Airfoils and airfoil assemblies with trailing edge features
An airfoil assembly for turbine engines is provided. The airfoil assembly includes a plurality of airfoils and an airfoil includes a first surface defining a pressure side and a second surface defining a suction side, a plurality of first chord sections defining at least one first chord length, a plurality of second chord sections defining at least one second chord length, and a plurality of wave-shaped projections extending along the trailing edge. The plurality of wave-shaped projections each define a wave peak and a wave trough. The wave-shaped projections have an amplitude that is a proportion of an average local chord length of the airfoil. The wave-shaped projections may be designed according to a relationship to power coefficient, fan pressure ratio, and/or thrust coefficient of a turbine engine to produce an airfoil with a sculpted trailing edge feature that reduces noise during operation of the turbine engine.
1 . An airfoil assembly comprising:
a plurality of airfoils, at least one airfoil of the plurality of airfoils including:
a first surface defining a pressure side opposite a second surface defining a suction side, the pressure side and the suction side each extending in an axial direction between a leading edge and a trailing edge, the pressure side and the suction side each extending in a radial direction between an inner root and an outer tip;
a plurality of first chord sections defining at least one first chord length, and a plurality of second chord sections defining at least one second chord length, the plurality of first chord sections extending from the leading edge to the trailing edge, and the plurality of second chord sections extending from the leading edge to the trailing edge; and
a plurality of wave-shaped projections extending along the trailing edge, each wave-shaped projection of the plurality of wave-shaped projections defining a wave peak and a wave trough, wherein adjacent wave-shaped projections define a peak-to-trough distance, the plurality of wave-shaped projections each characterized by an amplitude (L) that is half of the peak-to-trough distance and an average local chord length (c), a chord length being a distance from the leading edge to the trailing edge at a point in a streamwise direction;
wherein 0.005≤L/c≤−0.0027*C p +d P , for 0.0527≤d P ≤0.0727, and C p being a power coefficient defined by C p =P/(ρn 3 D 3 A) during subsonic cruise operation of an engine, where n=revolutions/second of the plurality of airfoils, ρ=air density, A is an annular area defined by the at least one airfoil,
A
=
π
(
r
T
(
L
E
)
2
-
r
H
(
L
E
)
2
)
,
where r T is a tip radius at the leading edge and r H is a hub radius at the leading edge of the at least one airfoil, D=diameter at the leading edge of the at least one airfoil, and P=power absorbed by the plurality of airfoils, for C p in a range from 1 to 10, inclusively;
wherein 0.005≤L/c≤0.07 for C p is in a range between but not including 0 to 1;
wherein the inner root includes an integral dovetail for mounting the at least one airfoil.
2 . The airfoil assembly of claim 1 , wherein at least one airfoil of the plurality of airfoils comprises a fan blade.
3 . The airfoil assembly of claim 1 , wherein at least one chord section of the plurality of first chord sections extends outward from the pressure side at the trailing edge, and at least one chord section of the plurality of second chord sections extends outward from the suction side at the trailing edge.
4 . The airfoil assembly of claim 1 , wherein at least one of the plurality of wave-shaped projections is a projection that is asymmetric about a wave peak of the projection or a wave trough of the projection.
5 . The airfoil assembly of claim 1 , wherein a radius of curvature of a wave peak of at least one of the plurality of wave-shaped projections is different than a radius of curvature of a wave trough of at least one of the plurality of wave-shaped projections.
6 . The airfoil assembly of claim 1 , wherein the plurality of wave-shaped projections is integrally formed with the trailing edge.
7 . The airfoil assembly of claim 1 , wherein L/c is not constant from the inner root to the outer tip of at least one of the plurality of airfoils.
8 . The airfoil assembly of claim 1 , wherein −0.0027*C p +0.0527≤L/c≤−0.0027*C p +0.0727, for C p in a range from 1 to 10, inclusively, and wherein 0.05≤L/c≤0.07, for C p in a range between but not including 0 to 1.
9 . The airfoil assembly of claim 1 , wherein 0.0527≤d P ≤0.0627.
10 . The airfoil assembly of claim 1 , wherein d P =0.0527.
11 . An airfoil assembly comprising:
a plurality of airfoils, at least one airfoil of the plurality of airfoils including:
a first surface defining a pressure side opposite a second surface defining a suction side, the pressure side and the suction side each extending in an axial direction between a leading edge and a trailing edge, the pressure side and the suction side each extending in a radial direction between an inner root and an outer tip;
a plurality of first chord sections defining at least one first chord length, and a plurality of second chord sections defining at least one second chord length, the plurality of first chord sections extending from the leading edge to the trailing edge, and the plurality of second chord sections extending from the leading edge to the trailing edge; and
a plurality of wave-shaped projections extending along the trailing edge, each wave-shaped projection of the plurality of wave-shaped projections defining a wave peak and a wave trough, wherein adjacent wave-shaped projections define a peak-to-trough distance, the plurality of wave-shaped projections each characterized by an amplitude (L) that is half of the peak-to-trough distance and an average local chord length (c), a chord length being a distance from the leading edge to the trailing edge at a point in a streamwise direction;
wherein 0.005≤L/c≤1/(B(FPR−1) 1/4 )≤0.07 for: 1.01<FPR<2, 35≤B≤200; and
wherein FPR is a fan pressure ratio for subsonic cruise operation of an engine defined by FPR=P T (TE)/P T (LE) where P T is a total pressure at the trailing edge and at the leading edge, respectively,
wherein the inner root includes an integral dovetail for mounting the at least one airfoil.
12 . The airfoil assembly of claim 11 , wherein at least one of the plurality of airfoils comprises a fan blade.
13 . The airfoil assembly of claim 11 , wherein a number of waves of the wave-shaped projections along the trailing edge, each wave being defined from a wave trough to an adjacent wave trough, is at least seven.
14 . The airfoil assembly of claim 11 , wherein B≥40.
15 . The airfoil assembly of claim 11 wherein B≥45.
16 . An airfoil assembly for a turbine engine having a fan with a plurality of fan blades, the airfoil assembly comprising:
a plurality of airfoils, at least one airfoil of the plurality of airfoils including:
a first surface defining a pressure side opposite a second surface defining a suction side, the pressure side and the suction side each extending in an axial direction between a leading edge and a trailing edge, the pressure side and the suction side each extending in a radial direction between an inner root and an outer tip;
a plurality of first chord sections defining at least one first chord length, and a plurality of second chord sections defining at least one second chord length, the plurality of first chord sections extending from the leading edge to the trailing edge, and the plurality of second chord sections extending from the leading edge to the trailing edge; and
a plurality of wave-shaped projections extending along the trailing edge, each wave-shaped projection of the plurality of wave-shaped projections defining a wave peak and a wave trough, wherein adjacent wave-shaped projections define a peak-to-trough distance, the plurality of wave-shaped projections each characterized by an amplitude (L) that is half of the peak-to-trough distance and an average local chord length (c), a chord length being a distance from the leading edge to the trailing edge at a point in a streamwise direction;
wherein 0.005<L/c≤−0.0171*C T +d T , for 0.0620≤d T ≤0.0820, and C T is a thrust coefficient of an engine at a Mach 0.25 takeoff condition defined by C T =T/(ρn 2 D 2 A) where n=revolutions/second of the plurality of airfoils, ρ=air density, A is the annular area defined by the at least one airfoil,
A
=
π
(
r
T
(
L
E
)
2
-
r
H
(
L
E
)
2
)
,
where r T is a tip radius at the leading edge and r H is a hub radius at the leading edge of the at least one airfoil, D=diameter at the leading edge of the at least one airfoil, T=thrust of a fan of the engine, for C T in a range from 0.7 to 3.6, inclusively,
wherein the inner root includes an integral dovetail for mounting the at least one airfoil.
17 . The airfoil assembly of claim 16 , wherein at least one of the plurality of airfoils comprises a fan blade.
18 . The airfoil assembly of claim 16 , wherein a number of waves of the wave-shaped projections along the trailing edge, each wave being defined from a wave trough to an adjacent wave trough, is at least seven.
19 . The airfoil assembly of claim 16 , wherein 0.0620≤d T ≤0.0720.
20 . The airfoil assembly of claim 16 , wherein d T =0.0620.