Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
  • F01D5/32—Locking, e.g. by final locking blades or keys
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
  • F01D5/3053—Fixing blades to rotors; Blade roots ; Blade spacers by means of pins
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
  • F01D5/32—Locking, e.g. by final locking blades or keys
  • F01D5/326—Locking of axial insertion type blades by other means

Definitions

• the present disclosure is directed to a pin of a gas turbine engine (GTE) and, more particularly, to a staking pin for staking a turbine blade in a turbine rotor disk of the GTE.
• GTE gas turbine engine
• GTEs produce power by extracting energy from a flow of hot gas produced by combustion of fuel in a stream of compressed air.
• turbine engines have an upstream air compressor coupled to a downstream turbine with a combustion chamber ("combustor") in between. Energy is released when a mixture of compressed air and fuel is burned in the combustor. The resulting hot gases are directed over blades of the turbine to spin the turbine and produce mechanical power.
• combustor combustion chamber
• Turbine blades and other components of GTEs are subject to high temperatures and high local stresses during operation. Due to rotation of a turbine rotor disk supporting the turbine blades, the turbine blades experience a centrifugal force, and therefore must be retained within the rotor disk. While a turbine blade root, for example a dovetail, can facilitate retention of the turbine blade, other or additional means to retain the turbine blade can be employed.
• U.S. Patent No. 3,165,294 (“the '294 patent”) describes a locking arrangement for holding blades of a rotor assembly in a fluid flow machine.
• a rotor drum is provided with a plurality of axially spaced circumferentially extending slots.
• a radially extending threaded or tapped hole is provided for a plug to be received therein.
• a blade having a root and a passage is positioned in the slot, and a plug is disposed in the passage. The blade is thus held against radial movement relative to the rotor drum, and the plug also holds an entire row of abutting blade roots against circumferential movement in the slot.
• the '294 patent further notes that during rotation of the rotor drum, centrifugal force urges the plug out of the threaded or tapped hole and into a locking direction.
• a staking pin for a gas turbine engine is disclosed.
• the staking pin may include a solid portion extending part of a length of the staking pin, and a hollow portion extending an additional part of the length of the staking pin.
• the staking pin may be constructed of Alloy X material having an average grain diameter of between about 0.0449 and 0.1270 mm.
• a gas turbine engine may include a compressor system, a combustor system, and a turbine system.
• the turbine system may include at least one turbine rotor disk and a plurality of turbine blades each retained in the turbine rotor disk. At least one of the turbine blades may be retained in the turbine rotor disk by a staking pin constructed of Alloy X material having an average grain diameter of between about 0.0449 and 0.1270 mm, and extending through a portion of the at least one turbine blade.
• a staking pin for a gas turbine engine may include a solid portion extending part of a length of the staking pin, and a hollow cylindrical portion including a hole extending an additional part of the length of the staking pin.
• the cylindrical portion may have a wall thickness of about 1 mm, and the staking pin may be constructed of Alloy X material having an average grain diameter of between about 0.0449 and 0.1270 mm.
• FIG. 1 is an illustration of an exemplary disclosed GTE
• FIG. 2 is a cross-sectional view of a portion of the GTE of FIG. 1 with one embodiment of a staking pin according to the present disclosure
• FIG. 3 is a magnified view of encircled portion "3" in FIG. 2
• FIG. 4 is a top view of one of the turbine blades of FIG. 2;
• FIG. 5 is a side view of the staking pin shown in FIG. 2;
• FIG. 6 is an end view of the staking pin of FIG. 5; and FIG. 7 is a magnified view of a portion of a surface of the staking pin of FIG. 2 showing one embodiment of the microstructure of the pin.
• FIG. 1 illustrates an exemplary gas turbine engine (GTE) 100.
• GTE 100 may have, among other systems, a compressor system 10, a combustor system 20, a turbine system 70, and an exhaust system 90 arranged along an engine axis 98.
• Compressor system 10 compresses air and delivers the compressed air to an enclosure of combustor system 20. The compressed air is then directed from the enclosure into a combustor 50.
• Liquid or gaseous fuel may be directed into the combustor 50 through fuel injectors 30. The fuel burns in combustor 50 to produce combustion gases at high pressure and temperature.
• the turbine system 70 may further include a plurality of turbine blades 72 installed on turbine rotor disks 76 (FIGS. 2 and 3). Additionally, the turbine system 70 can include a plurality of turbine nozzles as part of a series of turbine stators (not shown). The turbine blades 72, rotor disks 76, nozzles, and stators can be included in a series of turbine stages, for example, a first stage 73, a second stage 74, and a third stage 75. Although only three stages 73, 74, 75 are illustrated in FIG. 1, more or fewer turbine stages may make up part of the turbine system 70. In operation, the turbine system 70 extracts energy from the combustion gases and directs the exhaust gases through exhaust system 90.
• FIG. 2 is a cross-sectional view of a portion of the turbine system 70 shown in FIG. 1. Specifically, FIG. 2 shows a plurality of the turbine blades 72 installed on a turbine rotor disk 76 of one stage of the turbine system 70. Each turbine blade 72 includes a platform 12 and a root 14 to be received in a correspondingly shaped cutout in the rotor disk 76. As shown in FIG. 2, the root 14 may be configured as a dovetail; however, other root shapes and
• each turbine blade 72 and rotor disk 76 can be provided for each turbine blade 72 and rotor disk 76, respectively.
• Each root 14 is received and supported between rotor disk posts 16 of the rotor disk 76.
• FIG. 2 shows spaces between the rotor disk 76 and the roots 14 and platforms 12 for illustration purposes only. While these spaces may exist in the turbine system 70, the rotor disk 76 may be in direct contact with one or more surfaces of the root 14 and/or platform 12 of one or more of the turbine blades 72.
• the rotor disk 76 includes slots 34 that may be formed in each rotor disk post 16.
• the slots 34 extends circumferentially around an outer diameter of the rotor disk 76, such that the "slots" 34 may be referred to as a single slot 34. In other instances, however, the slots 34 may be formed so as to extend in an axial direction (i.e. parallel to the engine axis 98 and the flow of gas in the flow path 18) in each disk post 16.
• the slots 34 may also be referred to herein as channels, rotor disk grooves, or the like.
• each turbine blade 72 may include a hole 36 through the platform 12. This hole 36 may be configured to align with the slot 34 such that the hole 36 and the slot 34 can receive a staking pin 22. As described in more detail below, the staking pin 22 can be installed through the hole 36 and into the slot 34.
• the staking pin 22 may also be referred to herein as either a locking pin, a retaining pin, or the like.
• FIG. 3 is a magnified view of the encircled portion "3" in FIG. 2.
• FIG. 3 shows the staking pin 22 installed through the hole 36 and into the slot 34 so as to secure the turbine blade 72 to the rotor disk 16.
• the portion of the staking pin 22 disposed in the slot 34 exhibits what can be referred to as a flared or mushroom shape. That is, the portion of the staking pin 22 in the slot 34 extends beyond the edges of the hole 36 under part of the platform 12.
• FIG. 3 shows the portion of the staking pin 22 disposed in the slot 34 being flared or mushroomed in a substantially uniform manner, this may not always be the case.
• the portion of the staking pin 22 disposed in the slot 34 may deform in a non-uniform manner, such that parts of a wall of a hollow cylindrical portion are deformed more or less than other parts of the wall.
• the portion of the staking pin 22 disposed in the slot 34 may have a width substantially equal to a width 210 of the slot 34, which may be greater than a width of the portion of the staking pin 22 extending through the hole 36 of the platform 12.
• the staking pin 22 may abut the sides of the slot 34 defining the width 210, such that the staking pin 22 substantially spans the distance between the sides of the slot 34.
• FIG. 3 also shows a depth 220 of the slot 34 extending into the disk post 16.
• the staking pin 22 may protrude from the platform 12 and into the flow path 18 by a protrusion distance 200.
• the protrusion distance 200 may be between about
• the protrusion distance 200 may be less than about 0.508 mm (about 0.020 inches).
• the protrusion distance 200 may be about 0.381 mm (about 0.015 inches).
• FIG. 4 illustrates a top view of a turbine blade 72 according to the present application.
• the platform 12 may be shaped as a parallelogram, for example, a rectangle or a rhomboid.
• the platform 12 may include a first edge 24, a second edge 26, a third edge 28, and a fourth edge 32, wherein the second edge 26 and the fourth edge 32 may define a length 300 of the platform 12, and wherein the first edge 24 and the third edge 28 may define a width 306 of the platform 12.
• the length 300 may be between about 25.4 and 38.1 mm (about 1.0 and 1.5 inches), and the width 306 may be between about 12.7 and 25.4 mm (about 0.5 and 1.0 inches).
• FIG. 4 shows the hole 36 having the staking pin 22 disposed therein.
• FIG. 4 shows the hole 36 positioned on a pressure side 38 of the turbine blade 72.
• the hole 36 may be positioned on a suction side 40 of the turbine blade 72.
• the hole 36 may be located halfway between the first edge 24 and the third edge 28. That is, the hole 36 may be located at a distance 302 from edge 24 that is substantially equal to one-half the length 300 of the platform 12.
• the hole 36 may be offset from one edge of the platform 12, for example, the second edge 26, by a distance 304. In some embodiments, the distance 304 may be substantially equal to about one-fourth the width 306.
• FIG. 5 shows a side view of the staking pin 22 prior to installation.
• the staking pin 22 has a length 400, also referred to as a total length or an overall length, and an outer diameter 404. Additionally, the staking pin 22 may include the hollow cylindrical portion forming an open end of the staking pin 22, wherein the cylindrical portion may have a length 406 that is less than the total pin length 400. This cylindrical portion may define a hollow interior portion of the staking pin 22 having an inner diameter 402, and a tapered portion 410. As discussed below, the length 406 may be greater than the depth 220 of the slot 34 in the rotor disk 76.
• FIG. 6 shows a cross-sectional view of the cylindrical portion of the staking pin 22 along lines 6-6 in FIG. 5.
• the cylindrical portion may have a wall thickness 408, which is the difference between the outer diameter 404 and the inner diameter 402.
• the hollow interior portion is a blind hole that may be referred to herein as a staking pin hole 42, and the length 406 may be referred to as a staking pin hole depth.
• the staking pin hole 42 may be formed via drilling into the material forming the staking pin 22.
• the length of the staking pin 22 that is not defined by the cylindrical portion may be solid and thus referred to herein as a solid portion of the staking pin 22.
• the cylindrical portion may also be referred to herein as a deforming portion, a crumpling portion, a mushrooming portion, a crushing portion, or the like, because the cylindrical portion may be configured to deform within the slot 34 during installation, as described in more detail below.
• the outer diameter of the staking pin 22 in the slot 34 may be greater than the outer diameter of the staking pin 22 extending through the hole 36 in the turbine blade platform 12.
• the dimensions of the staking pin 22 may have various values.
• the length 400 may be between about 5.000 and 6.000 mm (between about 0.197 and 0.236 inches), for example, about 5.969 mm (about 0.235 inches).
• the length 406 of the cylindrical portion may be less than or equal to about half the length 400.
• the length 406 may be between about 2.000 and 3.000 mm (between about 0.079 and 0.1 18 inches), for example, about 2.500 mm (about 0.098 inches). That is, the ratio of the length 400 to the length 406 may be, for example, about 3 to 1, about 2 to 1, or, in some instances, about 2.4 to 1.
• the outer diameter 404 may be between about 3.000 and 3.500 mm (between about 0.118 and 0.138 inches), for example, about 3.162 mm (about 0.125).
• the inner diameter 402 may be about between about 2.000 and 2.500 mm (between about 0.079 and 0.098 inches), for example, about 2.108 mm (about 0.083 inches), or about 2.159 mm (about 0.085 inches).
• the thickness 408 may be between about 0.500 and 1.500 mm (about 0.020 to 0.059 inches), inclusive, or about 1.0 mm (about 0.039 inches).
• the staking pin 22 may be constructed from Alloy X material.
• Alloy X is a wrought nickel based superalloy, which exhibits both heat and oxidation resistance.
• a component such as a staking pin made of
• Alloy X may be oxidation resistant to a temperature of 1,200 °C (2,200 °F); however, oxidation resistance to other temperature values may be possible.
• Alloy X may exhibit high yield and ultimate tensile strengths, such that a minimum ultimate tensile strength (UTS) may be about 655 MPa (about 95 ksi), and a minimum yield strength (YS) may be about 240 MPa (about 35 ksi) at GTE operating temperatures.
• the Alloy X material used to construct the staking pin 22 may be provided as a bar, sheet, wire, or any other form. In some instances, the staking pin 22 may be machined from either a wrought or cast form of Alloy X. In other instances, the staking pin 22 may be cut from Alloy X weld wire having a diameter substantially equal to the outer diameter 404.
• a segment of Alloy X material may be formed into a cylindrical shape like that shown in FIG. 5, and a blind hole, such as staking pin hole 42, may then be formed (e.g., drilled) into one end of the material to create the cylindrical portion of the staking pin 22.
• FIG. 7 provides a magnified view of a portion of a surface of the staking pin 22 of FIG. 2 showing one embodiment of the microstructure of the pin 22.
• the microstructure of the staking pin 22 may include grains 55.
• the microstructure of the staking pin 22 may exhibit a specific grain size, which can influence the physical properties (e.g. oxidation resistance, corrosion resistance, strength, and temperature behavior) of the pin 22.
• the grain size may be referred to as an average diameter of one of the grains 55.
• the grain size may also be referred to as a number "N," where N equals the number of grains 55 per square inch measured at a magnification of one-hundred times.
• the staking pin 22 may be made from a material, such as Alloy X, having a grain size N between 32 and 4, which may correspond to an average grain diameter between about 0.0449 and 0.1270 mm (about 0.0018 and 0.0050 inches), respectively.
• the grains 55 may have an average grain diameter of between about 0.0449 and 0.0750 mm (about 0.0018 and 0.0030 inches). If the Alloy X from which the staking pin 22 is made is annealed, for example, the microstructure may exhibit larger grain sizes around outer edges of the pin 22. Thus, annealing may result in grain sizes around the outer edges of the pin 22 having an N value of approximately 4. Additionally, the annealing process may result in non-uniform grain sizes in the pin 22, such that sections of the pin 22 may have one grain size, while other sections of the pin 22 may have another grain size.
• the sizes (e.g., the average diameters) and shapes of the grains 55 are not limited to the examples discussed above and shown in the drawings.
• the root 14 of the turbine blade 72 is inserted into a slot 34 of the turbine rotor disk 76 between adjacent disk posts 16. In this position, the hole 36 in the platform 12 of the turbine blade 72 is aligned with the slot 34.
• the staking pin 22 is positioned above the hole 36 such that the cylindrical portion of the staking pin 22 is adjacent to or in contact with the hole 36. The staking pin 22 is then pushed or struck, for example, at an end of the staking pin 22 opposite the staking pin hole 42, to push the staking pin 22 through the hole 36 and into the slot 34 of the turbine rotor disk 76.
• the staking pin 22 may be struck manually with a hammer, or manually or automatically with any other instrument. As shown in FIGS. 2 and 3, the cylindrical portion of the staking pin 22 deforms or "mushrooms" within the slot 34 during installation, such that cylindrical portion of the staking pin 22 in slot 34 expands to extend under the platform 12. In the installed state, the expanded portion of the staking pin 22 may abut the walls of the slot 34 so as to substantially span the distance between the sides of the slot 34. As described herein, although FIG.
• the cylindrical portion of the staking pin 22 may be crushed or mushroomed during installation in a non-uniform manner.
• part of the wall of the cylindrical portion may contact a wall of the slot 34, while another part of the wall of the cylindrical portion may not be in contact with a wall of the slot 34.
• part of the wall of the cylindrical portion of the pin 22 may be bent at an angle that differs from the angle at which another part of the wall of the cylindrical portion is bent.
• the staking pin 22 may have a constant outer diameter 404 along its entire length 400.
• the staking pin hole 42 to form the cylindrical portion allows for the "mushrooming" of the staking pin 22 within the slot 34 to secure the staking pin 22 in the slot 34.
• the staking pin 22 prevents forward and aft movement of the turbine blade 72 during operation of the GTE 100.
• the outer diameter of the cylindrical portion disposed in the slot 34 may be greater than the initial outer diameter 404 prior to installation.
• FIGS. 2 and 3 show a uniform outer diameter of the portion of the staking pin 22 disposed in the slot 34, this outer diameter is not necessarily uniform, and may vary along the length 406 of the staking pin 22.
• a turbine blade 72 or staking pin 22 removal or "de-staking" operation may also be performed.
• a de-staking operation may be performed, for example, at the end of a predetermined service life, or if a problem with the turbine blade 72 is discovered during an inspection.
• an instrument such as a metallic block, may be used to strike a portion of the staking pin 22 protruding from a surface of the turbine blade platform 12. Doing so may shear the staking pin 22 at a desired location, for example, at a location that is flush with the surface of the platform 12.
• any remaining portions of the pin 22 may be removed from the turbine blade 72 to complete the de-staking operation.
• a new turbine blade 72 having a new, unused staking pin 22 can then be provided.
• a new staking pin 22 may be installed in a previously used turbine blade 72 in place of a de-staked pin 22.
• the above-disclosed staking pin system can be installed in an apparatus experiencing high temperatures and stresses, such as a GTE.
• the staking pin system may be installed in the combustor system, any stage of the turbine system, or the compressor system, including the stators.
• the staking pin can be used generally in applications or industries requiring retention of components subject to, for example, a centrifugal force.
• the GTE 100 produces power by extracting energy from a flow of hot gas produced by combustion of fuel in a stream of compressed fluid, for example air, from the compressor system 10. Energy is released when a mixture of the compressed air and fuel is burned in the combustor system 20.
• the fuel injectors 30 direct a liquid or gaseous fuel into the combustor system 20 for combustion.
• the resulting hot gases are directed through the turbine system 70, past the stages 73, 74, 75, over stator vanes and the turbine blades, to spin the turbine blades 72 and rotors 76 and produce mechanical power.
• Turbine blades 72 rotating within the turbine system 70 may each include a staking pin 22 disposed through the platform 12 and into the slot 34 of the turbine rotor disk 76.
• the turbine blades 72 may experience high stresses. Turbine blade failures should be prevented as they may damage a GTE, and cause inconvenient and unscheduled shutdowns to repair and/or replace damaged GTE components. If turbine blade staking pins are used, depending on their design, the staking pins may oxidize and fail as a result of crack formation in the pin. As GTEs continue to operate at higher temperatures, there is a need for oxidation-resistant components, such as staking pins, in order to prevent failures and premature shut-downs. Additionally, GTE components may experience corrosion due to, for example, salt or sulfur, leading to failure due to crack formation.
• the staking pin 22 may provide certain advantages.
• the material from which the staking pin 22 may be made i.e., Alloy X
• the staking pin 22 described in the instant application the risk of GTE failure and/or having to prematurely replace one of the turbine blades can be reduced.
• Alloy X is a high-strength wrought nickel based superalloy. Due to its high strength, the staking pin 22 is designed so as to prevent significant protrusion of the staking pin 22 from the surface of the platform 12 and into the flow path 18 when the staking pin 22 is installed.
• the inner diameter 402 of the staking pin hole 42 is such that the wall thickness 408 of the cylindrical portion is sufficiently thin to enable excellent deformation, or "mushrooming," of the pin 22 in the slot 34 during installation. Mushrooming in the slot 34 beneath the platform 12 may prevent the staking pin 22 from “backing out” of the hole 36 in the turbine blade platform 12 by locking the pin 22 in the hole 36. This, in turn, can secure the turbine blade 72 and prevent it from migrating in either a forward or aft direction. This may reduce a risk of damage to components, such as the turbine rotor 76 and/or turbine nozzles, in the turbine system 70 of the GTE 100. Either separately or in combination with providing a thin wall in the cylindrical portion of the staking pin 22, the overall length 400 of the pin 22 may be relatively short to limit protrusion of the pin 22 from the surface of the platform 12 when the pin 22 is installed.
• the staking pin 22 made from Alloy X material is both corrosion and heat resistant, and durable such that the staking pin 22 may withstand the stresses of GTE operation.
• a staking pin 22 made from Alloy X may also exhibit desirable creep performance to prevent failure due to creep. That is, the staking pin 22 described herein may have less of a tendency than a staking pin made of another material to permanently deform under the influence of stresses, such as high temperatures and loads, during operation.
• the Alloy X from which the pin 22 may be made can be inexpensive and readily available as weld wire having an outer diameter that may be acceptable for the staking pins 22, thereby reducing the time and expense of manufacturing the staking pins 22.
• the disclosed configurations of staking pin 22 may reduce the incidence of damage to staking pin 22, such as damage resulting from cracking due to oxidation.
• the staking pin 22 may be stable under GTE operating stresses, such that cracking, even in the cylindrical portion at the staking pin hole 42 where cracking may be expected to initiate, can be prevented.
• the staking pin 22 described herein may last at least as long as the turbine blade 72 in which it is installed. Therefore, unnecessary GTE shutdowns can be avoided, as can possible damage, such as cracking, to the turbine rotor disk post 16 due to removal of a turbine blade 72 whose staking pin prematurely failed.
• staking pins 22 enables a relatively simple de-staking operation. While the staking pins 22 securely hold the turbine blades 72 in place during operation, if de-staking is necessary, a brittle failure mode of the staking pins 22 may allow for clean shearing of the pins 22 during de-staking without damaging either the turbine rotor disk 76 or turbine blades 72. For example, the staking pins 22 may be broken or sheared at a location that is flush with a surface of the platform 12.
• the material from which the pin 22 is made for example, Alloy X, the microstructure of the pin 22 as described herein, and/or the dimensions of the pin 22, can contribute to the brittle failure mode of the staking pins 22 that allows for clean shearing during de-staking.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Turbine Rotor Nozzle Sealing (AREA)

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• 2013
  • 2013-01-29 US US13/752,532 patent/US20140286782A1/en not_active Abandoned
  • 2013-08-06 IN IN889DEN2015 patent/IN2015DN00889A/en unknown
  • 2013-08-06 CN CN201380041569.6A patent/CN104520539A/zh active Pending
  • 2013-08-06 BR BR112015002811A patent/BR112015002811A2/pt not_active IP Right Cessation
  • 2013-08-06 WO PCT/US2013/053763 patent/WO2014025758A1/en active Application Filing

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