US2045918A - Cavitation control means for blade periphery - Google Patents
Cavitation control means for blade periphery Download PDFInfo
- Publication number
- US2045918A US2045918A US704451A US70445133A US2045918A US 2045918 A US2045918 A US 2045918A US 704451 A US704451 A US 704451A US 70445133 A US70445133 A US 70445133A US 2045918 A US2045918 A US 2045918A
- Authority
- US
- United States
- Prior art keywords
- blade
- cavitation
- runner
- periphery
- groove
- 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.)
- Expired - Lifetime
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03B—MACHINES OR ENGINES FOR LIQUIDS
- F03B3/00—Machines or engines of reaction type; Parts or details peculiar thereto
- F03B3/04—Machines or engines of reaction type; Parts or details peculiar thereto with substantially axial flow throughout rotors, e.g. propeller turbines
- F03B3/06—Machines or engines of reaction type; Parts or details peculiar thereto with substantially axial flow throughout rotors, e.g. propeller turbines with adjustable blades, e.g. Kaplan turbines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03B—MACHINES OR ENGINES FOR LIQUIDS
- F03B11/00—Parts or details not provided for in, or of interest apart from, the preceding groups, e.g. wear-protection couplings, between turbine and generator
- F03B11/006—Sealing arrangements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03B—MACHINES OR ENGINES FOR LIQUIDS
- F03B11/00—Parts or details not provided for in, or of interest apart from, the preceding groups, e.g. wear-protection couplings, between turbine and generator
- F03B11/04—Parts or details not provided for in, or of interest apart from, the preceding groups, e.g. wear-protection couplings, between turbine and generator for diminishing cavitation or vibration, e.g. balancing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/20—Hydro energy
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S415/00—Rotary kinetic fluid motors or pumps
- Y10S415/914—Device to control boundary layer
Definitions
- This invention relates generally to improved' means for reducing or eliminating cavitation at the periphery of unshrouded blades of rotary hydraulic machines, such as hydraulic turbines or pumps, although the invention is especially described in its application to turbines.
- Cavitation has been one of the major problems with rotary hydraulic machines, and various arrangements and solutions have heretofore been proposed for controlling or eliminating cavitation at those parts of the equipment where cavitation is most likely to occur.
- My present invention has particular reference to the cavitation at the periphery of unshrouded runner blades, and it is one object of my invention to provide improved means for reducingcavitation at this point. A further object is to provide a relatively simple arrangement which will not only function to reduce cavitation but.
- a more specific object of the invention is to provide improved means whereby a double pressure reduction occurs as water flows through the clearance space around the runner periphery, the peripheral portion of the blades being recessed to deliberately provide a region of eddy currents at a point Where cavitation most likely occurs.
- Fig. 1 is a diagrammatic vertical sectional view of one form of propeller runner embodying my invention
- Fig. 2 is an enlarged fragmentary sectional view of a blade and a surrounding passage wall showing the manner in which internal eddy currents are formed at the periphery between the face and back surfaces of the blade;
- Fig. 3 is a modified arrangement of peripheral grooves whereby three pressurereductions occur
- Fig. 4 is a further modification of the peripheral grooves whereby the length of each narrow clearance passage is reduced to zero by the use of triangular grooves.
- each of the several runner blades 8 The 10 runner may, of course, be of any usual form whether of the axial or diagonal flow type or-it may have adjustable or non-adjustable blades. In any case, however, the peripheraledge of the blades is provided with a groove or slot generally indicated at 9. This groove may extend for the full peripheral length of each blade as diagrammatically indicated by line 9a. or may as shown at to in Fig. l terminate slightly short of the leading and trailing edges it and II respectively. 2
- This peripheral groove may be of any sufiicient depth to accomplish its purpose, but it is preferably of suflicient depth that the inner surface l3 is not within the range of the eddy currents indicated within the groove by arrows in Fig. 2.
- the groove may be made more shallow, while at the same time obtaining the general advantages of my improved o arrangement.
- the ratio of the depth of groove to the width of clearance shouldbe at least 2 to 1, or in another aspect, the groove should have a width at least equal to its depth.
- the surface I3 may if desired be positioned clear of the region of high velocity and intense eddy currents within groove 9, thus reedge of the blade, although as previously pointed out this surface may be moved nearer to the blade periphery and due to the pressure built up within the groove caused by the double reduction at clearances I4 and I5, cavitation will be materially controlled without excessivee detrimental effects.
- the grooves are made triangular, cutting away all or nearly all of the parallel narrow clearance passage, and controlling the leakage flow entirely by a series of enlargements.
- the peripheral surface a subject to cavitation has been eliminated, the flow being required to pass a series of relatively sharpcorners where the velocity past the corner is made to enter an enlarged chamber in which a part of its kinetic energy is dissipated eddies without harmful effects.
- L'A hydraulic machine having a runner and inlet and outlet passages therefor wherein water pressures above and belowatmosphere normally exist on opposite sides of the runner, said runner having a hub and a series of separate unshrouded propeller blades projecting from said hub at spaced points on a circle thereof, and each of said blades being provided with a normally peripheral groove formed as a recess between the 10 front and back blade surfaces to control cavitation at the blade peripheries.
- a hydraulic propeller type turbine having an unshrouded propeller runner disposed within a passage which comprises an inlet and draft tube and has a wall immediately surrounding the runner periphery with clearance therebetwee the peripheral edge of said runner blades having a normally open groove therein providing a recessed peripheral surface disposed entirely be-' tween the face and back surfaces of the blade,
- said recessed surface being set back from the region of high velocity leakage flow passing through said clearance.
- a rotary hydraulic'machine having unshrouded blades, a stationary passage wall im-
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Hydraulic Turbines (AREA)
Description
June so, 1936. F DY 2,045,918
CAVITATION CONTROL MEANS FOR BLADE PERIPHERY Filed Dec. 29. 1935 INVENTOR LFMooafy Patented June 30, 1936 4 PATENT OFFICE CAVITATION CONTROL MEANS FOR BLADE PERIPHERY,
Lewis Ferry Moody, Princeton, N. ',I., assignor to Baldwin-Southwark Corporation, a corporation of Delaware Application December 29, 1933, Serial No. 704,451
4 Claims. (01. 253-117) This invention relates generally to improved' means for reducing or eliminating cavitation at the periphery of unshrouded blades of rotary hydraulic machines, such as hydraulic turbines or pumps, although the invention is especially described in its application to turbines.
Cavitation has been one of the major problems with rotary hydraulic machines, and various arrangements and solutions have heretofore been proposed for controlling or eliminating cavitation at those parts of the equipment where cavitation is most likely to occur.
My present invention has particular reference to the cavitation at the periphery of unshrouded runner blades, and it is one object of my invention to provide improved means for reducingcavitation at this point. A further object is to provide a relatively simple arrangement which will not only function to reduce cavitation but.
also reduce leakage between the runner periphery and the surrounding stationary passage wall.
A more specific object of the invention is to provide improved means whereby a double pressure reduction occurs as water flows through the clearance space around the runner periphery, the peripheral portion of the blades being recessed to deliberately provide a region of eddy currents at a point Where cavitation most likely occurs.
- Specifically this is accomplished by slotting the peripheral edge of the runner blades while maintaining the normal peripheral clearance at' the face and back of the blades.
Other objects and advantages will be more apparent to those skilled in the art from. the following description of the accompanying drawing in which:
Fig. 1 is a diagrammatic vertical sectional view of one form of propeller runner embodying my invention;
Fig. 2 is an enlarged fragmentary sectional view of a blade and a surrounding passage wall showing the manner in which internal eddy currents are formed at the periphery between the face and back surfaces of the blade;
Fig. 3 is a modified arrangement of peripheral grooves whereby three pressurereductions occur;
Fig. 4 is a further modification of the peripheral grooves whereby the length of each narrow clearance passage is reduced to zero by the use of triangular grooves.
In the particular embodiment of the invention which is disclosed herein merely for the purpose of illustrating one specific form of the invention among possible others that it might take, I have diagrammatically shown a conventional type of rotary hydraulic machine specifically a turbine having a head cover I, adjustable inlet guide vanes 2, a transition space 3 inwhich thewater'is turned from a radial toward an axial direction to flow through an unshrouded runner generally; 5 indicated at 4. This runner is disposed within a suitable passage 5 whose stationary wall 6pref= erably, but not necessarily, of cylindrical form,
has a close running clearance with the periphery m,
'l of each of the several runner blades 8. The 10 runner may, of course, be of any usual form whether of the axial or diagonal flow type or-it may have adjustable or non-adjustable blades. In any case, however, the peripheraledge of the blades is provided with a groove or slot generally indicated at 9. This groove may extend for the full peripheral length of each blade as diagrammatically indicated by line 9a. or may as shown at to in Fig. l terminate slightly short of the leading and trailing edges it and II respectively. 2
This peripheral groove may be of any sufiicient depth to accomplish its purpose, but it is preferably of suflicient depth that the inner surface l3 is not within the range of the eddy currents indicated within the groove by arrows in Fig. 2. However, if the design of the runner blades is such that a groove of the foregoing depth cannot 'be conveniently used, then the groove may be made more shallow, while at the same time obtaining the general advantages of my improved o arrangement. Preferably the ratio of the depth of groove to the width of clearance shouldbe at least 2 to 1, or in another aspect, the groove should have a width at least equal to its depth.
As a consequence of my improved arrangement it is seen that a double clearance is provided, one at M and the other at l5,'with the result that the hydraulic fluid will undergo one loss of head due to sudden enlargement in passing through clearance It into groove 9 and a second loss of head 40 in passing from groove 9 through clearance l5 to the draft tube 5. At each point of enlargement velocity head is dissipated in eddies, thus reducing the efi'ective head causing the leakage flow. Hence there is a material reduction in the velocity and leakage of the fluid through the peripheral clearance and this is accompanied by a lower velocity and higher pressure within groove 9 than would occur if the peripheral edge of the blade were straight or continuouswith only a single pressure reduction. Also by my improved arrangement the surface I3 may if desired be positioned clear of the region of high velocity and intense eddy currents within groove 9, thus reedge of the blade, although as previously pointed out this surface may be moved nearer to the blade periphery and due to the pressure built up within the groove caused by the double reduction at clearances I4 and I5, cavitation will be materially controlled without excesive detrimental effects.
In the modification shown in Fig. 3, I have multiplied the effect of theFig; 2 form by providing a pair of grooves l6 and I1, thereby providing pressure reductions at clearances i8, i9 and 20. This modified arrangement is applicable where the runner blade thickness is sufficient to permit the use of two or even more grooves. Near the ends of the blade periphery where the blade is relatively thin, one of the grooves may terminate and a single gro ve continue.
In the modiflcatiom of Fig. 4, the grooves are made triangular, cutting away all or nearly all of the parallel narrow clearance passage, and controlling the leakage flow entirely by a series of enlargements. Here the peripheral surface a subject to cavitation has been eliminated, the flow being required to pass a series of relatively sharpcorners where the velocity past the corner is made to enter an enlarged chamber in which a part of its kinetic energy is dissipated eddies without harmful effects.
From the foregoing disclosure it is seen that I have provided an extremely simple and yet very effective means for reducing or eliminating cavitation at the blade periphery, this being accomplished without weakening the blade in any way and at Y the same time reducing the leakage through the clearance space. The reduction of the velocity of leakage flow through clearance It reduces the tendency toward cavitation on the under side of the blade near the peripheral edge due to the eddy produced by this leakage flow as it leaves the clearance space.
It will of course be understood that various changes in details of construction and arrange-.
ment of parts may be made by those skilled in the art without departing from the spirit of the invention as set forth in the appended claims.
I claim:
L'A hydraulic machine having a runner and inlet and outlet passages therefor wherein water pressures above and belowatmosphere normally exist on opposite sides of the runner, said runner having a hub and a series of separate unshrouded propeller blades projecting from said hub at spaced points on a circle thereof, and each of said blades being provided with a normally peripheral groove formed as a recess between the 10 front and back blade surfaces to control cavitation at the blade peripheries.
2. The combination set forth in claim'l further characterized in that said blade peripheries are each provided with a plurality of grooves thereby to eflect mutiple contractions and enlargements of the passage for leakage flow between the runner periphery and surrounding passage wall.
3. A hydraulic propeller type turbine having an unshrouded propeller runner disposed within a passage which comprises an inlet and draft tube and has a wall immediately surrounding the runner periphery with clearance therebetwee the peripheral edge of said runner blades having a normally open groove therein providing a recessed peripheral surface disposed entirely be-' tween the face and back surfaces of the blade,
to control cavitation at the blade periphery, said recessed surface being set back from the region of high velocity leakage flow passing through said clearance.
4. A rotary hydraulic'machine having unshrouded blades, a stationary passage wall im-
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US704451A US2045918A (en) | 1933-12-29 | 1933-12-29 | Cavitation control means for blade periphery |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US704451A US2045918A (en) | 1933-12-29 | 1933-12-29 | Cavitation control means for blade periphery |
Publications (1)
Publication Number | Publication Date |
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US2045918A true US2045918A (en) | 1936-06-30 |
Family
ID=24829542
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US704451A Expired - Lifetime US2045918A (en) | 1933-12-29 | 1933-12-29 | Cavitation control means for blade periphery |
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US (1) | US2045918A (en) |
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2751187A (en) * | 1953-12-08 | 1956-06-19 | English Electric Co Ltd | Feathering runner vane type hydraulic turbines and pumps |
US4050845A (en) * | 1975-09-30 | 1977-09-27 | Kraftwerk Union Aktiengesellschaft | Device for stabilizing the position of rotors of large steam turbines |
US5951162A (en) * | 1997-03-14 | 1999-09-14 | General Signal Corporation | Mixing impellers and impeller systems for mixing and blending liquids and liquid suspensions having efficient power consumption characteristics |
US5997251A (en) * | 1997-11-17 | 1999-12-07 | General Electric Company | Ribbed turbine blade tip |
WO2000020109A1 (en) * | 1998-10-01 | 2000-04-13 | General Signal Corporation | Mixing impeller system |
US6334705B1 (en) * | 1998-10-01 | 2002-01-01 | General Signal Corporation | Fluid mixing impellers with shear generating venturi |
WO2004051078A1 (en) * | 2002-11-29 | 2004-06-17 | Voith Siemens Hydro Power Generation Gmbh & Co. Kg | Water turbine |
FR3026428A1 (en) * | 2014-09-30 | 2016-04-01 | Snecma | RADIANT TURBOMACHINE TURBOMACHINE ROTOR BEARD |
JP2019007374A (en) * | 2017-06-21 | 2019-01-17 | 株式会社東芝 | Runner of movable blade water turbine, discharge ring of movable blade water turbine, and movable blade water turbine |
JP2019199801A (en) * | 2018-05-14 | 2019-11-21 | 株式会社東芝 | Runner vane and axial flow hydraulic machine |
US20200116160A1 (en) * | 2018-10-15 | 2020-04-16 | Asia Vital Components (China) Co., Ltd. | Fan blade unit and fan impeller structure thereof |
CN112065629A (en) * | 2020-08-06 | 2020-12-11 | 西安理工大学 | Method for detecting clearance cavitation primary of through-flow turbine |
DE102022114339B3 (en) | 2022-06-08 | 2023-06-01 | Voith Patent Gmbh | Turbine with swiveling rotor blades |
DE102022132483B3 (en) | 2022-12-07 | 2024-02-29 | Voith Patent Gmbh | Process for producing a rotor blade |
-
1933
- 1933-12-29 US US704451A patent/US2045918A/en not_active Expired - Lifetime
Cited By (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2751187A (en) * | 1953-12-08 | 1956-06-19 | English Electric Co Ltd | Feathering runner vane type hydraulic turbines and pumps |
US4050845A (en) * | 1975-09-30 | 1977-09-27 | Kraftwerk Union Aktiengesellschaft | Device for stabilizing the position of rotors of large steam turbines |
US5951162A (en) * | 1997-03-14 | 1999-09-14 | General Signal Corporation | Mixing impellers and impeller systems for mixing and blending liquids and liquid suspensions having efficient power consumption characteristics |
US5997251A (en) * | 1997-11-17 | 1999-12-07 | General Electric Company | Ribbed turbine blade tip |
EP0916811A3 (en) * | 1997-11-17 | 2000-08-23 | General Electric Company | Ribbed turbine blade tip |
WO2000020109A1 (en) * | 1998-10-01 | 2000-04-13 | General Signal Corporation | Mixing impeller system |
US6250797B1 (en) * | 1998-10-01 | 2001-06-26 | General Signal Corporation | Mixing impeller system having blades with slots extending essentially all the way between tip and hub ends thereof which facilitate mass transfer |
US6334705B1 (en) * | 1998-10-01 | 2002-01-01 | General Signal Corporation | Fluid mixing impellers with shear generating venturi |
WO2004051078A1 (en) * | 2002-11-29 | 2004-06-17 | Voith Siemens Hydro Power Generation Gmbh & Co. Kg | Water turbine |
FR3026428A1 (en) * | 2014-09-30 | 2016-04-01 | Snecma | RADIANT TURBOMACHINE TURBOMACHINE ROTOR BEARD |
JP2019007374A (en) * | 2017-06-21 | 2019-01-17 | 株式会社東芝 | Runner of movable blade water turbine, discharge ring of movable blade water turbine, and movable blade water turbine |
JP2019199801A (en) * | 2018-05-14 | 2019-11-21 | 株式会社東芝 | Runner vane and axial flow hydraulic machine |
US20200116160A1 (en) * | 2018-10-15 | 2020-04-16 | Asia Vital Components (China) Co., Ltd. | Fan blade unit and fan impeller structure thereof |
US11473591B2 (en) * | 2018-10-15 | 2022-10-18 | Asia Vital Components (China) Co., Ltd. | Fan blade unit and fan impeller structure thereof |
CN112065629A (en) * | 2020-08-06 | 2020-12-11 | 西安理工大学 | Method for detecting clearance cavitation primary of through-flow turbine |
CN112065629B (en) * | 2020-08-06 | 2022-01-07 | 西安理工大学 | Method for detecting clearance cavitation primary of through-flow turbine |
DE102022114339B3 (en) | 2022-06-08 | 2023-06-01 | Voith Patent Gmbh | Turbine with swiveling rotor blades |
DE102022132483B3 (en) | 2022-12-07 | 2024-02-29 | Voith Patent Gmbh | Process for producing a rotor blade |
WO2024120742A1 (en) * | 2022-12-07 | 2024-06-13 | Voith Patent Gmbh | Method for producing a rotor blade |
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