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. An indirect drive turbine engine, comprising:
a fan;
a turbomachine defining an engine centerline and comprising a compressor section, a combustor in fluid communication with the compressor section, a turbine section in fluid communication with the combustor, and a speed reduction device driven by the turbine section for rotating the fan;
the fan comprising a first stage of composite airfoils circumferentially arranged about the engine centerline, a first airfoil of the first stage of composite airfoils comprising:
a first composite portion extending chordwise between a first composite leading edge and a first trailing edge;
a first leading edge protector comprising a first sheath receiving at least a portion of the first composite leading edge of the first composite portion, the first leading edge protector extending chordwise from a first leading edge towards the first composite portion for a first leading length (FLL); and
the first composite portion and the first leading edge protector together defining an exterior surface of the first airfoil and extending chordwise between the first leading edge and the first trailing edge to define a first chord length (FCL);
a second stage of composite airfoils located downstream of the first stage of composite airfoils and circumferentially arranged about the engine centerline, a second airfoil of the second stage of composite airfoils comprising:
a second composite portion extending chordwise between a second composite leading edge and a second trailing edge;
a second leading edge protector comprising a second sheath receiving at least a portion of the second composite leading edge of the second composite portion, the second leading edge protector extending chordwise from a second leading edge towards the second composite portion for a second leading length (SLL); and
the second composite portion and the second leading edge protector together defining an exterior surface of the second airfoil and extending chordwise between the second leading edge and the second trailing edge to define a second chord length (SCL);
wherein the FLL and the FCL relate to the SLL and the SCL by a stage protection factor (SPF), wherein the
SPF
=
(
FLL
FCL
)
(
SLL
SCL
)
,
and the SPF is greater than or equal to 0.7 and less than or equal to 4 (0.7≤SPF≤4); and
wherein the first airfoil extends spanwise between a first root and a first tip to define a first span length and the second airfoil extends spanwise between a second root and a second tip to define a second span length less than the first span length.
2. The indirect drive turbine engine of claim 1 , wherein the turbine section includes a fan drive turbine and a second turbine, the second turbine is disposed forward of the fan drive turbine and the fan drive turbine includes a plurality of fan drive turbine stages with the speed reduction device driven by the fan drive turbine.
3. The indirect drive turbine engine of claim 1 , further comprising a fan casing or a nacelle.
4. The indirect drive turbine engine of claim 1 , wherein at least one of a bypass ratio is between 10:1 and 22:1, a fan blade tip speed of the fan is less than 1400 feet per second, or the speed reduction device is a power gearbox having a power gearbox reduction ratio between 2:1 and 5:1.
5. The indirect drive turbine engine of claim 1 , wherein the indirect drive turbine engine is an open rotor engine.
6. The indirect drive turbine engine of claim 5 , wherein at least one of a bypass ratio is between 25:1 and 125:1 or the speed reduction device is a power gearbox having a power gearbox reduction ratio between 6:1 and 12:1.
7. The indirect drive turbine engine of claim 1 , wherein the first stage of composite airfoils and the second stage of composite airfoils include a polymer matrix composite and wherein at least one of the first leading edge protector or the second leading edge protector is a metallic leading edge protector.
8. The indirect drive turbine engine of claim 1 , wherein the first stage of composite airfoils is a plurality of fan blades and the second stage of composite airfoils is a plurality of outlet guide vanes or fan guide vanes.
9. The indirect drive turbine engine of claim 1 , wherein the first stage of composite airfoils has a first number of airfoils and the second stage of composite airfoils has a second number of airfoils and the first number is different than the second number.
10. The indirect drive turbine engine of claim 1 , 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. An indirect drive turbine engine comprising:
a fan;
a turbomachine defining an engine centerline and comprising a compressor section, a combustor in fluid communication with the compressor section, a turbine section in fluid communication with the combustor, and a speed reduction device driven by the turbine section for rotating the fan;
a set of composite airfoils comprising a set of fan blades and a set of outlet guide vanes downstream from the set of fan blades, the set of composite airfoils circumferentially arranged about the engine centerline an airfoil of the set of composite airfoils comprising:
a composite portion extending chordwise between a composite leading edge and a trailing edge;
a leading edge protector coupled to the composite portion at the composite leading edge to define a seam, and extending chordwise between a leading edge and the seam to define a leading length (LL); and
the composite portion and the leading edge protector together defining an exterior surface of the airfoil and extending chordwise between the leading edge and the trailing edge to define a chord length (CL); and
wherein the LL and the CL relate to each other by an airfoil protection factor
(
APF
)
=
(
LL
)
(
CL
)
,
a first airfoil protection factor (APF1) for the set of fan blades is greater than or equal to 0.2 and less than or equal to 0.30 (0.2≤APF1≤0.3) and a second airfoil protection factor (APF2) for the set of outlet guide vanes is greater than or equal to 0.08 and less than or equal to 0.17 (0.08≤APF2≤0.17).
12. The indirect drive turbine engine of claim 11 , wherein the turbine section includes a fan drive turbine and a second turbine, the second turbine is disposed forward of the fan drive turbine and the fan drive turbine includes a plurality of fan drive turbine stages with the speed reduction device driven by the fan drive turbine.
13. The indirect drive turbine engine of claim 11 , further comprising a fan casing or a nacelle.
14. The indirect drive turbine engine of claim 13 , wherein at least one of a bypass ratio is between 10:1 and 22:1, a fan blade tip speed of the fan is less than 1400 feet per second, or the speed reduction device is a power gearbox having a power gearbox reduction ratio between 2:1 and 5:1.
15. The indirect drive turbine engine of claim 11 , wherein the indirect drive turbine engine is an open rotor engine.
16. The indirect drive turbine engine of claim 15 , wherein at least one of a bypass ratio is between 25:1 and 125:1 or the speed reduction device is a power gearbox having a power gearbox reduction ratio between 6:1 and 12:1.
17. The indirect drive turbine engine of claim 11 , wherein the APF1 relates to the APF2 by an expression:
APF
1
APF
2
to define a stage protection factor (SPF), wherein the SPF is greater than or equal to 0.7 and less than or equal to 4 (0.7≤SPF≤4).
18. The indirect drive turbine engine of claim 17 , wherein the SPF is greater than or equal to 0.95 and less than or equal to 2.5 (0.95≤SPF≤2.5).
19. The indirect drive turbine engine of claim 11 , wherein the set of composite airfoils extend spanwise between a root and a tip to define a span length and the APF is determined at a location between 20% and 80% of the span length.
20. The indirect drive turbine engine of claim 11 , wherein the composite portion is formed from a polymer matrix composite or the leading edge protector is a metallic leading edge protector.