ROTOR BLADE FOR A TURBOMACHINE, ASSOCIATED TURBINE MODULE, AND USE THEREOF

Abstract

A rotor blade (20) for placement in a gas channel (3) of a turbomachine (1), including a rotor blade airfoil (23) which, in relation to a flow in the gas channel (3), includes a front edge (23a) and a rear edge (23b) downstream therefrom, as well as a suction side (41) and a pressure side (42). The rotor blade airfoil (23) is provided with an inclination toward the suction side (41) over at least one section (45.1) of its radial rotor blade airfoil height (45). The inclination is set in such a way that during operation a centrifugal force bending moment (46), which effectuates the centrifugal force on the rotor blade airfoil (23) due to the inclination, is greater than a gas force bending moment (47) that acts on the rotor blade airfoil (23) due to the circulation around the rotor blade airfoil (23) in the gas channel (3).

Claims

1-15. (canceled)

16. A rotor blade for placement in a gas channel of a turbomachine, the rotor blade comprising: an airfoil, the airfoil, in relation to a flow in the gas channel, including a front edge and a rear edge downstream from the front edge, as well as a suction side and a pressure side, the airfoil being provided with an inclination toward the suction side over at least one section of a radial airfoil height, the inclination being set in such a way that during operation a centrifugal force bending moment effectuating a centrifugal force on the airfoil is greater than a gas force bending moment acting on the airfoil due to the circulation around the airfoil in the gas channel.

17. The rotor blade as recited in claim 16 wherein the inclination of the airfoil with respect to the suction side is designed in such a way that stress in the leading edges or trailing edges is reduced over at least 50% of the airfoil height by at least 30% compared to the centrifugal force average stress on the particular airfoil height.

18. The rotor blade as recited in claim 16 wherein the inclination of the airfoil with respect to the suction side is designed in such a way that stress in the leading edges or trailing edges is reduced over at least 50% of the airfoil height by at least 50% compared to the centrifugal force average stress on the particular airfoil height.

19. The rotor blade as recited in claim 16 wherein the inclination of the airfoil with respect to the suction side is designed in such a way that stress in the leading edges or trailing edges is reduced over at least 50% of the airfoil height by at least 70% compared to the centrifugal force average stress on the particular airfoil height.

20. The rotor blade as recited in claim 16 wherein the inclination of the airfoil with respect to the suction side is designed in such a way that stress in the leading edges or trailing edges is reduced from at least 50% to 80% of the airfoil height by at least 30% compared to the centrifugal force average stress on the particular airfoil height.

21. The rotor blade as recited in claim 16 wherein the inclination of the airfoil with respect to the suction side is designed in such a way that stress in the leading edges or trailing edges is reduced from at least 50% to 80% of the airfoil height by at least 50% compared to the centrifugal force average stress on the particular airfoil height.

22. The rotor blade as recited in claim 16 wherein the inclination of the airfoil with respect to the suction side is designed in such a way that stress in the leading edges or trailing edges is reduced from at least 50% to 80% of the airfoil height by at least 70% compared to the centrifugal force average stress on the particular airfoil height.

23. The rotor blade as recited in claim 16 wherein the inclination of the airfoil with respect to the suction side is designed in such a way that stress in the leading edges or trailing edges is reduced from at least 25% to 95% of the airfoil height by at least 30% compared to the centrifugal force average stress on the particular airfoil height.

24. The rotor blade as recited in claim 16 wherein during operation the centrifugal force bending moment is at least 1.25 times the gas force bending moment.

25. The rotor blade as recited in claim 16 wherein the inclination of the airfoil with respect to the suction side in a radially middle section of the airfoil height is greater than in a radially inner section.

26. The rotor blade as recited in claim 16 wherein the inclination of the airfoil in a radially middle section of the airfoil height is greater than in a radially outer section, or the inclination of the airfoil in a radially outer section deviates from the maximum inclination in the radially middle section by a maximum of 10%.

27. The rotor blade as recited in claim 16 wherein the airfoil has a radially outwardly decreasing profile surface over at least one section of the airfoil height.

28. The rotor blade as recited in claim 16 wherein the airfoil has a radially outwardly decreasing chord length in the at least one section of the airfoil height (45).

29. The rotor blade as recited in claim 16 further comprising an outer shroud situated radially outwardly at the airfoil, a single sealing fin being situated radially outwardly at the outer shroud.

30. The rotor blade as recited in claim 16 wherein at least the airfoil is made of a high temperature-resistant material.

31. The rotor blade as recited in claim 16 further comprising a coating at least at the front edge.

32. The rotor blade as recited in claim 31 wherein the coating is a multilayer system that includes a ceramic layer and a metallic layer, the metallic layer being situated between the ceramic layer and the airfoil.

33. The rotor blade as recited in claim 16 wherein the rotor blade designed for a high-speed rotor having an An.sup.2 of at least 2000 m/s.sup.2.

34. A turbine module for an aircraft engine comprising the rotor blade as recited in claim 16.

35. A geared turbofan engine comprising the rotor blade as recited in claim 16.

36. The turbine module as recited in claim 34 designed as a low-pressure turbine module or a high-speed fan-driving turbine module, or designed to supply a cooling fluid to an outer shroud of the rotor blade, the cooling fluid being supplied from outside the rotor blade.

37. A method for operating the rotor blade as recited in claim 16 comprising rotating the rotor blade with an An.sup.2 of at least 2000 m/s.sup.2.

38. A method for operating a rotor blade placed in a gas channel of a turbomachine, the rotor blade having an airfoil, the airfoil, in relation to a flow in the gas channel, including a front edge and a rear edge downstream from the front edge, as well as a suction side and a pressure side, the airfoil being provided with an inclination toward the suction side over at least one section of a radial airfoil height, the method comprising: rotating the rotor blade so that a centrifugal force and a gas force act on the rotor blade, the inclination being set in such a way that during operation a centrifugal force bending moment effectuating a centrifugal force on the airfoil is greater than a gas force bending moment acting on the airfoil due to the circulation around the airfoil in the gas channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention is explained in greater detail below with reference to one exemplary embodiment, it being possible for the individual features within the scope of the other independent claims besides the main claim to also be in some other combination that is essential to the present invention, in particular a distinction also not being made between the different claim categories.

[0031] FIG. 1 schematically shows a turbofan engine in an axial view;

[0032] FIG. 2 schematically shows a rotor blade of the engine according to FIG. 1 in a side view; and

[0033] FIG. 3 shows the rotor blade according to FIG. 2 in an axial view.

DETAILED DESCRIPTION OF THE INVENTION

[0034] FIG. 1 shows a turbomachine 1, specifically, a turbofan engine, in a schematic view. Turbomachine 1 is functionally divided into a compressor 1a, a combustion chamber 1b, and a turbine 1c, the latter including a high-pressure turbine module 1ca and a downstream high-speed turbine module 1cb, in particular a low-pressure turbine module, that drives the fan and during operation rotates more quickly than the fan. Compressor 1a and turbine 1c are each made up of multiple stages, each stage being made up of a guide blade ring and a rotor blade ring. In relation to the circulation in gas channel 2, each stage of the rotor blade ring is situated downstream from the guide blade ring. The rotor blades rotate about longitudinal axis 3 during operation.

[0035] FIG. 2 shows a rotor blade 20 in a schematic side view, in particular a rotor blade 20 of a rotor blade ring of turbine 1c, specifically, of turbine module 1cb. In the present case, the rotor blade includes a blade root 21, not of further particular relevance here, and radially outside same includes an inner platform 22. Rotor blade airfoil 23 extends radially outwardly from inner platform 22. An outer shroud 24 that includes exactly one sealing fin 24.1 is situated at the radially outer end of rotor blade airfoil 23. This is advantageous with regard to the weight and thus the edge load (cf. in particular the introduction to the description).

[0036] In relation to the circulation in the hot gas channel, airfoil 23 includes a front edge 23a, a rear edge 23b, and two side surfaces 23c, 23d that respectively connect front edge 23a and rear edge 23b to one another. One of side surfaces 23c, d forms the suction side of rotor blade 20, and the other side surface forms the pressure side. At front edge 23a, for protection from impact damage, rotor blade 20 is provided with a coating 25 made up of a metallic layer 25b on the airfoil and a ceramic layer 25a situated on the metallic layer, shown solely schematically. It is also apparent from the illustration according to FIG. 2 that schematically shown chord length 26 and thus profile surface 27 decrease radially outwardly, which likewise reduces the edge load.

[0037] FIG. 3 schematically shows rotor blade airfoil 23 in an axial view illustrating the inclination of rotor blade airfoil 23. In the illustration, suction side 41 of rotor blade airfoil 23 is on the left side thereof, and pressure side 42 is on the right side thereof. Rotor blade airfoil 23 is inclined toward suction side 41, in particular in a radially middle section 45.1 of rotor blade airfoil height 45. The inclination is less in radially inner section 45.2 and radially outer section 45.3; rotor blade airfoil 23 may also extend into the hub or the housing entirely without inclination.

[0038] The inclination with respect to suction side 41 is set in such a way that during operation, centrifugal force bending moment 46 acting on rotor blade airfoil 23 is greater than gas force bending moment 47. As a result, rotor blade airfoil 23 is bent toward pressure side 42, which reduces the stress there, and thus the vulnerability to impact at front edge 23a (cf. the introduction to the description).

LIST OF REFERENCE NUMERALS

[0039] turbomachine 1 [0040] compressor 1a [0041] combustion chamber 1b [0042] turbine 1c [0043] turbine module 1ca [0044] turbine module (high-speed) 1cb [0045] gas channel 2 [0046] longitudinal axis 3 [0047] rotor blade 20 [0048] blade root 21 [0049] inner platform 22 [0050] airfoil 23 [0051] front edge 23a [0052] rear edge 23b [0053] side surfaces 23c, d [0054] outer shroud 24 [0055] sealing fin 24.1 [0056] coating 25 [0057] chord length 26 [0058] profile surface 27 [0059] suction side 41 [0060] pressure side 42 [0061] rotor blade airfoil height 45 [0062] middle section 45.1 [0063] inner section 45.2 [0064] outer section 45.3 [0065] centrifugal force bending moment 46 [0066] gas force bending moment 47