US3851994A - Blading for axial flow turbo-machine - Google Patents
Blading for axial flow turbo-machine Download PDFInfo
- Publication number
- US3851994A US3851994A US00323094A US32309473A US3851994A US 3851994 A US3851994 A US 3851994A US 00323094 A US00323094 A US 00323094A US 32309473 A US32309473 A US 32309473A US 3851994 A US3851994 A US 3851994A
- Authority
- US
- United States
- Prior art keywords
- blade
- twist
- axis
- rotor
- blading
- 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
Links
Images
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
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/12—Blades
- F01D5/14—Form or construction
- F01D5/141—Shape, i.e. outer, aerodynamic form
Definitions
- the object of this invention is to provide a twisted blade strurcture in which the amount of twist will remain the same, i.e., both at-standstill and during operation. This objective is attained by selecting the degree vision need be made for any potential changes in shape of the blade during operation. 7
- FIG. I is aschematic presentation of a twisted blade illustrating the nature of the centrifugal forces acting upon it under dynamic conditions
- FIG. 2 is a view similar to FIG. 1 but wherein the blade is straight; i.e., non-twistedi I
- FIG. 3 illustrates a blade of the twist type when at rest, i.e., under static conditions;
- FIG. 4 illustrates a twisted blade constructed in accordance with the principles of this invention.
- the tip 1 which represents a thinsection of a turbine blade having an airfoil profile.
- the leading and trailing edges of the blade are designated by 2 and 3, respectively.
- the tip 1 is secured to pin 5 which is located vertically to the axis of rotation 6, and thus in a radial direction.
- Centrifugal forces acting upon the masses in the center of the mass exert a pull in the axial direction of the pin and are designated by vector 4-7.
- the centrifugal forces which originate from the masses at point 2 are depicted by a radial vector 2-8 which intersects the axis 'of rotation 6 vertically. Since point 2 is staggered in the peripheral direction in relation to point 4, the forces 2-8 and 4-7 are not parallel.
- Vector 2-8 can be resolved into two components, one such component 2-9 being parallel to vector 4-7, and the other component 9-8 perpendicular to the latter andfunctioning in a tangential direction.
- the radial forces 3-10 can be resolved into two components, one such component 3-11 being parallel to vector 4-7 and the other component I1-l0perpendicular to the latter.
- Those components which are 'parallel to the vector 4-7 will form a resultant which exerts a purely tensional force upon the pin 5 if, as stipulated, point 4 represents the center of mass for the tip 1. Under the same conditions will the perpendicular vector components exert a purely torsional force onto the pin 5.
- FIG. 2 shows a rotor 12 upon which is fastened a circumferential array of blading.
- the blade is not twisted about its longitudinal axis and it has a constant cross-sectional profile throughout its entire length.
- the axis 14 of the center of mass is located radially to the axis of rotation 6.
- FIG. 3 shows a blade which has a sharp twist
- the blade being in the rest, i.e., when the .rotor is at standstill.
- the forces generated on the turbine blade are not parallel to each other, and are not perpendicular, but rather are inclined to the axis of rotation 6.
- the blades 16 tend to straighten out under the influence of the centrifugal forces, and to assume a position perpendicular to the axis of rotation, thus tending to untwist the blade, in known manner, in the direction of the arrows 17.
- FIG. 4 illustrates an embodiment of a blade structured in accordance with the invention.
- the blade made of metal, is connected to the rotor 12 along the path 19-20-21. It is designedin the form of a control wing where all of the force generating vectors 19-22, 20-23 and 21-24 are located in a radial direction, that is to say, they intersect the axis of rotation 6 at an angle of It will be readily apparent that such a blade structure can not and'will not change its shape by twisting or untwisting when subjected to centrifugal forces during rotation of the rotor.
- the invention is not limited to the specific blade design illustrated in FIG. 4 but rather other configurations may be adopted by which the same result can be obtained.
- the thickness or the length of the cord of the profile diminishes from within to without.
- B is the angle between the principal inertia axis and the circumferential direction.
- dB/dr is the degree of blade twist
- T is the resultant torsion moment of the blade part from the distance r to the end of the blade P is the resultant tension force of this part of the blade A is the cross-sectional area of the profile
- I 1 are the maximum and minimum moments of inertia of the blade profile
- the shape of the blade can deviate somewhat in actual practice from the theoretical shape as defined by the above equation if a slight correction is indicated for purposes of flow-engineering.
- dB/dr is the degree of blade twist
- T is the resultant torsion moment of the blade part from the distance r to the end of the blade P is the resultant tension force of this part of the blade A is the cross-sectional area of the profile.
- l 1 are the maximum and minimum moments of inertia of the blade profile thereby maintaining constant the amount of the blade twist under the influence of centrifugal forces acting thereon when the motor is operating.
- Turbine blading as defined in claim 1 wherein all centrifugal force generating vectors along the surface of the blade between its leading and trailing edges extend in a radial direction from the axis of rotation of the rotor.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
Turbine blading for the rotors of turbo-machines of the axialflow type in which the blades are twisted to allow for a high ratio of external to internal diameter of the flow passageway, the amount of the twist being so selected that it will neither untwist nor increase its twist when subjected to the centrifugal forces which act on the blade when the rotor is operating.
Description
inited States Patent 1 91 Seippel I Dec. 3, 1974 BLADING FOR AXIAL FLOW TURBO-MACHINE [75] Inventor: Claude Seippel, Zurich, Switzerland [73] Assignee: BBC Brown Boveri & Company Limited, Baden, Switzerland [22] Filed: Jan, 12, 1973 [21] Appl. No.: 323,094
[30] I Foreign Application Priority Data Jan. 20, 1972 Switzerland 76772/72 52 us. 01. 416/223, 416/243 2 [51] Int. Cl. F01d 5/14 [58] Field of Search 416/223, 242, 243
[56] References Cited UNITED STATES PATENTS 2,116,055 5/1938 Weichwald 416/223 2,928,653 3/1960 Roberson 416/210 x FOREIGN PATENTS OR APPLICATIONS 1,187,872 3 1959 France 416/240 131,648 9/1919 Great Britain 416 240 614,074 12/1948 Great Britain 416/240 I Primary ExaminerEverette A. Powell, Jr. Attorney, Agent, or Firm-Pierce, Scheffler 8L Parker [57] ABSTRACT Turbine blading for the rotors of turbo-machines of the axial-flow type in which the blades are twisted to allow for a high ratio of external to internal diameter of the flow passageway, the amount of the twist being so selected that it will neither untwist nor increase its twist when subjected to the centrifugal forces which act on the blade when the rotor is operating.
2 Claims, 4 Drawing Figures BLADING FOR AXIAL FLOW TURBO-MACHINE locities which occur along the face of the blade between its root and tip. Experience has shown, however, that such twisted blades will tend to untwist due to the longitudinal pull exerted thereon as a result of the centrifugal forces to which the blade is subjected as it rotates at rather high speeds, with the result that the amount of the twist will differ, depending upon whether the rotor, and hence the blading is rotating, or at standstill. This will result not only in some uncertainty as to the aerodynamic effect of the blading, especially during the startingperiod, and also at lower speeds, but also in the generation of additional stresses which will be superimposed on the alreadyhigh centrifugal as well as bending stresses.
The object of this invention is to provide a twisted blade strurcture in which the amount of twist will remain the same, i.e., both at-standstill and during operation. This objective is attained by selecting the degree vision need be made for any potential changes in shape of the blade during operation. 7
The invention'will become more apparent from the following description of a preferred embodiment thereof and in conjunction with the accompanying drawings wherein:
' FIG. I is aschematic presentation of a twisted blade illustrating the nature of the centrifugal forces acting upon it under dynamic conditions,
FIG. 2 is a view similar to FIG. 1 but wherein the blade is straight; i.e., non-twistedi I FIG. 3 illustrates a blade of the twist type when at rest, i.e., under static conditions; and
FIG. 4illustrates a twisted blade constructed in accordance with the principles of this invention.
With reference now to FIG. I, there is shown the tip 1 which represents a thinsection of a turbine blade having an airfoil profile. The leading and trailing edges of the blade are designated by 2 and 3, respectively. At the center of mass 4, the tip 1 is secured to pin 5 which is located vertically to the axis of rotation 6, and thus in a radial direction. Centrifugal forces acting upon the masses in the center of the mass. exert a pull in the axial direction of the pin and are designated by vector 4-7. The centrifugal forces which originate from the masses at point 2, are depicted by a radial vector 2-8 which intersects the axis 'of rotation 6 vertically. Since point 2 is staggered in the peripheral direction in relation to point 4, the forces 2-8 and 4-7 are not parallel. Vector 2-8 can be resolved into two components, one such component 2-9 being parallel to vector 4-7, and the other component 9-8 perpendicular to the latter andfunctioning in a tangential direction. In the same manner, theradial forces 3-10 can be resolved into two components, one such component 3-11 being parallel to vector 4-7 and the other component I1-l0perpendicular to the latter. Those components which are 'parallel to the vector 4-7 will form a resultant which exerts a purely tensional force upon the pin 5 if, as stipulated, point 4 represents the center of mass for the tip 1. Under the same conditions will the perpendicular vector components exert a purely torsional force onto the pin 5.
FIG. 2 shows a rotor 12 upon which is fastened a circumferential array of blading. However, in order to simplify the disclosure only one such blade 13 has been included. The blade is not twisted about its longitudinal axis and it has a constant cross-sectional profile throughout its entire length. The axis 14 of the center of mass is located radially to the axis of rotation 6. When this blade system is rotated rapidly, the blades will stretch longitudinally and, as explained on the basis of FIG. 1, will twist in the direction of the arrows 15.
FIG. 3 shows a blade which has a sharp twist, the
blade being in the rest, i.e., when the .rotor is at standstill. The forces generated on the turbine blade are not parallel to each other, and are not perpendicular, but rather are inclined to the axis of rotation 6. During operationof the blading, the blades 16 tend to straighten out under the influence of the centrifugal forces, and to assume a position perpendicular to the axis of rotation, thus tending to untwist the blade, in known manner, in the direction of the arrows 17.
In accordance with the novel concept of this invention, the twist imparted to the blade is such that the twistingand untwisting forces just neutralize one another. FIG. 4 illustrates an embodiment of a blade structured in accordance with the invention. The blade, made of metal, is connected to the rotor 12 along the path 19-20-21. It is designedin the form of a control wing where all of the force generating vectors 19-22, 20-23 and 21-24 are located in a radial direction, that is to say, they intersect the axis of rotation 6 at an angle of It will be readily apparent that such a blade structure can not and'will not change its shape by twisting or untwisting when subjected to centrifugal forces during rotation of the rotor.
The invention is not limited to the specific blade design illustrated in FIG. 4 but rather other configurations may be adopted by which the same result can be obtained. For example, in contrast to the blade configuration depicted in FIG. 4, the thickness or the length of the cord of the profile diminishes from within to without.
The principle which determines the extent of the blade twist can be expressed by the equation dB/dr T/P All, I; wherein r is the axial pitch of any blade section on which the following values are based.
B is the angle between the principal inertia axis and the circumferential direction.
dB/dr is the degree of blade twist T is the resultant torsion moment of the blade part from the distance r to the end of the blade P is the resultant tension force of this part of the blade A is the cross-sectional area of the profile, and
I 1 are the maximum and minimum moments of inertia of the blade profile The shape of the blade can deviate somewhat in actual practice from the theoretical shape as defined by the above equation if a slight correction is indicated for purposes of flow-engineering.
I claim:
1. The improvement in turbine blading for the rotor of a turbo-machine of the axial-flow type wherein for the purpose of allowing a high ratio of external to internal diameter of the flow passageway each of the blades is given a twist about its horizontal axis which is determined at least approximately in accordance with the equation dB/dr T/P A/l 1 wherein r is the axial pitch of any blade section on which the following values are based. B is the angle between the principal inertia axis and the circumferential direction.
dB/dr is the degree of blade twist T is the resultant torsion moment of the blade part from the distance r to the end of the blade P is the resultant tension force of this part of the blade A is the cross-sectional area of the profile. and
l 1 are the maximum and minimum moments of inertia of the blade profile thereby maintaining constant the amount of the blade twist under the influence of centrifugal forces acting thereon when the motor is operating.
2. Turbine blading as defined in claim 1 wherein all centrifugal force generating vectors along the surface of the blade between its leading and trailing edges extend in a radial direction from the axis of rotation of the rotor.
Claims (2)
1. The improvement in turbine blading for the rotor of a turbomachine of the axial-flow type wherein for the purpose of allowing a high ratio of external to internal diameter of the flow passageway each of the blades is given a twist about its horizontal axis which is determined at least approximately in accordance with the equation d Beta /dr T/P . A/I1 + I2 wherein r is the axial pitch of any blade section on which the following values are based. Beta is the angle between the principal inertia axis and the circumferential direction. d Beta /dr is the degree of blade twist T is the resultant torsion moment of the blade part from the distance r to the end of the blade P is the resultant tension force of this part of the blade A is the cross-sectional area of the profile, and I1, I2 are the maximum and minimum moments of inertia of the blade profile thereby maintaining constant the amount of the blade twist under the influence of centrifugal forces acting thereon when the motor is operating.
2. Turbine blading as defined in claim 1 wherein all centrifugal force generating vectors along the surface of the blade between its leading and trailing edges extend in a radial direction from the axis of rotation of the rotor.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CH76772A CH541065A (en) | 1972-01-20 | 1972-01-20 | Twisted rotor blade of a turbomachine with an axial flow |
Publications (1)
Publication Number | Publication Date |
---|---|
US3851994A true US3851994A (en) | 1974-12-03 |
Family
ID=4194695
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00323094A Expired - Lifetime US3851994A (en) | 1972-01-20 | 1973-01-12 | Blading for axial flow turbo-machine |
Country Status (3)
Country | Link |
---|---|
US (1) | US3851994A (en) |
CH (1) | CH541065A (en) |
FR (1) | FR2168797A5 (en) |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4120609A (en) * | 1976-06-14 | 1978-10-17 | Wallace Murray Corporation | Sheet metal fan |
US4284388A (en) * | 1975-11-03 | 1981-08-18 | Polska Akademia Nauk, Instytut Maszyn Przeplywowych | Moving blade for thermic axial turbomachines |
US4585395A (en) * | 1983-12-12 | 1986-04-29 | General Electric Company | Gas turbine engine blade |
US4682935A (en) * | 1983-12-12 | 1987-07-28 | General Electric Company | Bowed turbine blade |
US5044885A (en) * | 1989-03-01 | 1991-09-03 | Societe Nationale D'etude Et De Construction De Moteurs D'aviation "S.N.E.C.M.A." | Mobile blade for gas turbine engines providing compensation for bending moments |
US5167489A (en) * | 1991-04-15 | 1992-12-01 | General Electric Company | Forward swept rotor blade |
US6338609B1 (en) * | 2000-02-18 | 2002-01-15 | General Electric Company | Convex compressor casing |
EP1331360A2 (en) * | 2002-01-18 | 2003-07-30 | ALSTOM (Switzerland) Ltd | Arrangement of vane and blade aerofoils in a turbine exhaust section |
WO2009126996A1 (en) * | 2008-04-14 | 2009-10-22 | Atlantis Resources Corporation Pte Limited | Blade for a water turbine |
US20110210548A1 (en) * | 2007-11-23 | 2011-09-01 | Conrad Sevenster | Control system for extracting power from water flow |
US8633609B2 (en) | 2008-04-14 | 2014-01-21 | Atlantis Resources Corporation Pte Limited | Sub sea central axis turbine with rearwardly raked blades |
US8664790B2 (en) | 2009-04-28 | 2014-03-04 | Atlantis Resources Corporation Pte Limited | Underwater power generator with dual blade sets |
US8920200B2 (en) | 2009-10-27 | 2014-12-30 | Atlantis Resources Corporation Pte | Connector for mounting an underwater power generator |
US20150337664A1 (en) * | 2012-12-13 | 2015-11-26 | Nuovo Pignone Srl | Turbomachine blade, corresponding turbomachine and method of manufacturing a turbine blade |
US9568009B2 (en) | 2013-03-11 | 2017-02-14 | Rolls-Royce Corporation | Gas turbine engine flow path geometry |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1993015321A1 (en) * | 1992-01-23 | 1993-08-05 | Tovarischestvo S Ogranichennoi Otvetstvennostju 'varion' | Axial fan |
RU2450166C1 (en) * | 2010-08-30 | 2012-05-10 | Открытое акционерное общество "Ракетно-космическая корпорация "Энергия" имени С.П. Королева" | Axial ventilator |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB131648A (en) * | ||||
US2116055A (en) * | 1936-01-17 | 1938-05-03 | Weichwald John | Propeller |
GB614074A (en) * | 1946-07-02 | 1948-12-09 | Aubrey Lawrence Collins | Improvements in or relating to fans |
FR1187872A (en) * | 1957-10-18 | 1959-09-17 | Rotary airfoil blade | |
US2928653A (en) * | 1955-12-22 | 1960-03-15 | Gen Electric | Variable angle blade for fluid flow machines |
-
1972
- 1972-01-20 CH CH76772A patent/CH541065A/en not_active IP Right Cessation
-
1973
- 1973-01-12 US US00323094A patent/US3851994A/en not_active Expired - Lifetime
- 1973-01-17 FR FR7301548A patent/FR2168797A5/fr not_active Expired
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB131648A (en) * | ||||
US2116055A (en) * | 1936-01-17 | 1938-05-03 | Weichwald John | Propeller |
GB614074A (en) * | 1946-07-02 | 1948-12-09 | Aubrey Lawrence Collins | Improvements in or relating to fans |
US2928653A (en) * | 1955-12-22 | 1960-03-15 | Gen Electric | Variable angle blade for fluid flow machines |
FR1187872A (en) * | 1957-10-18 | 1959-09-17 | Rotary airfoil blade |
Cited By (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4284388A (en) * | 1975-11-03 | 1981-08-18 | Polska Akademia Nauk, Instytut Maszyn Przeplywowych | Moving blade for thermic axial turbomachines |
US4120609A (en) * | 1976-06-14 | 1978-10-17 | Wallace Murray Corporation | Sheet metal fan |
US4585395A (en) * | 1983-12-12 | 1986-04-29 | General Electric Company | Gas turbine engine blade |
US4682935A (en) * | 1983-12-12 | 1987-07-28 | General Electric Company | Bowed turbine blade |
US5044885A (en) * | 1989-03-01 | 1991-09-03 | Societe Nationale D'etude Et De Construction De Moteurs D'aviation "S.N.E.C.M.A." | Mobile blade for gas turbine engines providing compensation for bending moments |
US5167489A (en) * | 1991-04-15 | 1992-12-01 | General Electric Company | Forward swept rotor blade |
US6338609B1 (en) * | 2000-02-18 | 2002-01-15 | General Electric Company | Convex compressor casing |
EP1331360A2 (en) * | 2002-01-18 | 2003-07-30 | ALSTOM (Switzerland) Ltd | Arrangement of vane and blade aerofoils in a turbine exhaust section |
EP1331360A3 (en) * | 2002-01-18 | 2004-08-18 | ALSTOM (Switzerland) Ltd | Arrangement of vane and blade aerofoils in a turbine exhaust section |
US20110210548A1 (en) * | 2007-11-23 | 2011-09-01 | Conrad Sevenster | Control system for extracting power from water flow |
CN102066744A (en) * | 2008-04-14 | 2011-05-18 | 亚特兰蒂斯能源有限公司 | Blade for a water turbine |
US20110176915A1 (en) * | 2008-04-14 | 2011-07-21 | Atlantis Resources Corporation Pte Ltd. | Blade for a water turbine |
WO2009126996A1 (en) * | 2008-04-14 | 2009-10-22 | Atlantis Resources Corporation Pte Limited | Blade for a water turbine |
US8633609B2 (en) | 2008-04-14 | 2014-01-21 | Atlantis Resources Corporation Pte Limited | Sub sea central axis turbine with rearwardly raked blades |
CN102066744B (en) * | 2008-04-14 | 2014-07-23 | 亚特兰蒂斯能源有限公司 | Blade for a water turbine |
US8801386B2 (en) | 2008-04-14 | 2014-08-12 | Atlantis Resources Corporation Pte Limited | Blade for a water turbine |
US8664790B2 (en) | 2009-04-28 | 2014-03-04 | Atlantis Resources Corporation Pte Limited | Underwater power generator with dual blade sets |
US8920200B2 (en) | 2009-10-27 | 2014-12-30 | Atlantis Resources Corporation Pte | Connector for mounting an underwater power generator |
US20150337664A1 (en) * | 2012-12-13 | 2015-11-26 | Nuovo Pignone Srl | Turbomachine blade, corresponding turbomachine and method of manufacturing a turbine blade |
US9568009B2 (en) | 2013-03-11 | 2017-02-14 | Rolls-Royce Corporation | Gas turbine engine flow path geometry |
Also Published As
Publication number | Publication date |
---|---|
CH541065A (en) | 1973-08-31 |
FR2168797A5 (en) | 1973-08-31 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US3851994A (en) | Blading for axial flow turbo-machine | |
US4105363A (en) | Overspeed control arrangement for vertical axis wind turbines | |
US3795462A (en) | Vibration dampening for long twisted turbine blades | |
US2435236A (en) | Superacoustic compressor | |
US4415312A (en) | Transverse axis fluid turbine | |
US2510734A (en) | Turbine or compressor rotor | |
US3536417A (en) | Impeller for axial or radial flow compressors | |
US4798519A (en) | Compressor part span shroud | |
US20090123276A1 (en) | Steam turbine | |
US9051839B2 (en) | Supersonic turbine moving blade and axial-flow turbine | |
US3059834A (en) | Turbo rotor | |
CA2196481C (en) | Steam turbine | |
US9546555B2 (en) | Tapered part-span shroud | |
US3069070A (en) | Diffuser vane system for turbomachinery | |
JP6842563B2 (en) | Centrifugal rotary machine impeller and centrifugal rotary machine | |
US3870434A (en) | Gear arrangement for variable pitch fan | |
US3719432A (en) | Articulated sleeve for turbine bucket lashing | |
US3871791A (en) | Blade for fluid flow machines | |
JPS6090992A (en) | Spiral blade type vertical shaft windmill | |
US4083655A (en) | Turbine rotor | |
US3771922A (en) | Stabilized rotary blades | |
US2944729A (en) | Induction and discharge means for effective camber control | |
US3627447A (en) | Radial turbines | |
US3677662A (en) | Multilayer ring damped turbomachine rotor assembly | |
FR2300233A1 (en) | Windmill with variable pitch blades - pitch of blade is automatically reduced as wind force increases |