Method and system for a combined air-oil cooler and fuel-oil cooler heat exchanger

A method of cooling a fluid using a heat exchanger assembly, the heat exchanger assembly comprising a plurality of unitary bodies, each of the plurality of unitary bodies comprising a first internal flow path, a second internal flow path, and a plurality of fin members, the method comprising:

• channeling a flow of a fluid to be cooled from a first inlet of the first internal flow path to a first outlet of the first internal flow path, the first internal flow path being enclosed within and formed integrally with one of the unitary bodies;
• channeling a flow of a first coolant from a second inlet of the second internal flow path to a second outlet of the second internal flow path, wherein the second internal flow path is not in fluid communication with the first internal flow path, and the second internal flow path is enclosed within and formed integrally with the one of the unitary bodies, wherein the second internal flow path is coupled in thermal communication with the first internal flow path, wherein channeling the flow of the first coolant from the second inlet of the second internal flow path to the second outlet of the second internal flow path comprises channeling a flow of fuel from the second inlet of the second internal flow path to the second outlet of the second internal flow path;
• and
• channeling a portion of air from a bypass airflow passage to a location that is proximate to the plurality of fin members of the one of the unitary bodies, wherein the plurality of fin members of the one of the unitary bodies is in thermal communication with the first internal flow path and is disposed on a circumferentially extending surface of the one of the unitary bodies.

A gas turbine engine comprising:

• a fan comprising a plurality of fan blades;
• a core engine that defines an outer casing;
• an outer nacelle that circumferentially surrounds the fan and at least a portion of the core engine;
• a bypass airflow passage defined between the outer nacelle and the core engine;
• a heat exchanger assembly comprising:
• a plurality of unitary bodies, each of the plurality of unitary bodies comprising:
• a first internal flow path configured to channel a flow of fluid to be cooled from a first inlet to a first outlet, the first internal flow path being enclosed within and formed integrally with the unitary body;
• a second internal flow path coupled in thermal communication with the first internal flow path and configured to channel a flow of a first coolant from a second inlet to a second outlet, wherein the flow of the first coolant comprises a fuel, wherein the second internal flow path is not in fluid communication with the first internal flow path, and the second internal flow path is enclosed within and formed integrally with the unitary body;
• and
• a plurality of fin members in thermal communication with the first internal flow path, each of the plurality of fin members being disposed on a circumferentially extending surface of the unitary body and extending into the bypass airflow passage.