Engine bypass valve
Aspects of the disclosure are directed to an engine of an aircraft. The engine may include a first fan configured to output a first air flow, a second fan configured to receive a first portion of the first air flow and output a second air flow, a core configured to receive a first portion of the second air flow and generate a first stream, and at least one valve configured to assume one of at least three states in association with a generation of a second stream and a third stream based on at least one of the first air flow and the second air flow.
1. An engine defined about an axial centerline, comprising:
a first fan configured to output a first air flow;
a second fan configured to receive a first portion of the first air flow and output a second air flow;
a core configured to receive a first portion of the second air flow and generate a first stream, the core including a combustor;
at least one valve configured to assume one of at least three states in association with a generation of a second stream and a third stream based on at least one of the first air flow and the second air flow;
a duct located radially outboard of the third stream; and
a heat exchanger,
wherein the first stream, the second stream, and the third stream are separate streams at an axial location that is aft of the combustor, and
wherein the third stream is radially outboard of the second stream, and
wherein the third stream is formed based on a portion of the second stream, and
wherein the duct is configured to bypass a portion of the third stream in conveying a fourth stream, and
wherein the third stream is based on an output of the heat exchanger, and
wherein the at least one valve is located aft of the second fan and forward of the heat exchanger with respect to the axial centerline.
2. The engine of claim 1 , wherein when the at least one valve is in a first of the at least three states the second stream and the third stream are generated based on a second portion of the second air flow.
3. The engine of claim 2 , wherein when the at least one valve is in a second of the at least three states the second stream is generated based on the second portion of the second air flow and the third stream is generated based on a second portion of the first air flow.
4. The engine of claim 3 , wherein when the at least one valve is in a third of the at least three states the second stream is generated based on a mixture of the second portion of the first air flow and the second portion of the second air flow, and wherein when the at least one valve is in the third of the at least three states the third stream is generated based on the second portion of the first air flow.
5. The engine of claim 3 , wherein the second portion of the first air flow bypasses the second fan.
6. The engine of claim 1 , wherein the first fan includes a plurality of stages, and wherein the core includes a turbine arranged as a plurality of sections, and wherein a first of the turbine sections is configured to drive the first fan, and wherein a second of the turbine sections is configured to drive the second fan.
7. The engine of claim 1 , wherein the first fan is located forward of the second fan with respect to an inlet air flow received by the first fan, and wherein the second fan is located forward of the core with respect to the inlet air flow.
8. The engine of claim 1 , further comprising:
a nozzle configured to output a mixture of the first stream and a portion of the second stream.
9. The engine of claim 1 , further comprising:
at least one nozzle configured to output at least the third stream.
10. The engine of claim 1 , wherein the duct is configured to convey a second portion of the second air flow when the at least one valve is in a first of the at least three states.
11. The engine of claim 10 , wherein the duct is configured to convey a second portion of the first air flow when the at least one valve is in a second of the at least three states, and wherein the duct is configured to convey the second portion of the second air flow when the at least one valve is in a third of the at least three states.
12. The engine of claim 1 , wherein the at least one valve includes a plurality of valves, and wherein a first of the valves is located at a first location and a second of the valves is located at a second location, and wherein the first and second locations coincide with a common axial location with respect to the axial centerline of the engine.
13. The engine of claim 1 , further comprising:
a first nozzle configured to exhaust the first stream from the engine; and
a second nozzle configured to exhaust a mixture of a second portion of the second stream, the third stream, and the fourth stream from the engine.
14. The engine of claim 1 , further comprising:
a first nozzle configured to exhaust a mixture of the first stream and a second portion of the second stream;
a second nozzle configured to exhaust the third stream; and
a third nozzle configured to exhaust a second portion of the first air flow.
15. The engine of claim 14 , wherein the first nozzle is located radially inward of the second nozzle with respect to the axial centerline, and wherein the second nozzle is located radially inward of the third nozzle with respect to the axial centerline, and wherein the third nozzle is located forward of the second nozzle with respect to the axial centerline, and wherein the second nozzle is located forward of the first nozzle with respect to the axial centerline.
16. The engine of claim 1 , wherein the heat exchanger interfaces with a mixture of the first air flow and the second air flow.
17. The engine of claim 1 , further comprising:
a first case structure;
a second case structure located radially outward of the first case structure with respect to the axial centerline; and
a third case structure located radially outward of the second case structure with respect to the axial centerline;
wherein the first case structure forms a first flowpath for the first stream, and
wherein the first case structure and the second case structure form a second flowpath for the second stream, and
wherein the second case structure and the third case structure form a third flowpath for the third stream.
18. An engine defined about an axial centerline, comprising:
a first fan configured to output a first air flow;
a second fan configured to receive a first portion of the first air flow and output a second air flow;
a core configured to receive a first portion of the second air flow and generate a first stream, the core including a combustor;
at least one valve configured to assume one of at least three states in association with a generation of a second stream and a third stream;
a duct located radially outboard of the third stream; and
a heat exchanger,
wherein the second stream is based on a second portion of the second air flow, and
wherein the first stream, the second stream, and the third stream are separate streams at an axial location that is aft of the combustor, and
wherein the third stream is radially outboard of the second stream, and
wherein the third stream is formed based on a portion of the second stream, and
wherein the duct is configured to bypass a portion of the third stream in conveying a fourth stream, and
wherein the third stream is based on an output of the heat exchanger, and
wherein the at least one valve is located aft of the second fan and forward of the heat exchanger with respect to the axial centerline.
19. The engine of claim 18 , wherein the second fan comprises a first inducer stage and a second inducer stage.