively small differences between all the remaining blades, is particularly advantageous in that it has a particularly favorable effect on the reduction of resonances and material fatigue in the turbomachine.

Preferably, this largest difference of the primary crystal orientations of the two adjacent blades, which occurs among the plurality of blades, corresponds at least to the largest 0.5 times, more preferably at least 0.8 times or exactly the difference between the largest and smallest primary crystal orientation of all the primary crystal orientations of all the blades of the blade ring.

A second largest difference in associated primary crystal orientations occurring among adjacent vanes of the plurality is preferably at most 0.8 times, at most 0.5 times, or even at most 0.3 times the difference between the largest and the smallest primary crystal orientation of all primary crystal orientations of all blades of the blade ring.

In some embodiments, the difference between the largest and the smallest primary crystal orientation of all primary crystal orientations of all blades of the blade ring is in the range between 0 ° and 30 ° or even between 4 ° and 16 °.

The blade ring may be a walking or a vane ring. It may be composed or monolithic as a blisk.

According to an advantageous embodiment of the present invention, one of said two adjacent vanes having the largest absolute difference of the primary crystal orientations is a first vane, and the other of the two adjacent vanes is the last vane of the plurality, ie the first vane with respect to a circumferential direction adjacent to the circumferential direction. Following the circumferential direction, therefore, there are between the first and the last a second, third, etc. and a penultimate blade. In this case, the blades have a monotonically growing or even monotonically growing primary crystal orientation with respect to the circumferential direction from the first to the last blade. Thus, in the circumferential direction, in this embodiment, the blades of the plurality are arranged such that from the first to a penultimate blade of the plurality, each blade has a primary crystal orientation that is at most equal to or smaller than a primary crystal orientation of the adjacent ones following scoop.

The largest occurring absolute difference of the associated primary crystal orientations, namely that between the last and the first blade, in this case thus results from the sum of all other differences in absolute value.

It is understood that the circumferential direction - corresponding to a positive or negative sign - one (fixed) of two possible, opposite circumferential directions around the central geometric axis.

Preferably, all blades of the blade ring comprise the same monocrystalline material; Alternatively, however, the blade ring may also comprise at least two blades containing mutually different monocrystalline materials.

The plurality of blades of the blade ring may include, for example, at least 30, at least 40, at least 60, at least 75, or at least 80 blades. Additionally or alternatively, the plurality of blades of the blade ring may comprise all blades of the blade ring or correspond to the number of all blades of the blade ring.

A turbomachine according to the invention comprises a blade ring according to the invention according to one of the embodiments disclosed in this document.

In the following preferred embodiments of the invention will be explained in more detail with reference to two drawings. It is understood that individual elements and components can be combined differently than shown.

• 1: einen exemplarischen Schaufelkranz gemäß einer Ausführungsform der vorliegenden Erfindung; und
• 2: eine Illustration einer exemplarischen Kristallorientierung bezogen auf die zentrale Achse eines Schaufelkranzes.

They show schematically:

• 1 FIG. 2 shows an exemplary blade ring according to an embodiment of the present invention; FIG. and
• 2 : An illustration of an exemplary crystal orientation with respect to the central axis of a blade ring.

In 1 is an exemplary shovel wreath 1 according to an embodiment of the present invention. It includes a plurality of blades S ₁ . S ₂ , ..., S _i . S _{i + 1} , ... S _n-1 . S _n ; where n is the number of blades of the plurality, in the illustrated embodiment, n = 75. The scoop wreath 1 , which may be a runner or a vane ring, for example, may be formed monolithically as a blisk.

The shovels S ₁ . S ₂ , ..., S _i . S _{i + 1} , ... S _n-1 . S _n of the scoop wreath 1 consist entirely or partially of a monocrystalline material (not visible in the figure), which may be in particular a superalloy and by which a primary crystal orientation of the respective blades is determined.

According to the invention, the plurality comprises two adjacent blades whose respective primary crystal orientations of all the adjacent blades of the plurality are the largest in magnitude Have difference; as these two shovels will be here in the 1 With S ₁ and S _n considered designated blades. The shovel S _n is the shovel S ₁ against a circumferential direction U adjacent. The circumferential direction U following are between the blades S ₁ and S _n arranged more shovels here in succession than S ₂ , ..., S _n-1 be designated. According to the invention, the difference in magnitude is the primary crystal orientations of the blades S ₁ and S _n is more than 10 times as large as an absolute difference of the primary crystal orientations of at least one other pair of adjacent blades of the plurality.

wobei N=10 sein kann. Denotes α ( S _i ) for i = 1, 2, ... n respectively the primary crystal orientation of the blade S _i , therefore, applies $$\left|\mathrm{\alpha }\left({\text{S}}_{\text{n}}\right)-\mathrm{\alpha }\left({\text{S}}_1\right)\right|>\text{N}\cdot \text{Max}\left\{\left|\mathrm{\alpha }\left({\text{S}}_{\text{i}+1}\right)-\mathrm{\alpha }\left({\text{S}}_{\text{i}}\right)\right|:\text{i}=\mathrm{1,}....\text{n}-1\right\}.$$

where N = 10.

In an advantageous embodiment, max {| α (S _{i + 1} ) -α (S _i ) |: i = 1,..., N-1} ≦ w, where w = 0.8 × D _max , w = 0 , 5 · D _max or w = 0.3 · D _max , where Dmax is the difference between the largest and smallest primary crystal orientation of all the primary crystal orientations of all the blades of the blade ring.

Preferably, | α (S _n ) -α (S ₁ ) | ≥ 0.5 · D _max or even | α (S _n ) - α (S ₁ ) | ≥ 0.8 · D _max or yes (S _n ) - α (S ₁ ) | = D _max .

According to a particularly advantageous embodiment, α (S _{i + 1} ) ≥ α (Si) holds for all i = 1,..., N-1, so that the blades are relative to the circumferential direction U with monotone increasing primary crystal orientation, or even α (S _{i + 1} )> α (S _i ) for all i = 1, ..., n-1, so that the blades are circumferentially oriented U are arranged with strictly monotone increasing primary crystal orientation. The circumferential direction U following then has up to the penultimate bucket S _n-1 (the only by the last shovel S _n separated from the first blade) of each of the blades S _i an adjacent, her following shovel S _{i + 1} whose primary crystal orientation is α ( S _{i + 1} ) is at least as large as or greater than the primary crystal orientation α ( S _i ) of the blade S _i itself. The (magnitude) largest difference α (S _n ) -α (S ₁ ) of the primary orientations of the first and the last blade thus results in this case as the sum of the differences of the primary orientations of all other pairs of adjacent blades of the plurality.

In 2 is schematically the definition of the primary orientation α represented a blade: It corresponds to half the opening angle of the straight circular cone K whose axis z in the radial direction of the blade ring and along the jacket of which the direction [001] of the elementary crystals of the monocrystalline material extends. The indication "[001]" is the usual Miller's corresponding index designation.

Disclosed is a blade ring 1 a turbomachine having a plurality of blades S ₁ . S ₂ , ..., S _i . S _{i + 1} . .. , S _n-1 . S _n includes, each consisting entirely or partially of a monocrystalline material. The majority has two adjacent blades S ₁ . S _n on, whose primary crystal orientations α have an absolute difference greater than 10 times an absolute difference in the primary crystal orientations of each other pair of adjacent blades of the plurality.

Also disclosed is a turbomachine with a blade ring.

LIST OF REFERENCE NUMBERS

1

blade ring

S ₁ , S ₂ , ..., S _i , S _{i + 1} , ... S _n-1 , S _n

shovel

α

primary crystal orientation

K

circular cone

U

circumferentially

z

central axis of the circular cone K

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

• EP 1217170 A2 [0003]
• EP 1571297 A2 [0004]
• EP 1728971 A1 [0005]
• DE 102013226015 A1 [0006]

Claims (7)

Blade ring (1) of a turbomachine, wherein the blade ring comprises a plurality of blades (S ₁ , S ₂ , ..., S _i , S _{i + 1} , ... S _n-1 , S _n ), each completely or partially composed of a monocrystalline material, the plurality comprising two adjacent blades (S ₁ , S _n ) whose primary crystal orientations (α) have an absolute difference greater than 10 times an absolute difference of the primary crystal orientations of at least one other Pair of adjacent blades of the plurality. Blade ring according to Claim 1 in which the difference in magnitude of the primary crystal orientations of said two adjacent blades (S ₁ , S _n ) is at least 0.5 times, more preferably at least 0.8 times the difference or exactly the difference between the largest and the smallest primary crystal orientation of all primary crystal orientations of all blades of the blade ring (1). Blade ring according to one of Claims 1 or 2 wherein a second largest difference in associated primary crystal orientations among adjacent blades of the plurality is at most 0.8 times, at most 0.5 times, or even at most 0.3 times the difference between the largest and smallest primary crystal orientations of all primary crystal orientations of all blades of the blade ring (1). A blade rim according to any one of the preceding claims, wherein the difference between the largest and the smallest primary crystal orientation of all primary crystal orientations of all blades of the blade ring is in the range between 0 ° and 30 °, preferably between 4 ° and 16 °. Blade ring according to one of the preceding claims, wherein one of said two adjacent blades having the largest absolute difference of the primary crystal orientations comprises a first blade (S ₁ ) and the other of the two adjacent blades with respect to a circumferential direction (U) a last blade (S _n ) of the plurality of blades and wherein the blades of the plurality with respect to the circumferential direction (U) from the first to the last blade having a monotonically growing or even strictly monotonically growing primary crystal orientation (α). Blade ring according to one of the preceding claims, which is designed as a running or as a vane ring. Turbomachine with a blade ring according to one of the preceding claims.

Images