Patent Application
20220268164
The invention relates to an intermediate element for a blade/rotor disk connection in a rotor of a fluid flow machine and to a rotor for a fluid flow machine.
In fluid flow machines, an intermediate element in the form of an anti-wear sheet is often arranged between the blade and the rotor disk in order to reduce the wear in the event of high loads. As a result, however, the air-system surfaces may be changed, in particular due to additional tolerances introduced by the intermediate element. In turn, this can lead to more air traveling past the blade root, meaning that the air in the cavity downstream of the blade in the flow direction becomes hotter.
This can reduce the performance of the fluid flow machine. It is also possible that the fluid flow machine is damaged as a result, or that the service life of the fluid flow machine is shortened.
In an embodiment, the present disclosure provides an intermediate element that is for a blade/rotor disk connection in a rotor of a fluid flow machine. The intermediate element is adapted to a shape of a blade root of a blade and to a blade root slot in a rotor disk for receiving the blade root such that, when arranged between the blade root and rotor disk, the intermediate element prevents contact between the blade root and rotor disk. The intermediate element has, on an outer surface that faces the rotor disk, at least one protrusion to reduce an air flow parallel to an axis of rotation of the rotor between the rotor disk and the intermediate element; and on an inner surface that faces the blade root, a recess that corresponds to the at least one protrusion.
Subject matter of the present disclosure will be described in even greater detail below based on the exemplary figures. All features described and/or illustrated herein can be used alone or combined in different combinations. The features and advantages of various embodiments will become apparent by reading the following detailed description with reference to the attached drawings, which illustrate the following:
The present disclosure describes an intermediate element for a blade/rotor disk connection in a rotor of a fluid flow machine in which the passage of air at the blade root or between the blade root and rotor disk is reduced.
An aspect of the present disclosure provides an intermediate element for a blade/rotor disk connection in a rotor of a fluid flow machine, in particular in a rotor of an engine, the intermediate element being adapted to the shape of a blade root of the blade and to a blade root slot in a rotor disk for receiving the blade root in such a way that, when in the state arranged between the blade root and the rotor disk, the intermediate element prevents direct contact between the blade root and the rotor disk, characterized in that, on its outer surface that faces the rotor disk in the state arranged between the blade root and the rotor disk, the intermediate element has at least one protrusion for reducing an air flow parallel to the axis of rotation of the rotor between the rotor disk and the intermediate element, and in that, on its inner surface that faces the blade root in the state arranged between the blade root and the rotor disk, the intermediate element has a recess that corresponds to the at least one protrusion on the outer surface of the intermediate element.
One advantage of this is that only a small amount of air or a slight air flow can flow through the intermediate region between the blade root and the rotor disk. The performance of the fluid flow machine is thus only reduced to an insignificant extent. At the same time, immediate or direct contact between the blade root and the rotor disk is prevented, thereby reducing the wear to the blade root and the rotor disk. Moreover, the introduction of heat into the cavity downstream of the blade in the flow direction of the air is reduced. Damage to the fluid flow machine is thus prevented. This lengthens the service life of the fluid flow machine. In addition, the blade or blade root can be arranged in the blade slot or rotor disk with play, meaning that the blade can yield in the event of temporarily high aerodynamic loads and/or in the event of foreign bodies appearing on the blade, and then radially realign itself on its own.
An aspect of the present disclosure provides a rotor for a fluid flow machine, in particular for an engine, the rotor comprising a rotor disk and a multiplicity of blades, which are fastened to the rotor disk, an intermediate element according to any of the preceding claims being arranged between at least one blade root of a blade and the rotor disk in such a way that the blade root does not directly touch the rotor disk. The rotor comprising the intermediate element has advantages that correspond to the above-mentioned advantages of the intermediate element.
An intermediate element can be adapted to a shape of a blade root of a blade and to a blade root slot in a rotor disk, and can be arranged between the blade root and the rotor disk in such a way that the blade root does not directly touch the rotor disk, the intermediate element being able to have recesses and one or more protrusions that are complementary to the recesses, the protrusion or protrusions reducing an air flow in a direction parallel to the axis of rotation of the rotor.
According to one embodiment, the intermediate element is in the form of a sheet, in particular an anti-wear sheet, and has an axial sectional contour, i.e. a contour within a sectional plane perpendicular to the axial direction, that corresponds to an axial sectional contour of the blade root. In this case, the blade root can, for example, have a fir-tree, dovetail or hammerhead profile or a different profile.
The at least one protrusion or the plurality of protrusions can be formed by sheet notches, such as corrugations. In this case, the sheet preferably does not contain any through-holes at the relevant sites and/or can have, at the site of each protrusion, an unchanged or substantially unchanged thickness compared with regions without the protrusions.
According to one embodiment, when in the arranged state, the intermediate element surrounds the blade root, in particular entirely, at the surface thereof facing the blade root slot. This means that in some embodiments the intermediate element can entirely cover or directly adjoin the outer surface of the blade root (the outer surface not pointing in the axial direction) within the blade root slot.
According to one embodiment, on its outer surface that faces the rotor disk in the state arranged between the blade root and the rotor disk, the intermediate element has a plurality of protrusions for reducing an air flow parallel to the axis of rotation of the rotor between the rotor disk and the intermediate element, and, on its inner surface facing the blade root, has a plurality of recesses that each correspond to the protrusions. The advantage of this is that the space or the distance between the intermediate element and the rotor disk can be reduced or made smaller at a plurality of sites. The undesirable passage of air or air flow between the intermediate element and the rotor disk can thus be reduced even further. This prevents the performance of the fluid flow machine being reduced.
According to one embodiment, in the state arranged between the blade root and the rotor disk, at least some of the plurality of protrusions are arranged next to one another in a sectional plane perpendicular to the axis of rotation of the rotor disk. The advantage of this is that a particularly large space between the blade root and the rotor disk can be made smaller by a plurality of individual protrusions. This reduces the air flow between the intermediate element and the rotor disk particularly effectively.
According to one embodiment, in the state arranged between the blade root and the rotor disk, the plurality of protrusions are arranged at different heights along the axis of rotation of the rotor. The advantage of this is that the air flow can be interfered with or reduced particularly effectively. The air flow mass can thus be reduced in a technically simple manner.
According to one embodiment, in the arranged state, the at least one protrusion or the plurality of protrusions is/are arranged in the region of a non-load-bearing flank of the blade root and/or of a bottom of the blade root slot, and extend(s) away from the blade root. In operation, during which the non-load-bearing flanks of the blade roots are pulled against the respective mating flanks of the blade root slot due to centrifugal force, a gap can be produced specifically in this non-load-bearing region, and an air flow through this gap can be reduced by the at least one protrusion. The protrusion(s) can thus extend into this gap, in particular transversely to the axial sectional contour of the blade root.
According to one embodiment, the at least one protrusion is substantially in the shape of a flattened dome. An advantage of this is that the protrusion can be manufactured in a particularly simple manner in technical terms. The protrusion can be produced in a technically simple manner by producing a spherical recess in the intermediate element.
According to one embodiment, in the state arranged between the blade root and the rotor disk, the at least one protrusion is of a substantially rectangular shape in an axial sectional plane, i.e. a sectional plane perpendicular to the axis of rotation of the rotor disk. In this way, a particularly large region between the intermediate element and the rotor disk is closed by the protrusion. The air flow flowing through the space between the intermediate element and the rotor disk can thus be throttled or reduced even more.
According to one embodiment, in the state arranged between the blade root and the rotor disk, the at least one protrusion is arranged on an end of the intermediate element facing away from the axis of rotation of the rotor. An advantage of this is that the air flow flowing through the space between the intermediate element and the rotor disk can be or is reduced at sites at which the air flow is usually particularly high when there is no protrusion. As a result, the protrusion can be arranged at sites at which the distance between the intermediate element and the rotor disk is particularly high during rotation of the rotor, and can thus reduce the air flow particularly effectively.
According to one embodiment, in the state arranged between the blade root and the rotor disk, an axial securing element, in particular an axial securing sheet, for axially securing the blade and/or radially preloading the blade root is arranged between an end of the intermediate element facing the axis of rotation of the rotor, and the rotor disk. The advantage of this is that the blade root is radially preloaded. The positions of the protrusions can thus be positioned particularly precisely. In this way, the air flow through the space between the intermediate element and the rotor disk can be reduced particularly effectively. By means of the axial securing element, the blade can, for example, be axially secured by bending axial ends of the axial securing element, which project beyond the blade root, down in the radial direction such that they cover some regions of both the blade root and the rotor disk and thus secure the blade root axially in the rotor disk.
According to one embodiment, the at least one protrusion is formed in a planar portion of the intermediate element. An advantage of this is that the protrusion can be formed or molded in a technically simple manner. In addition, the air flow between the intermediate element and the rotor disk can be considerably reduced specifically in the region in which the distance between the intermediate element and the rotor disk is usually the greatest.
According to one embodiment, the at least one protrusion extends substantially over the entire width of the planar portion of the intermediate element, the width of the planar portion extending in a sectional plane that runs perpendicularly to the axis of rotation of the rotor disk. As a result, the air flow between the intermediate element and the rotor disk can be reduced even more.
In the following description, the same reference numerals have been used for identical and identically functioning parts.
A blade 35 of a fluid flow machine is form-fittingly connected to a rotor disk 40 or form-fittingly fastened to the rotor disk 40 by its blade root 30 (i.e. the bottom end of the blade 35). To receive the blade root 30, the rotor disk 40 has a blade root slot, which is a depression corresponding to the blade root 30. The rotor disk 40 thus has a plurality of bumps 42, 43 and depressions. The blade root 30 has a plurality of depressions and bumps corresponding to the bumps and depressions. The blade root 30 contains the bottom part of the blade 35, the bottom part being arranged or received within the blade root slot or in the depression in the rotor disk 40.
The fluid flow machine can be a gas turbine, for example an engine for an aircraft. In particular, the rotor can be the rotor of a high-pressure compressor of an engine. It is also conceivable for the rotor to be part of a low-pressure compressor of an engine.
An intermediate element 10 is arranged between the blade root 30 and the rotor disk 40. The shape of the intermediate element 10 is adapted to the shape of the blade root slot in the rotor disk 40 or to the shape of the blade root 30. This means that the shape of the intermediate element 10 substantially follows the profile shape of the space between the blade root 30 and the rotor disk 40.
The intermediate element 10 can be in the form of a sheet. The intermediate element 10 can be an anti-wear sheet. The intermediate element 10 reduces the wear to the blade root 30 or rotor disk 40. In addition, the intermediate element 10 reduces the occurrence of vibrations. The intermediate element 10 prevents direct contact or immediate contact between the blade root 30 and the rotor disk 40. In other words, the intermediate element 10 ensures that the blade root 30 does not immediately or directly touch the rotor disk 40. This is particularly relevant to the situation during the rotation of the rotor disk 40 when the blade root 30 is pushed away from the axis of rotation of the rotor in the radial direction. In
The distance between the blade root 30 and the rotor disk 40 is different in different regions, as can be seen particularly clearly in
The protrusions 20-22 on the outside or outer surface 11 of the intermediate element 10 (the outside or outer surface 11 faces the rotor disk 40) correspond to recesses on the inside or inner surface 12 of the intermediate element 10. The inside or inner surface 12 of the intermediate element 10 faces the blade root 30.
The protrusions 20-22 on the outside or outer surface 11 of the intermediate element 10 and the recesses on the inside or inner surface 12 of the intermediate element 10 may be formed by indenting a part of the intermediate element 10. The protrusions 20-22 may be produced by pressing out a part of the intermediate element 10. Each protrusion 20-22 on the outside or outer surface 11 of the intermediate element 10 may then have a complementary or corresponding recess on the inside or inner surface 12 of the intermediate element 10.
In
In
The protrusions 20-22, and thus also the recesses, are each located in planar or flat regions of the intermediate element 10. This means that, in the regions around each recess and each protrusion 20-22, the intermediate element 10 runs in a planar or flat manner on the outside or outer surface 11 and/or on the inside or inner surface 12; in particular, it means that the regions (immediately) around each recess or each protrusion 20-22 do not have any curvature. However, it is also conceivable for the protrusions 20-22 or recesses to be formed in bent or curved regions of the intermediate element 10.
The axis of rotation of the rotor is located below the middle of the blade root 30 in
The intermediate element 10 has a flat or planar lower surface or underside facing the axis of rotation of the rotor. Between this flat or planar underside and the axis of rotation of the rotor, there is arranged an axial securing element, in particular an axial securing sheet 50. The axial securing sheet 50 presses against the intermediate element 10 in the radial direction such that the intermediate element 10 in turn presses or preloads the blade root 30 in the radial direction.
The intermediate element 10 can be formed symmetrically in relation to a plane of symmetry 60 running from the top downward in the middle of
The protrusion 20-22 having the rectangular cross section is formed such that the protrusion 20-22 almost touches the rotor disk 40 (in particular during rotation of the rotor). Only a very small space remains between the protrusion 20-22 and the rotor disk 40. The protrusions 20-22 on the right-hand side of the intermediate element 10 touch the rotor disk 40.
The recess in the intermediate element 10 is formed in the manner of a flattened dome. The recess on the inside or inner surface 12, which recess has a corresponding protrusion 20-22 on the outside or outer surface 11, is located in a planar or flat portion (not having the recess) of the intermediate element 10. The recess or protrusion 20-22 is located in the middle of the planar portion, i.e. the distance from the protrusion 20-22 to the planar-portion end that is further away from the axis of rotation of the rotor is the same as the distance from the protrusion 20-22 to the planar-portion end that is closer to the axis of rotation of the rotor.
The protrusion 20-22, and thus also the recess visible in
The recess or protrusion 22 is substantially rectangular parallelepiped-shaped, the wall of the recess being able to comprise a plurality of edges. The recess can thus merge into the planar portion of the intermediate element 10 over a plurality of edges.
In the embodiment shown in
The recess or depression is usually produced by indenting the edge at one point or in one portion. In
The protrusion 20-22 or the recess can each extend over the planar portion as far as into the curved portion of the intermediate element 10. The free surfaces 15-17 are usually formed in this curved portion of the intermediate element 10, i.e. the intermediate element 10 does not touch the rotor disk 40 and is often at a great distance from the rotor disk 40 here.
In particular, the intermediate element 10 can have a small thickness, the thickness being measured from the axis of rotation of the rotor toward the blade 35 or blade root 30. By way of example, the thickness of the intermediate element 10 can be in the range from approximately 1 mm to approximately 5 mm, in particular in the range from approximately 2 mm to approximately 4 mm, e.g. approximately 3 mm. The intermediate element 10 can thus be in the form of a (metal) sheet.
The recess or the protrusion 20-22 can be in the form of a corrugation in the intermediate element 10.
Each protrusion 20-22 or each recess is usually formed point-symmetrically in relation to the middle of each protrusion 20-22 or each recess. However, it is also conceivable for each protrusion 20-22 or each recess to have an asymmetrical shape.
While subject matter of the present disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Any statement made herein characterizing the invention is also to be considered illustrative or exemplary and not restrictive as the invention is defined by the claims. It will be understood that changes and modifications may be made, by those of ordinary skill in the art, within the scope of the following claims, which may include any combination of features from different embodiments described above.
The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B and C” should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of “A, B and/or C” or “at least one of A, B or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2019 210 699.4 | Jul 2019 | DE | national |
This application is a U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/DE2020/000154, filed on Jul. 14, 2020, and claims benefit to German Patent Application No. DE 10 2019 210 699.4, filed on Jul. 19, 2019. The International Application was published in German on Jan. 28, 2021 as WO 2021/013280 A1 under PCT Article 21(2).
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/DE2020/000154 | 7/14/2020 | WO |
