Gas turbine engine thermal management system

1. A thermal management system for a gas turbine engine, comprising:

a first fluid circuit including a first passage that divides into a first branch and a second branch, wherein said first fluid circuit delivers a first fluid to a first engine system downstream of said first branch and said second branch;

a second fluid circuit;

a heat exchanger incorporated into said first branch of said first fluid circuit and into said second fluid circuit;

a valve that controls an amount of said first fluid in said first passage that is communicated through said first branch to said heat exchanger, and that splits flow of said first fluid between said first branch and said second branch;

a first sensor that senses a first characteristic of a second fluid that is communicated in said second fluid circuit through said heat exchanger to exchange heat with said first fluid;

a second sensor separate from said first sensor and that senses a second characteristic of said second fluid;

a controller that controls a positioning of said valve based on at least one of said first characteristic and said second characteristic;

wherein said valve is moveable between first, second and third positions in response to said controller, said first position blocking flow from said first passage to both said first branch and said second branch, said second position permitting flow from said first passage to both said first branch and said second branch, and said third position blocking flow from said first passage to one of said first branch and said second branch, but permitting flow from said first passage to another one of said first branch and said second branch;

wherein said heat exchanger is a first heat exchanger, and said first fluid circuit includes a second heat exchanger and a third heat exchanger; and

wherein said first branch and said second branch join together at a first node downstream of said first heat exchanger and said second heat exchanger.

2. The system as recited in claim 1 , wherein said controller is operable to receive a signal from each of said first sensor and said second sensor.

3. The system as recited in claim 2 , wherein said controller modulates said valve to communicate said amount of said first fluid to said first heat exchanger in response to at least one of said signal from said first sensor and said signal from said second sensor.

4. The system as recited in claim 2 , wherein said controller modulates said valve to communicate said amount of said first fluid to said first heat exchanger in response to at least one of: altitude information, ambient temperature information, or engine power condition information.

5. The system as recited in claim 1 , wherein said first characteristic includes temperature information and said second characteristic includes pressure information.

6. The system as recited in claim 1 , wherein said first sensor senses a temperature of said second fluid after said second fluid exits said first heat exchanger.

7. The system as recited in claim 1 , comprising a pump, and said second sensor senses a flow rate of said second fluid through said pump.

8. The system as recited in claim 1 , wherein said first fluid is oil and said second fluid is fuel.

9. The system as recited in claim 1 , wherein said first fluid circuit delivers said first fluid to said first engine system and to a second engine system both downstream of said first node.

10. The system as recited in claim 9 , wherein said first fluid is oil and said second fluid is fuel.

11. The system as recited in claim 10 , wherein said first engine system is a portion of a geared architecture that interconnects a fan and a fan drive turbine.

12. The system as recited in claim 10 , further comprising:

a pump in said second fluid circuit between said first heat exchanger and a combustor section;

wherein said second sensor senses a flow rate of said second fluid through said pump;

wherein said controller is operable to receive a signal from each of said first sensor and said second sensor;

wherein said controller modulates said valve to communicate said amount of said first fluid to said first heat exchanger in response to at least one of said signal from said first sensor and said signal from said second sensor;

wherein said first characteristic includes temperature information and said second characteristic includes pressure information;

wherein said controller modulates said valve to communicate said amount of said first fluid to said first heat exchanger in response to at least one of: altitude information, ambient temperature information, or engine power condition information; and

wherein said first sensor senses a temperature of said second fluid after said second fluid exits said first heat exchanger.

13. The system as recited in claim 10 , wherein said first fluid circuit includes a bypass passage in parallel with said valve and that diverts a portion of said first fluid in said first passage to a second node downstream of said first node.

14. The system as recited in claim 13 , wherein said first engine system is a portion of a geared architecture that interconnects a fan and a fan drive turbine.

15. The system as recited in claim 14 , wherein said second engine system is an engine bearing compartment.