Patent ID: 12215622

DETAILED DESCRIPTION

FIG.1schematically illustrates an example propulsion system20that extracts water from a partial portion of the exhaust gas flow and applies the extracted water to targeted uses to improve engine efficiency. In one example embodiment, the extracted water is utilized for intercooling and is injected into a core flow. Example system embodiments are disclosed that illustrate additional features complimentary to extraction of water from only a partial portion of the exhaust gas flow.

The example propulsion system20includes a fan section24and a core engine22. The core engine22includes a compressor section26, a combustor section28and the turbine section30disposed along an engine longitudinal axis A. The fan section24drives a bypass airflow44along a bypass flow path B, while the compressor section26draws a core flow42along a core flow path C. The core flow42is compressed and communicated to the combustor section28where the compressed core flow42is mixed with a fuel flow38and ignited to generate an exhaust gas flow40. The exhaust gas flow40expands through the turbine section30where energy is extracted and utilized to drive the fan section24and the compressor section26.

Although an example engine architecture is disclosed by way of example, other turbine engine architectures are within the contemplation and scope of this disclosure. Moreover, although the disclosed non-limiting embodiment depicts a turbofan turbine engine, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines. Additionally, the features of this disclosure may be applied to other engine configurations utilized to generate shaft power.

A fuel system32, including at least a fuel tank34and a fuel pump36, provides the fuel flow38to the combustor28. The example fuel system32is configured to provide a hydrogen based fuel such as a liquid hydrogen (LH2). Although hydrogen is disclosed by way of example, other non-carbon based fuels could be utilized and are within the contemplation of this disclosure. Moreover, the disclosed features may also be beneficial in an engine configured to operate with traditional carbon fuels and/or biofuels, such as sustainable aviation fuel.

A condenser50is disposed downstream of the turbine section30and receives a partial portion of the exhaust gas flow40. The condenser50cools a portion of the exhaust gas flow40to condense and extract water52. Extracted water52is gathered in a tank56and pressurized by a pump58for communication to targeted locations within the core engine22.

The exhaust gas flow40is a mix of steam, and components from combustion of fuel. The components from combustion can include, among other possible components, nitrogen, carbon dioxide and oxygen. These combustion components reduce the case of condensing liquid water from the exhaust gas flow40in the condenser50. Moreover, cold sinks such as the bypass airflow44and the cryogenic fuel flows38have a limited capacity for cooling that may further limit condenser operation. The example propulsion system provides for improved condenser operation by separating the exhaust gas flow40into a first exhaust gas flow46and a second exhaust gas flow48. Only the second exhaust gas flow48is communicated to the condenser50.

In one disclosed example, the second exhaust gas flow48is equal to or less than that of the first exhaust gas flow46. In another disclosed example, the second exhaust gas flow48is less than about 40% of the total exhaust gas flow40. In yet another example, the second exhaust gas flow48can include more than 50% of the total exhaust gas flow40. The first and second exhaust gas flows46,48are recombined in a mixer70to form a recombined flow72that is exhausted through a nozzle74. The mixer70is configured to accommodate pressure differences that may be present between the first and second exhaust gas flows46,48to produce the recombined flow72.

In one disclosed example embodiment, a control device118is provided to control and vary the split between the first and second exhaust gas flows46,48. The example control device118is controlled by a controller125based on input information122indicative of engine operation. The control device118may be any structure or duct that is controllable to vary a ratio of flows provided into each of the first and second exhaust gas flows46,48. Moreover, although the control device118is illustrated at the exit of the turbine section30, the control device118may be arranged in any manner or location that provides control over the proportion that the exhaust gas flow40is split into the first exhaust gas flow46and the second exhaust gas flow48.

The example controller125is a device and/or system for performing necessary computing or calculation operations to facilitate operation of the control device118. The controller125may be specially constructed and programmed for operation of the control device118, or it may comprise at least a general-purpose computer selectively activated, programmed, and/or reconfigured by software instructions stored in a memory device. The controller125may further be part of full authority digital engine control (FADEC) or an electronic engine controller (EEC).

A refrigerant circuit62provides for cooling of the second exhaust gas flow48within the condenser50. In one example embodiment, the refrigerant circuit62includes a pump64for circulating coolant66to transfer heat away from the second exhaust gas flow48. The coolant66may be any coolant including, among other things, helium, glycol, and ammonia. The coolant66circulates through a heat exchanger68to further transfer heat into the fuel flow38, which may be cryogenic. Accordingly, the refrigerant circuit62provides for the transfer of heat from the second exhaust gas flow48to the fuel flow38.

Water52extracted from the second exhaust gas flow48within the condenser50is gathered in the tank56. A pump58pressurizes the extracted water to generate a pressurized water flow54. The water flow54is communicated to the core engine22for use in targeted locations to improve engine efficiency. In one disclosed example, the water flow54is communicated as an intercooling flow60and injected into the core flow42within the compressor section26. In the disclosed example, the intercooling flow60is directly injected into the core flow42for both cooling and to increase mass flow through the combustor28and turbine section30. Although depicted as being injected within the compressor section26, this is not intended to be so limiting and the water54may be injected in other locations of the propulsion system20.

Referring toFIG.2, another example propulsion system is schematically shown and indicated at120. The example propulsion system120includes a first heat exchanger in the form of an evaporator76disposed within the compressor section26for generating a steam flow78. Instead of directly injecting water into the core flow42within the compressor section26, the intercooling flow60is transformed into the steam flow78and injected into the combustor28. Thermal energy from the core flow42is used to heat the intercooling flow60and in doing so, cools the core flow42. The cooled core flow42increases compressor efficiency while the injected steam28provides an increased mass flow through the turbine section30.

The separated first exhaust gas flow46and second exhaust gas flow48may be of different pressures upon reaching the mixer70. However, operation of the propulsion system is more efficient if the two flows46,48are of the same or substantially the same pressure. The second exhaust gas flow48is cooled and pressure is reduced as it flows through the condenser50as compared to the first exhaust gas flow46. The imbalance of pressures is accommodated by an exhaust turbine80through which the first exhaust gas flow46is expanded. Expansion through the exhaust turbine80reduces pressure in the first exhaust gas flow46and also generates shaft power that can be utilized to drive accessory devices. In one example embodiment, the exhaust turbine80is coupled to a generator82to produce electric power. Although a generator82is shown by way of example, other accessory components and devices may be driven by the exhaust turbine82.

Operation of the exhaust turbine80is controlled to provide similar pressures within each of the first and second exhaust gas flows46,48as they are communicated to the mixer70for recombination. The exhaust turbine80may be controlled based on different sensed pressures within each of the gas flows46,48. Sensors may be provided that provide information indicative of different pressures within each of the flows46,48. Moreover, operation of the exhaust turbine80may be determined based on predefined engine operating conditions. In each example operating condition, the exhaust turbine80provides a means of matching pressures within the flows46,48for communication into the mixer70. The matching of the flows46,48may include matching of pressures within a defined range and/or flow rates to provide efficient combination of the flows46,48in the mixer.

Operation of the mixer70and the exhaust turbine80may be combined to provide for combination of the first and second exhaust gas flows into the recombined flow72. In one disclosed example embodiment, the first and second exhaust gas flows46,48are controlled to correspond with a heat capacity of the cryogenic fuel flow38. In the disclosed example embodiment, control is provided by operation of the exhaust turbine80and the mixer70. However, other control devices and actuators could be utilized to tailor operation to match a capacity of the cryogenic fuel flow38to accept thermal energy.

Referring toFIG.3, another example propulsion system220is schematically shown and includes a fuel turboexpander90to extract additional shaft power and to increase the capacity of the cryogenic fuel38to accept thermal energy. Additionally, a second exhaust gas flow84is taken from an earlier stage in the turbine section30. In one example embodiment, the example turbine section30includes an aft turbine108and a forward turbine110. The forward turbine is immediately downstream of the combustor28. The aft turbine108is the last turbine section that is coupled to drive the compressor section26and fan24. Moreover, the aft turbine108includes an aft exit106where the first exhaust gas flow46is emitted. Although an example turbine section configuration is shown and described by example, other turbine sections with different configurations could be utilized within the contemplation and scope of this disclosure.

The first exhaust gas flow46is emitted from the aft exit of the aft turbine108. The second exhaust gas flow84is taken from a location82that is upstream of the aft exit106. The location82provides exhaust gas flows at a higher pressure than is emitted through the aft exit106. The increased pressure of the second exhaust gas flow84compensates for the pressure drop through the condenser50that is not experienced by the first exhaust gas flow46. The location82is illustrated by way of example as disposed within an aft turbine section108, but may be located anywhere within the turbine section30that provides pressures and temperatures that align with functioning of the condenser50, matching flows in the mixer and that corresponds with a heat capacity provided by the cryogenic fuel flow38.

The fuel turboexpander90provides a cooled portion88of the cryogenic fuel flow38that may provide an increased capacity to accept thermal energy. In one disclosed embodiment, a first portion86of the fuel flow38accepts heat within the heat exchanger68. The heat comes from a combination of the refrigerant circuit62and a cooled portion88of the fuel flow. The first portion86of the fuel flow is expanded and cooled through the fuel turboexpander90and communicated back through the heat exchanger68to accept an additional amount of heat. The cooled portion88of the fuel flow38is communicated to the combustor28. The increased cooling capacity of the cooled portion88of the fuel flow38accommodates increased temperatures that may be incurred by taking the second exhaust gas flow84from an earlier stage of the turbine section30.

Referring toFIG.4, another example propulsion system320is shown schematically and includes a steam turbine94for extracting work and reheating of a steam flow. The steam flow78is expanded through the steam turbine94to extract mechanical power. The mechanical power could drive accessory components for other engine systems. Expanded steam flow94may be directed back through the evaporator76for reheating or directed as a steam flow98for injection into the combustor28. In one example embodiment, steam flow is routed back through the evaporator76where it accepts additional thermal energy to generate a reheated steam flow96. The reheated steam flow96is injected into the combustor28.

Alternatively, the expanded flow98is not rerouted, but is directly injected into the combustor28. The expanded flow98may be a cooled steam flow, or may be a combination of liquid and steam that is injected into the combustor28. Moreover, steam exiting the steam turbine94may be routed as a combination and communicated directly to the combustor as the expanded flow98and directed through the evaporator and provided to the combustor as the reheated flow96. The proportion between the flows96,98may be varied to adapt to engine specific operating conditions.

Additionally, the example propulsion system320includes a second condenser92that is disposed upstream of the condenser50. The second condenser92is cooled by a different cold sink source than the condenser50. In the illustrated example, the second condenser92is cooled by the bypass airflow44. However, other cold sink flows could be utilized within the scope and contemplation of this disclosure. Water114may be initially extracted and the second exhaust flow84initially cooled by the second condenser92. An initial or precooling of the second exhaust gas flow84may aid water extraction downstream in the condenser50.

Referring toFIG.5with continued reference toFIG.4, a fuel injection nozzle100is schematically shown along a nozzle axis104. The nozzle100provides for injection of the fuel flow38and a steam flow112into a combustor cavity102. The steam flow112may be one of or a combination of the flows96,98. The example nozzle100is one example of targeted use of water extracted in the condenser50. In nozzle100the steam flow112shrouds the fuel flow38as illustrated in the embodiment shown inFIG.5. The steam flow112and fuel flow38may also be mixed and remain within the contemplation of this disclosure. A targeted amount of the steam flow112provides for the elimination of certain products of combustion and also controls stabilization of combustion of hydrogen fuels.

In the disclosed nozzle100, the steam flow112is injected through an annular channel or a plurality of radially outward openings surrounding the inner fuel flow38. The inner fuel flow38proceeds through a central opening disposed along the central nozzle axis104as is shown. Although an example nozzle100is shown, other nozzle configurations that combine steam or water flow with the fuel flow may be utilized and are within the contemplation and scope of this disclosure.

Referring toFIG.6, another example propulsion system is schematically shown and indicated at420and includes a second nozzle116. In the illustrated example, the second exhaust gas flow84is drawn from the location82forward of the aft exit opening106. A portion of water is extracted from the second exhaust gas flow84in the condenser50utilizing a combination of the refrigeration circuit62and the fuel flow38as a cold sink. Although the example cold sink is shown as the cryogenic fuel flow38, other cold sink, such as the bypass airflow44could also be utilized and are within the contemplation of this disclosure.

Exhaust gas exiting the condenser50is communicated through the second nozzle116instead of being recombined with the first exhaust gas flow46. By not recombining the first and second exhaust gas flows46,84, complications caused by differing pressures and flow are eliminated. Accordingly, the example propulsion system420does not includes a mixer or other features for addressing the differences in exit pressures between the separated first and second exhaust gas flows46,84.

Several example propulsion systems are disclosed by way of example with features that compliment operation with the split exhaust gas flows. Although specific features and components are described by way of example in combination, each of the features and components described in the various example embodiments could be combined differently and remain within the contemplation and scope of this disclosure.

Accordingly, extraction of water from only a portion of the exhaust gas flow as is shown and illustrated by the disclosed example propulsion systems can alleviate challenges presented by condensing all of the exhaust gas flow and combined with targeting the extracted water to specific uses can improve engine efficiency.

Although an example embodiment has been disclosed, this disclosure is not intended to be just a material specification but is instead illustrative such that a worker of ordinary skill in this art would recognize that certain modifications are within the scope and contemplation of this disclosure. For that reason, the following claims should be studied to determine the scope and content of this disclosure.