WO2016068862A1 - Moteur à turbine à gaz - Google Patents

Moteur à turbine à gaz Download PDF

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Publication number
WO2016068862A1
WO2016068862A1 PCT/US2014/062536 US2014062536W WO2016068862A1 WO 2016068862 A1 WO2016068862 A1 WO 2016068862A1 US 2014062536 W US2014062536 W US 2014062536W WO 2016068862 A1 WO2016068862 A1 WO 2016068862A1
Authority
WO
WIPO (PCT)
Prior art keywords
main body
trailing edge
body portion
strut
edge flap
Prior art date
Application number
PCT/US2014/062536
Other languages
English (en)
Inventor
John A. Orosa
Original Assignee
Siemens Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Priority to PCT/US2014/062536 priority Critical patent/WO2016068862A1/fr
Publication of WO2016068862A1 publication Critical patent/WO2016068862A1/fr

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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
    • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
    • F01D25/30—Exhaust heads, chambers, or the like
    • 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
    • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
    • F01D25/16—Arrangement of bearings; Supporting or mounting bearings in casings
    • F01D25/162—Bearing supports
    • 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
    • F01D5/12—Blades
    • F01D5/14—Form or construction
    • F01D5/141—Shape, i.e. outer, aerodynamic form
    • F01D5/145—Means for influencing boundary layers or secondary circulations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2240/00—Components
    • F05D2240/10—Stators
    • F05D2240/12—Fluid guiding means, e.g. vanes
    • F05D2240/122—Fluid guiding means, e.g. vanes related to the trailing edge of a stator vane
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2240/00—Components
    • F05D2240/10—Stators
    • F05D2240/12—Fluid guiding means, e.g. vanes
    • F05D2240/127—Vortex generators, turbulators, or the like, for mixing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00—Geometry
    • F05D2250/20—Three-dimensional
    • F05D2250/29—Three-dimensional machined; miscellaneous
    • F05D2250/292—Three-dimensional machined; miscellaneous tapered
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00—Geometry
    • F05D2250/30—Arrangement of components
    • F05D2250/38—Arrangement of components angled, e.g. sweep angle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2260/00—Function
    • F05D2260/94—Functionality given by mechanical stress related aspects such as low cycle fatigue [LCF] of high cycle fatigue [HCF]
    • F05D2260/941—Functionality given by mechanical stress related aspects such as low cycle fatigue [LCF] of high cycle fatigue [HCF] particularly aimed at mechanical or thermal stress reduction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2260/00—Function
    • F05D2260/96—Preventing, counteracting or reducing vibration or noise

Definitions

  • the invention relates in general to turbine engines and, more particularly, to exhaust diffusers for turbine engines.
  • a turbine engine 10 generally includes a compressor section 12, a combustor section 14, a turbine section 16 and an exhaust section 18.
  • the compressor section 12 can induct ambient air and can compress it.
  • the compressed air from the compressor section 12 can enter one or more combustors 20 in the combustor section 14.
  • the compressed air can be mixed with the fuel, and the air-fuel mixture can be burned in the combustors 20 to form a hot working gas.
  • the hot gas can be routed to the turbine section 16 where it is expanded through alternating rows of stationary airfoils and rotating airfoils and used to generate power that can drive a rotor 26.
  • the expanded gas exiting the turbine section 16 can be exhausted from the engine 10 via the exhaust section 18.
  • the exhaust section 18 can be configured as a diffuser 28, which can be a divergent duct formed between an outer shell 30 and a center body or hub 32 and a tail cone 34 supported by support struts 36.
  • the exhaust diffuser 28 can serve to reduce the speed of the exhaust flow and thus increase the pressure difference of the exhaust gas expanding across the last stage of the turbine.
  • exhaust diffusion has been achieved by progressively increasing the cross-sectional area of the exhaust duct in the fluid flow direction, thereby expanding the fluid flowing therein, and is typically designed to optimize operation at design operating conditions.
  • gas turbine engines are generally designed to provide desirable diffuser inlet conditions at the design point, in which the exhaust flow passing from the turbine section 16 is typically designed to have radially balanced distributions of flow velocity and swirl.
  • a gas turbine engine having a turbine exhaust section extending along a longitudinal engine axis.
  • the turbine exhaust section comprises a pair of concentrically spaced rings including an outer ring and an inner ring, and a plurality of strut structures extending radially between the rings, interconnecting and supporting the rings.
  • the strut structures are supported downstream of a last row of rotating blades and comprise a main body portion having an elongated chordal dimension in the direction of an axial gas flow through the engine and defining a chordal axis extending in a downstream direction from an upstream end of the main body portion toward a downstream end of the strut structure.
  • a trail ing edge flap is located at the downstream end of each main body portion.
  • Each trailing edge flap has a forward edge affixed to the downstream end of a respective main body portion, and each trailing edge flap has a radial end affixed to one of the outer and inner rings in axially spaced relation from the downstream end of a respective main body portion.
  • a gap can be defined between the forward edge of each trailing edge flap and the downstream end of a respective main body portion.
  • each trailing edge flap can extend at an angle relative to the downstream end of a respective main body portion along a radial span of the gap.
  • a rearward edge of the trailing edge flap can be formed by a first radial portion adjacent to the one of the outer and inner rings, the first radial portion of the rearward edge extending at a first acute angle relative to a line perpendicular to the engine axis and a second radial portion extending at a second acute angle relative to the line perpendicular to the engine axis.
  • Each trailing edge flap can extend between 25% and 50% of the span of a respective main body portion.
  • Each trailing edge flap can have a chord length of between 10% and 50% of the chord of a respective main body portion.
  • Each trailing edge flap can be oriented to direct flow at an angle relative to the chordal axis of a respective main body portion.
  • each main body portion can be aligned parallel to the engine axis and each main body portion can be angled in a tangential direction, and each trailing edge flap can be angled relative to the chordal axis of a respective main body portion in the tangential direction of the main body portions.
  • a radially outer first flap and a radially inner second flap are affixed to the outer and inner rings, respectively, with each of the flaps having a chord length that tapers from a maximum chord adjacent to a respective outer and inner ring down to a minimum chord adjacent to a mid-span of the main body portion.
  • a radial space can be formed between the first and second flaps adjacent to the mid-span of the main body portion.
  • a gas turbine engine having a turbine exhaust section extending along a longitudinal engine axis.
  • the turbine exhaust section comprises a pair of concentrically spaced rings including an outer ring and an inner ring, and a plurality of strut structures extending radially between the rings, interconnecting and supporting the rings.
  • the strut structures are supported downstream of a last row of rotating blades and comprise a main body portion having an elongated chordal dimension in the direction of an axial gas flow through the engine and define a chordal axis extending in a downstream direction from an upstream end of the main body portion toward a downstream end of the strut structure.
  • a trailing edge flap is associated with each main body portion and has a forward edge affixed to a downstream end of a respective main body portion, and each trailing edge flap defines a part-span flap extending from one of the outer and inner rings to a location between 25% and 50% of the span on the respective main body portion.
  • a gap is defined by a space between the trailing edge flap and a joint between the trailing edge of the main body portion and the one of the outer and inner rings. The gap can be defined adjacent to an end of each of the trailing edge flaps that is affixed to the one of the outer and inner rings in axially spaced relation from the downstream end a respective main body portion.
  • the gap can be defined between the forward edge of each trailing edge flap and the downstream end of a respective main body portion.
  • Each trailing edge flap can have a chord length of between 10% and 50% of the chord of a respective main body portion.
  • Each trailing edge flap can be oriented to direct flow at an angle relative to the chordal axis of a respective main body portion.
  • Each main body portion can be angled in a tangential direction, and each trailing edge flap can be angled relative to the chordal axis of a respective main body portion in the tangential direction of the main body portions.
  • a gas turbine engine having structure defining an annular flow path for receiving exhaust gas from a turbine section.
  • the structure includes an inner wall and an outer wall extending along a longitudinal engine axis, the turbine exhaust section, and a casing for housing the structure.
  • a strut structure is located downstream from a last row of blades of the turbine section.
  • the strut structure comprises a main body portion including a strut and a strut cover located over the strut, the strut cover extending radially through the flow path between the inner wall and the outer wall.
  • a trailing edge flap defines a chord extending downstream from a downstream end of the strut cover, the trailing edge flap defining a part-span structure on the strut cover with an outer end affixed to one of the outer and inner walls and an inner end located between the outer wall and a location adjacent to the strut cover mid-span.
  • a gap is defined by a space between a leading edge of the trailing edge flap and the trailing edge of the main body portion.
  • the trailing edge flap can have a span that is between 25% and 50% of the span of the strut cover.
  • a rearward edge of the trailing edge flap can angle radially toward to a junction with the strut cover at a radial end of the trailing edge flap located between the outer and inner walls.
  • the trailing edge flap can have a chord length of between 10% and 50% of the chord of the strut cover.
  • Fig. 1 is a perspective view partially in cross-section of a known turbine engine
  • Fig. 2 is a side elevation cross-sectional view of an exhaust diffuser section of a turbine engine configured with an exhaust diffuser strut structure in accordance with aspects of the invention
  • Fig. 3A is an enlarged side elevation view of a strut structure illustrating aspects of the invention
  • Fig. 3B is an enlarged side elevation view of an alternative configuration of the strut structure illustrating aspects of the invention
  • Fig. 3C is an enlarged side elevation view of a further alternative
  • Fig. 4 is a diagrammatic end view, in a front to rear direction of the turbine exhaust casing, illustrating aspects of the invention
  • Fig. 5 is a cross-sectional view taken through a strut structure along line 5-5 in Fig. 4;
  • Fig. 6 is a diagrammatic end view, in a front to rear direction of the turbine exhaust manifold, illustrating aspects of the invention. DETAILED DESCRIPTION OF THE INVENTION
  • a design for an exhaust diffuser strut structure is described to reduce vibrations in the diffuser while providing improved control over gas flow passing the strut structure, without adversely affecting the structural integrity of the strut structure and adjacent components.
  • a common occurrence of vortex shedding from exhaust diffuser struts, and in particular struts operating at high incidence, with resulting high vibration and stresses in nearby components may be addressed by providing a radially tapered part-span flap at the downstream end of the strut.
  • Fig. 2 shows an exhaust section including a portion of an exhaust diffuser 40 of a gas turbine engine configured in accordance with aspects of the invention.
  • the exhaust diffuser 40 is downstream from a last row of rotating blades of a turbine section of the engine, which may correspond to the turbine section 16 of the engine 10 shown in Fig. 1 , and can include a turbine exhaust casing 39 and a turbine exhaust manifold 41 .
  • the exhaust diffuser 40 has an inlet 42 that can receive an exhaust flow or exhaust gases 44 exiting from the turbine section.
  • the exhaust diffuser 40 includes an inner wall or boundary 46, which may comprise an inner ring, and an outer wall or boundary 48, which may comprise an outer ring.
  • the outer boundary 48 is radially spaced from the inner boundary 46 such that a flow path 50 is defined between the inner and outer boundaries 46, 48.
  • the flow path 50 can be generally annular or can have any other suitable configuration.
  • the outer boundary 48 is shown as comprising a diffuser shell 52 having an inner peripheral surface 54 defining the outer boundary 48 of the flow path 50.
  • the inner boundary 46 can be defined by a center body, also referred to as a hub 58.
  • the hub 58 may be generally cylindrical and may include an upstream end 60 and a downstream end 62.
  • upstream and downstream are intended to refer to the general position of these components relative to the direction of fluid flow through the exhaust diffuser section 40.
  • the hub 58 can be interconnected and supported to the diffuser shell 52 by a plurality of radially extending strut structures that can comprise turbine exhaust casing strut structures 64 and turbine exhaust manifold strut structures 65.
  • the turbine exhaust casing strut structures 64 may comprise a structural strut 66 surrounded by a strut cover or shield 68, as seen in Fig. 5.
  • the strut structures 64, 65 are arranged in circumferential alignment in respective rows, as is illustrated diagrammatically by strut structures 64 A -F in Fig. 4 and by strut structures 65 A -c in Fig. 6.
  • the inner boundary 46 may also be defined by a tail cone 72 having an upstream end attached to the downstream end 62 of the hub 58 in any suitable manner.
  • the tail cone 72 can taper from the downstream end 62 of the hub 58 extending in the downstream direction.
  • the hub 58 and the tail cone 72 can be substantially concentric with the diffuser shell 52 and can share a common longitudinal axis 71 , corresponding to a central axis for the flow path 50 and for the turbine engine.
  • the inner surface 54 of the diffuser shell 52 is oriented to diverge from the longitudinal axis 71 in the downstream direction, such that at least a portion of the flow path 50 is generally conical.
  • the strut structures 64, 65 can include respective trailing edge flaps 80, 82 to alter the chord of the strut structures 64, 65 in order to control vortex shedding from the strut structures 64, 65.
  • the trailing edge flaps 80, 82 can reduce the amplitude and/or alter vibration frequencies of wakes shed from the strut structures 64, 65, such as to avoid exciting natural vibration frequencies during off design operation of the engine, e.g., during part load operation.
  • the following description of the trailing edge flaps 80, 82 is presented with particular reference to the trailing edge flaps 80 associated with the turbine exhaust casing strut structures 64.
  • the strut structures 64 and in particular the strut shields 68, may each be formed with an aerodynamic airfoil shape.
  • the illustrated strut shield 68 defines a main body portion 68 B and includes a leading edge at an upstream end 74, a trailing edge at a downstream end 76, and opposing sides 78a, 78b extending in an axial direction, i.e., in the direction of gas flow through the flow path 50, between the upstream and downstream ends 74, 76.
  • a chordal axis A c is defined by the opposing sides 78a, 78b extending in the downstream direction from the upstream end 74.
  • the axial direction of the chordal axis A c may be parallel to the longitudinal axis 71 , or may be angled relative to the longitudinal axis 71 , as may be dictated by the particular structural and/or flow characteristics of the exhaust section.
  • the trailing edge flap 80 is located at the downstream end 76 of the strut shield 68.
  • the trailing edge flap 80 has a forward edge 86 affixed to the downstream end 76 of the main body portion 68 B , and the trailing edge flap 80 has a radial end, i.e., a radial outer end 87, affixed to the outer boundary 48.
  • the trailing edge flap 80 can be affixed to the main body 68 B and the outer boundary 48 by any conventional means, such as by being affixed by welding, fasteners, or similar means.
  • the forward edge 86 includes at least an end portion 86 G that is located in axially spaced relation from the downstream end 76 of the main body portion 68 B to define a gap 70 extending axially between the forward edge 86 of the trailing edge flap 80 and the downstream end 76 of the main body portion 68 B .
  • the end portion 86 G can include a first end 86 G i located at the outer boundary 48 and axially spaced from the downstream end 76, and a second end 86 G 2 located at an intersection with the downstream end 76 of the main body portion 68 B .
  • the end portion 86 G can define a generally linear edge between the first and second ends 86 G i , 86G2 of the end portion 86 G extending at an angle of about 45°, i.e., 45° ⁇ 20°, relative to the downstream end 76 of the main body portion 68 B along a radial span of the gap 70. Further, the gap 70 can extend from the inner peripheral surface 54 to the second end 86 G 2 of the end portion 86 G a radial distance of 5% to 25% of the span of the main body portion 68 B .
  • inner and outer main body joints or junctions 88 1 and 88 0 between the main body portion 68 B and the inner and outer boundaries 46, 48, respectively, are formed with a predetermined fillet configuration to withstand stresses that may occur during operation, such as from vibrations and forces applied to the components.
  • the configuration of the trailing edge flaps 80, including the gap 70, separates the attachment location for the trailing edge flaps 80 from the main body junctions 88i and 88 0 , such that stresses associated with engagement of the trailing edge flaps 80 are distributed in spaced relation to stresses occurring at the main body junctions 88i and 88 0 to avoid adversely affecting the service life of the strut structures 64 at their attachment locations to the inner and outer boundaries 46, 48.
  • a rearward edge 90 of the trailing edge flap 80 angles radially toward to a mid-span junction 92 with the main body portion 68 B at a radial end of the trailing edge flap 80 located at an intermediate location between the inner and outer boundaries 46, 48.
  • mid-span and “mid-span location” refer to a 50% span location, i.e., a mid-point between the inner and outer boundaries 46, 48; and "adjacent to a mid-span” and “adjacent to a mid- span location” refer to a location spaced from either the inner boundary 46 or the outer boundary 48 by a distance of 25% to 50% of the main body span.
  • the rearward edge 90 can be generally linear, as depicted by dotted line 90 in Fig. 3A.
  • the rearward edge 90 of the trailing edge flap 80 is formed by a first radial portion 90a, illustrated adjacent to the outer boundary 48, and a second radial portion 90b extending from the first radial portion 90a to the downstream end 76 of the main body portion 68 B at the junction 92.
  • the first radial portion 90a extends at a first acute angle a relative to a line perpendicular to the engine axis
  • the second radial portion 90b extends at a second acute angle ⁇ relative to a line perpendicular to the engine axis, wherein the second acute angle ⁇ is greater than the first acute angle a.
  • the first acute angle a may be 30° and the second acute angle ⁇ may be 45°.
  • the trailing edge flap 80 extends less than a full span of the main body portion 68 B , i.e., defines a part-span flap.
  • a radial length of the trailing edge flap 80 from the outer boundary 48 to the mid-span junction 92 extends between 25% and 50% of the span of the main body portion 68 B .
  • the trailing edge flap has a chord length, D (Fig. 5), of between 10% and 50% of the chordal dimension of a respective main body portion 68 B , as may be measured from the upstream end 74 to the downstream end 76 of the main body portion 68 B along the chordal axis A c .
  • the chord length, D can be a maximum chord length as measured at a radial location corresponding to the connection between the trailing edge flap 80 and the outer boundary 48 and which can include the distance, D, from the downstream end 76, spanning the gap 70, and extending to the rearward edge 90 of the trailing edge flap 80.
  • the portion of the trailing edge flap 80 adjacent to the outer boundary 48, at the first radial portion 90a, defines the maximum chord for the trailing edge flap 80.
  • the first radial portion 90a provides a substantial axially extending surface generally located in an area where vortex shedding may be of greatest concern near the outer boundary 48.
  • the purpose of the tapered rearward edge 90 is to shed vorticity along the flap trailing edge span. This vorticity is aligned with the flow direction of the exhaust gases 44 and is steady in nature.
  • the strut vortex shedding that causes damage is unsteady in nature (oscillates). These strut vortices get shed from both the strut leading edge and trailing edge in an alternating pattern.
  • the strut vortices are aligned with the strut leading edge and trailing edge direction, which is generally perpendicular to the steady vortices from the tapered flap 80.
  • the tapered strut 80 can cause the unsteady strut vortices and steady flap vortices to interact in some manner that increases the strut shedding frequency and decreases its amplitude.
  • the presence of the flap steady vortices can be disruptive to the strut vortex shedding process. That is, the presence of the flap steady vortices may introduce an aerodynamic blockage that can accelerate flows outside the vortex cores and which can increase the shedding frequency.
  • the flap steady vortices can also induce radial flows that may relieve diffusion in the corners defined between the struts 64 and an adjacent endwall, e.g., the inner peripheral surface 54, and can reduce the intensity of associated unsteady flow separations.
  • the maximum chord defined at the first radial portion 90a of the trailing edge flap 80 is supported against flexing movement by its connection to the outer boundary 48.
  • the portion of the trailing edge flap 80 associated with the second radial portion 90b is spaced from support structure, such as the outer boundary 48, and its reduced chord facilitates a reduction in forces exerted by the gas flow along this radial section of the trailing edge flap 80.
  • the span of the main body portions 68 B can be angled in a tangential direction. That is, the main body portions 68 B can lean circumferential ly away from a radially extending line, extending from the inner boundary 46 to the outer boundary 48.
  • the turbine blades rotate in the counterclockwise direction when viewed in the downstream direction, such that the tangential lean of the main body portions 68 B can be opposite to the direction of rotation in the turbine.
  • the trailing edge flap 80 can be rotated by angle ⁇ relative to the chordal axis A c of the respective main body portion 68 B .
  • the flap 80 preferably projects into the oncoming flow 96 a sufficient amount to induce roughly 5° to 15° degrees of additional flow turning near its maximum chord location.
  • the "lift" generated by the flap 80 decreases quickly and a sheet of steady streamwise vorticity is shed from the flap rearward edge 90. This vortex sheet interferes with the unsteady vortex shedding process on the strut suction surface, e.g., side 78b, and effectively reduces its amplitude and increases its frequency.
  • unsteady strut vortex shedding is most common at low part load operating conditions where the strut incidence (angle ⁇ in Fig. 5) can reach 50° to 60°. At such high incidences a zero flap angle is sufficient to produce an effective trailing edge vortex sheet.
  • unsteady strut vortex shedding can occur at lower incidences.
  • various combinations of high strut thickness to chord ratio, tangentially leaned strut, high OD flowpath expansion angle, and hub- strong diffuser velocity profile can cause very high local diffusion at the strut OD acute angle corner, as denoted by reference numeral 63 in Fig. 4.
  • Unsteady vortex shedding can occur on the outer spans of such a strut even at a low incidence.
  • the flap 80 can be rotated or turned into the flow 96 by 10° to 20° (angle ⁇ ).
  • strut structure 64 can be provided with a trailing edge flap 80' adjacent to the inner boundary 46.
  • the trailing edge flap 80 of Fig. 3A can be referred to as an outer trailing edge flap 80 and the trailing edge flap of Fig. 3B can be referred to as an inner trailing edge flap 80'.
  • the elements and operation of the inner trailing edge flap 80' in relation to the main body portion 68 B and the inner boundary 46 is essentially the same as described above for the outer trailing edge flap 80 in relation to the main body portion 68 B and the outer boundary 48.
  • the inner trailing edge flap 80' has a forward edge 86' affixed to the downstream end 76 of the main body portion 68 B , and the trailing edge flap 80' has a radial end, i.e., a radial inner end 87', affixed to the inner boundary 46.
  • the forward edge 86' includes at least an end portion 86 G ' that is located in axially spaced relation from the downstream end 76 of the main body portion 68 B to define a gap 70' between the forward edge 86' of the trailing edge flap 80' and the downstream end 76 of the main body portion 68 B .
  • an end portion 86 G ' of the forward edge 86' can include a first end 86 G i' located at the inner boundary 46 and spaced from the downstream end 76, and a second end 860 2 ' located at an intersection with the downstream end 76 of the main body portion 68 B .
  • the end portion 86 G ' can define a generally linear edge between the first and second ends 86 G i', 860 2 ' of the end portion 86 G ' extending at an angle relative to the downstream end 76 of the main body portion 68 B along a radial span of the gap 70'.
  • a rearward edge 90' of the inner trailing edge flap 80' angles radially toward a mid-span junction 92' with the main body portion 68 B at a radial end of the inner trailing edge flap 80' located at an intermediate location between the inner and outer boundaries 46, 48.
  • the rearward edge 90' can be generally linear, as depicted by dotted line 90' in Fig. 3B.
  • the rearward edge 90' of the inner trailing edge flap 80' is formed by a first radial portion 90a', illustrated adjacent to the inner boundary 46, and a second radial portion 90b' extending from the first radial portion 90a' to the downstream end 76 at the junction 92'.
  • the first radial portion 90a' extends at a first acute angle a' relative to a line perpendicular to the engine axis
  • the second radial portion 90b' extends at a second acute angle ⁇ ' relative to a line perpendicular to the engine axis, wherein the second acute angle ⁇ ' is greater than the first acute angle ⁇ '.
  • the inner trailing edge flap 80' can be angled relative to the chordal axis, to maintain sufficient aerodynamic loading that it will shed a steady vortex sheet. For example, if the flap 80' is angled for low incidence flow, the flap 80' is preferably rotated or turned into the flow, as is depicted by flap 80' in Fig. 4.
  • the inner trailing edge flap 80' includes elements and functions similar to those described for the outer trailing edge flap 80, wherein the configuration of lengths and/or angles of the edges 86', 90' can mirror those of the outer trailing edge flap 80.
  • Fig. 3C illustrates a further alternative aspect for the present invention in which the strut structure 64 may include both an outer trailing edge flap 80 and an inner trailing edge flap 80'.
  • the outer and inner trailing edge flaps 80, 80' extend radially, having a maximum chord at the respective outer and inner boundaries 48, 46, and tapering to a minimum chord, i.e. to a chord of zero, at respective mid-span junctions 92, 92' with the trailing edge 76 of the main body portion 68 B .
  • a minimum chord i.e. to a chord of zero
  • a radial space 94 can be defined between the junctions 92, 92' of the trailing edge flaps 80, 80' wherein the size of the radial space 94 can be selected with reference to the particular flow characteristics of the engine and, in particular, with reference to the flow characteristics adjacent to the inner and outer boundaries 46, 48.
  • the trailing edge flaps 80, 80' may intersect with each other at or adjacent to the mid-span location of the main body portion 68 B to form a radially continuous trailing edge flap having a minimum chord at or adjacent to the mid-span location and maximum chord at each of the inner and outer boundaries 46, 48.
  • turbine exhaust manifold strut structures 65 A -c can be provided with trailing edge flaps 82 that correspond in form and function to the trailing edge flaps 80, 80' described for the turbine exhaust casing strut structures 64 with reference to Figs. 3A, 3B and 3C.

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  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Supercharger (AREA)

Abstract

Selon l'invention, une section d'échappement de turbine à gaz comprend une paire de bagues espacées de façon concentrique comprenant une bague externe (48) et une bague interne (46), et une pluralité de structures d'entretoise (64) s'étendant radialement entre les bagues (46, 48), interconnectant et supportant les bagues (46, 48). Les structures d'entretoise (64) comprennent une partie corps principale (68B) et un volet de bord de fuite (80) situé à l'extrémité aval de chaque partie corps principale (68B). Chaque volet de bord de fuite (80) comprend un bord avant (86) fixé à l'extrémité aval (76) d'une partie corps principale respective (68B), et chaque volet de bord de fuite (80) comprend une extrémité radiale (87) fixée à l'une des bagues externe et interne (46, 48) selon une relation axialement espacée à partir de l'extrémité aval (76) d'une partie corps principal respective (68B).
PCT/US2014/062536 2014-10-28 2014-10-28 Moteur à turbine à gaz WO2016068862A1 (fr)

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PCT/US2014/062536 WO2016068862A1 (fr) 2014-10-28 2014-10-28 Moteur à turbine à gaz

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3828390A1 (fr) * 2019-11-26 2021-06-02 General Electric Company Buse de turbomachine avec une surface portante dotée d'un bord de fuite curviligne
US11634992B2 (en) 2021-02-03 2023-04-25 Unison Industries, Llc Air turbine starter with shaped vanes

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040088989A1 (en) * 2002-11-07 2004-05-13 Siemens Westinghouse Power Corporation Variable exhaust struts shields
US20110018282A1 (en) * 2008-08-06 2011-01-27 Mitsubishi Heavy Indusstries, Ltd. Wind turbine blade and wind power generator using the same

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040088989A1 (en) * 2002-11-07 2004-05-13 Siemens Westinghouse Power Corporation Variable exhaust struts shields
US20110018282A1 (en) * 2008-08-06 2011-01-27 Mitsubishi Heavy Indusstries, Ltd. Wind turbine blade and wind power generator using the same

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3828390A1 (fr) * 2019-11-26 2021-06-02 General Electric Company Buse de turbomachine avec une surface portante dotée d'un bord de fuite curviligne
US11629599B2 (en) 2019-11-26 2023-04-18 General Electric Company Turbomachine nozzle with an airfoil having a curvilinear trailing edge
US11634992B2 (en) 2021-02-03 2023-04-25 Unison Industries, Llc Air turbine starter with shaped vanes

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