Turbine engine with composite airfoils
A turbine engine with an engine core defining an engine centerline and comprising a rotor and a stator. The turbine engine including a set of composite airfoils circumferentially arranged about the engine centerline and defining at least a portion of the rotor. An airfoil in the set of composite airfoils including a composite portion extending chordwise between a composite leading edge and a trailing edge and a leading edge protector coupled to the composite portion.
1 . A turbine engine comprising:
a fan;
a turbomachine comprising a compressor section, a combustor in fluid communication with the compressor section, and a turbine section in fluid communication with the combustor;
a speed reduction device driven by the turbine section and configured for rotating the fan; and
composite airfoils comprising at least one composite fan blade and at least one composite outlet guide vane downstream from the at least one composite fan blade;
wherein an airfoil of the composite airfoils comprises:
a composite body extending chordwise from a body leading edge to a body trailing edge, and
a leading edge protector having a protector leading edge different from the body leading edge and the leading edge protector receiving at least a portion of the body leading edge,
wherein a leading length (LL) extends chordwise from the protector leading edge to an end of the leading edge protector, and a chord length (CL) extends chordwise from the protector leading edge to the body trailing edge, and
wherein the LL is related to the CL by an airfoil protection factor
(
APF
)
=
(
LL
)
(
CL
)
;
and a first APF (APF1) for the at least one composite fan blade is greater than or equal to 0.2 and less than or equal to 0.30 (0.2≤APF1≤0.3) and a second APF (APF2) for the at least one composite outlet guide vane is greater than or equal to 0.08 and less than or equal to 0.17 (0.08≤APF2≤0.17); and
wherein at least one component of the turbine engine comprises a composite material having at least one toughened region comprising a toughened resin having a fracture toughness of at least 1.0 MPa-m 1/2 .
2 . The turbine engine of claim 1 , further comprising a fan casing and wherein the at least one component comprises the fan casing.
3 . The turbine engine of claim 2 , further comprising at least one toughened flange coupled to the at least one toughened region wherein the toughened flange is selected from the group consisting of mounting flanges, attachment end flanges, and combinations thereof.
4 . The turbine engine of claim 2 , further comprising at least one untoughened region and a transition region between the at least one toughened region and the at least one untoughened region.
5 . The turbine engine of claim 4 , wherein the at least one untoughened region includes untoughened resin.
6 . The turbine engine of claim 5 , wherein the untoughened resin, having a fracture toughness less than 1.0 MPa-m 1/2 , comprises a resin selected from the group consisting of vinyl ester resins, polyester resins, acrylic resins, epoxy resins, polyurethane resins, bismaelimide resins, polyimide resins, and combinations thereof.
7 . The turbine engine of claim 1 , wherein the composite material comprises a material selected from the group consisting of carbon fiber, glass fiber, ceramic fiber, graphite fiber, aramid fiber, and combinations thereof.
8 . The turbine engine of claim 1 , wherein the composite body is the at least one component having the at least one toughened region.
9 . The turbine engine of claim 1 , wherein the APF1 relates to the APF2 by an expression:
APF
1
APF
2
to define a stage protection factor (SPF), and wherein the SPF is greater than or equal to 0.7 and less than or equal to 4 (0.7≤SPF≤4).
10 . The turbine engine of claim 9 , wherein the SPF is greater than or equal to 0.95 and less than or equal to 2.5 (0.95≤SPF≤2.5).
11 . The turbine engine of claim 9 , wherein the at least one composite fan blade extends spanwise between a first root and a first tip to define a first span length and the at least one composite outlet guide vane extends spanwise between a second root and a second tip to define a second span length and the SPF is determined at a location between 20% and 80% of the first span length and the second span length, inclusive of endpoints.
12 . The turbine engine of claim 1 , wherein the speed reduction device is a power gearbox.
13 . The turbine engine of claim 1 , wherein a bypass ratio is from 10:1 to 22:1.