WO2008082397A1 - Pertes réduites de jeu radial dans des ventilateurs à flux axial - Google Patents

Pertes réduites de jeu radial dans des ventilateurs à flux axial Download PDF

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Publication number
WO2008082397A1
WO2008082397A1 PCT/US2006/049627 US2006049627W WO2008082397A1 WO 2008082397 A1 WO2008082397 A1 WO 2008082397A1 US 2006049627 W US2006049627 W US 2006049627W WO 2008082397 A1 WO2008082397 A1 WO 2008082397A1
Authority
WO
WIPO (PCT)
Prior art keywords
blade
facing step
set forth
vane
casing
Prior art date
Application number
PCT/US2006/049627
Other languages
English (en)
Inventor
Peter R. Bushnell
Original Assignee
Carrier Corporation
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 Carrier Corporation filed Critical Carrier Corporation
Priority to PCT/US2006/049627 priority Critical patent/WO2008082397A1/fr
Priority to PCT/US2007/005551 priority patent/WO2008082428A1/fr
Priority to US12/521,314 priority patent/US8568095B2/en
Publication of WO2008082397A1 publication Critical patent/WO2008082397A1/fr

Links

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
    • F04D29/00—Details, component parts, or accessories
    • F04D29/08—Sealings
    • F04D29/16—Sealings between pressure and suction sides
    • F04D29/161—Sealings between pressure and suction sides especially adapted for elastic fluid pumps
    • F04D29/164—Sealings between pressure and suction sides especially adapted for elastic fluid pumps of an axial flow wheel

Definitions

  • This invention relates generally to axial flow fans and, more particularly, to a method and apparatus for reducing their clearance flow losses.
  • Axial flow fans are used in a wide variety of applications, including
  • the rotor may utilize conventional blades that extend outward with blade tips approaching the casing, or it may utilize blades that include a rotating shroud attached to the blade tips. In either case backflow is driven from the high pressure side of the rotor to the suction side across the clearance gap, leading to reduced performance, increased noise level and reduced stability and stall-margin.
  • a sharp, forward facing step is provided in the fan casing which, when combined with an overlapping rearward facing step in the fan blade tips, tends to disrupt the backflow so as to thereby restrict clearance flow loss.
  • each of the blades has an attached vane on its suction side, with the vanes having a rearward facing step that overlaps the casing forward facing step.
  • FIG. 1 is a perspective view of an axial fan assembly in accordance with the present invention.
  • FIG. 2 is an enlarged view of a portion thereof.
  • FIGS. 3A and 3B are respective front and end views of a normal blade tip.
  • FIG. 3C is an axial cross sectional view thereof in relationship to the casing.
  • FIGS. 4A and 4B are respective front and end views of a blade tip with a step in accordance with the present invention.
  • FIGS. 5 A and 5B are respective front and end views of a blade tip with a vane in accordance with the present invention.
  • FIG. 6 is a suction side view of a blade tip and vane in accordance with the present invention.
  • FIG. 7 is a pressure side view of a blade tip and vane in accordance with the present invention.
  • FIG. 8 is a radially inward view of a blade tip and vane in accordance with the present invention.
  • FIG. 9 is an axial cross sectional view of the Figs. 4A and 4B embodiment of the blade tip in relationship to the casing.
  • FIG. 10 is an axial cross sectional view as seen along lines 10-10 of
  • FIG- 11 is an axial cross sectional view as seen along lines 11-11 of
  • FIG. 12 is a partial view thereof showing the flow of air therein.
  • FIG. 13 is an axial cross sectional view of the apparatus as shown in
  • the invention is shown generally at 10 as applied to an axial fan assembly 11 that includes in serial airflow relationship an axial fan 12 and a stator 13.
  • the axial fan 12 includes a rotatable hub 14 and a plurality of fan blades 16.
  • the stator 13 includes a stationary hub and a plurality of radially extending stationary vanes 17 having their radially outer ends integrally connected to a cylindrical outer housing 18.
  • the fan 12 is rotated at relatively high speeds to induce the flow of air through the casing 18, and in the process it creates a swirl in the direction of the fan rotation.
  • the stator vanes 17 are so disposed and shaped as to substantially remove the swirl from the main airflow stream such that the flow at the downstream end is substantially axial in direction.
  • the dimensions of the axial fan 12 are such that the radial clearance between the ends of the fan blades 16 and the inner diameter of the casing 18 are as small as possible but without engagement between the two elements. Because of this necessary radial clearance, there is a tendency for the air within the casing 18 to flow back through the radial gap to the forward side of the fan 12. This results directly in reduced pressure rise and efficiency.
  • the present invention is intended to significantly reduce the backfiow.
  • a normal blade is shown at 16A, with a generally planar tip being shown in Fig. 3B. That is, the blade tip is slightly curved to accommodate the curved inner diameter of the casing ISA, but is of a substantially constant radius throughout the length of the blade tip.
  • the blade tip of blade 16A in combination with a standard casing 18A is shown in Fig. 3C.
  • the blade 16B is shown to have a blade tip with a rearwardly facing (i.e. toward the downstream or pressure side of the blade 16B) step as shown at 19.
  • portion 21 of the blade tip nearest the leading edge is of one fixed radius and that portion 22 thereof nearest the trailing edge is of a constant reduced radius.
  • the face of the step 19 is generally planar in form and is aligned tangentially (i.e. normal to the fan axis).
  • FIG. 9 where the blade 16B is shown with its blade tip profile that includes the rearwardly extending step 19 and the leading edge portion 21 and trailing edge portion 22.
  • the casing 18B includes a matching forward facing step 23 which interconnects a larger radius portion 24 and a smaller radius portion 26 of the casing 18.
  • the forward facing step 23 is a generally planar surface and is aligned tangentially such that the rearwardly facing step 19 is generally parallel with and in close proximity to the fowardwardly facing step 23.
  • the blade tip leading edge portion 21 is closely radially spaced from the larger radius portion 24, and the trailing edge portion 22 of the blade tip is closely radially spaced from the smaller radius portion 26 of the casing 18. This combination is provided for the purpose of reducing the backflow and its associated swirl that would otherwise result in a normal blade tip and casing relationship as shown in Figs. 3 A and 3B.
  • a blade 16C is shown with a rearwardly facing step 19, leading edge portion 21 and trailing edge portion 22 as shown in Figs. 4 A and 4B.
  • the blade 16C is further modified to include a vane 27 which is attached to the suction side of the blade as shown in Fig. 2 and which forms part of the blade tip as shown in Figs. 5A and 5B.
  • the vane 27 can best be seen in Figs. 6, 7 and 8 where it is shown as being attached to the blade 16C.
  • Fig. 6 shows the blade 16 from the suction side
  • Fig. 7 shows it from the pressure side
  • Fig. 8 shows it from the radially inward direction as shown in Fig. 8.
  • the vane 27 forms a part of the blade tip and is placed approximately in the middle of the suction side of the blade 16C and extends approximately one-third of the way across.
  • the size and shape of the vane 27 can be selectively varied to meet the particular axial fan assembly and operating requirements.
  • An important feature of the vane 27 is that it too includes a rearwardly extending step 28 as will be seen in Fig. 7. This step 28 also interfaces with the forward facing step 23 of the casing 18B in a manner similar to the rearwardly facing step 19 of the blade tip as discussed hereinabove to provide a further reduction of backflow that would otherwise occur around the blade tips. This can be seen in Fig.
  • Fig. 10 is a sectional view through the stepped tip at a point forward of the vane 27, whereas Fig. 11 is a sectional view thereof at a point that includes both the stepped tip and the vane 27.
  • both the casing and the fan rotor are such that they can be produced using straight-pull tooling (e.g. injection molding or die casting).
  • straight-pull tooling e.g. injection molding or die casting.
  • the relationship of the stepped blade tip and casing produces a convoluted path for the tip clearance leakage flow, which is highly restrictive. The effect is essentially similar to a labyrinth seal where the backflow and recirculation is forced to turn abruptly multiple times. Each flow turning produces a pressure drop which then enables the flow system to withstand a higher differential pressure and a lower leakage loss.
  • Fig. 11 can be used as shown without the use of inlet bellmouth insert. It will operate similarly but will benefit from the further use of an inlet bellmouth insert 29 as shown in Fig. 13.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

L'invention concerne un ensemble ventilateur axial incluant une paroi de carter comportant un palier faisant face vers l'avant et un rotor de ventilateur comportant des pointes de pales, chacune comportant un palier faisant face vers l'arrière qui chevauche radialement le palier de carter de façon à réduire la perte de flux inverse du jeu dans l'ensemble. Une ailette est fixée sur le côté d'aspiration de chacune des pointes des pales, l'ailette comportant un palier faisant face vers l'arrière, lequel chevauche radialement le palier faisant face vers l'avant du carter afin de favoriser encore la réduction de flux inverse du jeu. Des variantes de l'invention incluent l'option d'une pièce supplémentaire de pavillon d'orifice d'entrée qui restreint encore le flux du jeu et de clavettes intégrées au palier de carter pour améliorer la stabilité de l'écoulement.
PCT/US2006/049627 2006-12-29 2006-12-29 Pertes réduites de jeu radial dans des ventilateurs à flux axial WO2008082397A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
PCT/US2006/049627 WO2008082397A1 (fr) 2006-12-29 2006-12-29 Pertes réduites de jeu radial dans des ventilateurs à flux axial
PCT/US2007/005551 WO2008082428A1 (fr) 2006-12-29 2007-03-02 Pertes d'espace d'extrémité réduites sur ventilateurs hélicoïdaux
US12/521,314 US8568095B2 (en) 2006-12-29 2007-03-02 Reduced tip clearance losses in axial flow fans

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2006/049627 WO2008082397A1 (fr) 2006-12-29 2006-12-29 Pertes réduites de jeu radial dans des ventilateurs à flux axial

Publications (1)

Publication Number Publication Date
WO2008082397A1 true WO2008082397A1 (fr) 2008-07-10

Family

ID=39588907

Family Applications (2)

Application Number Title Priority Date Filing Date
PCT/US2006/049627 WO2008082397A1 (fr) 2006-12-29 2006-12-29 Pertes réduites de jeu radial dans des ventilateurs à flux axial
PCT/US2007/005551 WO2008082428A1 (fr) 2006-12-29 2007-03-02 Pertes d'espace d'extrémité réduites sur ventilateurs hélicoïdaux

Family Applications After (1)

Application Number Title Priority Date Filing Date
PCT/US2007/005551 WO2008082428A1 (fr) 2006-12-29 2007-03-02 Pertes d'espace d'extrémité réduites sur ventilateurs hélicoïdaux

Country Status (1)

Country Link
WO (2) WO2008082397A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009140854A1 (fr) * 2008-05-22 2009-11-26 山东大学 Ventilateur centrifuge multifonction
WO2012025357A1 (fr) * 2010-08-23 2012-03-01 Rolls-Royce Plc Aube et soufflante correspondante
EP2538024A1 (fr) * 2011-06-24 2012-12-26 Alstom Technology Ltd Aube dans une turbomachine
CN107654420A (zh) * 2017-10-30 2018-02-02 广东美的制冷设备有限公司 空调器、轴流风机及其风道
US9885368B2 (en) 2012-05-24 2018-02-06 Carrier Corporation Stall margin enhancement of axial fan with rotating shroud

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4548548A (en) * 1984-05-23 1985-10-22 Airflow Research And Manufacturing Corp. Fan and housing
US5226783A (en) * 1990-07-30 1993-07-13 Usui Kokusai Sangyo Kaisha Ltd. Axial flow fan with centrifugal elements
US7004722B2 (en) * 2002-08-09 2006-02-28 Honda Giken Kogyo Kabushiki Kaisha Axial flow compressor

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5489186A (en) * 1991-08-30 1996-02-06 Airflow Research And Manufacturing Corp. Housing with recirculation control for use with banded axial-flow fans
US5577888A (en) * 1995-06-23 1996-11-26 Siemens Electric Limited High efficiency, low-noise, axial fan assembly
US6508624B2 (en) * 2001-05-02 2003-01-21 Siemens Automotive, Inc. Turbomachine with double-faced rotor-shroud seal structure

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4548548A (en) * 1984-05-23 1985-10-22 Airflow Research And Manufacturing Corp. Fan and housing
US5226783A (en) * 1990-07-30 1993-07-13 Usui Kokusai Sangyo Kaisha Ltd. Axial flow fan with centrifugal elements
US7004722B2 (en) * 2002-08-09 2006-02-28 Honda Giken Kogyo Kabushiki Kaisha Axial flow compressor

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009140854A1 (fr) * 2008-05-22 2009-11-26 山东大学 Ventilateur centrifuge multifonction
WO2012025357A1 (fr) * 2010-08-23 2012-03-01 Rolls-Royce Plc Aube et soufflante correspondante
EP2538024A1 (fr) * 2011-06-24 2012-12-26 Alstom Technology Ltd Aube dans une turbomachine
US9377029B2 (en) 2011-06-24 2016-06-28 General Electric Technology Gmbh Blade of a turbomachine
US9885368B2 (en) 2012-05-24 2018-02-06 Carrier Corporation Stall margin enhancement of axial fan with rotating shroud
CN107654420A (zh) * 2017-10-30 2018-02-02 广东美的制冷设备有限公司 空调器、轴流风机及其风道
CN107654420B (zh) * 2017-10-30 2024-04-09 广东美的制冷设备有限公司 空调器、轴流风机及其风道

Also Published As

Publication number Publication date
WO2008082428A1 (fr) 2008-07-10

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