Rotary kinetic fluid motors or pumps – Selectively adjustable vane or working fluid control means – Upstream of runner
Reexamination Certificate
1999-02-26
2001-09-04
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
Selectively adjustable vane or working fluid control means
Upstream of runner
C415S162000, C415S914000
Reexamination Certificate
active
06283705
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the aerodynamic performance of a gas turbine engine variable vane. More particularly, in one embodiment of the present invention a winglet is attached to one end of a variable vane so as to reduce end wall losses resulting from air leakage from the high pressure to the low-pressure side of the airfoil. Although, the present invention was developed for use in a gas turbine engine, certain applications may be outside of this field.
It is well known in the gas turbine engine field that the performance of the engine over its cycle may be improved by utilizing variable position airfoils within various portions of the engine. By way of example, some engines utilize variable vanes in the compressor section of the engine in order to provide improved performance at off-design operating conditions. The variable vanes rotate between a relatively closed position under low power conditions and a fully open position under full power conditions. The clearance between the vanes and the walls of the flow passageway allows leakage from the high-pressure side to the low-pressure sides of the vane which has an adverse effect upon engine performance. Larger clearances cause greater losses in performance.
Vanes are often classified according to their aspect ratio which defines a relationship between the vane's radial span and its chordal span. A conventional high aspect ratio variable vane comprises an airfoil, a boss/button, a spindle, and a rotational axis. The boss/button provides a structural transition from the airfoil to the spindle, and covers the inner diameter end and outer diameter end of the airfoil. The coverage of the ends is desirable since it minimizes endwall losses due to leakage flow at the endwall gap between the vanes and the walls of the flow passageway.
As compression system technology level increases, the airfoil aspect ratio typically decreases. A variable vane having a reduced aspect ratio results in reduced coverage by the boss/button at the airfoil inner diameter end and airfoil outer diameter end. The reduction in coverage is a result of geometric limits on button diameter causing a higher percentage of the airfoil chord to have an endwall gap. Further, the reduced coverage by the button/boss of the airfoil often causes a decreased dynamic performance due to a decrease in airfoil stiffness. Therefore, as the airfoil aspect ratio decreases there is often a performance penalty, both aerodynamic and structurally.
Heretofore, there has been a need for a winglet for improving the aerodynamic performance of a gas turbine engine variable vane by reducing endwall losses resulting from fluid losses from the high pressure to the low-pressure side of the airfoil. The present invention satisfies this need in a novel and unobvious way.
SUMMARY OF THE INVENTION
One form of the present invention contemplates a gas turbine engine variable vane, comprising an airfoil having an outer surface extending spanwise between an inner end and an outer end and further extending streamwise between a leading edge and a trailing edge; a first button coupled to one of the ends of the airfoil; and a first winglet positioned along one of the ends of the airfoil and extending from the outer surface.
Another form of the present invention contemplates a gas turbine engine variable vane, comprising an airfoil with a pressure side and a suction side, the airfoil including opposed inner and outer ends and opposed upstream and downstream ends, and a rotational axis extending between the opposed inner and outer ends; a first boss mounted to the inner end; and a first winglet formed with the first boss and mounted to the inner end of the airfoil, wherein the winglet is configured so as to reduce loss associated with a vortex flow caused by the leakage of a gas from the pressure side to the suction side of the airfoil by reducing the size of the vortex and forcing it away from the outer surface.
Yet another form of the present invention contemplates a gas turbine engine including a mechanical housing; a plurality of vanes disposed within a fluid flow path within the mechanical housing, each of the plurality of vanes comprising an airfoil with a pressure side and a suction side, the airfoil having an outer surface extending spanwise between an inner end and an outer end and further extending streamwise between a leading edge and a trailing edge, the airfoil having a rotational axis extending spanwise between the inner and outer ends; a boss coupled to the outer end of the airfoil; and a winglet running along one of the ends of the airfoil and extending from the outer surface, wherein the winglet does not extend past the leading edge of the airfoil.
One object of the present invention is to provide an improved variable vane with a winglet.
Related objects and advantages of the present invention will be apparent from the following description. dr
DESCRIPTION OF THE DRAWINGS
FIG. 1
illustrates an aircraft with a flight propulsion engine.
FIG. 2
illustrates the flight propulsion engine when it is a gas turbine engine.
FIG. 3
illustrates a conventional prior art high aspect ratio variable vane.
FIG. 4
illustrates a cross section taken along line
4
—
4
of the high aspect ratio variable vane of FIG.
3
.
FIG. 5
illustrates a cross section taken along line
5
—
5
of the high aspect ratio variable vane of FIG.
3
.
FIG. 6
illustrates a prior art low aspect ratio variable vane.
FIG. 7
is a perspective view of one embodiment of the present invention of a variable vane with a winglet on the pressure side of the airfoil.
FIG. 8A
is a different side perspective view of the variable vane with a winglet of FIG.
7
.
FIG. 8B
is a perspective view of an alternate embodiment of the present invention of a variable vane with a winglet on the suction side of the airfoil.
FIG. 8C
is a perspective view of another embodiment of the present invention of a variable vane with a winglet on the suction side and the pressure side of the airfoil.
FIG. 9
is a side view of the variable vane with a winglet of
FIGS. 7 and 8A
shown in place within an engine.
FIG. 10
is a side view of another embodiment of the present invention, a variable vane with two winglets, shown in place within an engine.
FIG. 11
is an illustrative view of a plurality of cantilevered variable vanes each with a winglet shown in place within an engine.
FIG. 12
is an illustrative view of another embodiment of the present invention, a plurality of cantilevered variable vanes each with two winglets.
FIG. 13
is a partial view of the variable vane with a winglet.
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patent: 4420288 (1983-12-01), Bischoff
patent: 4741665 (1988-05-01), Hanser
patent: 4768922 (1988-09-01), Kozak et al.
patent: 4867635 (1989-09-01), Tubbs
patent: 4978280 (1990-12-01), Tubbs
patent: 5215434 (1993-06-01), Greune et al.
patent: 5380152 (1995-01-01), Sikorski et al.
patent: 5466122 (1995-11-01), Charbonnel et al.
patent: 5492446 (1996-02-01), Hawkins et al.
Hansen Jeffrey Lister
Ress, Jr. Robert Anthony
Rice Edward Claude
Allison Advanced Development Company
Look Edward K.
Woo Richard
Woodard Emhardt Naughton Moriarty & McNett
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