JP2012532268A - Rotor blade and method for reducing tip friction load - Google Patents

Abstract

The airfoil (42) for use in the rotor assembly has a tip cutter (100) disposed on the side wall (44) near the tip (60), the tip cutter being free from tip friction. A portion of the abradable material (32) can be removed therein. The airfoil has a tip polishing section (120) disposed on the tip section, which can remove a portion of the abradable material (32) during tip friction. The airfoil has a tip rake (110) that facilitates reducing the load induced on the airfoil during tip friction. A method (300) for providing a tip frictional load on a rotor blade (15) incorporates a tip cutter portion (100) having a selected cutter profile (102) at a selected position on the blade (15), the tip The cutter unit (100) includes a step of removing a part of the fixed structure (32) during the tip friction to reduce the tip friction load.
[Selection] Figure 4

Description

  The present invention relates generally to gas turbine engines, and more specifically to a method and apparatus for reducing tip friction loads induced in rotor blades.

  At least some known gas turbine engines typically include a casing, a fan rotor assembly, low and high pressure compressors, a combustor, and at least one turbine. The compressor pressurizes the air, which is sent to the combustor where it is mixed with the fuel. The air-fuel mixture is then ignited to produce hot combustion gases. Combustion gas is sent to a turbine that extracts energy from the combustion gas to drive a compressor and generate useful work, propel an aircraft in flight, or drive a load such as a generator .

  Some known fan and compressor assemblies include a casing that encloses a rotor having a plurality of rotor blades. Under certain engine operating conditions, the rotor blades may be subjected to blade tip friction events that result in radial and tangential loads in the blade airfoil. Excessive friction loads can promote blade damage due to vibration and fatigue conditions. Excessive friction loads from blade friction can also promote secondary damage, including damage to non-adjacent blades and casings. When the blades penetrate the fan case abradable system, excessive fan blade friction can add significant friction loads to the rotating disk and bearings.

  Accordingly, it would be desirable to have a rotor and casing system with a rotor blade having features that reduce frictional loads during blade tip friction. It is desirable to have a rotor blade with an airfoil that mechanically removes casing abradable material during tip friction. It would be desirable to have a method of forming a rotor assembly with reduced blade tip friction loads.

  One or more of the needs described above include a first sidewall, a second sidewall coupled to the first sidewall at a leading edge and a trailing edge, and a tip extending between the first and second sidewalls. An exemplary embodiment providing an airfoil with a tip cutter portion disposed on a first sidewall near the tip and capable of removing a portion of the abradable material during tip friction. Can be dealt with by.

  In another embodiment, the airfoil includes a tip polishing section disposed on the tip section, which can remove a portion of the abradable material during tip friction.

  In another embodiment, the airfoil comprises a tip rake disposed on at least a portion of the tip and extending between the first and second sidewalls, the tip rake being on the airfoil during tip friction. It has a rake profile that facilitates the reduction of induced loads.

  In another embodiment, a blade assembly includes an airfoil and a metal leading edge (MLE) coupled to at least a portion of the airfoil, wherein the MLE is abradable material during tip friction. It has a tip cutter part which can remove a part of.

  In another embodiment, the blisk comprises a plurality of airfoils extending from the hub and a tip cutter portion disposed on the at least one airfoil, wherein the tip cutter portion is abradable during tip friction. Part of the material can be removed.

  In another embodiment, the blisk comprises a plurality of airfoils extending from the hub and a tip polishing portion disposed on the at least one airfoil, wherein the tip polishing portion is abradable during tip friction. Part of the material can be removed.

  In another aspect of the invention, a method is provided for reducing tip friction load on an airfoil, the method comprising: selecting a contact position between the airfoil and a stationary structure; A step of selecting a position on the airfoil part to be incorporated, a step of selecting a cutter profile of the tip cutter part, a tip cutter part is incorporated at a selected position on the airfoil part, and the tip cutter part is fixed during tip friction. Removing a part of the body so that the tip friction load can be reduced.

  In another aspect of the present invention, a method for reducing tip friction load on an airfoil provides a tip polishing portion disposed on the tip and capable of removing a portion of abradable material during tip friction. Including the steps of:

  In another aspect of the present invention, a method for reducing tip friction load on an airfoil is disposed on at least a portion of a tip of a blade assembly and is configured to reduce the load induced in the blade assembly during tip friction. Providing a tip rake having a rake profile that facilitates reduction.

  The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the claims appended hereto. However, the invention can best be understood by referring to the following description in conjunction with the accompanying drawings.

  In another aspect of the invention, a method of assembling a rotor assembly provides a blade assembly that includes an airfoil and a metal leading edge (MLE) coupled to at least a portion of the airfoil. Removing the material from a part of the MLE to form a tip cutter part having a cutter profile, and the tip cutter part machining the abradable material during tip friction and induced on the blade during tip friction Coupling the blade assembly to the rotor hub so as to reduce the radial load.

1 is a schematic diagram of an exemplary gas turbine engine including an airfoil according to an exemplary embodiment of the present invention. 1 is a perspective view of a rotor blade including an airfoil according to an exemplary embodiment of the present invention. FIG. The perspective view of the front-end | tip part of the airfoil part shown in FIG. FIG. 3 is a cross-sectional view of the tip of the airfoil shown in FIG. 2 positioned in the casing of the gas turbine engine shown in FIG. 1. FIG. 4 is a schematic diagram of an exemplary rotor blade, according to an alternative embodiment of the present invention. The flowchart which shows the step of the method of reducing a tip friction load.

  FIG. 1 is an exemplary illustration of the present invention of a blade 15 with a tip portion 60 that facilitates reducing friction loads induced on the rotor blade 15 when tip friction occurs between the rotor blade 15 and the casing 17. 1 is a schematic view of an exemplary engine assembly 10 having an embodiment. FIG. The engine assembly 10 having a longitudinal axis 12 includes a fan assembly 13, a booster compressor 14, a core gas turbine engine 16, and a low pressure turbine 26 coupled to the fan assembly 13 and booster compressor 14. . The core gas turbine engine 16 includes a high pressure compressor 22, a combustor 24, and a high pressure turbine 18. The booster compressor 14 includes a plurality of rotor blades 40 that extend substantially radially outward from the rotor disk 20 coupled to the first drive shaft 31. The engine assembly 10 has an intake side 28 and an exhaust side 30. The compressor 22 and the high pressure turbine 18 are coupled together by a second drive shaft 29.

  During operation, air flows into the engine 10 through the intake side 28 and flows through the fan assembly 13, and pressurized air is supplied from the fan assembly 13 to the booster compressor 14 and the high pressure compressor 22. The plurality of rotor blades 40 pressurize air and supply the pressurized air to the core gas turbine engine 16. The air stream is further pressurized by the high pressure compressor 22 and fed to the combustor 24. Hot gas from the combustor 24 drives the rotary turbines 18 and 26 and exits the gas turbine engine 10 through the exhaust side 30.

  The present invention provides exemplary apparatus and methods for reducing friction loads induced in airfoils, such as, for example, rotor blades 15 and rotor assemblies 13 used in gas turbine engines 10. FIG. 2 is a perspective view of the rotor blade 15 used in the fan or compressor section of the engine 10. In FIG. 1, the rotor blade indicated by reference numeral 15 is a fan rotor blade, and the rotor blade indicated by reference numeral 40 is a compressor section rotor blade. Although the present invention will be described with respect to fans and compressor rotor blades, the present invention is not limited to such components and is not limited to such components, but with an integral bladed disk ("BLISKS") with integral airfoils and turbine rotors 18,26. ]). In the exemplary embodiment shown in FIG. 2, the first side wall 44 (also referred to herein as “pressure side” and “concave side”), the second side wall 46 (also referred to herein as “ A rotor blade 15 is provided that includes an airfoil 42 having a suction side and a convex side), a root 54, and a tip 60. The rotor blade 15 includes an airfoil portion 42, a platform portion 55, and an integral dovetail portion 43 that is used to mount the rotor blade 15 to the rotor hub 21. The airfoil 42 includes a first side wall 44 and a second side wall 46. In the exemplary embodiment, the first side wall 44 is substantially concave and defines the pressure side of the rotor blade 15, and the second side wall 46 is substantially convex and defines the suction side of the rotor blade 15. The side walls 44 and 46 are joined together at a leading edge 48 and an axially spaced trailing edge 50. The trailing edge 50 is spaced in the chord direction and downstream from the leading edge 48. The first and second sidewalls 44 and 46 each extend from the blade root 54 to the blade tip 60 with a span 52 longitudinally or radially outward. The tip 60 is defined between the side walls 44 and 46 and includes a tip surface 62, a concave edge 64, and a convex edge 66. The dovetail portion 43 is positioned at the root portion 54 and includes a platform 55 that extends circumferentially outward from the first and second side walls 44 and 46, respectively. In the exemplary embodiment, dovetail 43 is positioned substantially axially adjacent to root portion 54. In an alternative embodiment, dovetail 43 is positioned substantially circumferentially adjacent root 54. The rotor blades 15, 40 can have any conventional form and may or may not include a dovetail 43 or platform 55. For example, the airfoil 42 of the rotor blades 15, 40 can be formed integrally with the rotor hub 21 or disk (or referred to herein as a blisk). In the blisk configuration, the rotor blades 15, 40 do not include the dovetail 43 and the platform 55.

  In the exemplary embodiment shown in FIGS. 1 and 4, the abradable material 32 is coupled to a casing 17 that extends circumferentially about the longitudinal axis 12. The platform 55 of the rotor blade 40 defines the inner boundary of the flow path 35 that extends through the booster compressor 14. In an alternative embodiment, for example, an inner boundary such as blisk 180 can be defined by the rotor disk 21 (shown in FIG. 1). The casing 17 and the abradable material 32 define the radially outer boundary of the flow path 35. As shown in FIG. 4, the abradable material 32 is spaced from each rotor blade tip 60 by distances D1 and D2, and a gap gap 33 is defined between the material 32 and the airfoil 42. It becomes like this. Specifically, the abradable material 32 is disposed at a distance D2 from the convex edge 66 and a distance D1 from the concave edge 64. The distances D1 and D2 are selected so that tip friction between the rotor blades 15, 40 and the abradable material 32 can be prevented during engine operation. In the exemplary embodiment, the inner and outer boundaries of the flow path are not parallel and the overlap axis 80 need not be perpendicular to the outer flow path boundary.

  During normal engine operation, the rotor disk 20 (and the rotor hub 21) rotate within a track diameter substantially about the longitudinal axis 12. Thus, the rotor blades 15, 40 are more specifically excluding minor fluctuations due to slight instability of the engine 10 so that the gap gap 33 (see FIG. 4) is substantially maintained. , Rotate about the longitudinal axis 12 so that the tip 60 remains at a distance D1 from the abradable material 32. The gap gap 33 is also sized to reduce the amount of air that can flow past the tip 60 during engine operation, i.e. tip leakage.

  Under some engine transient operating conditions, the blade 15 may be displaced so that the tip 60 rubs the abradable material 32. During such tip friction, a portion of the airfoil tip can be pushed into the abradable material 32 and radial and axial loads can be induced on the rotor blade. This type of frequent tip friction can increase radial loads and blade vibration. Such loads and vibrational stresses can increase and sustain the dynamic stress of conventional airfoils, which can subject the conventional airfoils to material fatigue. Continued operation with material fatigue over a period of time may cause blade cracking and / or reduce the useful life of the rotor blade.

  FIG. 2 illustrates an exemplary fan rotor blade 15 according to one embodiment of the present invention. FIG. 3 is a perspective view of the tip of the airfoil 42 of the rotor blade 15. 4 is a cross-sectional view of the tip of the airfoil 42 of the rotor blade shown in FIG. 2 positioned in the casing 17 of the gas turbine engine 10 shown in FIG. Specifically, in the exemplary embodiment shown in FIGS. 2-4, the rotor blade 15 is a tip that facilitates reducing the radial load induced on the blade 15 when tip friction occurs during engine operation. Part 60.

  In the exemplary embodiment of the present invention shown herein in FIGS. 1-5, a specification that promotes a reduction in the frictional load generated during friction with the abradable material 32 at the airfoil tip at a particular operating condition. Are provided near the airfoil tip 61 and the leading edge 48 region. Specifically, these features reduce the frictional load by removing a portion of the abradable material 32 by machining. One such feature shown in the exemplary embodiment herein (see FIG. 2) is a tip cutter portion 110 disposed near the tip portion 60. In the exemplary embodiment shown in FIG. 2, the tip cutter portion 100 is positioned near the leading edge 48 near the tip 61 on the “pressure side” (first side wall 44) of the airfoil 42. The tip cutter portion 100 has a cutter profile 102 with geometric features (see FIG. 4) that can remove a portion of the abradable material 32 by machining during tip friction. The exemplary cutter profile 102 shown in FIG. 4 includes a cutter angle 104 disposed at the leading edge 48 of the airfoil tip 61. As shown in FIG. 4, the cutter angle 104 is an angle between the leading edge 48 and the flat portion 108 of the blade tip 61. Cutter angle 104 is selected to facilitate machining and removal of abradable material 32 during a tip friction event. The cutter angle 104 can have a value between about 1 degree and 10 degrees. In a preferred embodiment, the cutter angle 104 has a value between about 2 degrees and about 5 degrees. The cutter profile 102 shown in FIG. 4 further includes an arcuate recess 106 that extends into the airfoil to a particular depth “B” (see FIG. 4). In a preferred embodiment, the depth “B” has a value of about 0.005 inches. In other embodiments, the depth “B” may have a value of about 0.050 inches. The cutter profile 102 near the tip 61 extends in the span direction along a portion of the leading edge 48 as shown in FIG. The cutter profile 102 also extends chordally along the portion of the airfoil 42 from the leading edge 48 toward the trailing edge 50, and the depth “B” and cutter angle 108 gradually decrease to zero. Thus, the air flow is smoothly continuous with the concave side surface 44 of the airfoil so as to promote a smooth air flow in the airfoil 42.

In another exemplary embodiment of the present invention, the airfoil 42 has a tip polisher 120 disposed on the tip 60, such as near the leading edge 48 as shown in FIG. The tip polishing unit 120 includes an abrasive that is applied to the tip of the airfoil and serves as a cutting agent for the abradable material 32 disposed in the casing 17. The abradable material of the tip abrasive can be regular or irregular in shape and can have sharp edges with a radius of less than 0.10 inches. The tip polisher 120 is made of a suitable material that can remove a portion of the abradable material 32 during tip friction. The tip polishing portion 120 is made of a ceramic, metal, or intermetallic bonding material having a composition composed of an embedded abrasive. In the case of metal and intermetallic particles, the material has a Vickers hardness (g / mm ² ) of over 750. A known abrasive can be used in the tip polishing portion 120. Preferred known abrasives used for the tip polishing section 120 include aluminum oxide, silicon carbide, CBN, or diamond. The tip grind 120 can be joined to the airfoil 42 using known methods such as brazing and welding. In a preferred embodiment, the tip polisher 120 is joined to the airfoil 42 by brazing. In an alternative embodiment of the blade 15, the tip abrasive 120 can be joined or attached to the airfoil 42 by thermal spraying or using a known adhesive. The tip polisher 120 is shown in FIG. 4 to be located near the tip of the leading edge 48, but in alternative embodiments, the blade tip near the trailing edge 50 or other suitable location on the tip 61. You may arrange in.

  In another aspect, the present invention includes a tip rake 110 (see FIG. 4) extending between first and second sidewalls 44, 46 disposed on at least a portion of the tip 60. The tip rake 110 has a rake profile 112 that facilitates reducing the load induced on the airfoil 42 during tip friction. In the exemplary embodiment shown in FIG. 4, the rake profile 112 has a rake angle 114 (“A”) relative to a plane 82 that is substantially perpendicular to the overlap axis 80 of the airfoil 42. The overlap axis 80 is an axis extending from the root portion 54 to the tip portion 60 in the span direction through the blade 15. The tip rake 110 may have a rake angle 114 between about 2 degrees and about 15 degrees. In a preferred embodiment, the tip rake 110 has a rake angle 114 between about 3 degrees and about 5 degrees.

  In the exemplary embodiment shown in FIGS. 2-5, the tip surface 62 extends diagonally between the airfoil sidewalls 44 and 46. More specifically, the tip surface 62 is oriented with a rake angle A. The rake angle A of the tip surface 62 is measured with respect to a plane 82 extending through the rotor blade 15 substantially perpendicular to the overlap axis 80. Plane 82 allows for the creation and orientation of tip surface 162. In one embodiment, during the fabrication process, the plane 82 is established using a plurality of reference points defined on the outer surface of the blade 15. Alternatively, the blade tip surface 62 can be directed to any rake angle A that allows the blade 15 to function as described herein.

  In the exemplary embodiment, tip surface 62 has a rake profile 112 defined by rake angle A. The orientation of the rake tip surface 62 defined by the rake profile 112 causes the gap gap 33 to be non-uniform across the blade tip 60. Specifically, in the exemplary embodiment, since the tip surface 62 is oriented at the rake angle A, the height D2 of the gap gap 33 at the convex edge 66 (see FIGS. 2 and 4) is a concave edge. It is larger than the height D1 of the gap gap 33 at the portion 64 (see FIGS. 2 and 4). In the exemplary embodiment, surface 62 having rake profile 112 is formed via a rake process. Alternatively, the surface 62 can be flat with a substantially constant rake angle A using any other known fabrication process, including but not limited to a machining process.

  In another exemplary embodiment of the present invention, a conventional blade can be modified to produce a blade 15 including a tip 60 as described herein. Specifically, the tip cutter portion 100 is formed near the tip of a blade as described herein by machining or other known methods. Further, optionally, the tip polisher 120 is coupled to an existing blade as described herein and shown in FIGS. Further optionally, excess blade material can be removed from the existing blade tip 60 via a rake process to prevent the convex edge 66 from contacting the abradable material 32 during tip friction. A tip 60 having a corresponding rake profile 112 and rake angle A is formed. The rake angle A can have a value between about 5 degrees and about 15 degrees. More specifically, in a preferred embodiment, rake angle A has a value between about 3 degrees and about 5 degrees. In an alternative embodiment, the blade 15 is formed by a known process with a rake profile 112 and a tip 60 having a rake angle A and a tip cutter portion 100, the tip 60 being a desired rake profile 112 and cutter. Formed with a profile 102 and, optionally, a tip polishing section 112 is added to the tip 61.

  During normal engine operation, the rotor disk 20 rotates within a track diameter substantially about the longitudinal axis 12. Accordingly, the rotor blades 15, 40 rotate about the longitudinal axis 12 and a sufficient gap gap 33 is maintained between the rotor blade tip 60 and the abradable material 32. If the blades 15, 40 are deflected, the tip 60 may unintentionally rub the abradable material 32. As shown in FIGS. 2 and 4, the tip 60 is directed to the rake angle A during tip friction, so the concave edge 64 is closer to the abradable material 32 than the convex edge 66. When the tip polishing portion 120 exists, the abradable material 32 is first contacted, and a part of the abradable material 32 is removed by machining. The tip cutter portion 100 is located at the leading edge of the blade 15 in the rotational direction 125 and removes a portion of the braidable material 32 by machining during a tip friction event. Cutter profile 102 is such that cutter angle 104 contacts abradable material 32 at an angle to machine it, and arcuate recess 106 removes machined abradable material 32 from tip 61. . As a result, it is possible to reduce the radial and axial loads induced on the rotor blade 15 during tip friction as compared to the conventional rotor blade. In addition, the dynamic stress induced in the blade 15 can lead to blade cracking in conventional blades due to material fatigue, which can also be reduced. Specifically, during tip friction, the abradable material 32 is removed by machining rather than being pushed into contact with the casing 17 as in a conventional blade, so that the loads and vibrations induced in the blade 15 Stress is reduced.

  FIG. 5 shows a schematic diagram of an alternative exemplary embodiment of the present invention for a blade 170 having features for reducing tip friction loads as described above. The exemplary blade 170 shown in FIG. 5 may be used with the gas turbine engine 10 (shown in FIG. 1). Fan blade 170 includes an airfoil 154 and a blade tip cap 150 that cooperates with a radially innermost surface (not shown) of casing 17 to form clearance 33 (shown in FIG. 1) therebetween. In an alternative exemplary embodiment shown in FIG. 5, the cap 150 is formed from a titanium metal sheet. Alternatively, the cap 150 is formed from any material that allows operation of the blade 170 as described herein. The blade 170 also includes a dovetail root 152 that allows coupling to the rotor hub 21. The airfoil 154 of the blade 170 is formed from a known material through processes known in the art. Such materials include, but are not limited to, composite materials. The blade 170 also includes a triangular edge guard 156. In the exemplary embodiment, guard 156 is formed from a titanium sheet metal. Alternatively, guard 156 is formed from any material that allows operation of blade 170 in engine 10. The airfoil 154 has a first radial length 157.

  The blade 170 further includes a metal leading edge (MLE) 158. The MLE 158 is formed from any metallic material that facilitates the operation of the fan assembly 13 in the engine 10, including but not limited to titanium alloys and inconel alloys. MLE 158 and cap 150 and guard 156 are coupled to airfoil 154 by methods known in the art, including but not limited to brazing, welding, and gluing. The MLE 158 includes a solid nose region 160 and a plurality of sidewalls 162 (only one exterior sidewall 162 is shown in FIG. 5). The MLE 158 extends along substantially all of the airfoil radial length 157. Further, the radially innermost portion of the MLE 158 extends radially inward along the root portion 152 and the radially outermost portion of the MLE 158 faces radially outward so that the MLE 158 is substantially flush with the cap 150. Extend. Accordingly, in the exemplary embodiment, MLE 158 is configured with a second radial length 163 that is greater than first radial length 157. Alternatively, the length 163 is any value that facilitates the operation of the blade 170 during a tip friction event as previously described herein.

  When assembled on the engine 10, the blade 170 and the casing 37 cooperate to form a clearance 33 therebetween. As already described herein, under certain engine operating conditions, the tip 61 of the rotor blade 170 may contact the abradable material 32 surrounding the blade tip (see FIGS. 1-4). it can. For example, a non-equilibrium condition in the engine 10 (shown in FIG. 1) may facilitate a reduction in the radial distance between the tip cap 150 and the casing 17, thereby abradable material in the cap 150 and the casing 17. The possibility of contact or friction with 32 increases. Such friction induces radial and tangential forces, and at least some of such loads are transmitted to the casing 17 and part of the airfoil 154. An alternative exemplary embodiment of the blade 170 shown in FIG. 5 is disposed within the blade tip 60 and has features that reduce tip friction loads as described hereinabove. The blade 170 has a tip cutter portion 100 disposed at the tip portion 60 of the blade leading edge solid nose region 160. The tip cutter portion 100 has a cutter profile 102 with a flat portion 108, a cutter angle 104, and an arcuate recess 106, as described hereinabove. Tip cutter portion 100 is configured to contact abradable material 32 at an angle during a tip friction event, which is machined away, resulting in a reduced friction load. The recess 106 of the cutter profile 102 is such that the abradable material 32 to be machined is removed from the contact area. The cutter angle 104 can have a value between about 1 degree and about 10 degrees. In a preferred embodiment, the cutter angle 104 has a value between about 2 degrees and about 5 degrees.

The blade 170 may further include a tip polishing portion 120 disposed at the blade tip portion 60 as described above. In FIG. 5, the tip polishing portion 120 is illustrated as being disposed at the tip portion 60 of the blade leading edge solid nose region 160. Alternatively, the tip polishing portion 120 may be disposed at another suitable position in the tip portion 60 of the blade tip cap 150. The tip polisher 120 is made of a suitable material that can remove a portion of the abradable material 32 during tip friction. The tip polishing portion 120 includes an abrasive that serves as a cutting agent for the abradable material 32 disposed in the casing 17. The abradable material of the tip abrasive can be regular or irregular in shape and can have sharp edges with a radius of less than 0.10 inches. The tip polishing portion 120 is made of a ceramic, metal, or intermetallic bonding material having a composition composed of an embedded abrasive. In the case of metal and intermetallic particles, the material has a Vickers hardness (g / mm ² ) of over 750. A known abrasive can be used in the tip polishing portion 120. Preferred known abrasives used for the tip polishing section 120 include aluminum oxide, silicon carbide, CBN, or diamond. The tip polishing portion 120 can be joined to the MLE 158 or the tip cap 150 using a known method such as brazing and welding. In a preferred embodiment, the tip polishing portion 120 is joined to the MLE 158 by brazing. In an alternative embodiment of the blade 15, the tip polisher 120 can be joined or attached to the MLE 158 and / or the tip cap 150 by thermal spraying or using a known adhesive.

  In another aspect, the blade 170 shown in FIG. 5 includes a tip rake 110 (e.g., FIG. 5) that extends between first and second sidewalls 44, 46 disposed on at least a portion of the tip 60 of the tip cap 150. 4). The tip rake 110 has a rake profile 112 that facilitates reducing the load induced on the airfoil 42 during tip friction. As already described herein (see FIG. 4), the rake profile 112 allows the contact between the blade tip 61 and the abradable material 32 at the concave edge of the blade tip during a tip friction event. It has a rake angle 114 ("A") that occurs to reduce the frictional load. The tip rake 110 may have a rake angle 114 between about 2 degrees and about 15 degrees. In a preferred embodiment, the tip rake 110 has a rake angle 114 between about 3 degrees and about 5 degrees.

  FIG. 6 is a flowchart illustrating the steps of a method 300 for reducing tip friction load. The method 300 includes selecting 305 a contact location during a tip friction event between the tip of the blade and a stationary structure such as abradable material 32. This is illustrated, for example, in FIG. 4 where the contact location is selected as the leading edge tip of the pressure side 44. Step 310 includes selecting a cutter profile 102 (as already described herein) for the tip cutter portion 100. Step 315 includes an optional step of selecting the tip polisher 120. Suitable materials that can machine the abradable material 32 can be selected as described above. Step 320 also includes an optional step of selecting a tip rake profile, as already described herein. Step 325 includes incorporating the tip cutter portion 100 onto the blade tip. This is preferably done by machining, but other known methods may be used. Step 330 includes the optional step of joining the tip polisher 120 as previously described (if selected in step 315). Step 335 includes an optional step that incorporates the rake profile 112 of the tip rake 110 on the blade (if selected in step 320).

  An exemplary embodiment of a rotor blade has been described in detail above. The rotor blades are not limited to the specific embodiments described herein, but rather the components of each assembly may be utilized separately and independently of the other components described herein. it can. For example, each rotor blade component can also be used in combination with other blade system components, including but not limited to blisks, and gas turbines and non-gas turbine engines. Although the invention described herein has been described in connection with the turbine engine shown in FIG. 1, the apparatus and method of the present invention has also been described herein with appropriate modifications. It will be appreciated by those skilled in the art and from the teachings described herein that it can be suitable for any engine with a compressor operable in this manner.

  This written description discloses the invention using examples, including the best mode, and also enables those skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other embodiments are within the scope of the invention if they have structural elements that do not differ from the words of the claims, or if they contain equivalent structural elements that have slight differences from the words of the claims. It shall be in

15 Blade 17 Casing 33 Gap gap 32 Fixed structure 40 Rotor blade 42 Airfoil portion 44 Side wall 46 Side wall 60 Tip portion 61 Airfoil tip 62 Tip surface 80 Overlapping axis 82 Plane 100 Tip cutter portion 102 Cutter profile 104 Cutter angle 106 Arc Concave portion 108 Flat portion 110 Tip rake 112 Rake profile 114 Rake angle 120 Tip polishing portion 125 Direction of rotation 170 Blade assembly

Claims (48)

A first side wall (44);
A second sidewall (46) coupled to the first sidewall (44) at a leading edge (48) and a trailing edge (50);
A tip (60) extending between the first and second side walls (44, 46);
A tip cutter (100) disposed on the first side wall (44) near the tip (60) and capable of removing a portion of the abradable material (32) during tip friction;
An airfoil (42) comprising:   The airfoil (42) according to claim 1, wherein the tip cutter (100) has a cutter profile (102) that facilitates reducing a load induced on the airfoil (42) during tip friction. .   The airfoil (42) of claim 2, wherein the cutter profile (102) includes a cutter angle (104) disposed at a leading edge (48) of the airfoil tip.   The airfoil (42) of claim 3, wherein the cutter angle (104) has a value between about 2 degrees and about 4 degrees.   The airfoil (42) of claim 1, wherein the tip cutter (100) extends along a portion of the leading edge (48).   The airfoil (42) of claim 1, wherein the tip cutter (100) extends in a chordal direction along a portion of the airfoil (42).   A tip polishing portion (120) disposed on the tip portion (60), the tip polishing portion (120) can remove a portion of the abradable material (32) during tip friction; The airfoil (42) according to claim 1.   A tip rake (110) disposed on at least a portion of the tip (60) and extending between the first and second sidewalls (44, 46), the tip rake (110) having tip friction; The airfoil (42) of claim 1, having a rake profile (112) therein that facilitates a reduction in loads induced on the airfoil (42). A first side wall (44);
A second sidewall (46) coupled to the first sidewall (44) at a leading edge (48) and a trailing edge (50);
A tip (60) extending between the first and second side walls (44, 46);
A tip polishing portion (120) disposed on at least a portion of the tip (60) and capable of removing a portion of the abradable material (32) during tip friction;
An airfoil (42) comprising:   The airfoil (42) according to claim 9, wherein the tip polishing portion is disposed near the leading edge (48).   The airfoil (42) according to claim 9, wherein the tip polishing portion (120) is disposed near the trailing edge (50).   The airfoil (42) of claim 9, wherein the tip polish (120) comprises a ceramic material.   The airfoil (42) according to claim 9, wherein the tip abrasive (120) is joined to the airfoil (42) by brazing.   The airfoil (42) according to claim 9, wherein the tip abrasive (120) is applied by the airfoil (42) by thermal spraying.   A tip rake (110) disposed on at least a portion of the tip (60) and extending between the first and second sidewalls (44, 46), the tip rake (110) having tip friction; The airfoil (42) of claim 9, having a rake profile (112) therein that facilitates reducing a load induced on the airfoil (42).   And an overlap axis (80) and a plane (82) substantially perpendicular to the overlap axis (80), wherein the tip rake (110) is about 5 degrees and about 15 with respect to the plane (82). The airfoil (42) of claim 15, having a rake angle (114) between degrees.   An airfoil (42) according to claim 15, disposed in a casing (17), the first distance measured between the casing (17) and the first side wall (44). An airfoil (42), wherein (131) is less than a second distance (132) measured between the casing (17) and the second sidewall (46).   The airfoil (42) of claim 15, wherein the abradable material (32) forms a part of the rotor assembly (13), wherein the abradable material (32) is a longitudinal axis (12) of the rotor assembly (13). The tip rake profile (112) causes the tip polishing portion (120) near the first sidewall (44) to contact the abradable material (32). The airfoil (42), wherein the second side wall (46) is allowed to contact the abradable material (32) during tip friction. A rotor hub (21);
A first side wall (44); a second side wall (46) coupled to the first side wall (44) at a leading edge (48) and a trailing edge (50); a root part (54); A tip (60) extending between the first and second side walls (44, 46) and disposed on the first side wall (44) in the vicinity of the tip (60) and abradable during tip friction A plurality of rotor blades coupled to the rotor hub (21), each including an airfoil (42) comprising a tip cutter (100) capable of removing a portion of the material (32). (15) and
A rotor assembly (13).   An abradable casing (17) extends circumferentially around the rotor assembly (13) to reduce the load induced on the airfoil (42) during tip friction of the tip cutter (100). The rotor assembly (13) of claim 19, wherein the rotor assembly (13) has a cutter profile (102) that facilitates. A rotor hub (21);
A first side wall (44); a second side wall (46) coupled to the first side wall (44) at a leading edge (48) and a trailing edge (50); a root part (54); A tip (60) extending between the first and second sidewalls (44, 46) and disposed on the tip (60) to remove a portion of the abradable material (32) during tip friction. A plurality of blades (15) coupled to the rotor hub (21), each including an airfoil (42) with a tip polishing portion (120) capable of
A rotor assembly (13).   An abradable casing (17) extends circumferentially around the rotor assembly (13) to reduce the load induced on the airfoil (42) during tip friction of the tip polishing portion (120). The rotor assembly (13) of claim 19, wherein the rotor assembly (13) promotes. An airfoil (154);
Metal leading edge (MLE) (MLE) having a tip cutter portion (100) coupled to at least a portion of the airfoil (154) and capable of removing a portion of the abradable material (32) during tip friction. 158),
A blade assembly (170) comprising:   The blade assembly (170) further includes a tip polishing portion (120) disposed on the tip portion (60), and the tip polishing portion (120) is part of the abradable material (32) during tip friction. 24. The blade assembly (170) of claim 23, wherein the blade assembly (170) can be removed.   A rake profile (112) disposed over at least a portion of the tip (60) of the blade assembly (170) to facilitate reduction of loads induced in the blade assembly (170) during tip friction. The blade assembly (170) of claim 23, further comprising a tip rake (110) having: A blisk (180) comprising a plurality of airfoils (42) extending from a hub (21), wherein each airfoil (42) comprises:
A first side wall (44);
A second sidewall (46) coupled to the first sidewall (44) at a leading edge (48) and a trailing edge (50);
The root (54),
A tip (60) extending between the first and second side walls (44, 46);
Disposed on the first sidewall (44) of the at least one airfoil (42) near the tip (60) and removing a portion of the abradable material (32) during tip friction. A tip cutter (100) capable of
Blisk (180) with A blisk (180) comprising a plurality of airfoils (42) extending from a hub (21), wherein each airfoil (42) comprises:
A first side wall (44);
A second sidewall (46) coupled to the first sidewall (44) at a leading edge (48) and a trailing edge (50);
The root (54),
A tip (60) extending between the first and second side walls (44, 46);
A tip polishing section (120) disposed on the tip (60) of the at least one airfoil (42) and capable of removing a portion of the abradable material (32) during tip friction;
Blisk (180) with A method (300) for reducing a tip friction load on an airfoil (42), comprising:
Selecting a contact position between the airfoil (42) and the stationary structure (32);
Selecting a position on the airfoil (42) to incorporate the tip cutter (100);
Selecting a cutter profile (102) of the tip cutter (100);
The tip cutter part (100) is incorporated at a selected position on the airfoil part (42), and the tip cutter part (100) removes a part of the fixed structure (32) during tip friction, and tip friction. Allowing the load to be reduced;
A method (300) comprising:   29. The method (300) of claim 28, wherein the stationary structure is an abradable material (32).   29. The method (300) of claim 28, wherein selecting the tip cutter profile (102) comprises selecting a cutter angle (104).   The method (300) of claim 28, wherein the tip cutter portion (100) extends along a portion of a leading edge (18) of the airfoil portion (42). The tip cutter (100) is
The method (300) of claim 28, wherein the method (300) extends in a chordal direction along a portion of the airfoil (42). The step of incorporating the tip cutter part (100) comprises:
The method (300) of claim 28, comprising machining the tip cutter profile (102) at selected locations on the airfoil (42).   The method (300) of claim 28, further comprising selecting a tip polisher (120).   35. The method (300) of claim 34, further comprising the step of joining the tip abrasive (120) to the airfoil (42).   35. The method (300) of claim 34, wherein the joining step comprises a brazing step.   29. The method (28) of claim 28, further comprising selecting a tip rake (110) having a tip rake profile (112) that facilitates reducing a load induced on the airfoil (42) during tip friction. 300).   38. The method (300) of claim 37, wherein the tip rake (110) is incorporated onto the airfoil (42) by machining. A method for assembling a rotor assembly (13) comprising:
A rotor including a first sidewall (44) and a second sidewall (46) connected to the leading edge (48) and the trailing edge (50) and extending in a span direction from the root portion (54) to the tip portion (60) Providing a blade (15);
Removing blade material from a portion of the tip (60) to form a tip cutter (100) having a cutter profile (102);
The tip cutter portion (100) machines the abradable material (32) during tip friction so that the rotor blade (15) is a rotor hub so that the radial load induced on the blade during tip friction can be reduced. Coupling to (21);
Including a method.   40. The method of claim 39, wherein the tip cutter portion (100) is formed near a leading edge (48) of the rotor blade (15).   40. The method of claim 39, wherein the cutter profile (102) comprises a cutter angle (104).   40. The method of claim 39, further comprising joining a tip polisher (120) to the rotor blade (15).   43. The method of claim 42, wherein the joining step includes a brazing step.   40. The method of claim 39, further comprising incorporating an end rake (110) having a rake profile (112) that facilitates reducing a load induced on the blade during tip friction.   45. The method of claim 44, wherein the tip rake (110) is incorporated onto the rotor blade (15) by machining. A method for assembling a rotor assembly (13) comprising:
Providing a blade assembly (170) comprising an airfoil (154) and a metal leading edge (MLE) (158) coupled to at least a portion of the airfoil (154);
Removing material from a portion of the MLE to form a tip cutter portion (100) having a cutter profile (102);
The blade assembly (170) can be machined by the tip cutter portion (100) during tip friction to reduce the radial load induced on the blade during tip friction. Coupling to the rotor hub (21);
Including a method.   Providing a tip polishing portion (120) disposed on the tip (60) of the blade assembly (170) and capable of removing a portion of the abradable material (32) during tip friction; 49. The method of claim 46, comprising.   A rake profile (112) disposed over at least a portion of the tip (60) of the blade assembly (170) to facilitate reduction of loads induced in the blade assembly (170) during tip friction. 47. The method of claim 46, further comprising providing a tip rake (110) having:

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