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WO2019143366A1 - Diffuseur d'échappement pour un moteur de turbine à gaz - Google Patents

Diffuseur d'échappement pour un moteur de turbine à gaz Download PDF

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Publication number
WO2019143366A1
WO2019143366A1 PCT/US2018/014646 US2018014646W WO2019143366A1 WO 2019143366 A1 WO2019143366 A1 WO 2019143366A1 US 2018014646 W US2018014646 W US 2018014646W WO 2019143366 A1 WO2019143366 A1 WO 2019143366A1
Authority
WO
WIPO (PCT)
Prior art keywords
exhaust diffuser
undulating portion
flowpath
point
strut
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/US2018/014646
Other languages
English (en)
Inventor
Kai Kadau
Jose Antonio PASCUAL-GUTIERREZ
Bogdan R. Raica
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Siemens Corp
Original Assignee
Siemens AG
Siemens Corp
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 AG, Siemens Corp filed Critical Siemens AG
Priority to PCT/US2018/014646 priority Critical patent/WO2019143366A1/fr
Publication of WO2019143366A1 publication Critical patent/WO2019143366A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • 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
    • F05D2250/70—Shape
    • F05D2250/71—Shape curved
    • F05D2250/711—Shape curved convex
    • 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
    • F05D2250/70—Shape
    • F05D2250/71—Shape curved
    • F05D2250/712—Shape curved concave

Definitions

  • the present invention relates to turbine engines, and more specifically to flow paths in exhaust diffusers in gas turbine engines.
  • a combustion system receives air from a compressor and raises it to a high energy level by mixing in fuel and burning the mixture, after which products of the combustor are expanded through a turbine.
  • the hot gas flow is passed through the turbine and expands to produce mechanical work used to drive an electric generator for power production.
  • the turbine generally includes multiple stages of stator vanes and rotor blades to convert the energy from the hot gas flow into mechanical energy that drives the rotor shaft of the engine.
  • Both the turbine section and the compressor section have stationary or non-rotating components, such as vanes, for example, that cooperate with rotatable components, such as blades, for example, for compressing and expanding the hot working gas.
  • An exhaust diffuser is located at an extreme aft end of the gas turbine, bolts to, and is supported by the exhaust frame.
  • An important element affecting the efficiency of a gas turbine is the aerodynamic performance of the exhaust diffuser (ED).
  • the role of the exhaust diffuser is to slow down the high speed flow exiting the last stage of the turbine as isentropically as possible in order to bring up its pressure back to ambient values.
  • an exhaust diffuser is the volume left between an inner cylinder and an outer cone concentrically surrounding the former.
  • the functionality of the ED is to gradually increase the flow path area so as to slow down the flow (See FIG. 1).
  • a turbine exhaust diffuser for a gas turbine engine having a turbine section comprises: a flowpath located downstream of the turbine section; wherein the flowpath is defined at least in part by a turbine casing having an inner casing forming an inner-diameter (ID) flowpath boundary and an outer casing forming an outer-diameter (OD) flowpath boundary; at least one strut positioned within the flowpath and spanning between the inner casing and the outer casing, wherein the at least one strut comprises a leading edge towards the upstream direction and a trailing edge towards the downstream direction; and an undulating portion located along at least one of the inner casing and the outer casing along the exhaust diffuser, wherein the undulating portion includes at least a first point positioned upstream of the at least one strut, a second point positioned approximately near a halfway span of the at least one strut, the undulating portion including radially and axially extending
  • FIG. 1 is a partial cross section of a turbine engine having features according to the prior art.
  • FIG. 2 is a detailed axial-radial cross section view of a turbine exhaust diffuser system of an exemplary embodiment of the present invention with straight segments.
  • FIG. 3 is a detailed axial-radial cross section view of a turbine exhaust diffuser system of an exemplary embodiment of the present invention with curved segments.
  • FIG. 4 is a detailed axial-radial cross section view of a turbine exhaust diffuser system of an exemplary embodiment of the present invention.
  • FIG. 5 is a perspective view of a turbine exhaust diffuser system of an exemplary embodiment of the present invention.
  • FIG. 6 is a chart comparing an exemplary embodiment of the present invention and the prior art.
  • FIG. 7 is a chart comparing an exemplary embodiment of the present invention and the prior art.
  • an embodiment of the present invention provides a turbine exhaust diffuser for a gas turbine engine having a turbine section
  • the exhaust diffuser includes a flowpath downstream of the turbine section.
  • the flowpath is defined at least in part by a turbine casing having an inner casing forming an ID flowpath boundary and an outer casing forming an OD flowpath boundary.
  • a least one strut is positioned within the flowpath and spans between the inner casing and the outer casing.
  • the exhaust diffuser includes an undulating portion located along at least one of the inner casing and the outer casing along the exhaust diffuser.
  • the undulating portion includes at least a first point upstream of the at least one strut and a second point approximate to a halfway span of the at least one strut.
  • the undulating portion includes radially and axially extending crests and troughs.
  • a gas turbine engine may comprise a compressor section, a combustor and a turbine section.
  • the compressor section compresses ambient air.
  • the combustor combines the compressed air with a fuel and ignites the mixture creating combustion products comprising hot gases that form a working fluid.
  • the working fluid travels to the turbine section.
  • Within the turbine section are circumferential rows of vanes and blades, the blades being coupled to a rotor.
  • the turbine section comprises a fixed turbine casing, which houses the vanes, blades and rotor.
  • a blade of a gas turbine receives high temperature gases from a combustion system to produce mechanical work of a shaft rotation.
  • an exhaust diffuser ED
  • An ED includes a turbine exit casing (TEC) followed by a turbine exit manifold (TEM).
  • TEC turbine exit casing
  • TEM turbine exit manifold
  • struts airfoil-shaped vanes, called struts, run from an inner casing, or hub, to an outer casing, or shroud.
  • Losses can occur in the ED caused by large turbulence regions that evolve from early onset of flow instabilities upstream. Further, computational fluid dynamics (CFD) simulations show that turbulence in the ED is initiated in the area of the struts. With high flow velocities having high Reynolds numbers, an uneven radial velocity and pressure profile, and a high tangential component of the velocity, which can be up to roughly thirty percent of the total, causes flow to meet the strut with high incidence angles.
  • CFD computational fluid dynamics
  • FIGS. 1 through 5 a portion of a gas turbine engine 10 is illustrated. As illustrated, the gas turbine engine 10 includes one or more turbine assemblies 46. A longitudinal axis 50 of the turbine engine 10 is shown. A flowpath 14 of turbine exhaust gases generally runs downstream from the one or more turbine assemblies 46 towards a far aft end of the turbine engine 10 through an exhaust diffuser 12.
  • the exhaust diffuser includes a turbine exit casing (TEC) 16 followed downstream by a turbine exit manifold (TEM) 48.
  • the exhaust diffuser 12 is roughly a volume that is left between an inner cylinder and an outer cone concentrically surrounding the former.
  • the exhaust diffuser 12 may include one or more flowpaths 14 downstream of the one or more turbine assemblies 46.
  • the flowpath 14 is defined by an outer casing 22 forming an OD flowpath boundary 24 and an inner casing 18 forming an ID flowpath boundary 20.
  • the exhaust diffuser 12 includes at least one strut 26. Within the TEC 16 the at least one strut 26 runs in length from the inner casing 18 to the outer casing 22.
  • the at least one strut 26 can be hollow in order to provide pathways for oil feed pipes and drain pipes to reach a bearing housing from outside the exhaust diffuser 12.
  • a similar configuration of the at least one strut 26 may be found in the TEM 48 as well.
  • Each strut 26 includes a leading edge 28 facing an upstream direction of the exhaust diffuser 12 towards the turbine section and a trailing edge 30 facing a downstream direction of the exhaust diffuser 12.
  • the relative terms“upstream” and“forward” refer to a direction along the longitudinal axis 50 toward the turbine section or beginning of the exhaust diffuser 12, while the relative terms“downstream” and“aft” refer to a direction along the longitudinal axis 50 toward an end of the exhaust diffuser 12 and turbine engine 10.
  • the upstream and downstream directions are in reference to the flowpath and how it relates to the location along the turbine engine.
  • FIGS. 2 through 5 Illustrated in FIGS. 2 through 5 are embodiments of the exhaust diffuser 12 that include an undulating portion 32.
  • the undulating portion 32 of the exhaust diffuser 12 is in reference to a portion of the ED 12 where at least one of the inner casing 18 and the outer casing 22 in the area of the exhaust diffuser 12 surrounding and covering the area including the at least one strut 26.
  • at least one of the inner casing 18 and the outer casing 22 includes radially and axially extending crests 42 and troughs 44.
  • the combination of crests 42 and troughs 44 can be designated as waves.
  • Each crest 42 can initiate a decline section. While each trough 44 can start an incline section.
  • Predefined degrees of freedom provide an optimization.
  • points of the outer casing 22 can be allowed to move axially and radially within given bounds to work towards a target of pressure recovery.
  • Manufacturing considerations may include whether only truncated cone-like structures are used for the outer casing 22, how many of these structures, and the like, can be considered.
  • FIG. 3 also shows an example of where the ID flowpath boundary and OD flowpath boundary would be positioned in a conventional exhaust diffuser.
  • the undulating portion 32 is broken up into different sections that either increase or decrease the cross-sectional area increase. Each section begins with a change in the either expansion or narrowing of the rate of the flowpath cross sectional area increase such as one of the crests 42 or troughs 44 indicating a high point and low point respectively.
  • Undulations in the ID flowpath boundary 20 and/or OD flowpath boundary 24 vary the function describing the rate of cross-sectional area increase with respect to axial location. Undulations may or may not narrow the cross-sectional area itself.
  • the cross-sectional area is, in principle, always increasing so as to slow down the flow.
  • a conventional TEC maintains the rate of cross-sectional area increase determined by a unique function of axial location. Using the undulating ID flowpath boundary 20 and/or OD flowpath boundary 24, however, the function describing the rate of cross-sectional area increase is changed.
  • the struts 26 pose a reduction of cross-sectional area or area blockage.
  • the ID flowpath boundary 20 or OD flowpath boundary 24 did not show undulations, the flow will experience a decrease in its deceleration as it encounters the struts 26.
  • the ID flowpath boundary 20 and/or OD flowpath boundary 24 open up to counteract the otherwise decrease in cross-sectional area.
  • the flow may be pinched, i.e. its rate of deceleration is reduced (not necessarily accelerated). This is achieved by reducing the rate of cross- sectional area increase.
  • the undulating portion 32 has at least a first point 34 and a second point 36 that initiates a first section 54 and second section 56 respectively.
  • the first point 34 can be positioned upstream of the stmt 26.
  • the first point 34 initiates an increasing rate of the cross-sectional area moving downstream from the one or more turbine assemblies 46 to allow for the decleration to be unaffected by the at least one stmt 26 or to increase the deceleration.
  • Approximately half way along a span of the stmt 26 is the second point 36. At the second point 36 the rate of the cross-sectional area starts to narrow, pinching the flow reducing the rate of deceleration.
  • an additional third point 38 may be added to the undulating portion 32.
  • the third point 38 may be positioned towards the trailing edge 30 of the stmt 26.
  • a trough 44 the rate of the cross- sectional area may start to increase again for a third section 62.
  • a fourth point 40 may be added downstream of the third point 38 and downstream of the stmt 26 as the beginning of a fourth section 64. At this optional fourth point 40, the rate of the cross-sectional area increase starts again to narrow before the cross-sectional area once again expands at a particular rate for the remainder of the exhaust diffuser 12. Additional points may be chosen if computational capacity allows and is compatible with the desired manufacturing processes.
  • FIG. 3 Illustrated in FIG. 3 is the radial-axial cross section with a wave like modification in that plane. This modification can also extend tangentially in an axisymmetric representation shown in FIG. 5.
  • the wave-like modifications shown in FIG. 3 and FIG. 5 can be on multiple length scales l ⁇ and with variable amplitude Ai. For example a first and second wave-length and amplitude can be applied with li > l 2 and Ai > A 2. Amplitudes of applied wavelengths can decrease further downstream when flow velocity is reduced (as indicated in FIG. 3 and FIG. 5).
  • first point 34 and the second point 36 may be a straight line (FIG. 2), a curved line (FIG. 3), or some combination of the two.
  • the resulting shape can include a wave- like modulation on multiple length scales and can also have degrees of freedom circumferentially such as shown in FIG. 5.
  • undulating portion is axisymmetric with the radially and axially extending crests and troughs on multiple wavelength and amplitudes. Strategies need to be made compatible with desired manufacturing and assembly processes. The general narrowing or expanding of the cross-sectional area between two points creates the undulation portion 32 of the exhaust diffuser 12.
  • the first point 34 of the undulating portion 32 of the exhaust diffuser 12 can provide a reduction of the flow acceleration.
  • the expansion of the rate of the cross-sectional area increase after the first point 34 slows down the flow 14 at it move towards the at least one strut 26.
  • the flow acceleration is caused by area blockage in the flow path due to the presence of the at least one strut 26. This flow acceleration is on top of the high velocities coming out of the turbine assemblies 46.
  • the geometry of the at least one strut 26 brings on flow separation at the leading edge 28 and trailing edge 30 of the strut 26.
  • the second point 36 initiates a pinching of the flow 14 that compresses the flow eliminating wall separation from the leading edge 28 of the strut 26.
  • Flow tendencies are to separate at the trailing edge 30 of the strut 26 as well due to the abrupt strut geometry in the flow path.
  • the third point 38 may provide a minimization of the separation of the flow 14 along the trailing edge 30 of the strut 26 by slowing down the flow 14 with an expansion of the rate of the cross-sectional area near the trialing edge 30 of the strut 26.
  • a pinching of the flow 14 is produced again reducing or eliminating the onset of flow instabilities prior to the eventual expansion downstream of the strut 26.
  • the waviness, or undulating features of the undulating portion 32 of the exhaust diffuser 12 compensates for the potential for flow separation leading from the abrupt strut geometry in the flow path.
  • FIG. 6 and 7 illustrate the increase in pressure recovery and decrease in pressure loss percentages when comparing a conventional exhaust diffuser with an embodiment that includes an undulating portion 32 as described above.
  • the undulating portion 32 provides a reduction in the affect of the at least one strut 26 within the exhaust diffuser 12.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
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Abstract

L'invention concerne un diffuseur d'échappement de turbine (12) pour un moteur à turbine à gaz ayant une section de turbine. Ledit diffuseur d'échappement (12) comprend un trajet d'écoulement (14) en aval de la section de turbine. Le trajet d'écoulement (14) est défini au moins en partie par un carter de turbine (16) ayant un boîtier interne (18) formant une limite de trajet d'écoulement ID (20) et un boîtier externe (22) formant une limite de trajet d'écoulement OD (24). Au moins une entretoise (26) est positionnée à l'intérieur du trajet d'écoulement (14) et s'étend entre le boîtier interne (18) et le boîtier externe (22). Le diffuseur d'échappement (12) comprend une partie ondulée (32) située le long d'au moins l'un du boîtier interne (18) et du boîtier externe (22) le long du diffuseur d'échappement (12). La partie ondulée (32) comprend au moins un premier point (34) en amont de l'au moins une entretoise (26) et un second point (36) s'approchant d'une portée à mi-chemin de l'au moins une entretoise (26). La partie ondulée (32) comprend des crêtes (42) et des creux s'étendant radialement et axialement.
PCT/US2018/014646 2018-01-22 2018-01-22 Diffuseur d'échappement pour un moteur de turbine à gaz Ceased WO2019143366A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/US2018/014646 WO2019143366A1 (fr) 2018-01-22 2018-01-22 Diffuseur d'échappement pour un moteur de turbine à gaz

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2018/014646 WO2019143366A1 (fr) 2018-01-22 2018-01-22 Diffuseur d'échappement pour un moteur de turbine à gaz

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110685755A (zh) * 2019-11-15 2020-01-14 重庆江增船舶重工有限公司 一种高效有机工质膨胀机

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2657482A1 (fr) * 2010-12-24 2013-10-30 Mitsubishi Heavy Industries, Ltd. Structure de trajet d'écoulement et diffuseur d'échappement de turbine à gaz
WO2015077067A1 (fr) * 2013-11-21 2015-05-28 United Technologies Corporation Décalage axisymétrique de parois d'extrémité profilées tridimensionnelles
EP3032032A1 (fr) * 2014-12-12 2016-06-15 MTU Aero Engines GmbH Aubes directrices de sortie et turboréacteur à double flux avec des aubes directrices de sortie

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2657482A1 (fr) * 2010-12-24 2013-10-30 Mitsubishi Heavy Industries, Ltd. Structure de trajet d'écoulement et diffuseur d'échappement de turbine à gaz
WO2015077067A1 (fr) * 2013-11-21 2015-05-28 United Technologies Corporation Décalage axisymétrique de parois d'extrémité profilées tridimensionnelles
EP3032032A1 (fr) * 2014-12-12 2016-06-15 MTU Aero Engines GmbH Aubes directrices de sortie et turboréacteur à double flux avec des aubes directrices de sortie

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110685755A (zh) * 2019-11-15 2020-01-14 重庆江增船舶重工有限公司 一种高效有机工质膨胀机

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