Heat exchanger and flow modulation system

1. A propulsion system, the system defining an axial centerline axis, an axial direction co-directional to the centerline axis, a radial direction extended from the centerline axis, and a circumferential direction extended relative to the centerline axis, the system comprising:

a first vane extended along the radial direction, and wherein the first vane is configured to rotate relative to a vane axis extended along the radial direction;

a second vane extended along the radial direction, and wherein the second vane is positioned aft along the axial direction of the first vane, wherein the second vane forms an inlet opening proximate to a second vane leading edge, and wherein the second vane forms an outlet opening proximate to a second vane trailing edge, wherein the inlet opening and the outlet opening together allow a flow of fluid through the second vane; and

a heat exchanger positioned within the second vane, wherein the inlet opening and the outlet opening allow the flow of fluid in fluid communication with the heat exchanger.

2. The system of claim 1 , wherein the first vane is configured to direct the flow of fluid into the inlet opening of the second vane via rotation of the first vane along the vane axis to a closed position.

3. The system of claim 2 , wherein the first vane is configured to direct the flow of fluid away from the inlet opening of the second vane via rotation of the first vane along the vane axis to an open position.

4. The system of claim 1 , the system comprising a plurality of the first vane positioned in circumferential arrangement.

5. The system of claim 4 , the system comprising a plurality of the second vane positioned in circumferential arrangement.

6. The system of claim 1 , wherein the inlet opening is positioned through a pressure side of the second vane.

7. The system of claim 6 , wherein the outlet opening is positioned through a suction side of the second vane.

8. The system of claim 1 , wherein the first vane is offset along the circumferential direction from the second vane.

9. The system of claim 8 , wherein a first vane trailing edge is co-axial to at least the second vane leading edge.

10. The system of claim 9 , wherein the first vane trailing edge is co-axial to the inlet opening at the second vane.

11. The system of claim 1 , the system comprising:

an outer radial wall extended along the axial direction; and

an inner radial wall extended co-directional to the outer radial wall,

wherein the outer radial wall and the inner radial wall together form a flowpath extended substantially along the axial direction, and

wherein the first vane and the second vane are each extended along the radial direction through the flowpath.

12. The system of claim 11 , wherein the outer radial wall and the inner radial wall form an inlet section configured to receive the flow of fluid into the flowpath.

13. The system of claim 11 , the system comprising:

a fan section comprising a plurality of fan blades, wherein a nacelle surrounds the plurality of fan blades, and wherein the outer radial wall is formed at the nacelle, and wherein the first vane and the second vane are positioned aft along the axial direction of the plurality of fan blades; and

a core engine, wherein an outer casing surrounds the core engine, and wherein the inner radial wall is formed at the outer casing.

14. The system of claim 11 , the system comprising:

a compressor section comprising a plurality of compressor blades extended along the radial direction through the flowpath, wherein the plurality of compressor blades is surrounded by the outer radial wall, and wherein the first vane and the second vane are positioned at the compressor section.

15. The system of claim 11 , the system comprising:

a fan section comprising a plurality of fan blades, wherein the plurality of fan blades is extended along the radial direction through a fan flow passage; and

a compressor section comprising a plurality of compressor blades extended along the radial direction through the flowpath, wherein the flowpath separates into a core flowpath in fluid communication with a heat addition system, and wherein the flowpath separates into a third stream flowpath in fluid communication with the fan flow passage downstream of the plurality of fan blades.

16. The system of claim 1 , the system comprising:

a fan section comprising a plurality of fan blades, wherein the plurality of fan blades is extended along the radial direction through a fan flow passage; and

a core engine, wherein an outer casing surrounds the core engine, wherein the first vane and the second vane are extended from the outer casing aft of the plurality of fan blades.

17. The system of claim 16 , wherein the fan section is unducted, and wherein the plurality of fan blades forms an open rotor configuration.

18. The system of claim 1 , the system comprising:

a supply conduit configured to allow a flow of a thermal load into the heat exchanger; and

a return conduit configured to remove the flow of the thermal load from the heat exchanger, wherein the flow of fluid in fluid communication with the heat exchanger is a flow of oxidizer, and wherein the heat exchanger allows the flow of oxidizer into thermal communication with the flow of the thermal load.

19. The system of claim 18 , wherein the flow of the thermal load is one or more of a flow of lubricant, a flow of fuel, a flow of hydraulic fluid, or a flow of heat transfer fluid.

20. The system of claim 1 , the system comprising:

an actuation system configured to rotate the first vane along the vane axis.