Patent Application
20190120255
The disclosure relates generally to fans and fan hubs of gas turbine engines.
Gas turbine engines typically include a fan section to drive inflowing air, a compressor section to pressurize inflowing air, a combustor section to burn a fuel in the presence of the pressurized air, and a turbine section to extract energy from the resulting combustion gases. The fan section may include a plurality of fan blades coupled to a fan hub. The fan hub may experience vibrational modes in operation.
In various embodiments the present disclosure provides a segmented structural link comprising a base portion having a first face, a tail portion, and a distal end having a second face. In various embodiments, the tail portion extends at an angle relative to the first face. In various embodiments, the tail portion comprises a first bend. In various embodiments, the tail portion further comprises a second bend. In various embodiments, the base portion further comprises at least one of a captured nut, a nut plate, or a self-clinching nut.
In various embodiments, the base portion is coupled at the first face to a first flange. In various embodiments, the distal end is coupled at the second face to a second flange. In various embodiments, the first flange is one of a J-flange or a scalloped flange. In various embodiments, the second flange is a forward flange of a hub comprising a cone arm coupled to a blade ring at a web. In various embodiments, the blade ring pivots over the cone arm about the web in response to a rotation of the hub. In various embodiments, the first flange is coupled to the blade ring and, in response to the blade ring pivoting over the cone arm about the web, is driven toward the second flange. In various embodiments, the segmented structural link is compressed in response to the first flange being driven toward the second flange.
In various embodiments the present disclosure provides a gas turbine engine comprising a fan section having a fan disk comprising a hub comprising a cone arm, a web, and a blade ring, a compressor section configured to compress a gas, a combustor section aft of the compressor section and configured to combust the gas, a turbine section aft of the combustor section configured to extract energy from the gas, and a segmented structural link wherein the segmented structural link comprises a base portion having a first face, a tail portion, and a distal end having a second face.
In various embodiments, the tail portion extends at an angle relative to the first face. In various embodiments, the tail portion comprises a first bend. In various embodiments, the base portion is coupled at the first face to a first flange and the distal end is coupled at the second face to a second flange. In various embodiments, a plurality of segmented structural links are distributed symmetrically about a circumference of the fan disk. In various embodiments, the segmented structural link extends around a portion of a circumference of the fan disk between a J-flange and a scalloped flange. In various embodiments, the segmented structural link is compressed in response to the first flange being driven toward the second flange.
In various embodiments, the present disclosure provides a method of tuning a vibrational response of a fan disk comprising calculating a vibrational mode shape of the fan disk, determining a point of maximum relative downward deflection of a blade ring of the fan disk, and coupling a segmented structural link to the fan disk at the point of maximum relative downward deflection between a first flange and a second flange.
The forgoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated herein otherwise. These features and elements as well as the operation of the disclosed embodiments will become more apparent in light of the following description and accompanying drawings.
The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present disclosures, however, may best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures, wherein like numerals denote like elements.
The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration and their best mode. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosures, it should be understood that other embodiments may be realized and that logical, chemical, and mechanical changes may be made without departing from the spirit and scope of the disclosures. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact.
In various embodiments and with reference to
Gas turbine engine 20 may generally comprise a low speed spool 30 and a high speed spool 32 mounted for rotation about an engine central longitudinal axis A-A′ relative to an engine static structure 36 via one or more bearing systems 38 (shown as bearing system 38-1 and bearing system 38-2). It should be understood that various bearing systems 38 at various locations may alternatively or additionally be provided, including for example, bearing system 38, bearing system 38-1, and bearing system 38-2.
Low speed spool 30 may generally comprise an inner shaft 40 that interconnects a fan 42, a low pressure (or first) compressor section 44 (also referred to a low pressure compressor) and a low pressure (or first) turbine section 46. Inner shaft 40 may be connected to fan 42 through a geared architecture 48 that can drive fan 42 at a lower speed than low speed spool 30. Geared architecture 48 may comprise a gear assembly 60 enclosed within a gear housing 62. Gear assembly 60 couples inner shaft 40 to a rotating fan structure. High speed spool 32 may comprise an outer shaft 50 that interconnects a high pressure compressor (“HPC”) 52 (e.g., a second compressor section) and high pressure (or second) turbine section 54. A combustor 56 may be located between HPC 52 and high pressure turbine 54. A mid-turbine frame 57 of engine static structure 36 may be located generally between high pressure turbine 54 and low pressure turbine 46. Mid-turbine frame 57 may support one or more bearing systems 38 in turbine section 28. Inner shaft 40 and outer shaft 50 may be concentric and rotate via bearing systems 38 about the engine central longitudinal axis A-A′, which is collinear with their longitudinal axes. As used herein, a “high pressure” compressor or turbine experiences a higher pressure than a corresponding “low pressure” compressor or turbine.
The core airflow C may be compressed by low pressure compressor 44 then HPC 52, mixed and burned with fuel in combustor 56, then expanded over high pressure turbine 54 and low pressure turbine 46. Mid-turbine frame 57 includes airfoils 59 which are in the core airflow path. Low pressure turbine 46, and high pressure turbine 54 rotationally drive the respective low speed spool 30 and high speed spool 32 in response to the expansion.
Gas turbine engine 20 may be, for example, a high-bypass geared aircraft engine. In various embodiments, the bypass ratio of gas turbine engine 20 may be greater than about six (6). In various embodiments, the bypass ratio of gas turbine engine 20 may be greater than ten (10). In various embodiments, geared architecture 48 may be an epicyclic gear train, such as a star gear system (sun gear in meshing engagement with a plurality of star gears supported by a carrier and in meshing engagement with a ring gear) or other gear system. Geared architecture 48 may have a gear reduction ratio of greater than about 2.3 and low pressure turbine 46 may have a pressure ratio that is greater than about 5. In various embodiments, the bypass ratio of gas turbine engine 20 is greater than about ten (10:1). In various embodiments, the diameter of fan 42 may be significantly larger than that of the low pressure compressor 44, and the low pressure turbine 46 may have a pressure ratio that is greater than about (5:1). Low pressure turbine 46 pressure ratio may be measured prior to inlet of low pressure turbine 46 as related to the pressure at the outlet of low pressure turbine 46 prior to an exhaust nozzle. It should be understood, however, that the above parameters are exemplary of various embodiments of a suitable geared architecture engine and that the present disclosure contemplates other gas turbine engines including direct drive turbofans.
In various embodiments, the next generation of turbofan engines may be designed for higher efficiency which is associated with higher pressure ratios and higher temperatures in the HPC 52. These higher operating temperatures and pressure ratios may create operating environments that may cause thermal loads that are higher than the thermal loads encountered in conventional turbofan engines, which may shorten the operational life of current components.
In various embodiments, HPC 52 may comprise alternating rows of rotating rotors and stationary stators. Stators may have a cantilevered configuration or a shrouded configuration. More specifically, a stator may comprise a stator vane, a casing support and a hub support. In this regard, a stator vane may be supported along an outer diameter by a casing support and along an inner diameter by a hub support. In contrast, a cantilevered stator may comprise a stator vane that is only retained and/or supported at the casing (e.g., along an outer diameter).
In various embodiments, rotors may be configured to compress and spin a fluid flow. Stators may be configured to receive and straighten the fluid flow. In operation, the fluid flow discharged from the trailing edge of stators may be straightened (e.g., the flow may be directed in a substantially parallel path to the centerline of the engine and/or HPC) to increase and/or improve the efficiency of the engine and, more specifically, to achieve enhanced compression and efficiency when the straightened air is compressed and spun by rotor 64.
According to various embodiments and with reference to
In various embodiments and with reference to
In various embodiments, hub 322 engages a shaft, such as inner shaft 40, at splines 324 and in response to rotation of the shaft transmits torque from the shaft via cone arm 326 and web 328 to blade ring 330 causing blade ring 330 to rotate about the axis of the shaft. Blade ring 330 comprises channels 334 configured to receive a blade at a blade root, such as, for example, receiving blade 206 at blade root 207, and in this regard a fan, such as fan 202, may be caused to rotate about the shaft. In response to the rotation of the fan about the shaft, vibrations may be induced in the structure of the fan manifesting as a vibrational bending mode such as, for example, a first bending mode, a second bending mode, or a third bending mode. Blade ring 330 is coupled to J-flange 312 and, in response to a bending mode, tends to pivot over cone arm 326 about web 328 tending to induce a torque 332 which tends to cause a downward (relative to the y-axis) deflection of J-flange 312 which is in turn transmitted as a downward (relative to the y-axis) load “F” at J-flange 312. Stated another way, J-flange 312 is driven relatively towards forward flange 316 by downward load “F”. Downward load “F” is transmitted through segmented structural link 302 into forward flange 316 and is resisted by upward (relative to the y-axis) load “C” at forward flange 316 tending thereby to place segmented structural link 302 in compression. In this regard, segmented structural link 302 may be said to increase the stiffness of a fan disk, such as fan disk 208, by resisting vibrationally induced bending loads.
In various embodiments and with reference to
In various embodiments, a blade ring, such as, for example, blade ring 330, may comprise one or more flanges or J-flanges, such as J-flange 312 or scalloped flange 313. In various embodiments, one or more segmented structural links such as, for example, segmented structural link 302 or segmented structural link 402, may be located circumferentially around the forward end of a fan disk, such as fan disk 300, and coupled between one or more flanges or J-flanges, such as J-flange 312 or scalloped flange 313, and a forward flange such as, for example forward flange 316 of a hub, such as hub 322, to resist vibrationally induced bending loads. In various embodiments, between one (1) and thirty-five (35) segmented structural links, or between five (5) and thirty (30) segmented structural links, or between ten (10) and twenty-five (25) segmented structural links may be distributed symmetrically about the circumference of a fan disk. In various embodiments, a segmented structural link, such as, for example segmented structural link 402, extends around a portion of the circumference of a fan disk, such as, for example, fan disk 400 between a J-flange and a scalloped flange or may extend around the entire circumference of a fan disk. In various embodiments, a fastener, such as fastener 314 or fastener 421, may comprise a threaded stud coupled to a forward flange, such as forward flange 316. In various embodiments, a captured nut, such as captured nut 321 or captured nut 420, may comprise a self-clinching nut, a nut plate, or any other captured fastener know to those skilled in the art. In various embodiments, a segmented structural link is one of a metal, an alloy, a steel, a titanium, a titanium alloy, a nickel, or a nickel alloy. In various embodiments angle θ is between zero degrees (0°) and sixty degrees (60°), or between ten degrees (10°) and fifty degrees (50°), or between twenty-five degrees (25°) and forty-five degrees (45°).
In various embodiments and with reference now to
Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosures.
The scope of the disclosures is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Different cross-hatching is used throughout the figures to denote different parts but not necessarily to denote the same or different materials.
Systems, methods and apparatus are provided herein. In the detailed description herein, references to “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiment
Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element is intended to invoke 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
