Fluid exchange apparatuses and methods of exchanging fluids between streams

A method of exchanging fluids between streams, the method comprising:

• directing a first fluid through a first interleaved pathway of a fluid exchange apparatus, the first fluid flowing from an upstream portion of a first duct into the first interleaved pathway and discharging into a downstream portion of a second duct;
• directing the first fluid across or through a first heat exchanger disposed upstream of the first interleaved pathway, the first heat exchanger coupled to the first interleaved pathway, the first heat exchanger comprising a first inlet in fluid communication with the upstream portion of the first duct and a first outlet in fluid communication with the first interleaved pathway, the first heat exchanger providing the fluid communication between the first interleaved pathway and the upstream portion of the first duct;
• directing a second fluid through a second interleaved pathway of a fluid exchange apparatus, the second fluid flowing from an upstream portion of the second duct into the second interleaved pathway and discharging into a downstream portion of the first duct;
• and
• directing the second fluid across or through a second heat exchanger disposed downstream of the second interleaved pathway, the second heat exchanger coupled to the second interleaved pathway, the second heat exchanger comprising a second inlet in fluid communication with the second interleaved pathway and a second outlet in fluid communication with the downstream portion of the first duct, the second heat exchanger providing the fluid communication between the second interleaved pathway and the downstream portion of the first duct;
• wherein the first duct comprises an annular inner bypass duct of a turbomachine and the second duct comprises an annular outer bypass duct of the turbomachine, or the first duct comprises the annular outer bypass duct and the second duct comprises the annular inner bypass duct;
• and
• wherein the first interleaved pathway comprises a decreasing cross-sectional surface area from an upstream side to a downstream side thereof, and the second interleaved pathway comprises an increasing cross-sectional surface area from an upstream side to a downstream side thereof.

A heat management system for a turbomachine, comprising:

• a first duct comprising a first upstream portion and a first downstream portion;
• a second duct comprising a second upstream portion and a second downstream portion;
• a fluid exchange apparatus comprising a first interleaved pathway and a second interleaved pathway, the first interleaved pathway in fluid communication with the first upstream portion of the first duct and the second downstream portion of the second duct, and the second interleaved pathway in fluid communication with the second upstream portion of the second duct and the first downstream portion of the first duct, and one or more crossover pathways providing fluid communication between the first interleaved pathway and the second interleaved pathway;
• a first heat exchanger disposed upstream of the first interleaved pathway, the first heat exchanger comprising a first inlet in fluid communication with the first upstream portion of the first duct and a first outlet in fluid communication with the first interleaved pathway, the first heat exchanger providing the fluid communication between the first interleaved pathway and the first upstream portion of the first duct;
• and
• a second heat exchanger disposed downstream of the second interleaved pathway, the second heat exchanger comprising a second inlet in fluid communication with the second interleaved pathway and a second outlet in fluid communication with a first downstream portion of the first duct, the second heat exchanger providing the fluid communication between the second interleaved pathway and the first downstream portion of the first duct;
• wherein the first duct comprises an annular inner bypass duct of the turbomachine and the second duct comprises an annular outer bypass duct of the turbomachine, or the first duct comprises the annular outer bypass duct and the second duct comprises the annular inner bypass duct.