US20200096002A1 - Axial compressor - Google Patents

Axial compressor Download PDF

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Publication number
US20200096002A1
US20200096002A1 US16/576,098 US201916576098A US2020096002A1 US 20200096002 A1 US20200096002 A1 US 20200096002A1 US 201916576098 A US201916576098 A US 201916576098A US 2020096002 A1 US2020096002 A1 US 2020096002A1
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US
United States
Prior art keywords
rotor
bleed
axial compressor
circumferential surface
tips
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.)
Abandoned
Application number
US16/576,098
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English (en)
Inventor
Koji Taima
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.)
Honda Motor Co Ltd
Original Assignee
Honda Motor Co Ltd
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 Honda Motor Co Ltd filed Critical Honda Motor Co Ltd
Assigned to HONDA MOTOR CO., LTD. reassignment HONDA MOTOR CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TAIMA, KOJI
Publication of US20200096002A1 publication Critical patent/US20200096002A1/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/009—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by bleeding, by passing or recycling fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D19/00—Axial-flow pumps
    • F04D19/02—Multi-stage pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/02—Surge control
    • F04D27/0207—Surge control by bleeding, bypassing or recycling fluids
    • F04D27/023—Details or means for fluid extraction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/52—Casings; Connections of working fluid for axial pumps

Definitions

  • the present invention relates to an axial compressor, and particularly to an axial compressor equipped with a bleed structure used in gas turbine engines for aircraft or the like.
  • Axial compressors used in gas turbine engines for aircraft are designed to operate properly with a large inflow air volume at rated operation (during large-output operation), such as when cruising, which occupies a large part of the operation time.
  • rated operation such as when idling or taxiing
  • the inflow air volume is small and the inflow condition differs from the inflow condition at the rated operation. Therefore, at non-rated operation, the vane cascade may not operate stably, rotating stall may occur, the pressure efficiency may decrease, and/or the total pressure loss may become large.
  • JP 559-168296A JP 559-168296A, for example.
  • a primary object of the present invention is to provide an axial compressor in which a bleed hole is provided at an appropriate position such that the pressure loss in the axial compressor is effectively reduced by air bleed.
  • an axial compressor ( 36 ), comprising: a cylindrical casing ( 14 ); a rotor ( 20 ) rotatably disposed in the casing; multiple rotor blades ( 39 ) arranged on an outer circumferential surface ( 20 B) of the rotor ( 20 ) at a predetermined pitch around a central axis (X) of the rotor; multiple stationary blades ( 41 ) arranged on an inner circumferential surface ( 14 A) of the casing ( 14 ) at a position adjacent to and behind the rotor blades ( 39 ) in an axial direction of the rotor, each stationary blade having a tip ( 41 A) opposing the rotor and having a chord length (LC) defined between a leading edge ( 41 B) and a trailing edge ( 41 C) of the tip; and at least one bleed passage ( 72 ) having a bleed opening ( 70 ) that opens out in the outer circumferential surface ( 20 B) of the rotor ( 20 ), wherein
  • the air bleed suppresses laminar flow separation produced in the downstream direction of the stationary blades, whereby rotating stall becomes less likely to occur and the pressure loss in the axial compressor is effectively reduced.
  • the bleed opening ( 70 ) is located axially rearward of the leading edges ( 41 B) of the tips ( 41 A) of the stationary blades ( 41 ) by 10-20% of the chord length.
  • the pressure loss in the axial compressor air bleed is reduced remarkably by air bleed particularly when the inflow air volume is small.
  • the at least one bleed passage ( 72 ) comprises multiple bleed passages arranged around the central axis (X) of the rotor ( 20 ) at a regular pitch.
  • the at least one bleed passage ( 72 ) extends from the bleed opening ( 70 ) obliquely rearward at a predetermined angle ( ⁇ ) relative to the axial direction of the rotor ( 20 ).
  • the compressed air containing vortices can flow from the bleed opening to the bleed passage easily and smoothly, whereby the pressure loss in the axial compressor is effectively reduced at non-rated operation.
  • the predetermined angle ( ⁇ ) is in a range from 20 to 40 degrees.
  • the compressed air containing vortices can flow from the bleed opening to the bleed passage easily and smoothly, whereby the pressure loss in the axial compressor is effectively reduced at non-rated operation.
  • the axial compressor of the present invention can reduce the pressure loss in the axial compressor effectively by air bleed.
  • FIG. 1 is a sectional view showing an overall structure of a gas turbine engine for aircraft including an axial compressor according to one embodiment of the present invention
  • FIG. 2 is a sectional view schematically showing a part of the axial compressor
  • FIG. 3 is a graph showing inflow air volume-pressure loss coefficient characteristics
  • FIG. 4 is a graph showing a relationship between total pressure and a span length.
  • a gas turbine engine 10 includes a substantially cylindrical outer casing 12 and an inner casing 14 that are arranged coaxially.
  • the inner casing 14 rotatably supports a low pressure rotary shaft (rotor) 20 therein via a front first bearing 16 and a rear first bearing 18 .
  • a tubular high pressure rotary shaft 26 is arranged so as to be rotatable around an outer circumference of an axially intermediate portion of the low pressure rotary shaft 20 .
  • the front portion of the high pressure rotary shaft 26 is supported by the inner casing 14 via a front second bearing 22 while the rear portion of the same is supported by the low pressure rotary shaft 20 via a rear second bearing 24 .
  • the low pressure rotary shaft 20 and the high pressure rotary shaft 26 are arranged coaxially, and the central axis thereof is denoted by a reference sign “X.”
  • the low pressure rotary shaft 20 includes a substantially conical tip portion 20 A that protrudes more forward than the inner casing 14 .
  • An outer circumference of the tip portion 20 A is provided with a front fan 28 including multiple fan blades 29 , which are made of titanium alloy or the like and arranged to be spaced apart from one another in the circumferential direction.
  • Multiple stator vanes 30 are arranged on a downstream side of the front fan 28 so as to be spaced apart from one another at a predetermined interval in the circumferential direction.
  • a bypass duct 32 defined between the outer casing 12 and the inner casing 14 to have an annular cross-sectional shape and an air compression duct (annular fluid passage) 34 defined coaxially (to be coaxial with the central axis X) in the inner casing 14 to have an annular cross-sectional shape are provided in parallel with each other.
  • An axial compressor 36 is provided in an inlet of the air compression duct 34 .
  • the axial compressor 36 includes two (front and rear) rotor blade tows 38 provided on an outer circumference of the low pressure rotary shaft 20 and two (front and rear) stationary blade rows 40 provided in the inner casing 14 , such that the rotor blade rows 38 and the stationary blade rows 40 are arranged adjacent to each other and alternate in the axial direction.
  • Each of the rotor blade rows 38 includes multiple rotor blades 39 (see FIG. 2 ) extending radially outward from an outer circumferential surface 20 B of the low pressure rotary shaft 20 in a cantilever fashion and arranged around the central axis X of the low pressure rotary shaft 20 at a predetermined pitch.
  • Each of the stationary blade rows 40 includes multiple stationary blades 41 (see FIG. 2 ) extending radially inward from an inner circumferential surface 14 A of the inner casing 14 (see FIG.
  • a centrifugal compressor 42 is provided in an outlet of the air compression duct 34 .
  • the centrifugal compressor 42 includes impellers 44 provided on an outer circumference of the high pressure rotary shaft 26 .
  • a stationary blade row 46 is provided in the outlet of the air compression duct 34 on an upstream side of the impellers 44 .
  • a diffuser 50 is provided at an outlet of the centrifugal compressor 42 , wherein the diffuser is fixed to the inner casing 14 .
  • a combustion chamber member 54 is provided to define a reverse-flow combustion chamber 52 to which compressed air is supplied from the diffuser 50 .
  • the inner casing 14 is provided with multiple fuel injection nozzles 56 for injecting fuel into the reverse-flow combustion chamber 52 .
  • the reverse-flow combustion chamber 52 produces high-pressure combustion gas by combusting air-fuel mixture therein.
  • a nozzle guide vane row 58 is provided in an outlet of the reverse-flow combustion chamber 52 .
  • a high pressure turbine 60 and a low pressure turbine 62 are provided such that the combustion gas produced in the reverse-flow combustion chamber 52 is blown thereto.
  • the high pressure turbine 60 includes a high pressure turbine wheel 64 fixed to an outer circumference of the high pressure rotary shaft 26 .
  • the low pressure turbine 62 is provided on a downstream side of the high pressure turbine 60 and includes multiple nozzle guide vane rows 66 fixed to the inner casing 14 and multiple low pressure turbine wheels 68 provided on an outer circumference of the low pressure rotary shaft 20 arranged in an axially alternating manner.
  • a starter motor (not shown in the drawings) drives the high pressure rotary shaft 26 to rotate.
  • the air compressed by the centrifugal compressor 42 is supplied to the reverse-flow combustion chamber 52 , and air-fuel mixture combustion takes place in the reverse-flow combustion chamber 52 to produce combustion gas.
  • the combustion gas is blown to the high pressure turbine wheel 64 and the low pressure turbine wheels 68 to rotate the turbine wheels 64 , 68 .
  • the low pressure rotary shaft 20 and the high pressure rotary shaft 26 rotate, which causes the front fan 28 to rotate and brings the axial compressor 36 and the centrifugal compressor 42 into operation, whereby the compressed air is supplied to the reverse-flow combustion chamber 52 . Therefore, the gas turbine engine 10 continues to operate after the starter motor is stopped.
  • part of the air suctioned by the front fan 28 passes through the bypass duct 32 and is blown out rearward, and generates the main thrust particularly in a low-speed flight.
  • the remaining part of the air suctioned by the front fan 28 is supplied to the reverse-flow combustion chamber 52 and mixed with the fuel and combusted, and the combustion gas is used to drive the low pressure rotary shaft 20 and the high pressure rotary shaft 26 to rotate before being blown out rearward to generate thrust.
  • the low pressure rotary shaft 20 constituting the rotor is formed with multiple bleed passages 72 arranged around the central axis X of the low pressure rotary shaft 20 at a regular pitch, wherein each bleed passage 72 includes a circular bleed opening 70 that opens out in the outer circumferential surface 20 B of the low pressure rotary shaft 20 toward the air compression duct 34 (compressed air passage).
  • Part of the compressed air produced by the axial compressor 36 flows from the bleed openings 70 to the bleed passages 72 to be bled to the outside of the axial compressor 36 .
  • each stationary blade 41 has a tip (free end edge) 41 A opposing the low pressure rotary shaft (rotor) 20 , and the tip 41 A of each stationary blade 41 has a leading edge (front end) 41 B and a trailing edge (rear end) 41 C such that a chord length LC of the stationary blade 41 is defined as a length between the leading edge 41 B and the trailing edge 41 C.
  • each bleed opening 70 opens at a position ahead of a position axially spaced rearward from the leading edges 41 B of the tips 41 A of the stationary blades 41 by one half of the chord length LC (0.5LC) in such a manner that the bleed opening 70 faces toward the tips 41 A of the stationary blades 41 .
  • the position of the bleed opening 70 may be measured as the position of the center of the bleed opening 70 .
  • each bleed opening 70 is located in a range from a position axially spaced rearward from the leading edges 41 B of the tips 41 A of the stationary blades 41 by 10% of the chord length LC to a position axially spaced rearward from the leading edges 41 B by 20% of the chord length LC.
  • the bleed opening 70 is preferably located in a chord position range of 0.1LC-0.2LC with respect to the leading edges 41 B.
  • FIG. 3 is a graph showing a relationship between the inflow air volume and the pressure loss coefficient for a case where no bleed openings 70 are provided and cases where the bleed openings 70 are provided at respective different chord positions.
  • a characteristic curve A represents the inflow air volume-pressure loss coefficient characteristics in a case where the bleed openings 70 are located in a range of 0.1LC-0.2LC axially rearward of the leading edges 41 B
  • a characteristic curve B represents the inflow air volume-pressure loss coefficient characteristics in a case where the bleed openings 70 are located in a range of 0.4LC-0.5LC axially rearward of the leading edges 41 B
  • a characteristic curve C represents the inflow air volume-pressure loss coefficient characteristics in a case where the bleed openings 70 are located in a range of 0.8LC-0.9LC axially rearward of the leading edges 41 B
  • a characteristic curve D represents the inflow air volume-pressure loss coefficient characteristics in a case where no bleed openings 70 are provided.
  • FIG. 4 is a graph showing a relationship between the span position and the total pressure for a case where no bleed openings 70 are provided and cases where the bleed openings 70 are provided at respective different chord positions.
  • the position of the outer circumferential surface 20 B of the low pressure rotary shaft 20 is represented by a span length of 0
  • the position of the inner circumferential surface 14 A of the inner casing 14 (outermost end position) is represented by a span length of 1.
  • provision of the bleed openings 70 improves (or suppresses) the decrease in the total pressure or the pressure loss on the side of the span length of 0.
  • the bleed openings 70 open ahead of a position axially spaced rearward from the leading edges 41 B by 0.5 LC, and are preferably located in the chord position range of 0.1LC-0.2LC axially rearward of the leading edges 41 B, such that the bleed openings 70 face toward the tips 41 A of the stationary blades 41 from the side of the span length of 0, the compressed air produced in the axial compressor 36 and containing vortices flows from each bleed opening 70 to the corresponding bleed passage 72 to be bled efficiently to the outside of the axial compressor 36 , whereby the laminar flow separation that occurs in the downstream direction of the stationary blades 41 is suppressed.
  • the pressure loss is effectively suppressed so that a high air compression efficiency is achieved.
  • the bleed openings 70 are provided at multiple positions around the central axis X of the low pressure rotary shaft 20 at a regular pitch, air bleed takes place at these positions around the central axis X of the low pressure rotary shaft 20 , so that the suppression of the laminar flow separation produced in the downstream direction of the stationary blades 41 can be achieved evenly all around the central axis X of the low pressure rotary shaft 20 . Thereby, the pressure loss in the axial compressor 36 can be reduced effectively.
  • Each bleed passage 72 extends from the corresponding bleed opening 70 rearward or in the direction of airflow in the axial compressor 36 and obliquely at a predetermined angle ⁇ relative to the outer circumferential surface 20 B (or axial direction) of the low pressure rotary shaft 20 .
  • the angle ⁇ is in a range from 20 to 40 degrees.
  • each bleed passage 72 is inclined as described above, the compressed air can flow from each bleed opening 70 to the corresponding bleed passage 72 easily and smoothly, whereby the pressure loss in the axial compressor 36 is reduced effectively.
  • bleed openings 70 may not be circular, and may be of any other shape such as an ellipse, a rectangle, or an oblong circle that extends along the tips of the stationary blades 41 .

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
US16/576,098 2018-09-26 2019-09-19 Axial compressor Abandoned US20200096002A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2018180085A JP7041033B2 (ja) 2018-09-26 2018-09-26 軸流圧縮機
JP2018180085 2018-09-26

Publications (1)

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US20200096002A1 true US20200096002A1 (en) 2020-03-26

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US16/576,098 Abandoned US20200096002A1 (en) 2018-09-26 2019-09-19 Axial compressor

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Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5562404A (en) * 1994-12-23 1996-10-08 United Technologies Corporation Vaned passage hub treatment for cantilever stator vanes
FR2875866B1 (fr) * 2004-09-30 2006-12-08 Snecma Moteurs Sa Procede de circulation d'air dans un compresseur de turbomachine, agencement de compresseur le mettant en oeuvre , etage de compression et compresseur comportant un tel agencement, et moteur d'aeronef equipe d'un tel compresseur
FR2882112B1 (fr) * 2005-02-16 2007-05-11 Snecma Moteurs Sa Prelevement en tete des roues mobiles de compresseur haute pression de turboreacteur
GB201015029D0 (en) * 2010-09-10 2010-10-20 Rolls Royce Plc Gas turbine engine
CN106368973B (zh) * 2016-11-09 2018-04-06 哈尔滨工业大学 压气机的静叶与端壁间的间隙流动控制方法及压气机

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JP7041033B2 (ja) 2022-03-23

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