US2962258A - Slotted vane turbine governor - Google Patents

Description

Nov. 29, 1960 2,962,258

W. A. WAGNER SLOTTED VANE TURBINE GOVERNOR Filed March 51, 1958 SPRING TLRBIN SPEED INVENTOR.

WILLIAM A. WAGNER I point.

storrnn VANE TURBINE GOVERNOR William A. Wagner, Sepulveda, Calif., assignor to The Marquardt Corporation, a corporation of California Filed Mar. 31, 1958, Ser. No. 724,987

8 Claims. (Cl. 25359) This invention relates to slotted vane turbine governors and more particularly to slotted vanes which produce a minimum aerodynamic load on the governor mechanism for controlling the vanes.

As illustrated in United States Patent No. 2,815,188, granted December 3, 1957, to Dwight D. Nelson, ram air turbines have utilized vanes moved by a governor mechanism to vary the mass flow through a ram air turbine to control the speed. Since the vanes assume various angles of attack relative to the air flow through the turbine, a variable aerodynamic load is transmitted to the governor mechanism. This aerodynamic vane load at any given position of the vane together with the force of the fiyballs and the spring force determine the operating characteristic of the governor. Since the aerodynamic vane load is not constant throughout the control speed range but increases with increase in angle of attack of the vanes, it is difficult to obtain a governor spring which can compensate for the variable vane load in order to provide proper governor control.

The present invention utilizes slots in the governor vanes to spoil the lift of the vanes and thus prevent the development of highly variable vane loads on the governor. While the vane loads developed by the slotted vanes may increase slightly with increased angleof the vanes, this increase can be easily compensated for by, the selection of a governor spring which will substantially reduce the governing band. The slotted vanes are moved directly by the fiyballs which act against the governor spring and the vanes control the air flow through the ram air turbine to control the speed of the turbine. The vanes are pivotally mounted for angular movement and a slot can be placed in each vane upstream of the pivot The size and angle of the slot and the location of the slot in each vane can be varied for each particular application.

It is therefore an object of the present invention to provide slotted governor vanes for a turbine in order to minimize the aerodynamic loads of the governor vanes.

Another object of the invention is to provide a governor for a ram air turbine in which slotted vanes are utilized to control air flow through the turbine in order to regulate its speed.

These and other objects of the invention will become readily apparent from the accompanying description and drawings in which:

Figure 1 is a side elevational view, partly in section, showing a ram air turbine and slotted governor vanes;

Figure 2 is an end elevational view of the ram air turbine along line 22 of Figure l;

Figure 3 is a horizontal section along line 3-3 of Figure 1 illustrating the slotted governor vanes;

Figure 4 is an end elevational view of one of the' governor vanes; and

Figure 5 is a graphic illustration of the aerodynamic vane load resulting from slotted governor vanes.

Referring to the embodiment of the invention chosen States PatentO 2,962,258 Paftented Nov. 29, 1960 ice I for illustration, the ram air turbine 10 can be supported in any suitable manner for insertion into the air in order to produce power. The turbine comprises a cup shaped stationary housing 11 having a central, hollow projection 12. A turbine shaft 13 extends through projection 12 and is supported for rotation by bearings 14 and 15 located between the projection and the shaft. A reduced end of shaft 13 extends through a rotor hub 16 to which is secured a plurality of turbine blades 17 by means of bolts 18. Also, the reduced end extends through back plate 19 of the nose section 20 and both the nose section and hub 16 are secured to shaft 13 by the nut 21. In assembled condition, the hub 16 and cylindrical sleeve 22 serve to retain the bearings 14 and 15. It is apparent that therotation of turbine blades 17 will cause rotation of shaft 13 and nose section 20. The end of shaft 13 opposite the rotor hub can be connected to any suitable power developing device, such as electrical generator or hydraulic pump, which is to be operated at substantial constant speed.

The side 23 of housing 11 contains a plurality of open ings 24 each of which contains a socket 25. Each socket 25 receives the ball end of a shaft 26, which extends through an opening 27 in one of the governor vanes 28 and is rigidly secured to the vane at locations 29 and 30. The opposite ball end of each shaft 26 is located in one of a plurality of sockets 31 located around the in groove 51. full lines in the fully open position in which the vanes circumference of ring 32. The ring 32 is supported by a plurality of struts 33 connected with the forward end of side 23 so as not to interfere with rotation ofthe turbine blades. 17 or angular movement of, governor vanes 28. Ring 32 and side 23 of housing 11 define an annular air passage 34 through which flows ram air in the direction indicated by the arrows of Figure l to drive the turbine blades 17.

An annular space 35 is located between projection 12 and side 23 and contains governor spring 36. One end of the spring bears against -a shim 37 located adjacent base 38 of housing 11 and the other end of the spring engages a slidable member 39. The base 38 and member 39 have grooves 40 and 41, respectively, which receive and position the ends of the spring. The member 39 also has cylindrical sliding surfaces 42 and 43 which engage projection 12 and side 23, respectively, and serve to guide the movement of member 39. An annular bearing 44 is located on member 39 and supports an angular member 45 for rotation, relative to member 39. The angular member 45 receives the force produced by a plurality of flyweights 46 which rotate with rotor hub 16. Each flyweight is located at one end or" an L- shaped arm 47 which is pivotally connected by a pin 48 to a set of lugs 49 carried by the rotor hub 16. The other end of each arm 47 carries a roller 50 which engages the angular member 45 and causes member 45 to rotatewith turbine hub 16. As the flyweights 46 move outwardly under the influence of centrifugal force, the rollers 50 move member 39 axially and compress spring 36.

The member 39contains an annular, circumferential groove 51 which slidably receives a pin 52 for each governor vane 28 and each pin projects through one of the openings 24 into a socket 53 in the inner end of one of the vanes. Referring to Figures 3 and 4, the inner end of-each vane 28 is reduced and carries an actuating arm 54 containing the socket 53. As member 39 is moved rearwardly by the flyweights, the pins 52 will pivot 'the governor vanes 28 about shafts 26 in a direc tion to reduce the area of passage 34. At the same time, the pins 52 will move in openings 24 and will slide In Figure 3, the vanes 28 are shown by are at a low angle of attack to the air flow. In the dotted line position of Figure 3, the pins 52 have been moved by the flyweights to increase the angle of attack of the vanes and reduced the flow area of passage 34.

Because of the location of shaft 26 in each of the vanes, the lift force on the vanes will produce a force tending to move the vanes in a direction to close passage 34 and thus the lift force acts with the force of the flyweights. Also, since each of the vanes is in the form of an airfoil, the lift of the vanes would normally increase substantially with increase in angle of attack. Such an increase in lift force or vane load would substantially effect the control characteristics of the governor since the force acting against the spring at overspeeds would be the sum of flyball forces and varying vane loads. In order to minimize the variations in lift force or vane load, a slot 55 is positioned behind the leading edge of each vane. The slots have the effect of spoiling the lift of the vane at all angles of attack so as to reduce the vane loads. As illustrated in Figure 3, the slots 55 are substantially transverse of the vanes and, at all angles of attack of the vanes, the slots permit air flow from one surface to the other surface of the vanes in a direction having an axial component. It is understood that the size and position of the slots, as well as the direction of the slots, can be varied to obtain the best results for any particular ram air turbine. Also, it is not necessary that every vane contain a slot or that the same shape of slot be utilized for every vane.

Referring to Figure 5, the governor forces are graphically illustrated as opening and closing forces on the vanes. The force of spring 36, as illustrated by curve A, is always in a direction to open the passages 34 while the vane load (curve B) and the flyweight force (curve C) arein a direction to close passage 34. As illustrated by curve D, the vane load for non-slotted vanes would increase rapidly and in an irregular manner over the speed range with accompanying variation in angle of attack. However, the curve B for slotted vanes illustrates that only a small increase in vane load results over the speed range and that this increase is at a substantially uniform rate so that the vane load can be easily compensated for in the design of the spring. The vane load curves B and D represent the combined forces on the vanes resulting from lift developed by the vane andfrom the fluid impact on the projected area of the vane presented to the air flow. It is understood that with some vane mounting, the vane loads could produce a vane closing force which would act with the spring force and against the flyball force.

In the operation of the ram air turbine, the governor will maintain a substantially constant speed of shaft 13 since overspeeding of the shaft will cause the flyweights to move the governor vanes in a direction to close the air passage 34. With the slotted vanes, the governor can be constructed for more accurate speed control. It is understood thatthe present invention can be utilized with various blade and governor constructions and with various turbine constructions which utilize air or any other suitable working fluid. Various other modifications are contemplated by those skilled in the art without departing from the spirit and scope of the invention as hereinafter defined by the appended claims.

What is claimed is:

1. In a ram air turbine having turbine blades located in an annular fluid passage, flyball means responsive to the speed of said turbine, means movable by said flyball means in response to a change in speed of said turbine, spring means operable upon said movable means for opposing movement of said movable means by said flyball means, a plurality of vanes in said passage having an airfoil shape, means for pivotally mounting said vanes, means connecting said vanes with said movable member for-pivotally moving said vanes to control the air flow through said passage and the speed of said turbine, and a slot in at least some of said vanes to spoil the lift thereof in order to minimize the aerodynamic vane load transmitted to said movable means.

2. In a ram air turbine as defined in claim 1 wherein said pivotal mounting means for each of said vanes comprises a shaft positioned radially in said passage, each of said vanes being located in a radial position in said passage and extending axially of said passage, the pivotal movement of said vanes causing a change in the angle of said vanes presented to the fluid flow through said passage.

3. In a turbine having blades located in a fluid passage and its speed controlled by a flyball mechanism operable against a governor spring, a plurality of airfoil vanes located in said passage and movable by said flyball mechanism to control the fluid flow through said passage and the speed of said turbine by varying the area of said passage, and a slot located in at least some of said vanes to spoil the lift thereof and cause the aerodynamic vane load transmitted to said flyball mechanism and spring combination to increase at a low, uniform rate during movement of said vanes to reduce the area of said passage.

4. In a turbine as defined in claim 3 wherein said vanes are located radially in said passage and extend lengthwise of the passage, means for pivotally mounting each of said vanes about an axis extending radially of said passage, said flyball mechanism causing pivotal movement of said vanes about said axis.

5. In a turbine as defined in claim 4 wherein said slots are positioned in said vanes at a location betvken said pivotal axis and the leading edge of the vanes.

6. In a turbine having blades located in a fluid passage, governor means connected with said blades and responsive to the speed of rotation of said blades, a plurality of airfoil vanes located in said passage and movable by said governor means to control the fluid flow through said passage and the speed of said turbine by varying the area of said passage, and an opening located in at least some of said vanes to spoil the lift thereof in order to minimize the aerodynamic vane load transmitted to said governor means during movement of said vanes to reduce the area of said passage.

7. In a turbine having radial blades located in an annular fluid passage, governor means connected with said blades and responsive to the speed of rotation of said blades, aplurality of airfoil vanes radially positioned in said passage and pivotally movable by said governor means to control the fluid flow through said passage and the speed of said turbine by varying the area of said passage, ,a slot in at least some of said vanes to spoil the lift thereof and cause the aerodynamic vane load transmitted to said governor mechanism to increase at a low, uniform rate during angular movement of said vanes to .reduce the area of said passage.

8. In a turbine as defined in claim 7 having a radially positioned pivotal axis for each vane located intermediate the leading and trailing edge of each vane, said slots being positioned in said vanes at a location between said pivotal axis and the leading edge.

References Cited in the file of this patent UNITED STATES PATENTS 1,808,464 Huiskamp June 2, 1931 2,045,383 Faber June 23, 1936 2,073,318 Peel Mar. 9, 1937 2,135,887 Fairey Nov. 8, 1938 2,340,417 Ellett Feb. 1, 1944 2,749,025 Stalker June 5, 1956 2,815,188 Nelson Dec. 3, 1957 FOREIGN PATENTS 7545056 Great Britain Aug. 1, 1956 764,686 Germany Mar. 30, 1-953 1,081,514 France June -9, 1954

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