FIELD

The present subject matter relates generally to a fuel oxygen reduction unit for an engine and a method of operating the same.

BACKGROUND

Typical aircraft propulsion systems include one or more gas turbine engines. The gas turbine engines generally include a turbomachine, the turbomachine including, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air is provided to an inlet of the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are routed from the combustion section to the turbine section. The flow of combustion gasses through the turbine section drives the turbine section and is then routed through the exhaust section, e.g., to atmosphere.

Certain operations and systems of the gas turbine engines and aircraft may generate a relatively large amount of heat. Fuel has been determined to be an efficient heat sink to receive at least some of such heat during operations due at least in part to its heat capacity and an increased efficiency in combustion operations that may result from combusting higher temperature fuel.

However, heating the fuel up without properly conditioning the fuel may cause the fuel to “coke,” or form solid particles that may clog up certain components of the fuel system, such as the fuel nozzles. Reducing an amount of oxygen in the fuel may effectively reduce the likelihood that the fuel will coke beyond an unacceptable amount. Fuel oxygen reduction systems have been proposed for such a purpose.

Downstream of the fuel oxygen reduction systems, the gas turbine engines may include one or more fuel oxygen sensors to ensure the fuel oxygen reduction system is operating at a desired level. However, the inventors of the present disclosure have found that in the event that such fuel oxygen sensor(s) fail or are otherwise not providing accurate information, damage may be caused to, e.g., the gas turbine engine through continued use of the fuel as a heat sink without such fuel having a sufficient amount of oxygen removed therefrom.

Accordingly, the inventors have found that a fuel oxygen reduction system having one or more backup systems for determining an oxygen level of a fuel flow downstream of the fuel oxygen reduction system would be useful.

BRIEF DESCRIPTION

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In one exemplary aspect of the present disclosure, a method is provided of operating a fuel oxygen reduction unit for a vehicle or a gas turbine engine of the vehicle, the fuel oxygen reduction unit including a contactor and a fuel gas separator, and further defining a stripping gas flowpath in flow communication with a stripping gas inlet of the contactor and a stripping gas outlet of the fuel gas separator. The method includes receiving data indicative of a parameter of a stripping gas flow through the stripping gas flowpath or of a component in flow communication with the stripping gas flow through the stripping gas flowpath; and determining an operability condition of the fuel oxygen reduction unit, or a component operable with the fuel oxygen reduction unit, based on the data received indicative of the parameter of the stripping gas flow or of the component in flow communication with the stripping gas flow.

In certain exemplary aspects receiving data indicative of the parameter of the stripping gas flow or of the component in flow communication with the stripping gas flow includes receiving data indicative of an oxygen level of the stripping gas flow through the stripping gas flowpath.

For example, in certain exemplary aspects receiving data indicative of the oxygen level of the stripping gas flow through the stripping gas flowpath includes sensing data indicative of an oxygen level of the stripping gas flow through the stripping gas flowpath with an oxygen sensor positioned in flow communication with the stripping gas flowpath.

In certain exemplary aspects receiving data indicative of the parameter of the stripping gas flow or of the component in flow communication with the stripping gas flow includes receiving data indicative of a makeup gas flow to the stripping gas flowpath.

For example, in certain exemplary aspects receiving data indicative of the makeup gas flow to the stripping gas flowpath includes sensing an amount of makeup gas provided to the stripping gas flowpath with a makeup gas sensor.

In certain exemplary aspects receiving data indicative of the parameter of the stripping gas flow or of the component in flow communication with the stripping gas flow includes receiving data indicative of at least one of a pressure of the stripping gas flow through the stripping gas flowpath, a temperature of the stripping gas flow through the stripping gas flowpath, or a flow rate of the stripping gas flow through the stripping gas flowpath.

In certain exemplary aspects receiving data indicative of the parameter of the stripping gas flow or of the component in flow communication with the stripping gas flow includes receiving a first set of data indicative of the parameter at a first location along the stripping gas flowpath and receiving a second set of data indicative of the parameter at a second location along the stripping gas flowpath.

For example, in certain exemplary aspects the fuel oxygen reduction unit includes a catalyst in flow communication with the stripping gas flowpath, and wherein the first location is upstream of the catalyst, and wherein the second location is downstream of the catalyst.

For example, in certain exemplary aspects the parameter is a temperature of the stripping gas flow.

For example, in certain exemplary aspects the first location is upstream of the gas boost pump, and wherein the second location is downstream of the gas boost pump.

For example, in certain exemplary aspects the parameter is a temperature of the stripping gas flow, a pressure of the stripping gas flow, or a combination of the two.

In certain exemplary aspects the stripping gas flowpath is a circulation gas flowpath extending from the stripping gas outlet of the fuel gas separator to the stripping gas inlet of the contactor, wherein the fuel oxygen reduction unit includes a catalyst in flow communication with the circulation gas flowpath, and wherein the method further includes: mixing within the contactor a received flow of liquid fuel with the flow of stripping gas through the circulation gas flowpath to generate a fuel/gas mixture; separating within the fuel gas separator the fuel/gas mixture back into the flow of stripping gas and the flow of liquid fuel and providing the separated flow of the stripping gas to the circulation gas flowpath; and reducing with the catalyst an oxygen content of the stripping gas flow through the stripping gas flowpath.

For example, in certain exemplary aspects reducing with the catalyst the oxygen content of the stripping gas flow through the stripping gas flowpath includes generating a byproduct, and wherein receiving data indicative of the parameter of the stripping gas flow or of the component in flow communication with the stripping gas flow includes receiving data indicative of the byproduct.

For example, in certain exemplary aspects determining the operability condition of the fuel oxygen reduction unit, or a component operable with the fuel oxygen reduction unit, includes indirectly determining a health parameter of the catalyst of the fuel oxygen reduction unit.

In certain exemplary aspects determining the operability condition of the fuel oxygen reduction unit, or a component operable with the fuel oxygen reduction unit, includes determining an oxygen level of a deoxygenated fuel flow from the fuel oxygen reduction unit.

In certain exemplary aspects the method further includes controlling operation of the vehicle or the gas turbine engine based on the determined operability condition of the fuel oxygen reduction unit.

In an exemplary embodiment of the present disclosure, a fuel oxygen reduction unit for a vehicle or an engine of the vehicle is provided. The fuel oxygen reduction unit includes a contactor defining a liquid fuel inlet, a stripping gas inlet, and a fuel/gas mixture outlet; a fuel gas separator defining an inlet in flow communication with the fuel/gas mixture outlet of the contactor, a liquid fuel outlet, and a stripping gas outlet, the fuel oxygen reduction unit defining a stripping gas flowpath in flow communication with the stripping gas inlet of the contactor and the stripping gas outlet of the fuel gas separator; and a controller including one or more processors and memory, the memory storing instructions that when executed by the one or more processors cause the controller to perform functions. The functions include: receiving data indicative of a parameter of a stripping gas flow through the stripping gas flowpath or of a component in flow communication with the stripping gas flow through the gas flowpath gas flowpath; and determining an operability condition of the fuel oxygen reduction unit, or the component operable with the fuel oxygen reduction unit, based on the data received indicative of the parameter of the stripping gas flow or of the component in flow communication with the stripping gas flow.

In certain exemplary embodiments the fuel oxygen reduction unit of further includes a sensor operably coupled to the circulation gas flowpath, wherein receiving data indicative of the parameter of the stripping gas flow or of the component in flow communication with the stripping gas flow includes receiving data from the sensor.

In certain exemplary embodiments the fuel oxygen reduction unit of further includes a makeup gas source in flow communication with the stripping gas flowpath, wherein receiving data indicative of the parameter of the stripping gas flow or of the component in flow communication with the stripping gas flow includes receiving data indicative of a flow of makeup gas from the makeup gas source to the stripping gas flowpath.

In certain exemplary embodiments the stripping gas flowpath is a circulation gas flowpath extending from the stripping gas outlet of the fuel gas separator to the stripping gas inlet of the contactor, wherein the fuel oxygen reduction unit includes a catalyst in flow communication with the circulation gas flowpath.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

