Patent Application
20240418125
The present disclosure relates to aircraft in general, and to an aircraft turbine engine system with turbine cooling in particular.
Turbine engines compress air, add fuel to the compressed air, and combust the air/fuel mixture. The combustion products are used to a power one or more turbine sections and in some instances is used to provide motive thrust. The aforesaid combustion products create a very high temperature environment that limits the types of materials that can be used in downstream components. To mitigate the high temperature environment, it is known to use cooling air to cool certain components exposed to the core flow path. The cooling lowers the component temperature and thereby makes it possible to construct the components from a material that has a lower maximum temperature threshold that would be required in the absence of cooling. Bleeding cooling air from the core flow path, however, very often negatively affects the efficiency of the engine since the work that can be performed by that air is dramatically reduced. Hence, there is always a need to improve turbine engine cooling to minimize the amount of bleed cooling air required.
According to an aspect of the present disclosure, an aircraft propulsion system is provided that includes a compressor section, a combustor section, a turbine section, a fuel source, a heat exchanger, a compressor bleed air passage, and a cooling air passage. The compressor section is configured to produce compressed air. The turbine section includes a vane stage and a rotor stage. The fuel source is configured to contain a non-hydrocarbon fuel. The heat exchanger has an air passage and a fuel passage. The air passage has an air inlet and outlet and is configured to permit a passage of the compressed air therethrough. The fuel passage is configured to permit a passage of the non-hydrocarbon fuel therethrough. The air and fuel passages are fluidically separate. The compressor bleed air passage is configured to receive compressed air bleed off a core flow path upstream of the combustor section. The compressor bleed air passage is in fluid communication with the air inlet of the heat exchanger air passage. The cooling air passage is configured to receive compressed air exiting the air outlet of the heat exchanger air passage and configured to direct the compressed bleed air exiting the air outlet of the heat exchanger air passage to the vane stage of the turbine section, or to the rotor stage of the turbine section, or both.
In any of the aspects or embodiments described above and herein, the vane stage may include a high pressure turbine (HPT) inlet guide vane stage and the rotor stage may include an HPT first rotor stage. The HPT inlet guide vane stage is disposed aft of the combustor section and the HPT first rotor stage is disposed aft of the HPT inlet guide vane stage. The cooling air passage may be configured to direct compressed bleed air exiting the air outlet of the heat exchanger air passage to the HPT inlet guide vane stage and to the HPT first rotor stage.
In any of the aspects or embodiments described above and herein, the cooling air passage may be configured to direct compressed bleed air to enter the HPT inlet guide vane stage and the HPT first rotor stage from an inner radial position.
In any of the aspects or embodiments described above and herein, the vane stage may further include an HPT second vane stage, wherein the HPT second vane stage is disposed aft of the HPT first rotor stage, and the cooling air passage may be configured to direct compressed bleed air exiting the air outlet of the heat exchanger air passage to the HPT second vane stage.
In any of the aspects or embodiments described above and herein, the cooling air passage may include a first cooling air passage segment and a second cooling air passage segment. The first cooling air passage segment may be configured to direct compressed bleed air to enter the HPT inlet guide vane stage and the HPT first rotor stage from an inner radial position, and the second cooling air passage segment may be configured to direct compressed bleed air to enter the HPT second vane stage from an outer radial position.
In any of the aspects or embodiments described above and herein, the system may further include a boost compressor configured to selectively increase the pressure of the compressed bleed air exiting the air outlet of the heat exchanger air passage, and the boost compressor may be in fluid communication with the first cooling air passage segment and the second cooling air passage segment.
In any of the aspects or embodiments described above and herein, the non-hydrocarbon fuel may include hydrogen.
In any of the aspects or embodiments described above and herein, the heat exchanger may be configured to permit the passage of the non-hydrocarbon fuel through the fuel passage in liquid form.
In any of the aspects or embodiments described above and herein, the compressor bleed air passage may be configured to receive compressed bleed air off the core flow path aft of the compressor and upstream of the combustor section.
According to an aspect of the present disclosure, a method of cooling an aircraft turbine engine is provided. The turbine engine includes a compressor section, a combustor section, a turbine section, and a fuel source. The method includes: providing a heat exchanger having an air passage that includes an air inlet and an air outlet, the air passage configured to permit a passage of air therethrough, and a fuel passage configured to permit a passage of a fuel therethrough, wherein the air passage and the fuel passage are fluidically separate; bleeding compressed air off of a core flow path upstream of the combustor section and directing the compressed bleed air through the heat exchanger air passage; directing the fuel through the heat exchanger fuel passage; and directing the compressed bleed air exiting the air outlet of the heat exchanger to a vane stage of the turbine section, or to a rotor stage of the turbine section, or both.
In any of the aspects or embodiments described above and herein, the fuel may include a non-hydrocarbon fuel.
In any of the aspects or embodiments described above and herein, the method may include directing compressed bleed air exiting the air outlet of the heat exchanger air passage to the HPT inlet guide vane stage and to the HPT first rotor stage.
In any of the aspects or embodiments described above and herein, the method may include directing compressed bleed air to the HPT inlet guide vane stage and to the HPT first rotor stage from an inner radial position.
In any of the aspects or embodiments described above and herein, the method may include directing compressed bleed air to the HPT second vane stage.
In any of the aspects or embodiments described above and herein, the method may include directing compressed bleed air to the HPT second vane stage from an outer radial position.
In any of the aspects or embodiments described above and herein, a boost compressor may be used to selectively increase the pressure of the compressed bleed air exiting the air outlet of the heat exchanger air passage.
In any of the aspects or embodiments described above and herein, the method may include bleeding compressed air from the core flow path aft of the compressor and upstream of the combustor section.
The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. For example, aspects and/or embodiments of the present disclosure may include any one or more of the individual features or elements disclosed above and/or below alone or in any combination thereof. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, the following description and drawings are intended to be exemplary in nature and non-limiting.
The turbine engine extends axially along an axis between an upstream, forward end and a downstream, aft end. The turbine engine includes a compressor section having a low pressure compressor (LPC) and a high pressure compressor (HPC), a combustor, and a turbine section having a high pressure turbine (HPT) and a low pressure turbine (LPT). In the exemplary engine embodiment shown in
As indicated above,
As indicated herein, embodiments of the present disclosure propulsion system 18 may be directed to a turbine engine 20 configured to combust non-hydrocarbon fuels such as hydrogen. Other embodiments of the present disclosure propulsion system 18 may be directed to a turbine engine 20 configured to combust hydrocarbon fuels; e.g., aviation fuel. In some present disclosure embodiments, the turbine engine 20 may be configured to combust a fuel that is 100% non-hydrocarbon; e.g., 100% H2. In some embodiments, the turbine engine 20 may be configured to combust a fuel that is less than 100% non-hydrocarbon; e.g., a mixture of H2 and a hydrocarbon fuel (e.g., aviation fuel). In some embodiments, the turbine engine 20 may be configured to combust a fuel that is 100% hydrocarbon based. The present disclosure is not limited to any combusting any particular fuel. In those embodiments wherein the present disclosure system combusts hydrogen, the present disclosure may include a fuel source 64 configured to store the hydrogen in liquid form.
Referring to
As will be described herein, prior to combusting the non-hydrocarbon fuel to produce motive power, the present disclosure system 18 uses the non-hydrocarbon fuel as a coolant. Hence, the present disclosure includes at least one heat exchanger 66 configured to receive the non-hydrocarbon fuel and another fluid (e.g., air). The present disclosure is not limited to using the non-hydrogen fuel to cool a single fluid. Aspects of the present disclosure may use the non-hydrocarbon fuel for a variety of purposes; e.g., cooling more than one fluid, to condense water vapor, to power a turboexpander, and the like. Air cooled within the system 18 may, in turn, be used to cool engine components; e.g., compressor components, combustor components, turbine components, and the like. In those systems 18 wherein more than one fluid is cooled, the system 18 may include more than one heat exchanger; e.g., a heat exchanger for each different fluid being cooled. In addition to heat exchangers, the system for handling the non-hydrogen fuel prior to combustion may include other components for handling the non-hydrogen fuel; e.g., valving, metering devices, regulators, and the like. Examples of how the present disclosure may be configured and operated to utilize non-hydrogen fuel to cool turbine components are described herein. The present disclosure is not limited to any particular system for handling the non-hydrogen fuel prior to combustion other than one that includes turbine cooling as described herein, however, and may include additional components for different functionalities. In those embodiments wherein the fuel is 100% hydrocarbon based, the hydrocarbon fuel may in certain applications be used as a coolant in the manner described above regarding a non-hydrocarbon fuel.
As is diagrammatically shown in
Referring to
The compressor bleed air exiting the heat exchanger 66 is directed to the turbine section 22 to be used, for example, as cooling air within turbine section components. The compressor bleed air (now cooled) passes from the heat exchanger 66 to the turbine section 22 via a cooling air passage 88. Bleed air introduced into the turbine section 22 must be at a pressure and temperature useful for such purpose; e.g., at a temperature that can accomplish useful component cooling and at a pressure sufficient to drive the bleed air to and through the respective turbine component to be cooled. In some applications, the present disclosure system 18 may include a boost compressor 90 to increase the pressure of the bleed air that has traversed the heat exchanger 66. As will be detailed herein, in some embodiments the compressor bleed air may be directed to different components within the turbine section 22. In such embodiments, the cooling air passage 88 may include a plurality of cooling air passage segments 88A, 88B, with each cooling air passage segment 88A, 88B directed to one or more different turbine section components.
The cooling requirements of the first few stages of the HPT (e.g., the inlet guide vane stage 28, the first rotor stage 30, the second vane stage 32, the second rotor stage 34, turbine shroud 92) in any given engine typically vary as a function of several different parameters. For example, the cooling requirements may vary as a function of the axial position of the component; e.g., gas within the core path flow 82 typically decreases in temperature as it travels axially aft. As another example, the cooling requirement of individual turbine components may vary as a function of their configuration. Examples of component cooling configurations include exterior film cooling, impingement cooling, internal cooling ducts, and the like, and combinations thereof. The present disclosure is not limited to use with any particular component cooling configuration.
The system example shown in
Regarding the HPT first rotor stage 30, the cooled compressor bleed air may be directed to a cavity in fluid communication with cooling air inlets disposed in the rotor hub 46 and/or the respective rotor blades 44A. Cooled compressor bleed air passes from the cavity to the hub 46 and then to the rotor blades 44A, and/or directly into the rotor blades 44A. The hub 46 and rotor blades 44A may be configured with one or more flow paths directing the cooling air to specific regions within each rotor blade 44A. For example, each rotor blade 44A may be configured with a flow path that directs the cooling air to the leading edge of that rotor blade 44A, or to the trailing edge of that rotor blade 44A, and so on. The cooled compressor bleed air may be directed through the walls of the respective rotor blade 44A and into the core flow path 82.
The aforesaid examples of where cooled compressor bleed air may be directed are provided to illustrate how the cooled compressor bleed air may be utilized. The present disclosure is not limited to these examples. For instance, cooled compressor bleed air directed to the outer radial position may be alternatively or in combination be directed to the turbine shroud 92 of the HPT first rotor stage 30 or elsewhere.
The present disclosure provides numerous advantages. A person of skill in the art will recognize that compressor bleed air is “expensive” in terms of engine efficiency. Consequently, it is very often desirable to minimize the amount of compressor air bled for cooling purposes. The utilization of significantly lower temperature non-hydrocarbon fuel as a cooling medium to cool the compressor bleed air is understood to either provide additional cooling in comparison to cooling that would be provided by the same amount of “untreated” compressor bleed air, or to provide the same amount of cooling that would be provided by “untreated” compressor bleed air now using less compressor bleed air.
While the principles of the disclosure have been described above in connection with specific apparatuses and methods, it is to be clearly understood that this description is made only by way of example and not as limitation on the scope of the disclosure. Specific details are given in the above description to provide a thorough understanding of the embodiments. However, it is understood that the embodiments may be practiced without these specific details.
It is noted that the embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a block diagram, etc. Although any one of these structures may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. The singular forms “a,” “an,” and “the” refer to one or more than one, unless the context clearly dictates otherwise. For example, the term “comprising a specimen” includes single or plural specimens and is considered equivalent to the phrase “comprising at least one specimen.” The term “or” refers to a single element of stated alternative elements or a combination of two or more elements unless the context clearly indicates otherwise. As used herein, “comprises” means “includes.” Thus, “comprising A or B,” means “including A or B, or A and B,” without excluding additional elements.
It is noted that various connections are set forth between elements in the present description and drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. Any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option.
No element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112 (f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprise”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While various inventive aspects, concepts and features of the disclosures may be described and illustrated herein as embodied in combination in the exemplary embodiments, these various aspects, concepts, and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present application. Still further, while various alternative embodiments as to the various aspects, concepts, and features of the disclosures—such as alternative materials, structures, configurations, methods, devices, and components, and so on—may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts, or features into additional embodiments and uses within the scope of the present application even if such embodiments are not expressly disclosed herein. For example, in the exemplary embodiments described above within the Detailed Description portion of the present specification, elements may be described as individual units and shown as independent of one another to facilitate the description. In alternative embodiments, such elements may be configured as combined elements. It is further noted that various method or process steps for embodiments of the present disclosure are described herein. The description may present method and/or process steps as a particular sequence. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the description should not be construed as a limitation.
