Actuated frame and tail cone for exhaust channel track selection
An aircraft propulsion system includes a dual exhaust path assembly that includes actuatable blocker doors moveable between a bypass configuration for directing the exhaust gas flow through an outer passage and a heat exchange configuration for directing the exhaust gas flow through a heat exchanger assembly.
1 . An aircraft propulsion system comprising:
a core engine comprising a main compressor where an inlet airflow is compressed and communicated to a combustor to generate an exhaust gas flow that is expanded through a main turbine section to generate power used to drive the main compressor and a propulsive fan;
a fuel system configured to provide at least two fuel types to the combustor for generating the exhaust gas flow;
a heat exchanger assembly operable for placing the exhaust gas flow in thermal communication with a working fluid flow;
a dual exhaust path assembly comprising actuatable blocker doors moveable between a bypass configuration for directing the exhaust gas flow through an outer passage and a heat exchange configuration for directing the exhaust gas flow through the heat exchanger assembly, wherein the dual exhaust path assembly comprises a single inlet configured to receive an exhaust gas flow from the main turbine section and an outlet for the exhaust gas flow from one of the outer passage and an inner passage housing the heat exchanger assembly and the blocker doors comprise forward blocker doors and aft blocker doors, the forward blocker doors are configured to direct the exhaust gas flow from the inlet to one of the outer passage and the inner passage; and
a controller programmed to operate the dual exhaust path assembly to switch between the bypass configuration and the heat exchange configuration based at least in part on a concentration of fuel of the at least two fuel types that the fuel system is providing to the combustor.
2 . The aircraft propulsion system as recited in claim 1 , wherein the heat exchanger assembly is disposed about an engine longitudinal axis.
3 . The aircraft propulsion system as recited in claim 2 , wherein the heat exchanger assembly comprises a disk shape disposed about the engine longitudinal axis.
4 . The aircraft propulsion system as recited in claim 1 , wherein the heat exchanger assembly is disposed within an inner passage and the outer passage comprises an annular passage disposed concentrically around the inner passage.
5 . The aircraft propulsion system as recited in claim 1 , wherein the outlet is disposed radially outward of the heat exchanger and wherein the aft blocker doors are configured to direct exhaust gas flow from either the outer passage or the inner passage through the outlet.
6 . The aircraft propulsion system as recited in claim 1 , wherein the outlet comprises an outer outlet for the exhaust gas flow from the outer passage and an inner outlet for exhaust gas flow from the heat exchanger assembly, and the aft blocker doors are configured to block the outer outlet when exhaust gas flow is routed through the heat exchanger assembly.
7 . The aircraft propulsion system as recited in claim 6 , wherein the inner outlet comprises a tail cone disposed about the engine longitudinal axis with a plurality of openings for the exhaust gas flow.
8 . The aircraft propulsion system as recited in claim 1 , wherein the dual exhaust path assembly is attached aft of a turbine exhaust case.
9 . The aircraft propulsion system as recited in claim 1 , further comprising a bottoming cycle system where thermal energy communicated into the working fluid flow within the heat exchanger assembly is utilized to generate shaft power.
10 . A bottoming cycle system for an aircraft propulsion system comprising:
a heat exchanger assembly operable for placing an exhaust gas flow in thermal communication with a working fluid flow;
a dual exhaust path assembly comprising actuatable blocker doors moveable between a bypass configuration for directing the exhaust gas flow through an outer passage and a heat exchange configuration for directing the exhaust gas flow through the heat exchanger assembly, wherein the outlet comprises an outer outlet for the exhaust gas flow from the outer passage and an inner outlet for exhaust gas flow from the inner passage, and the aft blocker doors are configured to block the outer outlet when exhaust gas flow is routed through the heat exchanger assembly;
a bottoming turbine where the heated working fluid flow from the heat exchanger assembly expands to generate shaft power; and
a controller programmed to operate the dual exhaust path assembly to switch between the bypass configuration and the heat exchange configuration in response to a concentration of fuel of at least two fuel types of the fuel system is providing to a combustor, wherein the controller is further programmed to operate the dual exhaust path assembly in the bypass configuration in response to more of the first fuel than the second fuel being provided to the combustor and in the heat exchange configuration in response to more of the second fuel than the first fuel being provided to the combustor.
11 . The bottoming cycle system as recited in claim 10 , wherein the heat exchanger assembly is disposed within an inner passage and the outer passage comprises an annular passage disposed concentrically around the inner passage.
12 . The bottoming cycle system as recited in claim 10 , wherein the dual exhaust path assembly comprises a single inlet configured to receive an exhaust gas flow from the main turbine section and an outlet for the exhaust gas flow from one of the outer passage and an inner passage housing the heat exchanger assembly.
13 . A method of operating an aircraft propulsion system comprising:
communicating a fuel flow comprising a selected one of a first fuel flow comprising a hydrocarbon based fuel and a second fuel flow comprising a cryogenic fuel to a combustor;
generating an exhaust gas flow within the combustor of a core engine by igniting a mixture of at least one of the first fuel flow and the second fuel flow and an inlet airflow within a combustor;
generating power by expanding the exhaust gas flow through a main turbine section to drive a compressor section and a propulsive fan; and
operating a dual exhaust path assembly comprising an inlet to both an outer passage and an inner passage, and forward blocker doors that are moveable between a bypass configuration and a heat exchange configuration, wherein operating the dual exhaust path assembly comprises moving the forward blocker doors to the bypass configuration to direct the exhaust gas flow from the main turbine section through the outer passage in response to generating the exhaust gas flow utilizing the first fuel flow and moving the blocker doors to the heat exchange configuration to direct the exhaust gas flow from the main turbine section through a heat exchanger assembly within the inner passage for communicating thermal energy from the exhaust gas flow into a working fluid flow in response to generating the exhaust gas flow utilizing the second fuel flow.
14 . The method as recited in claim 13 , further comprising generating shaft power by expanding the heated working flow through a bottoming cycle turbine.