EP0198784A1 - Ensemble de pales fixes pour diffuseur à section variable - Google Patents

Ensemble de pales fixes pour diffuseur à section variable Download PDF

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Publication number
EP0198784A1
EP0198784A1 EP86630038A EP86630038A EP0198784A1 EP 0198784 A1 EP0198784 A1 EP 0198784A1 EP 86630038 A EP86630038 A EP 86630038A EP 86630038 A EP86630038 A EP 86630038A EP 0198784 A1 EP0198784 A1 EP 0198784A1
Authority
EP
European Patent Office
Prior art keywords
impeller
wall member
vane
angle
disposed
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.)
Withdrawn
Application number
EP86630038A
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German (de)
English (en)
Inventor
Jarso Mulugeta
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.)
Carrier Corp
Original Assignee
Carrier 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 Carrier Corp filed Critical Carrier Corp
Publication of EP0198784A1 publication Critical patent/EP0198784A1/fr
Withdrawn legal-status Critical Current

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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
    • F01D17/00—Regulating or controlling by varying flow
    • F01D17/10—Final actuators
    • F01D17/12—Final actuators arranged in stator parts
    • F01D17/14—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits
    • F01D17/141—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits by means of shiftable members or valves obturating part of the flow path
    • F01D17/143—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits by means of shiftable members or valves obturating part of the flow path the shiftable member being a wall, or part thereof of a radial diffuser
    • 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
    • F04D27/0246—Surge control by varying geometry within the pumps, e.g. by adjusting vanes
    • 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
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/44—Fluid-guiding means, e.g. diffusers
    • F04D29/441—Fluid-guiding means, e.g. diffusers especially adapted for elastic fluid pumps
    • F04D29/444—Bladed diffusers
    • 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
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/44—Fluid-guiding means, e.g. diffusers
    • F04D29/46—Fluid-guiding means, e.g. diffusers adjustable
    • F04D29/462—Fluid-guiding means, e.g. diffusers adjustable especially adapted for elastic fluid 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
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/44—Fluid-guiding means, e.g. diffusers
    • F04D29/46—Fluid-guiding means, e.g. diffusers adjustable
    • F04D29/462—Fluid-guiding means, e.g. diffusers adjustable especially adapted for elastic fluid pumps
    • F04D29/464—Fluid-guiding means, e.g. diffusers adjustable especially adapted for elastic fluid pumps adjusting flow cross-section, otherwise than by using adjustable stator blades
    • 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
    • F05D2250/50—Inlet or outlet
    • F05D2250/52—Outlet

Definitions

  • the present invention relates to centrifugal vapor compressors, and more particularly to a fixed vane arrangement in a variable width diffuser for the compressor wherein the vanes are angularly disposed relative to the impeller within a range of angles for providing relatively high operating efficiencies and high pressure recoveries over relatively large operating ranges in, for example, refrigeration and air conditioning systems.
  • Flow stabilization through a centrifugal vapor compressor is a major problem when the compressor is used in situations where the load on the compressor varies over a wide operating range.
  • the compressor inlet, impeller, and diffuser passage are designed to accommodate the maximum volumetric flow rate through the compressor.
  • the compressor inlet, impeller, and diffuser passage are designed to accommodate the maximum volumetric flow rate then flow through the compressor may be unstable when the volumetric flow rate is relatively low.
  • a range of slightly unstable flow is entered. In this slightly unstable range of flow there appears to be a partial reversal of flow in the diffuser passage which creates noise and lowers the efficiency of the compressor.
  • the compressor enters what is known as surge, wherein there are periodic complete flow reversals in the diffuser passage which lower the efficiency of the compressor and which may degrade the integrity of compressor components.
  • Another modification is to vary the width of the diffuser passage in response to the load on the compressor. Normally, this is done by use of a movable diffuser wall which axially moves across the diffuser passage to throttle vapor flow therethrough.
  • Yet another modification includes utilizing vanes in the diffuser passage, usually in conjunction with a movable wall.
  • Another object of the present invention is to provide a centrifugal compressor having an improved diffuser assembly.
  • Yet another object of the present invention is to provide a unique diffuser assembly including a movable diffuser wall and fixed vanes for providing high operating efficiencies and high pressure recoveries over a relatively large operating range.
  • a centrifugal machine including a casing, an impeller rotatably mounted in the casing for moving a fluid therethrough, and a variable width diffuser assembly comprising a stationary wall member and a spaced-apart movable wall member generally radially disposed about the impeller to form therebetween a fluid passage leading from the impeller.
  • the movable wall member is selectively movable relative to the stationary wall member, whereby the width of the fluid passage is selectively varied.
  • a plurality of vanes are circumferentially disposed in the fluid passage and continuously span the distance between the wall members as the movable wall member moves relative to the stationary wall member.
  • Each vane is angularly disposed in the fluid passage relative to the impeller such that each vane forms with an extended radius of the impeller passing through the vane an angle between about 73° to about 78°, whereby the impeller can be designed for any desired flow rate and yet maintain relatively high operating efficiencies and high pressure recoveries over a relatively large operating range.
  • a centrifugal compressor 10 including main casing 12 having an inlet 14 that directs the refrigerant into a rotating impeller 16 through a series of adjustable inlet guide vanes 18.
  • Impeller 16 is secured to drive shaft 20 by any suitable means to align impeller 16 along the axis of compressor 10.
  • Impeller 16 includes central hub 22 supporting a plurality of blades 24. Blades 24 are arranged to create passages therebetween that turn the incoming axial flow of refrigerant fluid in a radial direction and discharge the compressed refrigerant fluid from respective blade tips 26 into diffuser section 28.
  • Diffuser section 28 is generally circumferentially disposed about impeller 16 and functions to direct the compressed refrigerant fluid into a toroidal-shaped volute 30, which directs the compressed fluid to the compressor outlet (not shown).
  • Diffuser section 28 includes a radially disposed stationary wall 32 and radially disposed movable wall 34 which is spaced-apart from stationary wall 32. Movable wall 34 is arranged to move axially towards and away from stationary wall 32 to vary the width of diffuser passage 36 formed therebetween, thereby altering the operating characteristics of compressor 10 in regard to varying load demands or flow rates.
  • Movable wall 34 is secured to carriage 38 by screws 40 received through aligned openings (not shown) in movable wall 34 and carriage 38. Screws 40 draw movable wall 34 tightly against the front of carriage 38.
  • Carriage 38 is movably mounted in compressor 10 between shroud 42 and main casing 12. Movable wall 34 is accurately located by means of dowel pins (not shown) received in aligned holes (not shown) in movable wall 34 and carriage 38.
  • Carriage 38 is illustrated as being fully retracted against stop surface 44 of main casing 12 to open diffuser passage 36 to a maximum flow handling position.
  • Carriage 38 is securely fixed by screws 46 to a double-acting piston 48.
  • the piston may be driven by either gas or liquid, it shall be assumed for explanatory purposes that it is liquid actuated.
  • Piston 48 is slidably mounted between shroud 42 and main casing 12 so that it can move movable wall 34 by means of carriage 38 between the previously noted maximum flow position against stop surface 44 and a minimum flow position wherein the piston is brought against shroud wall 50.
  • a first expandable chamber 52 is provided between piston front wall 54 and casing wall surface 56. Delivering fluid under pressure into chamber 52 drives piston 48 toward stationary wall 32.
  • a second expandable chamber 58 is similarly located between piston back wall 60 and shroud wall 50. Directing fluid under pressure to chamber 58 causes piston 48 to be driven forward to increase the width of diffuser passage 36.
  • Fluid is delivered into chambers 52, 58 from a supply reservoir (not shown) by means of a pair of flow circuits.
  • the first flow circuit leading to chamber 52 includes channels 62, 64.
  • the second circuit includes channels 66, 68, 70 and 72 which act to deliver the drive fluid into chamber 58.
  • Channels 62-72 are formed by drilling communicating holes into the machine elements and plugging the holes where appropriate.
  • Channels 62, 66 are drilled one behind the other and thus appear as a single channel in Figure 1. Both channels 62, 66 are connected to supply lines 74 in any suitable manner.
  • a suitable control system 76 containing electrically actuated valves regulates the flow of the fluid into and out of expandable chambers 52, 58 to either move piston 48 towards or away from stationary wall 32.
  • a series of 0-ring seals 78 encircle piston 48 and prevent fluid from passing between chambers 52, 58.
  • Control system 76 controls the position of carriage 38 and thus movable wall 34 to vary the width of diffuser passage 36.
  • a plurality of fixed vanes 82 are disposed in passage 36 in any suitable manner, for example, by securement to stationary wall 32.
  • Vanes 82 may be of any suitable contour, such as NACA airfoils, and are equally spaced in passage 36 so as to be slidably received in complementary-shaped slots 84 in movable wall 34. Vanes 82 continuously span diffuser passage 36 regardless of its width as determined by the position of movable wall 34.
  • Critical to the present invention is the angular relationship between vanes 82 and extended radii of impeller 16.
  • Compressors generally have an operating range at which the compressor optimally operates. However, once outside this range, the compressor's efficiency decreases to a point that it is desirable, and possibly a necessity, to design and construct another compressor having better efficiencies in these other ranges. Thus, over a relatively large operating range, several compressors having different efficiencies may be required to provide high operating efficiencies throughout this relatively large operating range.
  • the diffuser setting vane angle is that angle formed between a chord line 88 (Fig. 2) of a vane 82 and an extended radius 90 of impeller 16 passing through the leading edge point 92 of a respective vane 82.
  • chord line is meant a straight line drawn between the leading edge point 92 and the trailing edge point 94 of a vane 82.
  • vanes 82 can be angularly disposed relative to respective impeller radii 90 within a critical range of angles independently of impeller design.
  • This critical range of angles is between about 73° to about 78°, as measured between a chord line 88 and an impeller radius 90. Further testing revealed that an angle of 76.6° between a chord line 88 and a radius 90 is the optimum value within the just-mentioned critical range of angles.
  • the impeller tip width can be appropriately designed and used for any desired flow rate.
  • each graph is a plot of the head factor versus the flow factor of the optimum performance curve 96 of a designed prototype compressor.
  • the head factor Y is defined as 1,000 times the ratio of the polytropic head to the square of the sonic velocity at compressor inlet conditions
  • flow factor X is defined as the ratio of the flow rate at compressor inlet conditions to the sonic velocity at compressor inlet conditions.
  • the Figures 3, 4, and 5 further include plotted performance curves of three different compressors, which differ physically in the design of their respective impellers.
  • the nominal pressure ratio and lift capability of the compressor of Figure 3 is less than the nominal pressure ratio and lift capability of the compressor of Figure 4; and the nominal pressure ratio and lift capability of the compressor of Figure 4 is less than the nominal pressure ratio and lift capability of the compressor of Figure 5.
  • optimum performance curve 96 is plotted with head factor versus flow factor and illustrates the desired or optimum performance of a designed compressor.
  • Plotted against optimum performance curve 96 are plotted performance curves A, B, C and D of a first compressor.
  • the diffuser setting vane angle was varied so as to determine which angle resulted in a plotted performance curve most closely paralleling optimum performance curve 96.
  • plotted performance curve D was obtained by setting the diffuser setting vane angle to about 66.2°.
  • plotted performance curves C and B were obtained by setting the diffuser setting vane angle to about 70.2° and about 73.2°, respectively.
  • plotted performance curve A resulted therefrom.
  • plotted performance curves B, C, and D do not closely parallel optimum performance curve 96
  • plotted performance curve A does closely parallel curve 96.
  • plotted performance curve A is obtained by a selected diffuser setting vane angle, it is next desired to modify the first compressor so that plotted performance curve A overlies optimum performance curve 96 as closely as possible. This can be accomplished by appropriately designing the impeller tip width for the first compressor.
  • plotted performance curve A' was obtained from a diffuser setting vane angle of about 76.6°
  • plotted performance curve B' from a diffuser setting vane angle of about 73.2°
  • plotted performance curve E from a diffuser setting vane angle of about 78.0°.
  • the plotted performance curve of the second compressor of Figure 4 most closely parallels optimum performance curve 96 with a diffuser setting vane angle of about 76.6°.
  • the second compressor of Figure 4 is then optimally designed to approach optimum performance curve 96 by appropriately designing the impeller tip width so that plotted performance curve A' overlies curve 96 as closely as possible.
  • plotted performance curve A" was obtained from a diffuser setting vane angle of about 76.6°
  • plotted performance curve B" from a diffuser setting vane angle of about 73.2°
  • plotted performance curve F from a diffuser setting vane angle also of about 73.2°.
  • plotted performance curve that most nearly parallels optimum performance curve 96 is that plotted performance curve resulting from a diffuser setting vane angle of about 76.6°. Again, diffuser setting vane angles less than about 73° and greater than about 78° resulted in even more undesirable plotted performance curves.
  • Plotted performance curve A" can now be made to overlie as closely as possible optimum performance curve 96 by appropriately designing the impeller tip width.
  • the diffuser setting vane angle is substantially independent of design pressure ratios or flows created by impellers. Further, when the diffuser setting vane angle of vanes 82 are within the critical range of angles of about 73° to about 78°, the impeller tip width can be appropriately designed to maximize the increase in head for a given decrease in flow rate. The optimum performance of a compressor design in accordance with the principles of the present invention is obtained when the diffuser setting vane angle is about 76.6°.
  • centrifugal compressor 10 designed as described above having the angular relationship between vanes 82 and impeller 16 will have high efficiencies and high pressure recoveries in a relatively large operating range.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
EP86630038A 1985-03-15 1986-03-06 Ensemble de pales fixes pour diffuseur à section variable Withdrawn EP0198784A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US71205785A 1985-03-15 1985-03-15
US712057 1985-03-15

Publications (1)

Publication Number Publication Date
EP0198784A1 true EP0198784A1 (fr) 1986-10-22

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ID=24860621

Family Applications (1)

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EP86630038A Withdrawn EP0198784A1 (fr) 1985-03-15 1986-03-06 Ensemble de pales fixes pour diffuseur à section variable

Country Status (2)

Country Link
EP (1) EP0198784A1 (fr)
JP (1) JPS61218795A (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2211246A (en) * 1987-12-23 1989-06-28 Sundstrand Corp Controlling fluid flow through centrifugal pump
GB2234295A (en) * 1989-07-21 1991-01-30 Rolls Royce Plc Gas turbine engine compressor assembly
EP0484111A1 (fr) * 1990-10-30 1992-05-06 Carrier Corporation Compresseur centrifugal avec diffuseur tubulaire et collecteur
EP0688398A1 (fr) * 1994-01-12 1995-12-27 Dresser-Rand Company Diffuseur a ailettes
CN103225627A (zh) * 2012-01-26 2013-07-31 株式会社Ihi 旋转机械及离心压缩机
CN107002709A (zh) * 2014-12-02 2017-08-01 三菱重工业株式会社 压缩机、具备这种压缩机的增压器及压缩机的喷口通道宽度调整方法
US11415148B2 (en) 2018-04-09 2022-08-16 Carrier Corporation Variable diffuser drive system

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR682818A (fr) * 1928-10-05 1930-06-03 Perfectionnements apportés aux hélices, pompes et ventilateurs
US2996996A (en) * 1958-01-20 1961-08-22 Sulzer Ag Radial diffuser for a radial turbomachine
US4378194A (en) * 1980-10-02 1983-03-29 Carrier Corporation Centrifugal compressor

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1138616B (it) * 1980-10-02 1986-09-17 Carrier Corp Compressore centrifugo

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR682818A (fr) * 1928-10-05 1930-06-03 Perfectionnements apportés aux hélices, pompes et ventilateurs
US2996996A (en) * 1958-01-20 1961-08-22 Sulzer Ag Radial diffuser for a radial turbomachine
US4378194A (en) * 1980-10-02 1983-03-29 Carrier Corporation Centrifugal compressor

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2211246A (en) * 1987-12-23 1989-06-28 Sundstrand Corp Controlling fluid flow through centrifugal pump
GB2234295A (en) * 1989-07-21 1991-01-30 Rolls Royce Plc Gas turbine engine compressor assembly
US5059091A (en) * 1989-07-21 1991-10-22 Rolls-Royce Plc Gas turbine engine compressor assembly
GB2234295B (en) * 1989-07-21 1993-07-21 Rolls Royce Plc Gas turbine engine compressor assembly
EP0484111A1 (fr) * 1990-10-30 1992-05-06 Carrier Corporation Compresseur centrifugal avec diffuseur tubulaire et collecteur
EP0688398A1 (fr) * 1994-01-12 1995-12-27 Dresser-Rand Company Diffuseur a ailettes
EP0688398A4 (fr) * 1994-01-12 1998-07-29 Dresser Rand Co Diffuseur a ailettes
CN103225627A (zh) * 2012-01-26 2013-07-31 株式会社Ihi 旋转机械及离心压缩机
CN107002709A (zh) * 2014-12-02 2017-08-01 三菱重工业株式会社 压缩机、具备这种压缩机的增压器及压缩机的喷口通道宽度调整方法
US11415148B2 (en) 2018-04-09 2022-08-16 Carrier Corporation Variable diffuser drive system

Also Published As

Publication number Publication date
JPS61218795A (ja) 1986-09-29

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Inventor name: MULUGETA, JARSO