Turbine engine system with heat exchanger in bypassable secondary duct

1. An assembly for a turbine engine, comprising:

a primary duct;

a bleed duct extending from a bleed duct inlet to a bleed duct outlet, the bleed duct inlet fluidly coupled with the primary duct;

a plurality of secondary ducts arranged in parallel between the bleed duct outlet and the primary duct, the plurality of secondary ducts including a first duct and a second duct;

a heat exchanger configured with the second duct; and

a flow regulator configured to direct at least a majority of fluid flowing through the bleed duct outlet to

the first duct during a first mode of operation; and

the second duct during a second mode of operation;

wherein a sidewall is located between the first duct and the second duct, and the sidewall extends axially along the heat exchanger.

2. The assembly of claim 1 , wherein the flow regulator is configured to direct at least substantially all of the fluid flowing through the bleed duct outlet to

the first duct during the first mode of operation; and

the second duct during the second mode of operation.

3. The assembly of claim 1 , wherein the flow regulator comprises a two way valve.

4. The assembly of claim 1 , wherein the flow regulator is located between the bleed duct and the first duct.

5. The assembly of claim 1 , wherein the flow regulator is located between the bleed duct and the second duct.

6. The assembly of claim 1 , wherein

the flow regulator includes a door configured to move between a first position and a second position;

the door is configured to block flow from the bleed duct outlet to the second duct when the door is in the first position; and

the door is configured to block flow from the bleed duct outlet to the first duct when the door is in the second position.

7. The assembly of claim 1 , wherein the heat exchanger is configured as a gas-to-liquid heat exchanger.

8. The assembly of claim 1 , wherein the heat exchanger is configured as a gas-to-gas heat exchanger.

9. The assembly of claim 1 , wherein the heat exchanger extends radially across the second duct to the sidewall.

10. The assembly of claim 1 , wherein the primary duct is a bypass duct of the turbine engine.

11. The assembly of claim 1 , further comprising:

an engine core; and

a core nacelle housing at least a portion of the engine core;

wherein the bleed duct and the plurality of secondary ducts are located between the core nacelle and a case of the engine core.

12. The assembly of claim 1 , wherein

the primary duct extends from a primary duct inlet to a primary duct outlet;

the bleed duct inlet is downstream of the primary duct inlet; and

the plurality of secondary ducts are fluidly coupled with the primary duct upstream of the primary duct outlet.

13. The assembly of claim 1 , wherein

the first duct is radially between the primary duct and the second duct relative to a centerline of the turbine engine; and

the sidewall is radially between the heat exchanger and the first duct.

14. The assembly of claim 1 , wherein the first duct is an open duct.

15. An assembly for a turbine engine, comprising:

a primary duct;

a bleed duct extending from a bleed duct inlet to a bleed duct outlet, the bleed duct inlet fluidly coupled with the primary duct;

a bypass secondary duct and a heat exchange secondary duct arranged in parallel with the bypass secondary duct between the bleed duct outlet and the primary duct;

a heat exchanger within the heat exchange secondary duct; and

a flow regulator, the assembly configured such that at least a majority of fluid flowing through the bleed duct outlet flows into

the bypass secondary duct when the flow regulator operates in a first mode; and

the heat exchange secondary duct when the flow regulator operates in a second mode;

wherein a radial height of the heat exchanger is larger than a radial height of a portion of the bypass secondary duct that axially overlaps the heat exchanger.

16. The assembly of claim 15 , wherein the assembly is configured such that at least substantially all of the fluid flowing through the bleed duct outlet flows into

the bypass secondary duct during the first mode; and

the heat exchange secondary duct during the second mode.

17. The assembly of claim 15 , wherein the flow regulator comprises a two way valve arranged between the bleed duct outlet and the bypass and the heat exchange secondary ducts.

18. The assembly of claim 15 , wherein

a first flow path from the primary duct, through the bleed duct and the bypass secondary duct, back to the primary duct has a first pressure drop; and

a second flow path from the primary duct, through the bleed duct and the heat exchange secondary duct, back to the primary duct has a second pressure drop that is greater than the first pressure drop.

19. An assembly for a turbine engine, comprising:

a primary duct;

a bleed duct fluidly coupled with the primary duct;

a first secondary duct configured as an open duct;

a second secondary duct arranged in parallel with the first secondary duct between the bleed duct and the primary duct;

a flow impediment within the second secondary duct; and

a valve arranged at an intersection between the bleed duct, the first secondary duct and the second secondary duct, the valve configured to substantially close an inlet to the second secondary duct during a first mode, and the valve further configured to substantially close an inlet to the first secondary duct during a second mode;

wherein a radial height of the flow impediment is larger than a radial height of a portion of the first secondary duct that axially overlaps the flow impediment.

20. The assembly of claim 19 , wherein

the valve includes a door configured to move between a first position and a second position;

the door is configured to close a passage from the bleed duct to the second secondary duct when the door is in the first position; and

the door is configured to close a passage from the bleed duct to the first secondary duct when the door is in the second position.