Rotor blade system for turbine engine

Abstract

A rotor blade system for a turbine engine having a longitudinal centerline axis. The rotor blade system includes a rotor configured to rotate about a longitudinal centerline axis and a plurality of rotor blades coupled circumferentially about the rotor, each rotor blade having a leading edge, a trailing edge, a suction side, and a pressure side. At least one rotor blade of the plurality of rotor blades has an axial sweep of a leading edge and a trailing edge compared to a base blade of the plurality of rotor blades.

Description

Technical Field

[0001] The present disclosure generally relates to rotor blade systems for turbine engines. Background Art

[0002] A turbine engine generally comprises a fan and a core arranged in flow communication with each other. The core comprises one or more turbines and one or more compressors. The turbines and compressors comprise one or more stages, wherein each stage comprises rotor blades and stator vanes. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The foregoing and other features and advantages will be apparent from the following more particular description of various exemplary embodiments, as illustrated in the drawings, in which like reference numerals generally indicate identical, functionally similar, and / or structurally similar elements.

[0004] Figure 1 A schematic cross-sectional view of a ducted indirect drive gas turbine engine according to the present disclosure, taken along the longitudinal centerline axis of the engine, is shown.

[0005] Figure 2 A schematic perspective view of a rotor blade system according to the present disclosure is shown.

[0006] Figure 3A A schematic suction side view of a rotor blade according to the present disclosure is shown, which may be Figure 2 The rotor blades of the rotor blade system.

[0007] Figure 3B It shows that according to the present disclosure Figure 3A Schematic blade tip view of a rotor blade.

[0008] Figure 4A A schematic suction side view of a rotor blade according to the present disclosure is shown, which may be Figure 2 The rotor blades of the rotor blade system.

[0009] Figure 4B It shows that according to the present disclosure Figure 4A Schematic blade tip view of a rotor blade.

[0010] Figure 5A A schematic trailing edge view of a rotor blade according to the present disclosure is shown, which may be Figure 2 The rotor blades of the rotor blade system.

[0011] Figure 5B It shows that according to the present disclosure Figure 5A Schematic blade tip view of a rotor blade.

[0012] Fig. 6AA schematic trailing edge view of a rotor blade according to the present disclosure is shown, which may be Figure 2 The rotor blades of the rotor blade system.

[0013] Figure 6B It shows that according to the present disclosure Fig. 6A Schematic blade tip view of a rotor blade.

[0014] Figure 7 A schematic blade tip view of a rotor blade having a blade sweep combination according to the present disclosure is shown, which blade sweep combination may be Figure 2 The rotor blade system.

[0015] Figure 8 A schematic blade tip view of a rotor blade having a blade sweep combination according to the present disclosure is shown, which blade sweep combination may be Figure 2 The rotor blade system. DETAILED DESCRIPTION

[0016] Features, advantages and embodiments of the present disclosure are set forth or apparent by considering the following detailed description, drawings and claims.In addition, the following detailed description is exemplary and is intended to provide further explanation without limiting the scope of the present disclosure as claimed.

[0017] Various embodiments of the present disclosure are discussed in detail below. Although specific embodiments are discussed, this is for illustrative purposes only. Those skilled in the relevant art will recognize that other components and configurations may be used without departing from the spirit and scope of the present disclosure.

[0018] As used herein, the terms “first” and “second” may be used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of each component.

[0019] The terms "upstream" and "downstream" refer to relative directions relative to the flow of a fluid in a fluid path. For example, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing.

[0020] The terms "front" and "rear" refer to relative positions within a turbine engine or vehicle, and refer to the normal operating attitude of the turbine engine or vehicle. For example, with respect to a turbine engine, front refers to a position closer to the engine inlet, while rear refers to a position closer to the engine nozzle or exhaust.

[0021] As used herein, the terms "low," "medium" (or "medium"), and "high," or their respective comparatives (e.g., "lower" and "higher," as applicable), when used with a compressor, turbine, shaft, fan, or turbine engine component, refer to relative pressures, relative speeds, relative temperatures, and / or relative power outputs within an engine, unless otherwise specified. For example, a "low power" setting defines an engine that is configured to operate at a power output lower than a "high power" setting for the engine, while a "medium power" setting defines an engine that is configured to operate at a power output higher than the "low power" setting and lower than the "high power" setting. The terms "low," "medium" (or "medium"), or "high" in such above-mentioned terms may additionally or alternatively be understood as relative to a minimum allowable speed, pressure, or temperature, or relative to a minimum or maximum allowable speed, pressure, or temperature for normal, desired, steady-state, etc., operation of the engine.

[0022] Unless otherwise indicated herein, the terms "coupled," "fixed," "attached," "connected," and the like refer to both direct coupling, fixing, attachment, or connection and indirect coupling, fixing, attachment, or connection through one or more intermediate components or features. These terms include integral and unitary constructions (e.g., a blisk rotor blade system).

[0023] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0024] As used herein, the terms "axial" and "axially" refer to directions and orientations extending substantially parallel to the centerline of the turbine engine. Additionally, the terms "radial" and "radially" refer to directions and orientations extending substantially perpendicular to the centerline of the turbine engine. Additionally, as used herein, the terms "circumferential" and "circumferentially" refer to directions and orientations extending in an arc around the centerline of the turbine engine.

[0025] A turbine engine includes a rotor blade system including a plurality of rotor blades in a turbine and a compressor. During rotation of the rotor blades, there are vibration modes in which all rotor blades vibrate. By detuning the rotor blades, the uniform vibration modes of the rotor blades can be disrupted, thereby reducing the overall vibration level of the rotor blade system. Detuning results in non-uniformity in the vibration modes, which reduces the vibration response. Detuning takes the form of sweeping of the blades in an axial direction, a circumferential direction, or an axial direction and a circumferential direction. The blade sweep occurs without adding or removing material from the rotor blade, or only requiring minimal changes to the geometry of the airfoil of the rotor blade (e.g., within 10% of the chord length or within 25% of the blade thickness, or both).

[0026] Figure 1A schematic cross-sectional view of a turbine engine 100 is shown, taken along a longitudinal centerline axis 102 of the turbine engine 100, according to an embodiment of the present disclosure. The turbine engine 100 includes, in downstream serial flow relationship: a fan section 104 including a fan 106; a compressor section 108 including a supercharger or low pressure (LP) compressor 110 and a high pressure (HP) compressor 112; a combustion section 114 including a combustor 116; a turbine section 118 including a high pressure (HP) turbine 120, a low pressure (LP) turbine 122; and an exhaust nozzle 124. Figure 1 As shown, the turbine engine 100 defines an axial direction A, a radial direction R, and a circumferential direction C. As shown and described herein, the turbine engine 100 is a ducted indirect drive gas turbine engine 100 .

[0027] The fan section 104 includes a fan case 126 fixed to a nacelle (omitted for clarity) surrounding the fan 106. The fan 106 includes a plurality of fan blades 128 radially arranged about the longitudinal centerline axis 102. The HP compressor 112, the combustor 116, and the HP turbine 120 form an engine core 130 of the turbine engine 100, which generates combustion gases. The engine core 130 is surrounded by a core case 132 coupled to the fan case 126. The fan case 126 is supported relative to the turbine by circumferentially spaced outlet guide vanes 134.

[0028] A high-speed shaft 136 (also referred to herein as a high-pressure shaft 136) is coaxially disposed about the longitudinal centerline axis 102 of the turbine engine 100 and drivingly connects the HP turbine 120 to the HP compressor 112. A low-speed shaft 138 (also referred to herein as a low-pressure shaft 138) coaxially disposed about the longitudinal centerline axis 102 of the turbine engine 100 and within the larger diameter annular high-speed shaft 136 drives the LP turbine 122 to the LP compressor 110 and the fan 106 (either directly or indirectly through a gearbox assembly 140). The high-speed shaft 136 and the low-speed shaft 138 are rotatable about the longitudinal centerline axis 102.

[0029] The LP compressor 110 and the HP compressor 112 include respective multiple compressor stages 142, 144, wherein respective sets of compressor blades 146, 148 rotate relative to respective sets of compressor vanes 150, 152 to compress or pressurize gas entering through an inlet 154. Each compressor stage 144 of the HP compressor 112 includes a plurality of compressor blades 148 (or blades and disks integrated together, referred to as blisks) disposed on a rotor disk 156, also referred to herein as rotor compressor blades 148 or rotor blades 148. Each compressor blade 148 extends radially outward from a blade platform to a blade tip relative to the longitudinal centerline axis 102. The compressor vanes 152 (also referred to herein as stator vanes 152) are positioned upstream / downstream of and adjacent to the rotor compressor blades 148. A rotor disk 156 for one stage of the compressor blades 148 is mounted to the high-speed shaft 136. A compressor stage 144 of the HP compressor 112 may refer to a single disk of rotor compressor blades 148, or may refer to a single disk of rotor compressor blades 148 and a single disk of adjacent stator vanes 152. Either meaning may be applied in the context of the present disclosure without loss of clarity. The same description applies to each compressor stage 142 of the LP compressor 110 (e.g., each compressor stage 142 of the LP compressor 110 includes a plurality of compressor blades 146 (also referred to as rotor blades 146) and stator compressor vanes 150).

[0030] The HP turbine 120 has one or two turbine stages 158. In a single turbine stage 158, turbine blades 160 are disposed on a rotor disk 162, also referred to herein as rotor blades 160. Each turbine blade 160 extends radially outward from a blade platform to a blade tip relative to the longitudinal centerline axis 102. The HP turbine 120 may also include stator turbine vanes 164, also referred to as stator turbine nozzles. The HP turbine 120 may have an upstream nozzle adjacent to the outlet of the combustor 116 and a downstream nozzle behind the rotor (e.g., turbine blades 160), or the HP turbine 120 may have a nozzle upstream of the rotor blades (e.g., turbine blades 160) or downstream of the rotor blades.

[0031] Air exiting the HP turbine 120 enters the LP turbine 122, which has a plurality of turbine stages 166 of rotor blades 168. The LP turbine 122 may have three, four, five, or six stages. In a single LP turbine stage 166 (comprising a plurality of rotor blades 168 coupled to the low-speed shaft 138), the rotor blades 168 are disposed on a rotor disk (connected to the low-speed shaft 138) and extend radially outward from a blade platform to a blade tip relative to the longitudinal centerline axis 102. The LP turbine 122 may also include stator turbine buckets 170, also referred to as stator turbine nozzles. The LP turbine 122 may have an upstream nozzle and a downstream nozzle behind the turbine stage 166, followed by an exhaust nozzle 124.

[0032] During operation of the turbine engine 100, a certain amount of air A1 enters the turbine engine 100 through the inlet 172 of the fan case 126. When the certain amount of air A1 passes through the fan section 104 and passes through the fan blades 128, the first part of the air A1, air A2, is directed or directed into the bypass airflow passage 174, and the second part of the air A1, air A3, is directed or directed into the inlet 154 at the upstream section of the core airflow passage 176. The ratio between the first part of the air A2 and the second part of the air A3 is generally referred to as the bypass ratio. Then, when the second part of the air A3 is directed through the HP compressor 112 and enters the combustion section 114, the pressure of the second part of the air A3 increases, and in the combustion section 114, the highly pressurized air is mixed with the fuel and burned to provide combustion gases 178.

[0033] The combustion gases 178 are directed into and expanded through the HP turbine 120, where a portion of the thermal and / or kinetic energy from the combustion gases 178 is extracted via sequential stages of rotor blades 160 and HP turbine 120 turbine blades 164 coupled to the high-speed shaft 136, thereby rotating the high-speed shaft 136, thereby supporting the operation of the HP compressor 112. The combustion gases 178 are then directed into and expanded through the LP turbine 122. Here, a second portion of the thermal and kinetic energy is extracted from the combustion gases 178 via sequential stages of LP turbine rotor blades 168 and LP turbine 122 turbine blades 170 coupled to the low-speed shaft 138, thereby rotating the low-speed shaft 138. The rotation of the low-speed shaft 138 thereby supports the operation of the LP compressor 110 and the rotation of the fan 106 (when present, via the gearbox assembly 140).

[0034] The combustion gases 178 are then directed through the exhaust nozzle 124 to provide propulsive thrust. At the same time, the pressure of the first portion of air A2 is significantly increased as it is directed through the bypass airflow passage 174 before being discharged from the fan nozzle exhaust 180, also providing propulsive thrust.

[0035] Turbine engine 100 is provided as an example only. In other embodiments, the gas turbine engine may have any other suitable configuration, including, for example, any other suitable number or configuration of shafts or spools, fan blades, turbines, compressors, or combinations thereof. Gearbox assembly 140 may have any suitable configuration, including, for example, a star gear configuration, a planetary gear configuration, a single stage, multiple stages, epicyclic, non-episodic, etc., as further described below. Gearbox assembly 140 may have a gear ratio in the range of 3:1 to 4:1, 3:5 to 4:1, 3.25:1 to 3.5:1, or 4:1 to 5:1. The fan assembly may be any suitable fixed pitch assembly or a variable pitch assembly. Turbine engine 100 may include Figure 1 Additional components not shown in the fan assembly, such as rotor blades, stator blades, etc., may be included. The fan assembly may be configured in any other suitable manner (e.g., as a fixed pitch fan) and may also be supported using any other suitable fan frame configuration. Aspects of the present disclosure may be incorporated into any other suitable turbine engine (including, but not limited to, turbofan engines, propfan engines, turbojet engines, turboprop engines, and turboshaft engines, aviation turbine engines, marine turbine engines, land-based turbine engines, industrial turbine engines, power generation turbine engines, etc.).

[0036] As described above, the high pressure compressor and turbine and the low pressure compressor and turbine include one or more stages, each stage having two types of blades: stator blades and rotor blades. The blades, whether stator or rotor, are arranged about a longitudinal centerline axis 102 ( Figure 1 ) are arranged in a circumferential manner. That is, each stage of the compressor and turbine is associated with an annular or circumferential row of stator blades and an annular or circumferential row of rotor blades. The rotor blades or stator blades are axisymmetric around the longitudinal centerline axis 102.

[0037] Figure 2 According to the present disclosure, the turbine engine 100 ( Figure 1 ) is a front perspective view of a rotor blade system 200 isolated from the turbine engine 100. The rotor blade system 200 defines a circumferential direction C and has a rotor 202 and a plurality of rotor blades 204 mounted thereon. The rotor blade system 200 rotates about a longitudinal centerline axis 12 that is parallel to the turbine engine 100 ( Figure 1) is aligned with the longitudinal centerline axis 102. The rotor blade system 200 may be one or more of a fan 106 having fan blades 128, an LP compressor 110 having rotor blades 146, an HP compressor 112 having rotor blades 148, an LP turbine 122 having rotor blades 168, or an HP turbine 120 having rotor blades 160. The rotor blade system 200 is also applicable to industrial gas turbines (IGTs) or power generation turbines. The present rotor blade system is not limited to turbine engines, but may be used in any airfoil system.

[0038] A plurality of rotor blades 204 are evenly and circumferentially spaced about rotor 202. Rotor blades 204 may be integrally formed with rotor 202 or may be connected to rotor 202. Each rotor blade 204 is formed of an airfoil and extends from a blade root 206 at rotor 202 to a blade tip 208 and includes a leading edge 210 and a trailing edge 212. Figure 2 As shown, the airfoil of each rotor blade 204 may have a twist or profile. For example, each rotor blade 204 may be profiled or twisted relative to a longitudinal blade axis 218 extending from a blade root 206 to a blade tip 208. Each rotor blade 204 includes a pressure side 214 joined to a suction side 216 at a leading edge 210 and a trailing edge 212. The pressure side 214 is concave and the suction side 216 is convex.

[0039] There is a passage length, also referred to as the inter-blade spacing, between adjacent rotor blades 204. Pitch P is the inter-blade spacing and is defined as the distance between adjacent rotor blades 204 at each blade tip 208. Adjacent rotor blades are defined as two rotor blades 204 with no intermediate rotor blade 204 between them.

[0040] One or more of the rotor blades 204 may be detuned without requiring material to be removed or added from the rotor blades 204, or with only minimal removal or addition (e.g., within 10%). That is, one or more of the rotor blades 204 may include a blade sweep extending from the blade tip toward the blade root. The blade sweep (also referred to as blade shift) enables blade detuning without requiring or requiring only minimal material removal or addition, and also without requiring or requiring only minimal (e.g., 10%) blade weight change.

[0041] In some examples, according to reference FIG. 3A to FIG. 8In one or more of the described embodiments, all of rotor blades 204 may be detuned. In some examples, the detuning of rotor blades 204 may be a predetermined patterned arrangement, which may be a predetermined grouped arrangement or a predetermined alternating arrangement. That is, for example, when less than all of rotor blades 204 are detuned, the detuning may be performed according to a predetermined arrangement. For example, rotor blades 204 may adopt any number of patterns, including but not limited to an "AB" pattern, an "AAB" pattern, an "ABB" pattern, an "ABC" pattern, an "AABC" pattern, an "AABBC" pattern, an "AABBCC" pattern, and the like, or a combination thereof, where A is a base blade and each of B and C is a detuned blade. Although the pattern describes only two types of detuned blades, more types (e.g., D, E, F, etc.) may be provided, such that multiple exemplary embodiments of detuned blades may be present in rotor blade system 200. B and C (as well as D, E, F, etc.) represent rotor blades with different detuning (e.g., according to FIG. 3A to FIG. 8 In another example, the predetermined grouping arrangement may include a subset of detuned rotor blades arranged adjacent to each other and located at a single position around the rotor 202 of the rotor blade system 200. For example, relative to the clockwise direction of the clockwork, the predetermined group of detuned rotor blades may be positioned from the twelve o'clock position to the three o'clock position, while the base rotor blade is positioned from the three o'clock position (clockwise) to the twelve o'clock position. This is exemplary only, and any grouping of detuned rotor blades is contemplated.

[0042] FIG. 3A to FIG. 8 Exemplary embodiments of rotor blades that may be used as one or more of rotor blades 204 are shown. As described below, the blades include blade sweeps in one or more directions. In some examples, the blades include axial blade sweeps, circumferential blade sweeps, or axial blade sweeps and circumferential blade sweeps. FIG. 3A to FIG. 8 The detuning provided in allows air damping to reduce non-synchronous response. FIG. 3A to FIG. 8 The rotor blades are shown schematically and therefore no relative Figure 2 However, this is only to simplify the description, and it should be understood that FIG. 3A to FIG. 8 The rotor blades also include Figure 2 The curvature shown in .

[0043] Figure 3A , Figure 3B , Figure 4A and Figure 4BA rotor blade is shown that exhibits an axial blade sweep of the leading edge and the trailing edge. As described in more detail below, the axial blade sweep is defined as an axial variation of the leading edge or the trailing edge relative to the leading edge or the trailing edge of the base blade, respectively. The axial blade sweep results in the leading edge or the trailing edge of the rotor blade being positioned further forward or further aft compared to the base blade. In the embodiments described herein, the axial sweep occurs over a portion of the span length of the rotor blade. That is, the base blade is substantially linear relative to a lower portion of the leading edge or the trailing edge, while the swept blade is non-linear relative to the leading edge or the trailing edge above the lower portion.

[0044] Figure 3A and Figure 3B A rotor blade 300a is shown having a blade tip 308a, a blade root 306, a leading edge 310a, and a trailing edge 312a. A chord length 318a is defined between the leading edge 310a and the trailing edge 312a at the blade tip 308a. Figure 2 As shown, due to the curvature of the rotor blade 300a, the chord length 318a may not be a linear measurement. Figure 3A The view of FIG. 31 shows the suction side 316 of the rotor blade 300 a . Figure 3B A view of the blade tip 308a is shown. Figure 3A and 3B As shown, the blade tip 308a of the leading edge 310a is in the axial direction A (as shown in FIG. Figure 1 and Figure 2 ) toward the turbine engine 100 ( Figure 1 ). The axial sweep is associated with the base blade 300b. The base blade 300b has a base blade leading edge 310b, a base blade trailing edge 312b, a base blade tip 308b, and a base blade root. The base blade tip 308b and the blade tip 308a are coplanar. The base blade root and the blade root 306 are coplanar. At the blade root 306, the leading edge and the trailing edge of each of the base blade 300b and the rotor blade 300a are at the same axial position, and there is no axial sweep.

[0045] Figure 3AThe leading edge 310a is shown to be substantially collinear with respect to the base blade leading edge 310b along a lower portion 327 of the leading edge 310a extending from the blade root 306 to the sweep point 324a. After the sweep point 324a, along an upper portion 325 of the leading edge 310a, the leading edge 310a is not collinear with respect to the base blade leading edge 310b. Thus, the sweep point 324a defines the point at which the leading edge 310a diverges from the base blade leading edge 310b. Similarly, the trailing edge 312a is substantially collinear with respect to the base blade trailing edge 312b along a lower portion of the trailing edge 312a extending from the blade root 306 to the sweep point 324b. After the sweep point 324b and extending from the sweep point 324b to the blade tip 308a, the trailing edge 312a is not collinear with respect to the base blade trailing edge 312b. Thus, the sweep point 324b defines the point at which the trailing edge 312a diverges from the base blade trailing edge 312b.

[0046] As described above, the leading edge 310a is oriented in the axial direction A toward the turbine engine 100 ( Figure 1 ) is swept forward. “Axially swept” means that the leading edge 310a is axially farther in the forward direction than the base blade leading edge 310b. As described above, the axial sweep of the leading edge 310a occurs from the sweep point 324a to the blade tip 308a. Similarly, the trailing edge 312a is more directed in the axial direction A toward the turbine engine 100 ( ) than the base blade trailing edge 312b. Figure 1 ). The axial sweep of the trailing edge 312a occurs from the sweep point 324b to the blade tip 308a. The sweep of the leading edge 310a and the trailing edge 312a is such that a chord length 318a defined between the leading edge 310a and the trailing edge 312a remains constant relative to a base blade chord length 318b of the base blade 300b. A constant chord length 318a is a chord length that is within ten percent (greater or less) of a base blade chord length 318b defined between the base blade leading edge 310b and the base blade trailing edge 312b. In some examples, the chord length 318a is equal to the base blade chord length 318b. By maintaining a constant chord length 318a, the rotor blade 300a performs approximately the same amount (e.g., within 10%) of work as the base blade 300b while benefiting from the detuned characteristic of disrupting the vibration mode.

[0047] At the blade tip 308a, the leading edge 310a sweeps in the axial direction A by an amount equal to the leading edge axial chord sweep 320. The leading edge axial chord sweep 320 is defined between the leading tip edge 320a and the base blade leading tip edge 320b. Figure 3A and Figure 3B, the leading tip edge 320a is a substantially circumferentially extending edge of the blade tip 308a at the leading edge 310a, and the base blade leading tip edge 320b is a circumferentially extending edge of the base blade tip 308b at the base blade leading edge 310b. "Substantially circumferential" means that the edge extends more in the circumferential direction than in the radial direction or the axial direction. Similarly, at the blade tip 308a, the trailing edge 312a sweeps in the axial direction A by an amount equal to the trailing edge axial chord sweep 322. The trailing edge axial chord sweep 322 is defined between the trailing tip edge 322a and the base blade trailing tip edge 322b. Reference Figure 3A and Figure 3B , the rear tip edge 322a is a substantially circumferentially extending edge of the blade tip 308a at the trailing edge 312a, and the base blade rear tip edge 322b is a circumferentially extending edge of the base blade tip 308b at the base blade trailing edge 312b.

[0048] The leading edge axial chord sweep 320 and the trailing edge axial chord sweep 322 may increase from the sweep points 324a, 324b to the blade tip 308a. That is, the distance between the leading edge 310a and the base blade leading edge 310b may increase from the sweep point 324a to the blade tip 308a, or the distance may be constant. The same is true for the trailing edge axial chord sweep 322. In some examples, the leading edge axial chord sweep 320 and the trailing edge axial chord sweep 322 are equal. In some examples, the leading edge axial chord sweep 320 and the trailing edge axial chord sweep 322 are different while maintaining the chord length 318a within 10% of the base blade chord length 318b. The leading edge axial chord sweep 320 is greater than 0% to 15% of the chord length 318a, and preferably is 5% to 10% of the chord length 318a. The trailing edge axial chord sweep 322 is greater than 0% to 15% of the chord length 318a, and preferably is 5% to 10% of the chord length 318a.

[0049] A span length 326 is defined between the blade tip 308a and the blade root 306. The axial sweep of the leading edge 310a and the trailing edge 312a may extend from the axis 324 to the blade tip 308a. The axis 324 extends through a sweep point 324a (e.g., a point where the leading edge 310a and the trailing edge 312a no longer sweep and are collinear with the base blade leading edge 310b and the base blade trailing edge 312b, respectively). The percentage of the span length 326 of the rotor blade 300a that exhibits an axial blade sweep is defined by a radial distance 328 between the blade tip 308a and the axis 324. The radial distance 328 is greater than 0% to 40% of the span length 326. In some examples, the radial distance is 5% to 25% of the span length 326 of the rotor blade 300a. In some examples, the radial distance is 25% of the span length 326 of the rotor blade 300a.

[0050] Figure 4A and Figure 4B A rotor blade 400a is shown having a blade tip 408a, a blade root 406, a leading edge 410a, and a trailing edge 412a. Figure 4A The suction side 416 of the rotor blade 400a is shown. Figure 4B A view of a blade tip 408a is shown. In addition to the leading edge 410a and the trailing edge 412a of the rotor blade 400a, the rotor blade 400a is oriented in the axial direction A toward the turbine engine 100 ( Figure 1 ), rotor blade 400a is equal to rotor blade 300a. Thus, except for the direction of axial sweep, Figure 3A and 3B A full description of the Figure 4A and 4B .

[0051] That is, compared to the base blade leading edge 410b and the base blade trailing edge 412b of the base blade 400b, the leading edge 410a and the trailing edge 412a are swept in the axial direction by the leading edge axial chord sweep 420 and the trailing edge axial chord sweep 422, respectively. Figure 3A For example, the leading edge axial chord sweep 420 is defined between the leading tip edge 420a and the base blade leading tip edge 420b. Figure 4A and Figure 4B , the leading tip edge 420a is the circumferentially extending edge of the blade tip 408a at the leading edge 410a, and the base blade leading tip edge 420b is the circumferentially extending edge of the base blade tip at the base blade leading edge 410b. The trailing edge axial chord sweep 422 is defined between the trailing tip edge 422a and the base blade trailing tip edge 422b. Figure 4A and 4B , the trailing tip edge 422a is the circumferentially extending edge of the blade tip 408a at the trailing edge 412a, and the base blade trailing tip edge 422b is the circumferentially extending edge of the base blade tip at the base blade trailing edge 412b.

[0052] In some examples, the leading edge axial chord sweep 420 and the trailing edge axial chord sweep 422 may be equal. In some examples, the leading edge axial chord sweep 420 and the trailing edge axial chord sweep 422 are different while maintaining a constant chord length, for example, maintaining the chord length 418a within 10% of the base chord length 418b. As previously described, by maintaining a constant chord length 418a, the rotor blade 400a performs approximately the same amount of work (e.g., within 10%) as the base blade 400b while benefiting from the detuned characteristics of disrupting the vibration mode. The leading edge axial chord sweep 420 is greater than 0% to 15% of the chord length 418a, preferably 5% to 10% of the chord length 418a. The trailing edge axial chord sweep 422 is greater than 0% to 15% of the chord length 418a, preferably 5% to 10% of the chord length 418a.

[0053] like Figure 3A As shown, a sweep point 424b exists along the trailing edge 412a of the rotor blade 400a. The trailing edge 412a is substantially collinear with respect to the base blade trailing edge 412b along a lower portion 427 of the trailing edge 412a extending from the blade root 406 to the sweep point 424b. After the sweep point 424b along the upper portion 425, the trailing edge 412a is not collinear with respect to the base blade trailing edge 412b. Thus, the sweep point 424b defines the point at which the trailing edge 412a diverges from the base blade trailing edge 412b. The sweep point 424a is located along the leading edge 410a and is described previously with respect to the trailing edge 412a. Figure 3A and Figure 4A The same manner as described above.

[0054] A span length 426 is defined between the blade tip 408a and the blade root 406. The axial sweep of the leading edge 410a and the trailing edge 412a may extend from the axis 424 to the blade tip 408a. The axis 424 extends through a sweep point 424b (e.g., a point where the leading edge 410a and the trailing edge 412a no longer sweep and are collinear with the base blade leading edge 410b and the base blade trailing edge 412b, respectively). The percentage of the span length 426 of the rotor blade 400a that exhibits an axial blade sweep is defined by a radial distance 428. The radial distance 428 is defined between the blade tip 408a and the axis 424, which extends through a point where the leading edge 410a and the trailing edge 412a no longer sweep and are collinear with the base blade leading edge 410b and the base blade trailing edge 412b, respectively. The radial distance may be greater than 0% to 40% of the span length 426 of the rotor blade 400a. In some examples, the radial distance is 5% to 25% of the span length of the rotor blade 400a. In some examples, the radial distance is 25% of the span length of the rotor blade 400a.

[0055] Figure 5A , Figure 5B , Fig. 6A and Figure 6BThe rotor blades are shown to have a tangential sweep of the suction and pressure sides in the circumferential direction. That is, Figure 5A , Figure 5B , Fig. 6A and Figure 6B The rotor blades are at pitch P( Figure 2 ) direction and thus extends into the inter-blade spacing.

[0056] Figure 5A A rotor blade 500a is shown having a blade tip 508a, a blade root 506, a leading edge 510a, a trailing edge 512a, a pressure side 514a, and a suction side 516a. Figure 5A The view of shows a rear end view of the rotor blade 500a such that the leading edge is not visible in this view. Figure 5B A view of blade tip 508a is shown taken at plane 550 such that Figure 5B Only the blade tip 508a and the base blade tip 508b are visible. Figure 5A and Figure 5B In the example of FIG. 5 , the suction side 516a is in contact with the turbine engine 100 ( Figure 1 ) in the circumferential direction C (such as Figure 1 and Figure 2 Circumferential sweep is associated with base blade 500b. Base blade 500b has base blade suction side 516b, base blade pressure side 514b, base blade trailing edge 512b, base blade tip 508b and base blade root. As in the aspects of FIGS. 3 and 4 , base blade tip 508b and base blade root are collinear with blade tip 508a and blade root 506, respectively. At the blade root, the leading edge and trailing edge of each of base blade 500b and rotor blade 500a are at the same axial position, and there is no axial sweep.

[0057] As described above, the suction side 516a is in contact with the turbine engine 100 ( Figure 1 ) is swept in the circumferential direction C in the direction opposite to the rotation of the turbine engine 100 ( ). "Circumferential sweep" means that the suction side 516a is swept in the circumferential direction C in comparison with the suction side 516b of the base blade. Figure 1 ) is further circumferentially in the direction opposite to the rotation of the turbine engine 100 (). Similarly, the pressure side 514a is closer to the turbine engine 100 () than the base blade pressure side 514b. Figure 1 ) is swept in the circumferential direction C in the rotationally opposite direction of the suction side 516a and the pressure side 514a. The sweep of the suction side 516a and the pressure side 514a makes the chord length (such as about Figure 3A and Figure 3B ) is constant (e.g., within 10%) between rotor blade 500a and base blade 500b (e.g., as described with respect to FIG. 3A to FIG. 4BIn some examples, blade thickness 518a defined between suction side 516a and pressure side 514a is within 25% of blade thickness 518b defined between base blade suction side 516b and base blade pressure side 514b. In some examples, blade thickness 518a is equal to blade thickness 518b.

[0058] Figure 5A The suction side 516b is shown to be substantially collinear with respect to the base blade suction side 516b along a lower portion 527 of the suction side 516a extending from the blade root 506 to the sweep point 524a. After the sweep point 524a, along an upper portion 525 of the suction side 516a, the suction side 516a is not collinear with respect to the base blade suction side 516b. Thus, the sweep point 524a defines the point at which the suction side 516a diverges from the base blade suction side 516b. Likewise, the pressure side 514a is substantially collinear with respect to the base blade pressure side 514b along a lower portion of the pressure side 514a extending from the blade root 506 to the sweep point 524b. After the sweep point 524b and extending from the sweep point 524b to the blade tip 508a, the pressure side 514a is not collinear with respect to the base blade pressure side 514b. Thus, the sweep point 524b defines the point at which the pressure side 514a diverges from the base blade pressure side 514b.

[0059] The circumferential sweep of the suction side 516a and the pressure side 514a may extend from an axis 524 to the blade tip 508a. The axis 524 extends through a point where the suction side 516a and the pressure side 514a no longer sweep and are collinear with the base blade suction side 516b and the base blade pressure side 514b, respectively. At the blade tip 508a, the suction side 516a sweeps in the circumferential direction C by an amount equal to the suction side circumferential sweep 520. The suction side circumferential sweep 520 is defined between a suction side tip edge 520a and a base blade suction side tip edge 520b. Figure 5A and Figure 5B , the suction side tip edge 520a is the substantially axially extending edge of the blade tip 508a at the suction side 516a, and the base blade suction side tip edge 520b is the substantially axially extending edge of the base blade tip 508b at the base blade suction side 516b. "Substantially axial" means that the edge extends more in the axial direction than in the radial or circumferential direction. Similarly, at the blade tip 508a, the amount swept by the pressure side 514a in the circumferential direction C is equal to the pressure side circumferential sweep 522. The pressure side circumferential sweep 522 is defined between the pressure side tip edge 522a and the base blade pressure side tip edge 522b. Reference Figure 5A and Figure 5B, the pressure side tip edge 522a is the substantially axially extending edge of the blade tip 508a at the pressure side 514a, and the base blade pressure side tip edge 522b is the substantially axially extending edge of the base blade tip 508b at the base blade pressure side 514b.

[0060] The suction side circumferential sweep 520 and the pressure side circumferential sweep 522 may be equal. The suction side circumferential sweep 520 is the pitch (e.g., Figure 2 , pitch P) is greater than 0% to 25%. The pressure side circumferential sweep 522 is greater than 0% to 25% of the pitch. In some examples, the suction side circumferential sweep 520 or the pressure side circumferential sweep 522 or both are 2% to 10%. Figure 2 As shown, pitch is the inter-blade spacing, defined as the distance between adjacent rotor blades 500a at the respective blade tips. Figure 5A or Fig. 6A The term ) is the percentage of the inter-blade spacing between the rotor blade 500a and the adjacent rotor blade upstream or downstream (depending on the sweep direction). Adjacent means that there are no intermediate rotor blades between the two rotor blades.

[0061] A span length 526 is defined between the blade tip 508a and the blade root 506. The percentage of the span length 526 of the rotor blade 500a that exhibits an axial blade sweep is defined by a radial distance 528. The radial distance 528 is defined between the blade tip 508a and the axis 524. The radial distance 528 is greater than 0% to 40% of the span length 526. In some examples, the radial distance is 5% to 25% of the span length of the rotor blade 500a. In some examples, the radial distance is 25% of the span length of the rotor blade 500a.

[0062] Fig. 6A and Figure 6B A rotor blade 600a is shown. The rotor blade 600a has a blade tip 608a, a leading edge 610a, a trailing edge 612a, a pressure side 614a, and a suction side 616a. Fig. 6A A rear end view of rotor blade 600a and base blade 600b is shown such that trailing edge 612a of rotor blade 600a and trailing edge 612b of base blade 600b are visible, while the leading edge of each blade is not visible in this view. Figure 6B A view of blade tip 608a is shown taken at plane 650, such that Figure 6B Only the blade tip 608b and the base blade tip are visible. In addition to the suction side 616a and the pressure side 614a of the rotor blade 600a in the turbine engine 100 ( Figure 1 ) in the circumferential direction C, the rotor blade 600a and Figure 5A and Figure 5BThe rotor blade 500a is identical to the rotor blade 500a. Therefore, except for the direction of circumferential sweep, Figure 5A A full description of the Fig. 6A .

[0063] That is, the suction side 616a and the pressure side 614a are swept in the circumferential direction by the suction side circumferential sweep 620 and the pressure side circumferential sweep 622, respectively, compared to the base blade suction side 616b and the base blade pressure side 614b, respectively, of the base blade 600b. Figure 5A For example, the suction side circumferential sweep 620 is defined between the suction side tip edge 620a and the base blade suction side tip edge 620b. Fig. 6A and Figure 6B , the suction side tip edge 620a is the substantially axially extending edge of the blade tip 608a at the suction side 616a, and the base blade suction side tip edge 620b is the substantially axially extending edge of the base blade tip at the base blade suction side 616b. The pressure side circumferential sweep 622 is defined between the pressure side tip edge 622a and the base blade pressure side tip edge 622b. Fig. 6A and Figure 6B , the pressure side tip edge 622a is the substantially axially extending edge of the blade tip 608a at the pressure side 614a, and the base blade pressure side tip edge 622b is the substantially axially extending edge of the base blade tip at the base blade pressure side 614b.

[0064] The suction side circumferential sweep 620 and the pressure side circumferential sweep 622 may be equal. The suction side circumferential sweep 620 is greater than 0% to 25%. The pressure side circumferential sweep 622 is greater than 0% to 25%. In some examples, the suction side circumferential sweep 620 or the pressure side circumferential sweep 622 or both are 2% to 10%. The percentage of the rotor blade 600a exhibiting circumferential sweep is determined by the radial distance and the pressure side circumferential sweep. Figure 5A The radial distance is greater than 0% to 40% of the span length of rotor blade 600a. In some examples, the radial distance is 5% to 25% of the span length of rotor blade 500a. In some examples, the radial distance is 25% of the span length of rotor blade 500a. As in the previous examples, the chord length (e.g., about Figure 3A and Figure 3B ) is constant (e.g., within 10%) between rotor blade 600a and base blade 600b (e.g., as described with respect to FIG. 3A to FIG. 4B In some examples, the blade thickness of rotor blade 600a (eg, Figure 5A and Figure 5B The thickness of the base blade 600b is within 25% of the blade thickness of the base blade 600b, or is the same as the thickness of the base blade 600b.

[0065] like Figure 5B and Figure 6B As shown, the circumferential sweep is such that the blade tip of the rotor blade does not overlap the base blade tip of the base blade. However, there may be overlap, as described with respect to Figure 8 Shown and described.

[0066] As mentioned earlier, FIG. 3A to FIG. 4B shows the axial chord sweep of the rotor blades, and FIG. 5A to FIG. 6B The circumferential sweep of the rotor blades is shown. Although the examples are described individually, any combination of sweeps may be provided on the rotor blades (e.g., Figure 2 In one or more of the rotor blades 204 described.

[0067] For example, Figure 7 and Figure 8 As shown in the top views of , respectively, blade tip 708a and blade tip 808a, the rotor blades may be swept axially and circumferentially compared to the base blades. Figure 7 and Figure 8 Each of the images is taken at a plane extending through the blade tip so that only the blade tips 708a, 808a and the base blade tip are visible. Figure 7 The specific example of 700a shows an axial forward sweep and a circumferential sweep of the rotor blade 700a in the direction of rotation of the engine compared to the base blade 700b. Figure 8 The specific example of shows that the rotor blade 800a is swept axially backward and circumferentially in the direction of rotation of the engine compared to the base blade 800b. Figure 7 In the example of FIG. 7 , the circumferential sweep is such that there is no overlap between the base blade 700b and the rotor blade 700a at the blade tip 708a, while at Figure 8 In the example of FIG. 8 , the circumferential sweep is such that there is an overlap between the base blade 800b and the rotor blade 800a at the blade tip 808a. Similarly, the rotor blade may exhibit a circumferential sweep in the relative rotational direction, whether axially forward or axially backward. In this example, there may or may not be an overlap between the base blade and the rotor blade at the blade tip.

[0068] These are just two exemplary combinations, and the combinations may be presented in other ways. For example, the rotor blades may have an axial rearward sweep and a circumferential sweep in the direction of rotation of the engine, and an axial forward sweep and a circumferential sweep in the direction opposite to the rotation of the engine, or an axial forward sweep and a circumferential sweep in the direction of rotation of the engine. In any of these combinations, the circumferential sweep may or may not include an overlap at the blade tip.

[0069] In addition, as mentioned earlier, FIG. 3A to FIG. 8 Any of the examples may be applied to the rotor blade 204 ( Figure 2 ). In some examples, the same swept blade arrangement is provided to all of the one or more rotor blades 204. In some examples, more than one different swept blade arrangement is provided to the one or more rotor blades 204.

[0070] although FIG. 3A to FIG. 8 The base rotor blades shown in FIG. 1 are parallelepipeds, but these images are only schematic and other shapes are conceivable. That is, for example, the base rotor blades may have a twist or other profile of the blade, such as about Figure 2 As shown and described. The rotor blade of the present disclosure is then swept from the base blade, maintaining any original twist or profile of the base blade.

[0071] Thus, the rotor blade of the present disclosure changes the airfoil shape without meaningfully adding material or removing material. That is, the sweep described herein does not add material or remove material from the rotor blade. Meaningless addition of material or removal of material means that the chord length of the swept rotor blade is within 10% of the base blade, the blade thickness of the swept rotor blade is within 25% of the base blade, or the chord length of the swept rotor blade is within 10% of the base blade, and the blade thickness of the swept rotor blade is within 25% of the base blade.

[0072] As shown and described herein, the leading edge and the trailing edge are swept in the same direction (e.g., forward or aft), and the pressure side and the suction side are swept in the same direction (e.g., in the direction of rotation or in a direction opposite to the direction of rotation). However, in some examples, the sweep may be in different directions as long as the chord (for axial sweep) or thickness (for circumferential sweep) is maintained within 10% of the chord or thickness of the base blade.

[0073] Further aspects are provided by the subject matter of the following clauses.

[0074] A rotor blade system for a turbine engine having a longitudinal centerline axis, comprising: a rotor configured to rotate about the longitudinal centerline axis; and a plurality of rotor blades circumferentially coupled about the rotor, each rotor blade having a leading edge, a trailing edge, a suction side, and a pressure side. At least one rotor blade of the plurality of rotor blades has a leading edge axial sweep of the leading edge compared to a leading edge of a base blade of the plurality of rotor blades, and has a trailing edge axial sweep of the trailing edge compared to a trailing edge of the base blade of the plurality of rotor blades.

[0075] A rotor blade system as claimed in the preceding clause, wherein the leading edge axial sweep is equal to the trailing edge axial sweep.

[0076] A rotor blade system according to any preceding clause, wherein the leading edge axial sweep and the trailing edge axial sweep extend in a forward direction of the turbine engine.

[0077] A rotor blade system according to any preceding clause, wherein the leading edge axial sweep and the trailing edge axial sweep extend in a rearward direction of the turbine engine.

[0078] A rotor blade system according to any preceding clause, wherein the at least one rotor blade comprises a blade tip and a blade root, and the base blade comprises a base blade tip and a base blade root, and there is an overlap between the blade tip and the base blade tip.

[0079] A rotor blade system according to any preceding clause, wherein the at least one rotor blade comprises a blade tip and a blade root, and the base blade comprises a base blade tip and a base blade root, and wherein there is no overlap between the blade tip and the base blade tip.

[0080] A rotor blade system according to any preceding clause, wherein the base blade comprises a twist and the at least one rotor blade comprises a twist that is the same as the twist of the base blade.

[0081] A rotor blade system according to any preceding clause, wherein said at least one rotor blade has no or very little material added or removed compared to said base blade.

[0082] A rotor blade system as in any preceding clause, wherein said at least one rotor blade comprises all rotor blades of said plurality of rotor blades.

[0083] A rotor blade system according to any preceding clause, wherein the at least one rotor blade comprises a plurality of rotor blades, and wherein the plurality of rotor blades are arranged in a predetermined pattern around the rotor having a plurality of base blades.

[0084] A rotor blade system according to any preceding clause, wherein the predetermined pattern is an alternating pattern.

[0085] A rotor blade system as in any preceding clause, wherein the at least one of the plurality of rotor blades further comprises a circumferential sweep defined in an inter-blade spacing between the at least one of the plurality of rotor blades and an adjacent rotor blade of the plurality of rotor blades.

[0086] A rotor blade system as in any preceding clause, wherein a pitch is defined between blade tips of adjacent rotor blades of the plurality of rotor blades, and wherein the circumferential sweep is greater than 0% to 25% of the pitch.

[0087] A rotor blade system as in any preceding clause, wherein said at least one rotor blade defines a chord length between said leading edge and said trailing edge, and wherein said leading edge axial sweep or said trailing edge axial sweep is greater than 0% to 15% of said chord length.

[0088] A rotor blade system according to any preceding clause, wherein the leading edge axial sweep or the trailing edge axial sweep is 5% to 10% of the chord length.

[0089] A rotor blade system according to any preceding clause, wherein said at least one rotor blade defines a span length between a blade tip and a blade root, and said leading edge axial sweep or said trailing edge axial sweep is greater than 0% to 40% of said span length.

[0090] A rotor blade system according to any preceding clause, wherein the leading edge axial sweep or the trailing edge axial sweep is 5% to 25% of the span length.

[0091] A rotor blade system according to any preceding clause, wherein the at least one rotor blade defines a chord length between the leading edge and the trailing edge, the base blade defines a base blade chord length between the leading edge of the base blade and the trailing edge of the base blade, and the chord length is within 10% of the base blade chord length.

[0092] A rotor blade system as in any preceding clause, wherein the chord length is equal to the base blade chord length.

[0093] A rotor blade system according to any preceding clause, further comprising a circumferential sweep, wherein the circumferential sweep is in a direction of rotation of the turbine engine.

[0094] A rotor blade system according to any preceding clause, further comprising a circumferential sweep, wherein the circumferential sweep is in a direction opposite to the rotation of the turbine engine.

[0095] A rotor blade system according to any preceding clause, further comprising a circumferential sweep, and wherein the leading edge axial sweep and the trailing edge axial sweep are in a forward direction of the turbine engine, and the circumferential sweep is in a rotational direction of the turbine engine.

[0096] A rotor blade system according to any preceding clause, further comprising a circumferential sweep, and wherein the leading edge axial sweep and the trailing edge axial sweep are in a forward direction of the turbine engine, and the circumferential sweep is in a direction opposite to the rotation of the turbine engine.

[0097] A rotor blade system according to any preceding clause, further comprising a circumferential sweep, and wherein the leading edge axial sweep and the trailing edge axial sweep are in a rearward direction of the turbine engine, and wherein the circumferential sweep is in a rotational direction of the turbine engine.

[0098] A rotor blade system according to any preceding clause, further comprising a circumferential sweep, and wherein the leading edge axial sweep and the trailing edge axial sweep are in a rearward direction of the turbine engine, and the circumferential sweep is in a direction opposite to the rotation of the turbine engine.

[0099] A rotor blade system as claimed in any preceding clause, wherein the circumferential sweep is greater than 0% to 40% of the span length.

[0100] A rotor blade system as claimed in any preceding clause, wherein the circumferential sweep is between 5% and 25% of the span length.

[0101] A rotor blade system as claimed in any preceding clause, wherein said circumferential sweep is between 2% and 10% of said pitch.

[0102] A rotor blade system according to any preceding clause, wherein the at least one rotor blade comprises a blade tip and a blade root, the base blade comprises a base blade tip and a base blade root, and the blade tip and the blade root are coplanar with the base blade tip and the base blade root, respectively.

[0103] A rotor blade system as in any preceding clause, wherein there is no sweep at the blade root.

[0104] A rotor blade system according to any preceding clause, wherein the at least one rotor blade defines a blade thickness between the leading edge and the trailing edge, the base blade defines a base blade thickness length between the leading edge of the base blade and the trailing edge of the base blade, and the blade thickness is within 25% of the base blade thickness.

[0105] Rotor blade system according to the preceding clause, wherein said blade thickness is equal to said base blade thickness.

[0106] A rotor blade system according to any preceding clause, further comprising a sweep point on the leading edge, wherein the leading edge axial sweep occurs from the sweep point to the blade tip, and wherein the leading edge of the at least one rotor blade and the leading edge of the base blade are collinear from the sweep point to the blade root.

[0107] A rotor blade system according to any preceding clause, further comprising a sweep point on the trailing edge, wherein the trailing edge axial sweep occurs from the sweep point to the blade tip, and wherein the trailing edge of the at least one rotor blade and the trailing edge of the base blade are collinear from the sweep point to the blade root.

[0108] A rotor blade system as in any preceding clause, further comprising a radial distance extending from a blade tip to a sweep point, the sweep point defining a point at which axial sweep of the leading edge ceases, and the leading edge of the at least one rotor blade is co-linear with a leading edge of the base blade.

[0109] The rotor blade system according to the preceding clause, wherein said radial distance is greater than 0% to 40% of said span length of said at least one rotor blade.

[0110] Rotor blade system according to the preceding clause, wherein said radial distance is 5% to 25% of said span length of said at least one rotor blade.

[0111] A rotor blade system for a turbine engine having a longitudinal centerline axis, comprising: a rotor configured to rotate about the longitudinal centerline axis; and a plurality of rotor blades circumferentially coupled about the rotor, each rotor blade having a leading edge, a trailing edge, a suction side, and a pressure side. At least one rotor blade of the plurality of rotor blades has a suction side circumferential sweep of the suction side compared to a suction side of a base blade of the plurality of rotor blades, and has a pressure side circumferential sweep of the pressure side compared to a pressure side of the base blade of the plurality of rotor blades.

[0112] A rotor blade system as described in the preceding clause, wherein the suction side circumferential sweep is equal to the pressure side circumferential sweep.

[0113] A rotor blade system according to any preceding clause, wherein the suction side circumferential sweep and the pressure side circumferential sweep extend in a direction of rotation of the turbine engine.

[0114] A rotor blade system according to any preceding clause, wherein the suction side circumferential sweep and the pressure side circumferential sweep extend in a direction of relative rotation of the turbine engine.

[0115] A rotor blade system according to any preceding clause, wherein the at least one rotor blade comprises a blade tip and a blade root, and the base blade comprises a base blade tip and a base blade root, and there is an overlap between the blade tip and the base blade tip.

[0116] A rotor blade system according to any preceding clause, wherein the at least one rotor blade comprises a blade tip and a blade root, and the base blade comprises a base blade tip and a base blade root, and wherein there is no overlap between the blade tip and the base blade tip.

[0117] A rotor blade system according to any preceding clause, wherein the base blade comprises a twist and the at least one rotor blade comprises a twist that is the same as the twist of the base blade.

[0118] A rotor blade system according to any preceding clause, wherein said at least one rotor blade has no or very little material added or removed compared to said base blade.

[0119] A rotor blade system as in any preceding clause, wherein said at least one rotor blade comprises all rotor blades of said plurality of rotor blades.

[0120] A rotor blade system according to any preceding clause, wherein the at least one rotor blade comprises a plurality of rotor blades, and wherein the plurality of rotor blades are arranged in a predetermined pattern around the rotor having a plurality of base blades.

[0121] A rotor blade system according to any preceding clause, wherein the predetermined pattern is an alternating pattern.

[0122] A rotor blade system as in any preceding clause, wherein the circumferential sweep is defined in an inter-blade spacing defined between the at least one rotor blade in the plurality of rotor blades and an adjacent rotor blade in the plurality of rotor blades.

[0123] A rotor blade system as in any preceding clause, wherein a pitch is defined between blade tips of adjacent rotor blades of the plurality of rotor blades, and wherein the circumferential sweep is greater than 0% to 25% of the pitch.

[0124] A rotor blade system as claimed in any preceding clause, wherein said circumferential sweep is between 2% and 10% of said pitch.

[0125] A rotor blade system according to any preceding clause, wherein said at least one rotor blade defines a span length between a blade tip and a blade root, and said suction side circumferential sweep or said pressure side circumferential sweep is greater than 0% to 40% of said span length.

[0126] A rotor blade system according to any preceding clause, wherein the suction side circumferential sweep or the pressure side circumferential sweep is 5% to 25% of the span length.

[0127] A rotor blade system according to any preceding clause, wherein the at least one rotor blade defines a chord length between the leading edge and the trailing edge, the base blade defines a base blade chord length between the leading edge of the base blade and the trailing edge of the base blade, and the chord length is within 10% of the base blade chord length.

[0128] A rotor blade system as in any preceding clause, wherein the chord length is equal to the base blade chord length.

[0129] A rotor blade system according to any preceding clause, further comprising an axial sweep, wherein the axial sweep is in a forward direction of the turbine engine.

[0130] A rotor blade system according to any preceding clause, further comprising an axial sweep, wherein the axial sweep is in a rearward direction of the turbine engine.

[0131] A rotor blade system according to any preceding clause, further comprising an axial sweep, and wherein the axial sweep is in a forward direction of the turbine engine, and wherein the suction side circumferential sweep and the pressure side circumferential sweep are in a rotational direction of the turbine engine.

[0132] A rotor blade system according to any preceding clause, further comprising an axial sweep, and wherein the axial sweep is in a forward direction of the turbine engine, and the suction side circumferential sweep and the pressure side circumferential sweep are in a direction opposite to the rotation of the turbine engine.

[0133] A rotor blade system according to any preceding clause, further comprising an axial sweep, and wherein the axial sweep is in an aft direction of the turbine engine, and wherein the suction side circumferential sweep and the pressure side circumferential sweep are in a rotational direction of the turbine engine.

[0134] A rotor blade system according to any preceding clause, further comprising an axial sweep, and wherein the axial sweep is in an aft direction of the turbine engine, and the suction side circumferential sweep and the pressure side circumferential sweep are in a direction opposite to the rotation of the turbine engine.

[0135] A rotor blade system as claimed in any preceding clause, wherein the axial sweep is greater than 0% to 40% of the span length.

[0136] A rotor blade system as claimed in any preceding clause, wherein the axial sweep is between 5% and 25% of the span length.

[0137] A rotor blade system as in any preceding clause, wherein said at least one rotor blade defines a chord length between said leading edge and said trailing edge, and wherein said axial sweep is greater than 0% to 15% of said chord length.

[0138] A rotor blade system as claimed in any preceding clause, wherein the axial sweep is 5% to 10% of the chord length.

[0139] A rotor blade system as claimed in any preceding clause, wherein the axial sweep comprises a leading edge axial sweep that is equal to a trailing edge axial sweep.

[0140] A rotor blade system according to any preceding clause, wherein the leading edge axial sweep and the trailing edge axial sweep extend in a forward direction of the turbine engine.

[0141] A rotor blade system according to any preceding clause, wherein the leading edge axial sweep and the trailing edge axial sweep extend in a rearward direction of the turbine engine.

[0142] A rotor blade system according to any preceding clause, wherein the at least one rotor blade comprises a blade tip and a blade root, the base blade comprises a base blade tip and a base blade root, and the blade tip and the blade root are coplanar with the base blade tip and the base blade root, respectively.

[0143] A rotor blade system as in any preceding clause, wherein there is no sweep at the blade root.

[0144] A rotor blade system according to any preceding clause, wherein the at least one rotor blade defines a blade thickness between the leading edge and the trailing edge, the base blade defines a base blade thickness length between the leading edge of the base blade and the trailing edge of the base blade, and the blade thickness is within 25% of the base blade thickness.

[0145] Rotor blade system according to the preceding clause, wherein said blade thickness is equal to said base blade thickness.

[0146] The rotor blade system of any preceding clause, further comprising a sweep point on the suction side, wherein the suction side circumferential sweep occurs from the sweep point to the blade tip, and wherein the suction side of the at least one rotor blade and the suction side of the base blade are collinear from the sweep point to the blade root.

[0147] The rotor blade system of any preceding clause, further comprising a sweep point on the pressure side, wherein the pressure side circumferential sweep occurs from the sweep point to the blade tip, and wherein the pressure side of the at least one rotor blade and the pressure side of the base blade are collinear from the sweep point to the blade root.

[0148] A rotor blade system as in any preceding clause, further comprising a radial distance extending from a blade tip to a sweep point, the sweep point defining a point at which a circumferential sweep of the suction side ceases, and the suction side of the at least one rotor blade being co-linear with a suction side of the base blade.

[0149] The rotor blade system according to the preceding clause, wherein said radial distance is greater than 0% to 40% of said span length of said at least one rotor blade.

[0150] Rotor blade system according to the preceding clause, wherein said radial distance is 5% to 25% of said span length of said at least one rotor blade.

[0151] A turbine engine comprising a rotor blade system according to any preceding clause.

[0152] The turbine engine according to the preceding clause, further comprising a low-pressure turbine, wherein said rotor blade system is included in at least one stage of said low-pressure turbine.

[0153] A turbine engine according to any preceding clause, further comprising a high pressure turbine, wherein the rotor blade system is included in at least one stage of the high pressure turbine.

[0154] The turbine engine of any preceding clause, further comprising a low-pressure compressor, wherein the rotor blade system is included in at least one stage of the low-pressure compressor.

[0155] The turbine engine of any preceding clause, further comprising a high pressure compressor, wherein the rotor blade system is included in at least one stage of the high pressure compressor.

[0156] A turbine engine according to any preceding clause, further comprising a fan, wherein said rotor blade system is included in said fan.

[0157] Although the above description is directed to the preferred embodiments of the present disclosure, other changes and modifications will be apparent to those skilled in the art and may be made without departing from the spirit or scope of the present disclosure. In addition, the features described in conjunction with one embodiment of the present disclosure may be used in conjunction with other embodiments, even if not explicitly stated above.

Claims

1. A rotor blade system for a turbine engine having a longitudinal centerline axis, characterized in that The rotor blade system comprises: a rotor configured to rotate about the longitudinal centerline axis; and a plurality of rotor blades coupled circumferentially about the rotor, each rotor blade having a leading edge, a trailing edge, a suction side, and a pressure side, At least one rotor blade of the plurality of rotor blades has a leading edge axial sweep compared to a leading edge of a base blade of the plurality of rotor blades and has a trailing edge axial sweep compared to a trailing edge of the base blade of the plurality of rotor blades.

2. The rotor blade system according to claim 1, characterized in that in, The leading edge axial sweep is equal to the trailing edge axial sweep.

3. The rotor blade system according to claim 1, characterized in that in, The leading edge axial sweep and the trailing edge axial sweep extend in a forward direction of the turbine engine.

4. The rotor blade system according to claim 1, characterized in that in, The leading edge axial sweep and the trailing edge axial sweep extend in a rearward direction of the turbine engine.

5. The rotor blade system according to claim 1, characterized in that: in, The at least one rotor blade comprises a blade tip and a blade root, and the base blade comprises a base blade tip and a base blade root, and there is an overlap between the blade tip and the base blade tip.

6. The rotor blade system according to claim 1, characterized in that in, The at least one rotor blade comprises a blade tip and a blade root, and the base blade comprises a base blade tip and a base blade root, and there is no overlap between the blade tip and the base blade tip.

7. The rotor blade system according to claim 1, characterized in that in, The base blade comprises a twist, and the at least one rotor blade comprises a twist that is the same as the twist of the base blade.

8. The rotor blade system according to claim 1, characterized in that in, The at least one rotor blade has no or very little material added or removed compared to the base blade.

9. The rotor blade system according to claim 1, characterized in that in, The at least one rotor blade includes all rotor blades of the plurality of rotor blades.

10. The rotor blade system according to claim 1, characterized in that in, The at least one rotor blade includes a plurality of rotor blades, and the plurality of rotor blades are arranged in a predetermined pattern around the rotor having a plurality of base blades.

Images