Strut microtube counterflow evaporator

An aircraft propulsion system comprising:

• a core engine section defining a core flow path where an inlet airflow is compressed, mixed with fuel, and ignited to generate an exhaust gas flow;
• an inner nacelle assembly surrounding the core engine section;
• an outer nacelle assembly spaced radially apart from the inner nacelle assembly;
• and
• a strut heat exchanger extending radially between the inner nacelle assembly and the outer nacelle assembly, wherein within the strut heat exchanger a portion of the exhaust gas flow is placed in thermal communication with a second flow for transferring thermal energy, wherein the strut heat exchanger comprises an outer fairing assembly defining an outer surface that extends between a leading edge, a trailing edge, a radially inner end at the inner nacelle assembly and a radially outer end at the outer nacelle assembly,
• an inner cavity that extends between an inner opening open through the inner nacelle assembly and an outer opening that is open into the outer nacelle assembly, and a plurality of tube assemblies that extend through the inner cavity between the inner nacelle assembly and the outer nacelle assembly, wherein the portion of the exhaust gas flow is communicated through the inner cavity and the second flow is communicated through at least one of the plurality of tube assemblies;
• a condenser where water is extracted from the exhaust gas flow;
• and
• an evaporator system where thermal energy from the exhaust gas flow is utilized to generate a steam flow from at least a portion of water extracted by the condenser for injection into the core flow path, wherein the second flow comprises a flow of water and at least a portion of thermal energy from the exhaust gas flow is communicated to the water flow within the strut heat exchanger.

A heat exchanger for an aircraft propulsion system comprising:

• an outer fairing assembly defining an outer surface that extends between a leading edge, a trailing edge, a radially inner end, and a radially outer end;
• an inner cavity defined within the outer fairing that defines a first flow path for an exhaust gas flow that extends between an inner opening disposed at the radially inner end and an outer opening disposed at the radially outer end;
• and
• a plurality of tube assemblies that extend through the inner cavity that define a second flow path for a water flow between the inner end and the outer end, wherein the thermal energy from the exhaust gas flow in the first flow path is utilized to generate a steam flow from the water flow within the second flow path.

A method of operating a gas turbine engine, the method comprising:

• generating an exhaust gas flow;
• routing a portion of the exhaust gas flow through an inner cavity of a strut heat exchanger extending through a fan bypass flow passage between an inner nacelle and an outer nacelle;
• extracting water from the exhaust gas flow in a condenser outside of the strut heat exchanger;
• routing a flow of extracted water through a plurality of tubes extending through the strut heat exchanger in thermal communication with the exhaust gas flow flowing though the inner cavity of the strut heat exchanger;
• and
• generating a steam flow by heating the portion of the flow of extracted water with heat from the exhaust gas flow transferred into the water flow within the strut heat exchanger.