Turbine engine including fan assembly having damper

Abstract

The turbine engine is subjected to 1P vibrations. The turbine engine includes a turbocharged engine, a compressor for compressing air, and a combustor for combusting fuel and compressed air to produce combustion gases. The turbine receives the combustion gas and drives the fan assembly. The fan assembly includes a fan disk and a fan blade having a fan blade centerline axis. The fan blades bear 1P load and generate 1P vibration. The fan blade roots are fixed to the fan blades, connected with the fan disc, aligned with the axis of the center line of the fan blades and used for conducting 1P vibration. A damper positioned radially between the fan blade root and the fan disk dampens 1P vibrations.

Description

Technical Field

[0001] The present disclosure generally relates to a turbine engine including a damper. Background Art

[0002] A turbine engine generally comprises a fan and a core section arranged in flow communication with each other. A combustor is arranged in the core section to generate combustion gases for driving a turbine in the core section of the turbine engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Features and advantages will become apparent from the following description of various exemplary embodiments as illustrated in the accompanying drawings, in which like reference numbers generally indicate identical, functionally similar, and / or structurally similar elements.

[0004] Figure 1 A schematic diagram of a ductless three-flow gas turbine engine is shown, taken along the longitudinal centerline axis of the turbine engine, according to one embodiment of the present disclosure.

[0005] Figure 2A A schematic diagram of an unducted three-flow gas turbine engine at a non-zero incidence angle is shown according to one embodiment of the present disclosure.

[0006] Figure 2B A schematic diagram of an unducted three-flow gas turbine engine at a non-zero yaw angle according to one embodiment of the present disclosure is shown.

[0007] Figure 2C A schematic diagram of an unducted three-flow gas turbine engine at a non-zero angle of attack is shown according to one embodiment of the present disclosure.

[0008] Figure 3 is a schematic diagram of a fan blade assembly according to one embodiment of the present invention.

[0009] Figure 4 is a schematic diagram of a fan blade mounting assembly according to one embodiment of the present disclosure.

[0010] Figure 5 is a schematic diagram of a fan blade mounting assembly according to one embodiment of the present disclosure.

[0011] Figure 6 is a schematic diagram of a fan blade mounting assembly according to one embodiment of the present disclosure.

[0012] Figure 7 is a schematic diagram of a fan blade mounting assembly according to one embodiment of the present disclosure.

[0013] Figure 8 is a schematic diagram of a fan blade mounting assembly according to one embodiment of the present disclosure.

[0014] Figure 9 is a schematic diagram of a squeeze film damper according to one embodiment of the present invention.

[0015] Figure 10 is a schematic diagram of a damper according to an embodiment of the present invention.

[0016] Figure 11 is a schematic diagram of a damper according to an embodiment of the present invention.

[0017] Figure 12 is a schematic diagram of a damper according to an embodiment of the present invention.

[0018] Figure 13 is a schematic diagram of a damper according to an embodiment of the present invention.

[0019] Figure 14 is a schematic diagram of a damper according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] Features, advantages, and embodiments of the present disclosure are set forth or apparent from consideration of the following detailed description, drawings, and claims. Furthermore, the following detailed description is exemplary and intended to provide further explanation without limiting the disclosure as claimed.

[0021] Various embodiments 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 present disclosure.

[0022] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to indicate the position or importance of each component.

[0023] The terms "fore" and "aft" refer to relative positions within a turbocharged engine or vehicle and to the normal operating attitude of the turbocharged engine or vehicle. For example, for a gas turbine engine, the front position refers to the position closer to the engine inlet, while the aft position refers to the position closer to the engine nozzle or exhaust.

[0024] The terms "upstream" and "downstream" refer to relative directions relative to the flow of 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.

[0025] Unless otherwise indicated herein, the terms "coupled," "fixed," and the like refer to both direct coupling, fixing, or attachment as well as indirect coupling, fixing, or attachment through one or more intermediate components or features.

[0026] As used herein, unless otherwise specified, the terms "low," "medium" (or "medium level"), and "high," or their respective comparatives (e.g., "lower" and "higher," where applicable), when used with respect to 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. For example, a "low power" setting defines an engine configured to operate at a power output lower than the engine's "high power" setting, while a "medium level power" setting defines an engine 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 level"), or "high" within these 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.

[0027] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0028] Unless otherwise stated, the terms "low" and "high" or their respective comparatives (e.g., "lower" and "higher" where applicable), when used with compressor, turbine, shaft or spool components, refer to relative pressures and / or relative speeds within the engine. For example, a "low-speed shaft" defines a component that is configured to operate at a rotational speed (e.g., a maximum allowable rotational speed) that is lower than the "high-speed shaft" of the engine. Alternatively, unless otherwise stated, the above terms may be understood as their superlatives. For example, a "low-pressure turbine" may refer to the lowest maximum pressure within the turbine section, while a "high-pressure turbine" may refer to the highest maximum pressure within the turbine section. The terms "low" or "high" may additionally or alternatively be understood as relative to the minimum allowable speed and / or pressure, or relative to the minimum or maximum allowable speed and / or pressure for normal, desired, steady-state, etc. operation of the engine.

[0029] The term "housing" herein refers to a structure (eg, a duct wall or housing) that defines an airflow path. The housing may be mounted by direct bolting or via a load-bearing frame.

[0030] As used herein, "static structure" refers to any non-rotating structural part of an engine.

[0031] As used herein, the term "damper" refers to a device or component that absorbs, reduces, or otherwise mitigates vibrations generated by the operation of a gas turbine engine. Such vibrations may or may not include significant relative motion. The vibrations may originate from the fan blade assembly. As used herein, a damper may include a device or component for radial damping or bending damping. A damper may suppress motion or vibration. Figures 9 to 14 An example of a damper is provided.

[0032] As used herein, a "spring-mass-damper system" refers to a system or assembly used to dampen vibrations, generally defined by the following formula:

[0033]

[0034] Where F is force, t is time, m is mass, x is displacement, c is the damping coefficient, and k is the spring constant.

[0035] As used herein, "angle of attack" refers to the upward or downward angle between the longitudinal centerline axis of the turbine engine and the direction of travel of the aircraft. For example, the angle of attack α ( Figure 2C ) may be zero or near zero in level flight with minimal ambient wind. Alternatively, the angle of attack may be non-zero during acceleration, deceleration, climb, descent, or ambient wind conditions.

[0036] As used herein, "yaw angle" refers to the left or right angle between the longitudinal centerline axis of the turbine engine and the direction of travel of the aircraft. For example, the yaw angle β ( Figure 2B ) may be zero or close to zero in straight flight with minimal ambient wind. Alternatively, the yaw angle may be non-zero when the aircraft is maneuvering or when subject to an ambient crosswind.

[0037] As used herein, “inboard” and “outboard” refer to relative locations closer to and further from the longitudinal centerline axis of the turbine engine, respectively.

[0038] Here and throughout the specification and claims, range limitations are combinable and interchangeable, and unless context or language indicates otherwise, these ranges are defined and include all subranges contained therein. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

[0039] One or more components of the turbocharged engine described below may be manufactured or formed using any suitable process, such as an additive manufacturing process, such as a three-dimensional (3D) printing process. Use of such a process may allow such a component to be formed as a single, integral component or as any suitable number of subcomponents. Specifically, the additive manufacturing process may allow such a component to be formed as a whole and include various features that are not possible using existing manufacturing methods. For example, the additive manufacturing methods described herein are capable of manufacturing shafts having unique features, configurations, thicknesses, materials, densities, passages, manifolds, and mounting structures that may not be possible or impractical using existing manufacturing methods. Some of these features are described herein.

[0040] The present disclosure and various embodiments relate to turbocharged engines, also known as turbine engines, gas turbine engines, turboprop engines, or turbines. These turbocharged engines can be applied to a variety of technologies and industries. Various embodiments may be described herein in the context of aerospace engines and aircraft machinery.

[0041] In some cases, a turbocharged engine is configured as a direct-drive engine. In other cases, a turbocharged engine may be configured as an indirect-drive engine with a gearbox. In some cases, the propeller of a turbocharged engine may be a fan enclosed within a fan casing and / or nacelle. This type of turbocharged engine may be referred to as a "ducted engine." In other cases, the propeller of a turbocharged engine may be exposed (e.g., not within a fan casing or nacelle). This type of turbocharged engine may be referred to as an "open rotor engine" or a "ductless engine."

[0042] The various power levels of the turbine engines described herein are defined as percentages of the maximum engine rated thrust at sea level static (SLS). Low power operation includes, for example, less than thirty percent (30%) of the turbine engine's SLS maximum engine rated thrust. Medium power operation includes, for example, thirty percent (30%) to eighty-five percent (85%) of the turbine engine's SLS maximum engine rated thrust. High power operation includes, for example, greater than eighty-five percent (85%) of the turbine engine's SLS maximum engine rated thrust. The thrust values ​​for low power operation, medium power operation, and high power operation of the turbine engine are exemplary only, and other thrust values ​​may be used to define low power operation, medium power operation, and high power operation.

[0043] Referring now to the accompanying drawings, Figure 1 A schematic diagram of an unducted, three-flow gas turbine engine 10 for an aircraft is shown, which may incorporate one or more embodiments of the present disclosure. The gas turbine engine 10 is a "three-flow engine" because its structure provides three different airflows (labeled S1, S2, and S3) that generate thrust during operation, as described in further detail below.

[0044] like Figure 1As shown, the gas turbine engine 10 defines an axial direction A, a radial direction R, and a circumferential direction C. Furthermore, the gas turbine engine 10 defines a longitudinal centerline axis 12, also referred to as an engine centerline axis, extending along the axial direction A. Generally, the axial direction A extends parallel to the longitudinal centerline axis 12, the radial direction R extends outwardly and inwardly from the longitudinal centerline axis 12 in a direction orthogonal to the axial direction A, and the circumferential direction C extends three hundred and sixty degrees (360°) about the longitudinal centerline axis 12. The gas turbine engine 10 extends between a forward end 14 and an aft end 16, e.g., along the axial direction A.

[0045] As used below in the discussion of the gas turbine engine 10, Figure 1 2 ), the terms "axial" and "axially" refer to directions and orientations that extend generally parallel to the longitudinal centerline axis 12 of the turbine engine. Additionally, the terms "radial" and "radially" refer to directions and orientations that extend generally perpendicular to the longitudinal centerline axis 12 of the gas turbine engine 10. Furthermore, as used herein, the terms "circumferential" and "circumferentially" refer to directions and orientations that extend in an arc about the longitudinal centerline axis 12 of the turbine engine.

[0046] The gas turbine engine 10 includes a turbocharger 20 and a fan assembly 50 located upstream thereof. Generally speaking, the turbocharger 20 includes a compressor section, a combustion section, a turbine section, and an exhaust section in a series flow order. Specifically, Figure 1 As shown, the turbocharged engine 20 includes an engine core 18 and a core cover 22 annularly surrounding the turbocharged engine 20. The turbocharged engine 20 and the core cover 22 define an annular core inlet 24. The core cover 22 further surrounds and supports a low-pressure (LP) compressor 26 (also known as a supercharger) for compressing air entering the turbocharged engine 20 through the core inlet 24. A high-pressure (HP) compressor 28 receives compressed air from the LP compressor 26 and further increases the air pressure. The compressed air flows downstream to the combustor 30, where fuel is injected into the compressed air and ignited and combusted, increasing the temperature and energy level of the compressed air and generating combustion gases 67.

[0047] The combustion gases 67 flow downstream from the combustor 30 to the high pressure (HP) turbine 32. The HP turbine 32 rotationally drives the HP compressor 28 via a first shaft (also referred to as the high pressure (HP) shaft 36, or "high speed shaft"). In this regard, the HP turbine 32 is rotationally and drivingly coupled to the HP compressor 28. The HP compressor 28, the combustor 30, and the HP turbine 32 collectively define the engine core 18. The combustion gases 67 then flow to the power turbine or low pressure (LP) turbine 34. The LP turbine 34 rotationally drives the LP compressor 26 and components of the fan assembly 50 via a second shaft (also referred to as the low pressure (LP) shaft 38, or "low speed shaft"). In this regard, the LP turbine 34 is rotationally and drivingly coupled to the LP compressor 26 and components of the fan assembly 50. Figure 1 In the illustrated embodiment, the low-speed shaft 38 is coaxially arranged with the high-speed shaft 36. After driving each of the HP turbine 32 and the LP turbine 34, the combustion gases 67 exit the turbocharger engine 20 through the core exhaust nozzle 40. The turbocharger engine 20 defines a core flow path (also referred to as a core duct 42) extending between the core inlet 24 and the core exhaust nozzle 40. The core duct 42 is an annular duct located generally inwardly of the core shroud 22 along the radial direction R.

[0048] The fan assembly 50 includes a main fan 52. Figure 1 In the embodiment of FIG. 5 , the main fan 52 is an open rotor fan, also known as a non-ducted fan. However, in other embodiments, the main fan 52 may be ducted, for example, by a fan housing or nacelle (not shown) circumferentially surrounding the main fan 52. The main fan 52 includes an array of fan blades 54 ( Figure 1 Only one is shown). The fan blades 54 are rotatable about the longitudinal centerline axis 12 via the fan shaft 59. Figure 1 As shown, the fan shaft 59 is rotationally coupled to the low speed shaft 38 via a reduction gearbox (also referred to as a gearbox assembly 53, for example, in an indirect drive configuration). Figure 1 Schematically shown in FIG. The gearbox assembly 53 includes a plurality of gears for adjusting the rotational speed of the fan shaft 59, thereby adjusting the rotational speed of the main fan 52 relative to the low-speed shaft 38 to a more efficient fan rotational speed. The gearbox assembly can have a gear ratio of 4:1 to 12:1, or 7:1 to 12:1, or 4:1 to 10:1, or 5:1 to 9:1, or 6:1 to 9:1, and can be configured as a sun gear or planetary gear configuration. The gearbox can be a single-stage or compound gearbox.

[0049] The fan blades 54 may be arranged at equal intervals about the longitudinal centerline axis 12. Each fan blade 54 has a root and a tip and a span defined therebetween. Each fan blade 54 defines a fan blade centerline axis 57. Figure 1In some embodiments, each fan blade 54 of the main fan 52 is capable of rotating about its respective fan blade centerline axis 57, e.g., in synchronization with one another. One or more actuators 58 are controlled to cause the fan blades 54 to pitch about their respective fan blade centerline axis 57. In other embodiments, each fan blade 54 is fixed or cannot pitch about the fan blade centerline axis 57.

[0050] The fan assembly 50 also includes a fan guide vane array 60 including fan guide vanes 62 ( Figure 1 Only one is shown). Figure 1 In the embodiment of the present invention, the fan guide vanes 62 are not rotatable about the longitudinal centerline axis 12. Each fan guide vane 62 has a root and a tip and a span defined therebetween. The fan guide vanes 62 may be configured as follows: Figure 1 It is shown without a shroud, or it may be shrouded, for example, by an annular shroud spaced outwardly from the tips of the fan guide vanes 62 in the radial direction R. Each fan guide vane 62 defines a central vane axis 64. Figure 1 In some embodiments, each fan guide vane 62 of the fan guide vane array 60 is rotatable about its respective central vane axis 64, e.g., in synchronization with one another. One or more actuators 66 are controlled to pitch the fan guide vanes 62 about their respective central vane axes 64. In other embodiments, each fan guide vane 62 is fixed or cannot be pitched about the central vane axis 64. The fan guide vanes 62 are mounted to a fan housing 70.

[0051] The fan shroud 70 annularly surrounds at least a portion of the core shroud 22 and is generally located outside the core shroud 22 in the radial direction R. Specifically, a downstream section of the fan shroud 70 extends above the front of the core shroud 22 to define a fan flow path, also referred to as a fan duct 72. Incoming air enters the fan duct 72 through a fan duct inlet 76 and exits through a fan exhaust nozzle 78 to generate propulsive thrust. The fan duct 72 is an annular duct that is generally located outside the core duct 42 in the radial direction R. The fan shroud 70 and the core shroud 22 are connected together and are connected by a plurality of struts 74 ( Figure 1 The plurality of struts 74 (only one shown) extend generally radially and are spaced circumferentially about the longitudinal centerline axis 12. The plurality of struts 74 each have an aerodynamic profile to direct the flow of air through the struts 74. In addition to the plurality of struts 74, other struts may be used to connect and support the fan shroud 70 and / or the core shroud 22.

[0052] The gas turbine engine 10 further defines or includes an inlet duct 80. The inlet duct 80 extends between an engine inlet 82 and the core inlet 24 and the fan duct inlet 76. The engine inlet 82 is generally defined at the forward end of the fan casing 70 and is located between the main fan 52 and the fan guide vane array 60 in the axial direction A. The inlet duct 80 is an annular duct located inwardly of the fan casing 70 in the radial direction R. Air flowing downstream along the inlet duct 80 is divided (not necessarily evenly) into the core duct 42 and the fan duct 72 by a flow divider 84 of the core casing 22. The inlet duct 80 is wider in the radial direction R than the core duct 42. The inlet duct 80 is also wider in the radial direction R than the fan duct 72.

[0053] The fan assembly 50 also includes an intermediate fan 86. The intermediate fan 86 includes a plurality of intermediate fan blades 88 (only in the Figure 1 One is shown in FIG). A plurality of intermediate fan blades 88 are capable of rotating, for example, about the longitudinal centerline axis 12. The intermediate fan 86 is drive-coupled to the LP turbine 34 via the low-speed shaft 38. The plurality of intermediate fan blades 88 may be arranged at equal circumferential spacing about the longitudinal centerline axis 12. The plurality of intermediate fan blades 88 are annularly surrounded by the fan cover 70 (e.g., forming a duct). In this regard, the intermediate fan 86 is located inside the fan cover 70 along the radial direction R. The intermediate fan 86 is positioned within the inlet duct 80 upstream of both the core duct 42 and the fan duct 72. The ratio of the span of the fan blade 54 to the span of the intermediate fan blade 88 (the span is measured from the root to the tip of the corresponding blade) is greater than two and less than ten. To achieve the expected benefits of the third flow (S3), in particular the additional thrust it provides to the engine, the design allows the fan blade 54 to have a smaller diameter (facilitating engine installation).

[0054] Thus, air flowing through inlet duct 80 passes over a plurality of intermediate fan blades 88 and is accelerated downstream thereof. At least a portion of the air accelerated by intermediate fan blades 88 flows into fan duct 72 and is ultimately discharged through fan exhaust nozzle 78 to generate propulsive thrust. Furthermore, at least a portion of the air accelerated by intermediate fan blades 88 flows into core duct 42 and is ultimately discharged through core exhaust nozzle 40 to generate propulsive thrust. Typically, intermediate fan 86 is a compression device located downstream of engine inlet 82. Mid-fan 86 is operable to accelerate air into fan duct 72, also known as a secondary bypass duct.

[0055] During operation of gas turbine engine 10, an initial or incoming airflow passes through fan blades 54 of main fan 52 and is split into a first airflow and a second airflow. The first airflow bypasses engine inlet 82 and flows outward from fan casing 70 generally in axial direction A along radial direction R. The first airflow, accelerated by fan blades 54, passes through fan guide vanes 62 and continues downstream to generate a main propulsive flow or first thrust flow S1. The majority of the net thrust generated by gas turbine engine 10 is generated by first thrust flow S1.

[0056] The second airflow enters the inlet duct 80 through the engine inlet 82. The second airflow flowing downstream through the inlet duct 80 flows through a plurality of intermediate fan blades 88 of the intermediate fan 86 and is then compressed. The second airflow flowing downstream from the intermediate fan blades 88 is split by the splitter 84 located at the front end of the core cover 22. Specifically, a portion of the second airflow flowing downstream from the intermediate fan 86 enters the core duct 42 through the core inlet 24. The portion of the second airflow entering the core duct 42 is gradually compressed by the LP compressor 26 and the HP compressor 28 and is ultimately discharged into the combustion section. The discharged compressed air flows downstream to the combustor 30, where fuel is introduced to generate combustion gases 67 or combustion products.

[0057] The combustor 30 defines an annular combustion chamber generally coaxial with the longitudinal centerline axis 12. The combustor 30 receives compressed air from the HP compressor 28 via the HP compressor discharge outlet. A portion of the compressed air flows into a mixer. Fuel is injected by fuel nozzles (omitted for clarity) and mixed with the compressed air to form a fuel-air mixture, which is then provided to the combustor for combustion. Ignition of the fuel-air mixture is accomplished by one or more igniters (omitted for clarity), resulting in combustion gases 67 flowing in an axial direction A toward and into the first-stage turbine nozzle 33 of the HP turbine 32. The first-stage turbine nozzle 33 is defined by an annular flow path and includes a plurality of radially extending, circumferentially spaced nozzle vanes 35. These nozzle vanes 35 rotate the combustion gases 67, causing them to flow at an angle and impact the first-stage turbine blades of the HP turbine 32. The combustion gases 67 exit the HP turbine 32 and flow through the LP turbine 34, exiting the core duct 42 through the core exhaust nozzle 40, generating a core air flow (also referred to as a secondary thrust flow S2). As previously described, the HP turbine 32 drives the HP compressor 28 via the high-speed shaft 36 , and the LP turbine 34 drives the LP compressor 26 , the main fan 52 , and the intermediate fan 86 via the low-speed shaft 38 .

[0058] Another portion of the second airflow flowing downstream from the intermediate fan 86 is split by the splitter 84 into the fan duct 72. The air enters the fan duct 72 through the fan duct inlet 76. The air flows through the fan duct 72 generally in the axial direction A and is ultimately discharged from the fan duct 72 through the fan exhaust nozzle 78 to generate a third flow, also referred to as a third thrust flow S3.

[0059] The third thrust stream S3 is a secondary air flow that increases fluid energy to produce a smaller portion of the total thrust of the propulsion system. In some embodiments, the pressure ratio of the third stream is higher than the pressure ratio of the main propulsion stream (e.g., bypass stream or propeller-driven propulsion stream). Thrust can be generated by a dedicated nozzle or by mixing the secondary air flow with the main propulsion stream or core air flow (e.g., entering a common nozzle). In certain embodiments, the operating temperature of the secondary air flow is lower than the maximum compressor discharge temperature of the engine. In addition, in certain embodiments, various aspects of the third stream (e.g., airflow properties, mixing properties, or exhaust properties) and their relative percentage contribution to total thrust are passively adjusted during engine operation or purposefully adjusted using engine control features (e.g., fuel flow, motor power, variable stator, variable inlet guide vanes, valves, variable exhaust geometry, or flow characteristics) to adjust or improve overall system performance under a wide range of potential operating conditions.

[0060] Figure 1 The gas turbine engine 10 shown in FIG is for example only. In other embodiments, the gas turbine engine 10 may have any other suitable configuration. For example, in other embodiments, the main fan 52 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. Alternative configurations may include a turbine engine 10 without a fan guide vane array 60 or a turbine engine 10 with rotating blades in the fan guide vane array 60. Although the following discussion is directed to a ductless configuration, other embodiments are also contemplated in which the main fan 52 may be ducted through the fan case or nacelle, thereby forming a bypass passage between the fan case and the fan cowl 70. Furthermore, in other embodiments, any other suitable number or configuration of compressors, turbines, shafts, or combinations thereof may be provided. In yet other embodiments, aspects of the present disclosure may be incorporated into any other suitable turbine engine, such as a turbofan engine, a propfan engine, a turbojet engine, a turboprop engine, a turboshaft engine, and / or a turbine engine that defines two flows (e.g., a bypass flow and a core air flow).

[0061] Now refer to Figures 2A to 2CUnducted turbine engines, such as the gas turbine engine 10 discussed herein, typically have larger fan blades 54 than other turbine engine configurations of comparable capacity. The fan blades 54 of an unducted gas turbine engine 10 are typically larger in both chord length and chord thickness. Consequently, the fan blades 54 of an unducted gas turbine engine 10 are more susceptible to the effects of misaligned incident air flow Si. The incident air flow Si may enter the flow path of the gas turbine engine 10 from a direction that is not aligned with the longitudinal centerline axis 12 of the gas turbine engine 10. The angle of incidence γ is the angle at which the incident air flow Si is misaligned relative to the longitudinal centerline axis 16 of the turbine engine 10.

[0062] Certain flight conditions and / or environmental conditions may affect the angle of incidence γ. For example, Figure 2B As shown, the longitudinal centerline axis 12 may be offset by a non-zero yaw angle β to the left or right of the direction of travel T. This may occur in crosswind conditions, or during a taxiing maneuver, and affect the resulting angle of incidence γ.

[0063] Alternatively or additionally, certain flight conditions, such as takeoff and landing situations, may result in a non-zero angle of attack α when the aircraft may be in a pitch-up attitude, such as Figure 2C As shown. Figure 2C As shown, the angle of attack α is positive, meaning that the front end of the gas turbine engine 10 is oriented upward relative to the direction of travel T, as shown. Figure 2C A pitch-up state is shown in FIG, but flight conditions and maneuvers may also dictate a dive state, which may also result in a non-zero angle of attack α.

[0064] The incident air flow Si is the air flow that initially contacts the fan blades 54 when entering the fan assembly 50. The magnitude of the incident air flow Si is determined by the airspeed of the aircraft, but is also determined by environmental conditions. The angle of incidence γ of the incident air flow Si that contacts the fan blades 54 is primarily determined by the angle of attack α and the yaw angle β, but is also affected by environmental conditions and aircraft operating events. Therefore, the incident air flow Si may be substantially aligned with the direction of travel T and in the opposite direction. However, the incident air flow Si may not be aligned with the direction of travel T due to the angle of incidence γ. The magnitude of the angle of incidence γ may be exacerbated at relatively low speeds, such as during aircraft takeoff and landing. Environmental conditions that affect the direction or magnitude of the incident air flow Si may include steady winds or gusts upward, downward, or laterally (also referred to as updrafts, downdrafts, or crosswinds, respectively), while examples of aircraft operating events include sudden aircraft maneuvers and payload releases.

[0065] Figure 2A Shown Figure 1FIGURE 1 illustrates a schematic diagram of gas turbine engine 10 with a non-zero angle of incidence γ. In an unducted configuration, such as illustrated by fan assembly 50, incident air flow Si is not redirected or reoriented in any manner prior to contact with each fan blade 54. Because the fan assembly is not oriented along a direction of travel T, fan blades 54 experience different stresses from incident air flow Si at different locations during their rotation.

[0066] exist Figure 2A , gas turbine engine 10 is at a non-zero angle of incidence γ. When aligned by upper blade 55 as shown, each fan blade 54 is in its highest position (also referred to as the twelve o'clock position). Conversely, when aligned by lower blade 56 as shown, each fan blade 54 is in its lowest position (also referred to as the six o'clock position). Similarly, leftmost blade 45 and rightmost blade 46 are at respective three o'clock and nine o'clock positions, respectively. Figure 2B .) The leftmost blade 45 will be subjected to a different load than the rightmost blade 46 due to the influence of the incident airflow Si. With each rotation of the main fan 52, the load on each fan blade 54 will cycle from the load on the leftmost blade 45 to the load on the rightmost blade 46 and back again. This cyclical load occurs once per rotation and is also referred to as a "1P load." The 1P load causes 1P periodic vibrations, also known as "1P vibrations," that coincide with the rotational frequency of the main fan 52. This 1P load originates from the fan blade 54 and is transmitted through interconnected components to the connected structure of the gas turbine engine 10. As used herein, "1P load" and "cyclic load" refer to the cyclic forces experienced by the fan blade 54 and transmitted to the interconnected components of the gas turbine engine 10 and the aircraft, as well as the cyclic vibrations in these components caused by the cyclic loads, or both. 1P loads can also cause undesirable and potentially damaging flutter in the fan blades. Undesirable 1P loads may even be perceived outside the gas turbine engine, in the aircraft structure, and by operators and passengers.

[0067] Furthermore, vibrations may be caused by distortions or unevenness in the inflow of incident airflow Si. Furthermore, individual variations between fan blades 54 may also contribute to vibrations. Inherent manufacturing variations within fan blades 54 may also contribute to vibrations. For example, due to manufacturing precision limitations, the geometry of each individual blade 54 may vary slightly. Consequently, each blade 54 will generate slightly different torques on fan assembly 50, causing vibrations.

[0068] The chord thickness of fan blades 54, the chord length of fan blades 54, and the pitch angle of fan blades 54 relative to fan blade centerline axis 57 exacerbate the effects of 1P loads. In the absence of features that align incident airflow Si with longitudinal centerline axis 12, such as the nacelle inlet, 1P loads increase. All of these features are present in the ductless configuration of gas turbine engine 10, relative to other turbine engines. Consequently, gas turbine engine 10 is subject to significant 1P loads.

[0069] 1P loads can cause a variety of adverse conditions in the gas turbine engine 10, including cyclic vibration, cyclic stress, and cyclic bending. 1P cyclic loads cause 1P cyclic vibrations, which can cause damage elsewhere in the engine. 1P cyclic vibrations can also cause fatigue in engine components and can cause discomfort to operators or passengers.

[0070] At larger or varying angles of incidence γ, the 1P load experienced by fan blades 54 may be more pronounced. The 1P load may become more or less pronounced as speed increases. Similar to the 1P load experienced per revolution due to angle of incidence γ, blades 54 may experience a 1P load per revolution due to changes in ambient wind direction.

[0071] Figures 3 to 14 The terms “inner bearing” and “inner tapered roller bearing” used in the detailed description of the mid-fan blade mounting assembly refer to a position radially closer to the longitudinal centerline axis of the gas turbine engine 10, while the terms “outer bearing”, “outer tapered roller bearing” and “outer roller bearing” refer to a position radially further away from the longitudinal centerline axis 12 of the gas turbine engine 10.

[0072] Figures 4 to 8 The term "outer race" as used in the detailed description of FIG. 5 refers to the outer side of the bearing relative to the bearing centerline axis (fan blade centerline axis 57).

[0073] Figure 3 A fan blade assembly 90 is shown. Fan blade assembly 90 includes fan blade 54 secured to fan blade root 92 and rotatable about fan blade centerline axis 57.

[0074] As in the following Figures 4 to 8 Various fan blade mounting assemblies shown and Figures 9 to 14 As used in the discussion of the various dampers shown, the terms "axial" and "axially" refer to directions and orientations extending generally parallel to fan blade centerline axis 57. Additionally, the terms "radial" and "radially" refer to directions and orientations extending generally perpendicular to fan blade centerline axis 57. Furthermore, as used herein, the terms "circumferential" and "circumferentially" refer to directions and orientations extending arcuately about fan blade centerline axis 57.

[0075] The fan blade assembly 90 includes an outer bearing 94 and an inner bearing 96. The outer bearing 94 and the inner bearing 96 facilitate rotation of the fan blade 54 about its respective fan blade centerline axis 57, as shown in FIG. Figure 1 As described. In all cases where a 1P load is applied to the fan blade 54, the cyclic load on the fan blade 54 is transmitted through the mounting structure (including the fan blade root 92, the outer bearing 94 and the inner bearing 96) to the gas turbine engine 10 to which the fan blade assembly 90 is connected. This transmitted cyclic load may cause the gas turbine engine 10 to vibrate, which in turn may negatively affect the performance of the gas turbine engine 10. The cyclic load or the vibration generated thereby may have additional negative effects on the durability of the gas turbine engine 10 or its components through impact or wear between adjacent components, through fatigue and / or through other destructive mechanical events. Fan disks 412, 512, 612 and 712 (such as Figures 4 to 7 1P load is transmitted from the fan blade assembly 90 to the fan disk 412, 512, 612, and 712.

[0076] The support structure in and around the fan blade assembly 90 is typically constructed of rigid materials. The damping of vibrations is affected by the geometry of the assembly and the materials of the various components. The materials used in the fan blade assembly may include metallic materials such as steel, aluminum, various alloys, or composite materials. Such generally rigid materials result in a higher natural frequency of the overall structure. Applying softer materials in the dampers will lower the natural frequency of the fan blade assembly 90. Various materials can also provide different damping properties. The desired natural frequency can be achieved by selectively applying dampers that are relatively soft compared to the support structure. In this way, the entire assembly can be adjusted to the desired natural frequency and damping to reduce the 1P loads of the fan blade assembly at the frequencies in operation.

[0077] The 1P load experienced in the fan blade assembly 90 is conducted to the fan blade root 92. The 1P load is greatest at the point closest to the center of force, which occurs in the fan blade 54. Therefore, damping of the 1P vibration by the fan blade root 92 is best achieved at a point of the fan blade root 92 close to the fan blade. Figure 3 In the configuration shown, the 1P load at the outer bearing 94 is greater than the 1P load at the inner bearing 96 .

[0078] Figure 4An embodiment of a fan blade mounting assembly 400 is shown. The fan blade mounting assembly 400 employs an outer bearing that is mounted between the fan blade root 402 and the fan disk 412. The fan blade mounting assembly 400 also includes an inner bearing that is mounted between the fan blade root 402 and the fan disk 412. The outer bearing and the inner bearing may be an outer tapered roller bearing 404 and an inner tapered roller bearing 406, respectively. The outer tapered roller bearing 404 and the inner tapered roller bearing 406 together facilitate rotation of the fan blade root 402 relative to the fan disk 412 about the fan blade centerline axis 57.

[0079] The outer tapered roller bearing 404 is secured by a locking nut 408. The locking nut 408 is threaded onto the outer race 414 of the outer tapered roller bearing 404, thereby preloading the outer tapered roller bearing 404 radially inward. The orientation of the outer tapered roller bearing 404 and the preload on the outer tapered roller bearing 404 can be configured such that the outer tapered roller bearing 404 applies both a radially inward compressive load about the fan blade centerline axis 57 and an axially outward load along the fan blade centerline axis 57 on the fan blade root 402. The orientation of the inner tapered roller bearing 406 is configured such that the axial load in the fan blade root 402 along the fan blade centerline axis 57 from the locking nut 408 and the outer tapered roller bearing 404 is transferred to the fan disk 412. Together, the outer tapered roller bearing 404 and the inner tapered roller bearing 406 facilitate rotation of the fan blade root 402 about the fan blade centerline axis 57. The compressive load applied by lock nut 408 to outer tapered roller bearing 404 is at least large enough to prevent the cyclic load transmitted from fan blade root 402 to fan disk 412 from being reversed when the 1P load is at its cyclic minimum. Lock nut 408 provides only the aforementioned radial preload and does not apply an axial load to fan disk 412. This prevents the 1P load from being transmitted to fan disk 412 through lock nut 408.

[0080] Fan blade mounting assembly 400 also includes a damper 410. Damper 410 is generally cylindrical and is positioned between outer tapered roller bearing 404 and fan disk 412. The vibrations damped by damper 410 are (1P) radial vibrations because damper 410 is radially disposed between outer ring 414 and fan disk 412. The damping performance of damper 410 may be attributed to one or more materials of damper 410, or may be a result of the shape of the components of damper 410.

[0081] At least a portion of the 1P load on fan blade mounting assembly 400 is transmitted from fan blade 54 through fan blade root 402, through outer tapered roller bearing 404, and ultimately to fan disk 412. Damper 410 is mounted between outer tapered roller bearing 404 and fan disk 412 and dampens the 1P load experienced by fan assembly 50. By damping the 1P load on fan blade assembly 50 by damper 410 mounted between outer tapered roller bearing 404 and fan blade root 402, the 1P load experienced by fan disk 412 can be reduced.

[0082] Reducing the 1P loads experienced by the fan disk 412 in turn reduces the 1P loads experienced by other parts of the gas turbine engine 10. Reducing the 1P loads in the fan disk 412 can further improve the fan disk 412 because the fan disk 412 does not need to withstand as many 1P loads and, therefore, does not need to withstand as much fatigue. Such improvements may include a smaller fan disk 412, which has less mass, or may allow the use of cheaper or more common materials. The reduction in 1P loads can also improve the size, shape, and materials of other components within the gas turbine engine 10 because these components will be subject to smaller 1P loads. In addition, because the 1P loads are damped, the gas turbine engine 10 may have longer maintenance intervals than an otherwise equivalent turbine engine with an undamped fan blade assembly, thereby reducing operating costs.

[0083] Damper 410 is radially aligned with outer tapered roller bearing 404 such that 1P vibration experienced by fan blade mounting assembly 400 is transmitted through outer tapered roller bearing 404 before being damped by damper 410. The damped 1P vibration is immediately applied to fan disk 412 after being damped by damper 410. In this configuration, the 1P vibration experienced by the outer tapered roller bearing is undamped when it reaches outer tapered roller bearing 404.

[0084] exist Figure 4 In the configuration of FIG, the damper is radially received in the outer race 414 of the outer tapered roller bearing 404 and in the annular step 428 in the fan disk 412. The damper 410 is axially received in the annular step 428 in the fan disk 412 and in the outer race 414 of the outer tapered roller bearing 404.

[0085] pass Figure 4 In the illustrated arrangement, the inclusion of damper 410 in fan blade mount assembly 400 does not require additional hardware and does not increase the overall footprint relative to an otherwise equivalent fan blade mount assembly without damper 410. In fact, by including damper 410 in fan blade mount assembly 400, the overall footprint may actually be reduced because fan disk 412 is subject to reduced 1P loads due to the inclusion of damper 410 and is therefore less susceptible to fatigue, thereby allowing for a reduction in size.

[0086] Figure 5 An embodiment of a fan blade mounting assembly 500 is shown. Similar to the configuration of fan blade mounting assembly 400, fan blade mounting assembly 500 includes an outer bearing and an inner bearing mounted between a fan blade root 502 and a fan disk 512, which may be an outer tapered roller bearing 404 and an inner tapered roller bearing 406, respectively, as described with respect to FIG. Figure 4 As discussed, outer tapered roller bearing 404 and inner tapered roller bearing 406 together facilitate rotation of fan blade root 502 relative to fan disk 512 about fan blade centerline axis 57 .

[0087] Damper 510 damps (1P) radial vibrations. Damper 510 is generally cylindrical and positioned radially between fan blade root 502 and outer tapered roller bearing 404. More specifically, damper 510 is positioned radially between flange 520 of fan blade root 502 and outer race 414 of outer tapered roller bearing 404. Damper 510 damps 1P vibrations that are radially transmitted from fan blade root 502 to damper 610, and then transmits the damped 1P vibrations to outer tapered roller bearing 404 and ultimately to fan disk 512. Because the damper acts on outer race 414 of outer tapered roller bearing 404, outer tapered roller bearing 404 must be radially preloaded by locknut 408 sufficiently to prevent cyclic load unloading of outer tapered roller bearing 404. Lock nut 408 is threadedly connected to outer ring 414 of outer tapered roller bearing 404, thereby radially preloading outer tapered roller bearing 404 inward. Lock nut 408 only provides the aforementioned radial preload and does not apply an axial load to fan disk 512. This prevents the IP load from being transmitted to fan disk 512 through lock nut 408.

[0088] The damper 510 is positioned axially between the flange 520 of the fan blade root 502 and the fan disk 512. More specifically, the damper 510 is positioned axially between the annular step 522 of the flange 520 and the retaining ring 524.

[0089] In this discussion, and in the subsequent Figures 6 to 8 In the discussion of FIG, the retaining ring may be fastened to the fan blade root by any suitable connection process, including threading, press fitting, bonding, or welding. Alternatively, the retaining ring may be secured by one or more fasteners, such as bolts, screws, or rivets. Alternatively, other fastening methods are contemplated such that the retaining ring is secured to the fan blade root to adequately hold the damper in place.

[0090] Damper 510 is in radial contact with outer race 414 of outer tapered roller bearing 404. However, damper 510 acts on the end of outer tapered roller bearing 404 that is closest to fan blade 54, closer than the force exerted by fan blade root 502 on fan disk 512 through outer tapered roller bearing 404. Therefore, damper 510 is actually closer to fan blade 54 (not shown) than outer tapered roller bearing 404 and inner tapered roller bearing 406.

[0091] When damper 510 is positioned radially between flange 520 of fan blade root 502 and outer ring 414, damper 510 damps vibrations at an axial location between the fan blade and outer tapered roller bearing 404. Thus, damper 510 reduces vibrations before they reach outer tapered roller bearing 404 and inner tapered roller bearing 406. This can reduce vibration damage and fatigue to outer tapered roller bearing 404, inner tapered roller bearing 406, and fan disk 512.

[0092] Figure 6 An embodiment of a fan blade mounting assembly 600 is shown. Similar to the configuration of fan blade mounting assembly 400, fan blade mounting assembly 600 includes an outer bearing and an inner bearing mounted between a fan blade root 602 and a fan disk 612, which may be an outer tapered roller bearing 404 and an inner tapered roller bearing 406, respectively, as described with respect to FIG. Figure 4 As discussed, outer tapered roller bearing 404 and inner tapered roller bearing 406 together facilitate rotation of fan blade root 602 relative to fan disk 612 about fan blade centerline axis 57 .

[0093] Damper 610 damps (IP) radial vibrations. Damper 610 is generally cylindrical and is radially located between fan blade root 602 and fan disk 612. More specifically, damper 610 is radially located between flange 620 of fan blade root 602 and extension 626 of fan disk 612. Axially, damper 610 is positioned between fan disk 612 and retaining ring 624. More specifically, damper 610 is positioned between annular step 628 within extension 626 of fan disk 612 and retaining ring 624.

[0094] The outer tapered roller bearing 404 is retained by a lock nut 408. The lock nut 408 preloads the outer tapered roller bearing 404 radially inward. The lock nut 408 preloads the outer tapered roller bearing 404 by being threaded onto the outer race 414 of the outer tapered roller bearing 404. The compressive load applied by the lock nut 408 to the outer tapered roller bearing 404 is at least such that the cyclic load transmitted from the fan blade root 402 to the fan disk 412 is not reversed when at the minimum value of the cycle. The lock nut 408 is similar to Figure 4In the manner described in

[15] , a preload is applied directly to outer tapered roller bearing 404, thereby applying a preload to inner tapered roller bearing 406 and fan blade root 602. As configured in fan blade mounting assembly 600, the preload on outer tapered roller bearing 404 and inner tapered roller bearing 406 does not preload damper 610. Locking nut 408 provides only the aforementioned radial preload and does not apply an axial load to fan disk 612. This prevents the 1P load from being transmitted to fan disk 612 through locking nut 408.

[0095] Damper 610 is radially positioned between flange 620 of fan blade root 602 and extension 626 of fan disk 612, damping vibrations at an axial location between the fan blade and outer tapered roller bearing 404. Consequently, less vibration reaches outer tapered roller bearing 404 and inner tapered roller bearing 406, thereby reducing vibration damage and fatigue to outer tapered roller bearing 404, inner tapered roller bearing 406, and fan disk 612.

[0096] Figure 7 An embodiment of a fan blade mounting assembly 700 is shown. Similar to the configuration of fan blade mounting assembly 400, fan blade mounting assembly 700 includes an outer bearing and an inner bearing mounted between a fan blade root 702 and a fan disk 712, which may be an outer tapered roller bearing 404 and an inner tapered roller bearing 406, respectively, as described with respect to FIG. Figure 4 As discussed, outer tapered roller bearing 404 and inner tapered roller bearing 406 together facilitate rotation of fan blade root 702 relative to fan disk 712 about fan blade centerline axis 57 .

[0097] The fan blade mounting assembly 700 includes a damper 710 radially mounted between a retaining ring 724 and a fan disk 712. The damper 710 damps (IP) radial vibrations. The damper 710 is radially positioned between an annular step 728 within an extension 726 of the fan disk 712 and the retaining ring 724. The damper 710 is axially positioned between the fan disk 712 and the fan blade root 702. More specifically, the damper 710 is axially positioned between an annular step 728 within an extension 726 of the fan disk 712 and a flange 720 of the fan blade root 702.

[0098] The outer tapered roller bearing 404 is held by a lock nut 408. The lock nut 408 preloads the outer tapered roller bearing 404 radially inward. The lock nut 408 preloads the outer tapered roller bearing 404 by being threaded onto the outer race 414 of the outer tapered roller bearing 404. The compressive load applied by the lock nut 408 on the outer tapered roller bearing 404 is at least such that the cyclic load transmitted from the fan blade root 402 to the fan disk 712 is not reversed at the minimum value of the cycle. The lock nut 408 is similar to Figure 4 In the manner described in

[15] , a preload is applied directly to outer tapered roller bearing 404, and thus to inner tapered roller bearing 406 and fan blade root 702. As configured in fan blade mounting assembly 700, the preload on outer tapered roller bearing 404 and inner tapered roller bearing 406 does not preload damper 710. Locking nut 408 provides only the aforementioned radial preload and does not apply an axial load to fan disk 712. This prevents the IP load from being transmitted to fan disk 712 through locking nut 408.

[0099] Damper 710 is radially positioned between retaining ring 724 and annular step 728 of extension 726 of fan disk 712, and dampers 710 damp vibrations at an axial location between the fan blades and outer tapered roller bearing 404. Thus, vibrations are reduced before reaching outer tapered roller bearing 404 and inner tapered roller bearing 406, thereby reducing vibration damage and fatigue to outer tapered roller bearing 404, inner tapered roller bearing 406, and fan disk 712.

[0100] Figure 8 An embodiment of a fan blade mounting assembly 800 is shown. Similar to the configuration of fan blade mounting assembly 400, fan blade mounting assembly 800 includes an outer bearing and an inner bearing mounted between a fan blade root 802 and a fan disk 812. The outer bearing may be an outer roller bearing 804. The inner bearing may be an inner tapered roller bearing 406. Figure 4 The outer roller bearing 804 and the inner tapered roller bearing 406 cooperate to facilitate rotation of the fan blade root 802 relative to the fan disk 812 about the fan blade centerline axis 57 .

[0101] Fan blade root 802 includes an annular gap 814. An inner portion 816 of fan blade root 802 is located inboard of annular gap 814. Inner portion 816 provides material continuity and provides stiffness to fan blade root 802 in the area of ​​annular gap 814.

[0102] Fan blade mounting assembly 800 includes a damper 810. Damper 810 is mounted in an annular gap 814 in fan blade root 802. Damper 810 is retained radially inward and radially outward by annular gap 814, which is sized to appropriately accommodate damper 810 and accommodate proper function of damper 810. Axially, damper 810 is retained inboard by an inner portion 816 of fan blade root 802. Alternatively, damper 810 may be retained outboard by a retaining ring (not shown).

[0103] An insert 818 with an L-shaped cross-section is assembled inside the fan disk 812. The outer roller bearing 804 is axially retained by the flange 820 on the fan blade root 802 and the insert 818. The outer roller bearing is also radially retained by the fan blade root 802 and the insert 818. A locking nut 408 is fastened to the insert 818. The locking nut 408 applies a radial compressive preload to the outer roller bearing 804 via the insert 818. In turn, the outer roller bearing 804 applies a radial compressive preload to the fan blade root 802, which in turn applies a radial compressive preload to the damper 810. The radial compressive preload applied by the locking nut 408 to the outer roller bearing 804 is at least sufficient to prevent the cyclic load transmitted from the fan blade root 802 to the fan disk 812 from reversing at the minimum of the cycle. The locking nut 408 provides only the aforementioned radial preload and does not apply an axial load to the fan disk 812. This prevents the IP load from being transmitted through the lock nut 408 to the fan tray 812 .

[0104] Damper 810 is positioned radially within annular gap 814 and damps vibrations at an axial location between the fan blades and outer roller bearing 804. Thus, damper 810 reduces vibrations before they reach outer roller bearing 804 and inner tapered roller bearing 406, thereby mitigating vibration damage to outer roller bearing 804, inner tapered roller bearing 406, and fan disk 812.

[0105] In the description of the aforementioned fan blade mounting assemblies 400, 500, 600, 700 and 800, various bearings, including tapered roller bearings and roller bearings, were discussed for mounting the fan blade roots 92, 402, 502, 602, 702 and 802 to the fan disks 412, 512, 612, 712 and 812. It is contemplated that alternative bearings may be used to facilitate rotation of the fan blade roots 92, 402, 502, 602, 702 and 802 relative to the fan disks 412, 512, 612, 712 and 812. Examples of alternative bearing types include rolling bearings, such as ball bearings, needle bearings, tapered roller bearings and cylindrical roller bearings. Further alternative bearing types may include plain bearings, such as journals and journal bearings (bushings), or may include fluid film bearings. A liquid or semi-viscous lubricant (such as water, oil or grease) may lubricate the bearings. The bearings may be self-lubricating by incorporating a fabric liner, a composite liner, or dry film lubrication. The liner may include polytetrafluoroethylene (PTFE) or other materials to facilitate relative motion within the bearing function, as may be envisioned. The rolling bearings may be in a single row configuration, a double row configuration, or any other multi-row configuration to best facilitate rotation of the fan blade roots 92, 402, 502, 602, 702, and 802. The bearing bushings (sleeves) or rings may be segmented or continuous. The bearings may be provided with or without one or more seals to mitigate penetration of debris or contaminants or to retain lubricant. The specific bearing configuration may be determined by the total load of the system, including the IP load, the weight of the blade 54, and the offset moment.

[0106] The following Figures 9 to 14 The detailed description of discusses various damper configurations, wherein the damper is positioned between the outer tapered roller bearing 404 and the fan disk 412. However, the following Figures 9 to 14 The damper configuration may be applicable to the dampers 410 , 510 , 610 , 710 , and 810 previously mentioned for fan blade mounting assemblies 400 , 500 , 600 , 700 , and 800 .

[0107] Figures 9 to 14 The terms "inner ring" and "inner ring body" used in the detailed description of the damper refer to a position radially closer to the centerline axis 57 of the fan blade, while the terms "outer ring" and "outer ring body" refer to a position radially farther from the centerline axis 57 of the fan blade.

[0108] Figure 9An embodiment of a damper 900, also known as a squeeze film damper, is shown. Damper 900 has an outer ring 902 and an inner ring 904. An elastomer (also known as a spring member 906) integrally connects outer ring 902 and inner ring 904, such that outer ring 902, spring member 906, and inner ring 904 are a single, continuous, solid member. A fluid gap 908 separates outer ring 902 and inner ring 904. Fluid gap 908 is generally circumferential and also surrounds spring member 906. Fluid gap 908 contains a semi-viscous fluid or a viscoelastic fluid. (The fluid is not shown.)

[0109] Damper 900 allows relative movement of outer ring 902 and inner ring 904 relative to each other. Spring member 906 resists relative radial movement and has a radial displacement spring constant such that the greater the radial displacement of inner ring 904 relative to outer ring 902, the greater the resistance exerted by spring member 906 on outer ring 902 and inner ring 904.

[0110] Furthermore, as inner ring 904 displaces relative to outer ring 902, the fluid gap contracts in the area where inner ring 904 is closer to outer ring 902. Consequently, on the diametrically opposite sides, fluid gap 908 expands. The fluid in fluid gap 908 must flow from the contracting area to the expanding area, including through the coiling of spring member 906. The viscosity of the fluid, and therefore the resistance to fluid flow from the contracting area to the expanding area, dampens radial oscillations and vibrations in damper 900.

[0111] Together, the spring member 906 resisting relative motion and the viscosity of the fluid in the fluid gap 908 act as a spring-mass-damper system, damping radial vibrations through the damper 900 .

[0112] for Figure 4 In fan blade mounting assembly 400 , damper 900 can damp radial vibrations induced in fan blade 54 due to flight conditions and subsequently transmitted through fan blade root 402 and outer tapered roller bearing 404 , such that the vibrations ultimately transmitted by damper 900 to fan disk 412 have a reduced amplitude relative to the vibrations transmitted from outer tapered roller bearing 404 to damper 900 .

[0113] Figure 10 Damper 1000 is shown positioned between outer tapered roller bearing 404 and fan disk 412 in fan blade mounting assembly 400. Damper 1000 includes two compressible rings 1002. Compressible rings 1002 are generally annular in shape. The material properties of compressible rings 1002 (e.g., hardness or compressibility) can help dampen IP vibrations. Compressible rings 1002 are composed of a relatively soft and compressible material (e.g., rubber).

[0114] for Figure 4In fan blade mounting assembly 400, damper 1000 can damp radial vibrations induced in fan blade 54 due to flight conditions and subsequently conducted through fan blade root 402 and outer tapered roller bearing 404. Damper 1000 transmits the vibrations to fan disk 412 via compressible ring 1002. The vibrations transmitted by damper 1000 to fan disk 412 have a reduced amplitude relative to the vibrations transmitted to damper 1000 by outer tapered roller bearing 404.

[0115] like Figure 10 As shown, damper 1000 includes two compressible rings 1002. Compressible rings 1002 can have known properties, such as compressibility and vibration absorption. These properties together produce damping performance. The number of compressible rings 1002 can be modified to suit the specific application of damper 1000. Figure 10 The embodiment shown shows two compressible rings 1002, however, the damper 1000 may include more or fewer compressible rings 1002 to achieve a target damping performance.

[0116] Figure 11 A damper 1100 is shown positioned between the outer tapered roller bearing 404 and the fan disc 412 in the fan blade mounting assembly 400. The damper 1100 consists of an annular metal ring 1104 having an inner ring body 1106 and an outer ring body 1108 connected by an annular bend 1110. The metal ring 1104 is generally U-shaped, or U-shaped in cross-section, with an inner ring body thickness 1112, an outer ring body thickness 1114, and a gap thickness 1116. The metal ring 1104 can be constructed of a metal material (such as steel or titanium nickel alloy). Alternatively, the metal ring 1104 can be made of other suitable metal materials suitable for the application, including shape memory alloys. It is well known that shape memory alloys have a damping effect that is superior to other metals and alloys. In addition, shape memory alloys generally allow deflection and deformation at relatively cold temperatures and tend to return to their neutral shape when heated.

[0117] The generally U-shaped cross-section or the geometry of the U-shaped cross-section allows the damper 1100 to deform. Specifically, the inner ring body 1106 may displace relative to the outer ring body 1108 under radial loads and vibrations. The annular bend 1110 resists displacement of the inner ring body 1106 relative to the outer ring body 1108 and restores the metal ring to its neutral shape. If the metal ring 1104 is made of a shape memory alloy, the metal ring 1104 can also provide a useful damping effect. The spring-like resistance to deflection and damping behavior of the metal ring 1104 provide a spring-mass damper function in the radial direction.

[0118] for Figure 4In fan blade mounting assembly 400, damper 1100 can damp radial vibrations induced in fan blade 54 due to flight conditions and subsequently transmitted through fan blade root 402 and outer tapered roller bearing 404. Damper 1100 transmits the vibrations to fan disk 412 via metal ring 1104. The vibrations transmitted by damper 1100 to fan disk 412 have a reduced amplitude relative to the vibrations transmitted to damper 1100 by outer tapered roller bearing 404.

[0119] Figure 12 A damper 1200 is shown positioned between the outer tapered roller bearing 404 and the fan disk 412 in the fan blade mounting assembly 400 and is composed of a compressible ring 1002 and a metal ring 1104. One or more compressible rings 1002 are positioned between an inner ring body 1106 and an outer ring body 1108 of the metal ring 1104. The resistance of the metal ring 1104 to displacement between the inner ring body 1106 and the outer ring body 1108 acts as a spring in the radial direction. The relative softness and vibration absorbing properties of the compressible ring 1002 can act as a damper. The compressible ring 1002 and the metal ring together act as a radial spring-mass damper system to damp radial loads and vibrations.

[0120] for Figure 4 In fan blade mounting assembly 400, damper 1200 can damp radial vibrations induced in fan blade 54 due to flight conditions and subsequently transmitted through fan blade root 402 and outer tapered roller bearing 404. Damper 1200 transmits the vibrations to fan disk 412 via metal ring 1104 and compressible ring 1002. The vibrations transmitted to fan disk 412 by damper 1200 have a reduced amplitude relative to the vibrations transmitted to damper 1200 by outer tapered roller bearing 404.

[0121] Figure 13 Damper 1300 is shown positioned between outer tapered roller bearing 404 and fan disk 412 in fan blade mounting assembly 400. The damper comprises a metal ring 1104 and one or more hydraulic dampers 1306 that act radially and are arranged circumferentially about fan blade axis 57. One or more hydraulic dampers 1306 are located between inner ring body 1106 and outer ring body 1108 of metal ring 1104. The resistance of metal ring 1104 to displacement between inner ring body 1106 and outer ring body 1108 acts as a spring in the radial direction, while hydraulic damper 1306, comprised of multiple parts, including cylinder 1308 and piston 1310, acts in the radial direction. The resistance to deflection of metal ring 1104 and the damping of hydraulic damper 1306 together act as a spring-mass damper system to damp radial loads and vibrations.

[0122] for Figure 4In fan blade mounting assembly 400, damper 1300 can damp radial vibrations induced in fan blade 54 due to flight conditions and subsequently transmitted through fan blade root 402 and outer tapered roller bearing 404. Damper 1300 transmits the vibrations to fan disk 412 via metal ring 1104, cylinder 1308, and piston 1310. The vibrations transmitted to fan disk 412 by damper 1300 have a reduced amplitude relative to the vibrations transmitted to damper 1300 by outer tapered roller bearing 404.

[0123] Figure 14 The damper 1400 positioned between the outer tapered roller bearing 404 and the fan disk 412 in the fan blade mounting assembly 400 is shown. The damper 1400 is composed of a metal ring 1104 and a wave ring 1402. The wave ring 1402 has a wavy cross-sectional shape and is made of a shape memory alloy. The shape memory alloy of the metal ring 1104 and the wave ring 1402 both act as a spring-mass damper system, as previously described. In the wave ring 1402, the wavy shape and the shape memory alloy material work together so that once deflection occurs (possibly due to radial displacement of the inner ring body 1106 relative to the outer ring body 1108), the wave ring 1402 will apply a reaction force to the inner ring body 1106 and the outer ring body 1108 to return to its neutral shape while damping radial vibrations. In this way, the wave ring 1402 functions like a spring. If the wave ring 1402 is made of a shape memory alloy, the wave ring 1402 will also damp radial vibrations. By resisting radial deflection and damping radial vibrations, the wave ring 1402 can function as a spring-mass-damper system. If the metal ring 1104 is made of a second shape memory alloy, it can also function as a spring-mass-damper system in the radial direction, as previously described, thereby providing performance at frequencies different from those of the shape memory alloy of the wave ring 1402, which expands the overall frequency range damped by the damper 1400.

[0124] for Figure 4 In fan blade mounting assembly 400, damper 1400 can damp radial vibrations induced in fan blade 54 due to flight conditions and subsequently transmitted through fan blade root 402 and outer tapered roller bearing 404. Damper 1300 transmits vibrations through metal ring 1104 and wave ring 1402. The vibrations transmitted to fan disk 412 by damper 1400 have a reduced amplitude relative to the vibrations transmitted to damper 1400 by outer tapered roller bearing 404.

[0125] In front of Figures 9 to 14In the discussion of various dampers in FIG. 1 , dampers 900, 1000, 1100, 1200, 1300, and 1400 are described in the context of fan blade mounting assembly 400. This context is for example purposes only. Dampers 900, 1000, 1100, 1200, 1300, and 1400 are not exclusive to any particular configuration of fan blade mounting assemblies 400, 500, 600, 700, and 800. Any of dampers 900, 1000, 1100, 1200, 1300, and 1400 may be used in any of the following embodiments: Figures 4 to 7 , and one or more embodiments of fan blade mounting assemblies 400, 500, 600, 700, and 800 are shown in FIG. Furthermore, other configurations of dampers not contemplated herein may be equally applied to any of fan blade mounting assemblies 400, 500, 600, 700, and 800 while still providing the functionality and performance of fan blade mounting assemblies 400, 500, 600, 700, and 800 and damping as described.

[0126] In the foregoing discussion, the various fan blade mounting assemblies 400, 500, 600, 700, and 800 facilitate rotation of the fan blades 54 relative to the fan blade centerline axis 57. This rotatability of the propeller or fan of an aircraft engine is referred to as "variable pitch" and is achieved in part by the various bearings discussed. Engines with non-rotatable propeller or fan blades (referred to as "fixed pitch") may also experience 1P loads. Therefore, similarly, various configurations of fan blade mounting assemblies 400, 500, 600, 700, and 800, as well as various configurations of dampers 900, 1000, 1100, 1200, 1300, and 1400, are contemplated without the need for bearings in order to still mitigate the effects of the 1P load. In configurations without bearings, the dampers still mitigate the undesirable vibrations of the 1P load.

[0127] The fan blade mounting assemblies 400, 500, 600, 700, and 800 are subject to 1P vibrations due to 1P loads and factors including aircraft attitude, individual blade 54 variations, and environmental conditions. 1P cyclical vibrations can cause fatigue in gas turbine engine 10 components and may result in operator or passenger discomfort. The fan blade mounting assemblies 400, 500, 600, 700, and 800 reduce 1P vibrations by incorporating dampers 410, 510, 610, and 710 between the fan blades 54 and the fan disks 412, 512, 612, and 712. Thus, the arrangement of the fan blade mounting assemblies 400, 500, 600, 700, and 800 reduces fatigue in gas turbine engine 10 components and improves operator or passenger comfort. Reduced fatigue can extend the service life of gas turbine engine 10 components or reduce their cost. Dampers 900 , 1000 , 1100 , 1200 , 1300 , and 1400 may be employed within fan blade mounting assemblies 400 , 500 , 600 , 700 , and 800 to reduce vibrations.

[0128] Dampers 900, 1000, 1100, 1200, 1300, and 1400 can reduce the load on blades 54, thereby extending the service life of blades 54 due to the reduction in vibration stress, and extending the service life of the entire fan assembly 50 and its component parts. In addition, the reduction in vibration stress enables the use of lighter structures and materials.

[0129] Further aspects of the disclosure are provided by the subject matter of the following clauses.

[0130] A turbine engine subjected to 1P vibration, the turbine engine comprising: a turbocharger engine having a longitudinal centerline axis; a compressor, the compressor compressing air; a combustor, the combustor receiving fuel and the compressed air and burning the compressed air and the fuel to produce combustion gases; a turbine, the turbine receiving the combustion gases and rotating; and a fan assembly, the fan assembly being driven by the turbine and rotating about the longitudinal centerline axis, the fan assembly comprising: a fan disk, the fan disk being aligned with the longitudinal centerline axis; fan blades, the fan blades A fan blade having a fan blade centerline axis orthogonal to the longitudinal centerline axis, the fan blade bearing a 1P load and generating the 1P vibration; a fan blade root, the fan blade root being fixed to the fan blade and connected to the fan disk, the fan blade root being aligned with the fan blade centerline axis and conducting the 1P vibration; and a damper, the damper being radially positioned between the fan blade root and the fan disk, damping the 1P vibration so that the 1P vibration in the fan disk has a reduced amplitude relative to the 1P vibration in the fan blade root.

[0131] The turbine engine according to the preceding clause, further comprising at least one shaft, said at least one shaft rotationally connecting said compressor, said turbine and said fan disk, wherein rotation of said turbine causes rotation of said fan assembly, and said IP vibration is transmitted to said compressor and said turbine via said shaft.

[0132] The turbine engine according to any of the preceding clauses, further comprising a first shaft rotationally fixed to the compressor and the turbine; a gearbox assembly; and a second shaft rotationally fixed to the fan assembly, wherein the first shaft and the second shaft are attached to the gearbox assembly such that the rotational speed of the second shaft is reduced relative to the rotational speed of the first shaft.

[0133] A turbine engine as in any preceding clause, wherein the fan assembly is ductless.

[0134] The turbine engine according to any of the preceding clauses, further comprising a retaining ring fastened to the fan blade root, positioning the damper axially, radially or axially and radially relative to the fan blade root.

[0135] A turbine engine according to any preceding clause, wherein the fan blade root comprises an annular gap, and wherein the damper is positioned within the annular gap.

[0136] Turbine engine according to any of the preceding clauses, wherein the fan blade root comprises a flange for radially, axially or radially and axially positioning the damper.

[0137] Turbine engine according to any of the preceding clauses, wherein the fan disk comprises an extension that positions the damper axially, radially, or axially and radially.

[0138] A turbine engine according to any of the preceding clauses, wherein the damper is a squeeze film damper comprising an inner ring, an outer ring, a spring member and a fluid gap, the spring member connecting the inner ring and the outer ring, the fluid gap containing a semi-viscous fluid or a viscoelastic fluid, wherein the squeeze film damper allows displacement of the inner ring relative to the outer ring, and the displacement is resisted by the spring member and the flow of the semi-viscous fluid or the viscoelastic fluid.

[0139] A turbine engine according to any preceding clause, wherein the damper comprises at least one compressible ring.

[0140] The turbine engine according to any of the preceding clauses, further comprising at least one bearing, said at least one bearing being located between said fan blade root and said fan disk, said at least one bearing facilitating rotation of said fan blade root and said fan blade relative to said fan disk about said fan blade centerline axis, said at least one bearing transmitting said 1P vibration.

[0141] A turbine engine according to any of the preceding clauses, wherein at least one bearing is a first bearing, the turbine engine further comprising a second bearing located between the fan blade root and the fan disk, the second bearing facilitating rotation of the fan blade root and the fan blade relative to the fan disk about the fan blade centerline axis, and the damper being located outboard of the first bearing and the second bearing.

[0142] A turbine engine according to any of the preceding clauses, wherein the damper is positioned radially between the fan blade root and the at least one bearing so that the IP vibrations transmitted by the at least one bearing have a reduced amplitude relative to the IP vibrations transmitted by the fan blade root.

[0143] A turbine engine according to any of the preceding clauses, wherein the damper is positioned radially between the at least one bearing and the fan disk such that the IP vibrations conducted by the fan disk have a reduced amplitude relative to the IP vibrations conducted by the at least one bearing.

[0144] A turbine engine according to any of the preceding clauses, wherein the locking nut applies a radially inward preload on the at least one bearing, the damper, or the at least one bearing and the damper, but does not apply an axial load on the fan disk and does not transmit IP vibrations to the fan disk.

[0145] A turbine engine according to any preceding clause, wherein the damper comprises a metal ring having a substantially U-shaped cross section or a U-shaped cross section.

[0146] Turbine engine according to any of the preceding clauses, wherein the metal ring of substantially U-shaped cross section or of U-shaped cross section is made of steel, a titanium nickel alloy or a shape memory alloy.

[0147] A turbine engine as described in any preceding clause, wherein the damper further comprises one or more compressible rings.

[0148] A turbine engine according to any preceding clause, wherein the damper comprises a wave ring constructed from a shape memory alloy.

[0149] A turbine engine according to any preceding clause, wherein the damper further comprises at least one hydraulic damper.

[0150] A turbine engine according to any preceding clause, wherein said at least one hydraulic damper comprises a cylinder and a piston.

[0151] A turbine engine according to any preceding clause, wherein said at least one bearing is a tapered roller bearing.

[0152] A turbine engine according to any preceding clause, wherein said at least one bearing is a roller bearing.

[0153] The turbine engine according to any of the preceding clauses, further comprising a retaining ring secured to the fan blade root, radially positioning the damper relative to the fan blade root and radially conducting the IP vibrations from the fan blade root to the damper.

[0154] A turbine engine according to any of the preceding clauses, wherein the fan blade root includes a flange, the flange radially positioning the damper relative to the fan blade root, the flange radially conducting the IP vibrations between the fan blade root and the damper.

[0155] A turbine engine according to any of the preceding clauses, wherein the fan disk includes an extension portion, the extension portion radially positioning the damper relative to the fan blade root, the extension portion conducting 1P vibrations from the damper, the 1P vibrations from the damper having a reduced amplitude relative to the 1P vibrations in the fan blade root.

[0156] A turbine engine according to any of the preceding clauses, wherein the shape memory alloy is a first shape memory alloy and the damper further comprises a metal ring made of a second shape memory alloy having a substantially U-shaped cross section or a U-shaped cross section.

[0157] 1. A fan assembly subjected to 1P vibration, the fan assembly rotating about a longitudinal centerline axis, the fan assembly comprising a fan disk, the fan disk being aligned with the longitudinal centerline axis; fan blades, the fan blades having fan blade centerline axes orthogonal to the longitudinal centerline axis, the fan blades bearing 1P loads and generating the 1P vibrations; fan blade roots fixed to the fan blades and connected to the fan disk, the fan blade roots being aligned with the fan blade centerline axis and conducting the 1P vibrations; and a damper radially positioned between the fan blade roots and the fan disk, damping the 1P vibrations so that the 1P vibrations in the fan disk have a reduced amplitude relative to the 1P vibrations in the fan blade roots.

[0158] The fan assembly of the preceding clause, wherein the fan assembly is ductless.

[0159] A fan assembly according to any preceding clause, further comprising a retaining ring secured to the fan blade root, positioning the damper axially, radially or axially and radially relative to the fan blade root.

[0160] A fan assembly as described in any preceding clause, wherein the fan blade root comprises an annular gap, and wherein the damper is positioned within the annular gap.

[0161] A fan assembly according to any preceding clause, wherein the fan blade root comprises a flange for radially, axially or radially and axially positioning the damper.

[0162] A fan assembly according to any preceding clause, wherein the fan disk includes an extension that positions the damper axially, radially, or axially and radially.

[0163] A fan assembly according to any of the preceding clauses, wherein the damper is a squeeze film damper comprising: an inner ring; an outer ring; a spring member connecting the inner ring and the outer ring; and a fluid gap containing a semi-viscous fluid or a viscoelastic fluid, wherein the squeeze film damper allows displacement of the inner ring relative to the outer ring, and the displacement is resisted by the spring member and the flow of the semi-viscous fluid or the viscoelastic fluid.

[0164] The fan assembly of any preceding clause, wherein the damper comprises at least one compressible ring.

[0165] The fan assembly according to any of the preceding clauses further comprises at least one bearing, said at least one bearing being between said fan blade root and said fan disk, said at least one bearing facilitating rotation of said fan blade root and said fan blade relative to said fan disk about said fan blade centerline axis, said at least one bearing transmitting said 1P vibration.

[0166] A fan assembly according to any of the preceding clauses, wherein the at least one bearing is a first bearing, the turbine engine further comprising a second bearing located between the fan blade root and the fan disk, the second bearing facilitating rotation of the fan blade root and the fan blade relative to the fan disk about the fan blade centerline axis, and the damper being located outboard of the first bearing and the second bearing.

[0167] A fan assembly according to any of the preceding clauses, wherein the damper is positioned radially between the fan blade root and the at least one bearing so that the IP vibrations transmitted by the at least one bearing have a reduced amplitude relative to the IP vibrations transmitted by the fan blade root.

[0168] A fan assembly according to any of the preceding clauses, wherein the damper is positioned radially between the at least one bearing and the fan disk such that the IP vibrations conducted by the fan disk have a reduced amplitude relative to the IP vibrations conducted by the at least one bearing.

[0169] A fan assembly according to any of the preceding clauses, wherein the locking nut applies a radially inward preload on the at least one bearing, the damper, or the at least one bearing and the damper, but does not apply an axial load on the fan disc and does not transmit IP vibrations to the fan disc.

[0170] A fan assembly as described in any preceding clause, wherein the damper comprises a metal ring having a generally U-shaped cross-section or a U-shaped cross-section.

[0171] A fan assembly according to any of the preceding clauses, wherein the metal ring having a substantially U-shaped cross section or a U-shaped cross section is made of steel, a titanium nickel alloy or a shape memory alloy.

[0172] The fan assembly of any preceding clause, wherein the damper further comprises one or more compressible rings.

[0173] The fan assembly of any preceding clause, wherein the damper comprises a wave ring constructed from a shape memory alloy.

[0174] The fan assembly of any preceding clause, wherein the damper further comprises at least one hydraulic damper.

[0175] The fan assembly of any preceding clause, wherein the at least one hydraulic damper comprises a cylinder and a piston.

[0176] A fan assembly as described in any preceding clause, wherein the at least one bearing is a tapered roller bearing.

[0177] A fan assembly as described in any preceding clause, wherein the at least one bearing is a roller bearing.

[0178] A fan assembly according to any of the preceding clauses, further comprising a retaining ring secured to the fan blade root, radially positioning the damper relative to the fan blade root, and radially conducting the IP vibration from the fan blade root to the damper.

[0179] A fan assembly as claimed in any preceding clause, the fan blade root comprising a flange, the flange radially positioning the damper relative to the fan blade root, the flange radially conducting the IP vibrations between the fan blade root and the damper.

[0180] A fan assembly according to any of the preceding clauses, wherein the fan disc includes an extension portion that radially positions the damper relative to the fan blade root, the extension portion conducting 1P vibrations from the damper, the 1P vibrations from the damper having a reduced amplitude relative to the 1P vibrations in the fan blade root.

[0181] The fan assembly of any preceding clause, wherein the shape memory alloy is a first shape memory alloy, and the damper further comprises a metal ring having a generally U-shaped cross-section made of a second shape memory alloy.

[0182] Although the above description is directed to preferred embodiments of the present disclosure, it will be apparent to those skilled in the art that other changes and modifications may be made without departing from the present disclosure. In addition, even if not explicitly stated above, features described in conjunction with one embodiment of the present disclosure may also be used in conjunction with other embodiments.

Claims

1. A turbine engine subjected to 1P vibration, characterized in that The turbine engine comprises: a turbocharged engine having a longitudinal centerline axis; a compressor that compresses air; a combustor that receives fuel and the compressed air and combusts the compressed air and the fuel to generate combustion gas; a turbine that receives the combustion gas and rotates; and a fan assembly driven by the turbine and rotating about the longitudinal centerline axis, the fan assembly comprising: a fan disk, said fan disk being aligned with said longitudinal centerline axis; a fan blade having a fan blade centerline axis orthogonal to the longitudinal centerline axis, the fan blade bearing a 1P load and generating the 1P vibration; a fan blade root secured to the fan blade and connected to the fan disk, the fan blade root being aligned with the fan blade centerline axis and conducting the IP vibration; and A damper, positioned radially between the fan blade root and the fan disk, damps the IP vibrations such that the IP vibrations in the fan disk have a reduced amplitude relative to the IP vibrations in the fan blade root.

2. The turbine engine according to claim 1, characterized in that Further including: a first shaft rotationally fixed to the compressor and the turbine; Gearbox assembly; as well as a second shaft rotationally fixed to the fan assembly, Wherein the first shaft and the second shaft are attached to the gearbox assembly such that a rotational speed of the second shaft is reduced relative to a rotational speed of the first shaft.

3. The turbine engine according to claim 1, characterized in that The fan assembly is ductless.

4. The turbine engine according to claim 1, characterized in that Further included is a retaining ring secured to the fan blade root, positioning the damper axially, radially, or axially and radially relative to the fan blade root.

5. The turbine engine according to claim 1, characterized in that Wherein the fan blade root includes an annular gap, and the damper is positioned within the annular gap.

6. The turbine engine according to claim 1, characterized in that The fan blade root includes a flange for radially, axially, or radially and axially positioning the damper.

7. The turbine engine according to claim 1, characterized in that The fan disk includes an extension that positions the damper axially, radially, or axially and radially.

8. The turbine engine according to claim 1, characterized in that The damper is a squeeze film damper, comprising: inner ring; Outer ring; a spring member connecting the inner ring and the outer ring; and a fluid gap, the fluid gap comprising a semi-viscous fluid or a viscoelastic fluid, The squeeze film damper allows displacement of the inner ring relative to the outer ring, and the displacement is resisted by the spring member and the flow of the semi-viscous fluid or the viscoelastic fluid.

9. The turbine engine according to claim 1, characterized in that Wherein the damper comprises at least one compressible ring.

10. The turbine engine according to claim 1, characterized in that Further comprising at least one bearing, said at least one bearing being between said fan blade root and said fan disk, said at least one bearing facilitating rotation of said fan blade root and said fan blade relative to said fan disk about said fan blade centerline axis, said at least one bearing transmitting said 1P vibration.

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