Transonic turbine engine with circumferential critical fluid system

Abstract

A near-critical fluid system of a thermal management system associated with a turbine engine can include one or more sensors configured to generate sensor outputs corresponding to one or more phase properties of a near-critical fluid flowing through a cooling loop of the thermal management system, and a controller configured to generate control commands based at least in part on the sensor outputs, the control commands configured to control one or more controllable components of the thermal management system. The one or more sensors can include one or more phase detection sensors, such as acoustic sensors.

Description

Technical Field

[0001] This disclosure generally relates to monitoring and controlling the phase properties of pericritical fluids, including supercritical and near-supercritical fluids. More particularly, this disclosure generally relates to pericritical fluids used in conjunction with engines, such as turbine engines, including thermal management systems and fuel systems that utilize pericritical fluids. Background Technology

[0002] Engines such as turbine engines can utilize pericritical fluids for a variety of purposes. These pericritical fluids can be used when exhibiting near-supercritical or supercritical phase states. For example, pericritical fluids can be used in near-supercritical or supercritical states to cool various fluid flows or components of an engine. As another example, engines can use fuels with pericritical states, such as near-supercritical or supercritical phase states.

[0003] One or more operations of an engine may be affected by the phase state of such a pericritical fluid. For example, an engine may be configured to use a pericritical fluid in a pericritical phase state (such as a near-supercritical phase state and / or a supercritical phase state). Additionally or alternatively, one or more operations of the engine may be affected by changes in one or more phase properties of the pericritical fluid (such as changes corresponding to phase transitions in the pericritical fluid and / or changes that may occur within the corresponding phase state of the pericritical fluid). Attached Figure Description

[0004] The specification with reference to the accompanying drawings sets forth a complete and feasible disclosure for those skilled in the art, including its best mode, wherein:

[0005] Figure 1 An exemplary power generation system including an engine and a pericritical fluid system is schematically depicted;

[0006] Figures 2A-2E Exemplary thermal management systems are schematically depicted, which may use or include features such as those described above. Figure 1 A pericritical fluid system combining a power generation system and / or an engine;

[0007] Figure 3A and 3B Exemplary fuel systems are schematically depicted, which may use or include, for example, fuel systems with... Figure 1 A pericritical fluid system combining a power generation system and / or an engine;

[0008] Figure 4 An exemplary circumcritical fluid system is schematically depicted, which can be composed of... Figures 2A-2E Exemplary thermal management systems use or include Figures 2A-2E In an exemplary thermal management system, and / or may be Figure 3A and 3B Exemplary fuel systems used or included Figure 3A and 3B An exemplary fuel system;

[0009] Figures 5A-5D An exemplary phase diagram of a fluid with respect to temperature and pressure is schematically depicted;

[0010] Figure 5E An exemplary phase diagram of a fluid with respect to pressure and density is schematically depicted;

[0011] Figure 6 An exemplary control system that can be used for controllable operation according to this disclosure is schematically depicted; and

[0012] Figure 7 A flowchart depicting an exemplary method for controlling the phase state of a fluid, such as that integrated with a thermal management system or a fuel system, is shown.

[0013] The repeated use of reference characters in this specification and drawings is intended to indicate the same or similar features or elements of this disclosure. Detailed Implementation

[0014] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation rather than limitation of the present disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from its scope or spirit. For example, features shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the present disclosure is intended to cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0015] The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as superior or better than other implementations. Additionally, unless explicitly stated otherwise, all embodiments described herein should be considered exemplary.

[0016] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of the individual components.

[0017] The terms “up,” “down,” “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” “lateral,” “longitudinal,” etc., should be used in relation to their orientation in the accompanying drawings. However, it should be understood that various alternative orientations may be assumed in this disclosure unless explicitly stated otherwise. It should also be understood that the specific devices shown in the drawings and described in the following description are merely exemplary embodiments of this disclosure. Therefore, the specific dimensions and other physical characteristics associated with the embodiments disclosed herein should not be considered limiting.

[0018] The terms "front" and "rear" refer to relative positions within a turbocharged engine, with "front" referring to the position closer to the engine inlet and "rear" referring to the position closer to the engine nozzle or exhaust port.

[0019] The terms "upstream" and "downstream" refer to the relative directions of fluid flow within a fluid path. For example, "upstream" refers to the direction from which the fluid flows, while "downstream" refers to the direction from which the fluid flows.

[0020] Unless the context clearly indicates otherwise, the singular forms “a,” “a,” and “the” include plural references.

[0021] Unless otherwise specified herein, the terms “connection,” “fixed,” “attached to,” etc., refer to both direct connection, fixation, or attachment, and indirect connection, fixation, or attachment via one or more intermediate components or features.

[0022] As used throughout the specification and claims, approximate language is applied to modify any quantitative expression that allows for variation without altering its underlying function. Therefore, values ​​modified by terms such as “about,” “approximate,” and “substantially” are not limited to specified exact values. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value, or the precision of the method or machine used to construct or manufacture the component and / or system. For example, approximate language may refer to a margin of 1%, 2%, 4%, 10%, 15%, or 20%.

[0023] Throughout this specification and claims, scope limitations are combined and interchanged, and unless the context or language otherwise indicates otherwise, such scopes are identified and include all subscopes contained herein. For example, all scopes disclosed herein include endpoints, and endpoints may be combined independently of each other.

[0024] In a context such as “at least one of A, B and C”, the term “at least one” means only A, only B, only C, or any combination of A, B and C.

[0025] Additionally, unless otherwise specified, the terms “low,” “high,” or their corresponding comparatives (e.g., lower, higher, where applicable) each refer to a relative speed within the engine. For example, a “low-pressure turbine” operates at a pressure substantially lower than that of a “high-pressure turbine.” Alternatively, unless otherwise specified, the above terms may be understood in their superlative degree. For example, a “low-pressure turbine” may refer to the turbine with the lowest maximum pressure within the turbine section, while a “high-pressure turbine” may refer to the turbine with the highest maximum pressure within the turbine section.

[0026] The term "turbine" refers to a machine that includes a combustor section and a turbine section having one or more turbines, which together generate thrust output and / or torque output. In some embodiments, the turbine may include a compressor section having one or more compressors that compress air or gas flowing to the combustor section.

[0027] As used herein, the term "turbo engine" refers to an engine that may include a turbine as a power source, in whole or in part. Examples of turbo engines include gas turbine engines and hybrid electric turbine engines, such as turbofan engines, turboprop engines, turbojet engines, turboshaft engines, etc.

[0028] One or more components of the engine described herein can be manufactured or formed using any suitable process, such as additive manufacturing or 3D printing. The use of such a process can allow the component to be formed integrally, as a single monolithic part, or as any suitable number of sub-parts. In particular, additive manufacturing processes can allow the integral formation of such components and include various features that would be impossible to achieve using prior manufacturing methods. For example, the additive manufacturing methods described herein can allow the manufacture, or specific positioning and integration, of unique features, constructions, thicknesses, materials, densities, fluid passages, manifolds and mounting structures, channels, conduits, cavities, openings, housings, manifolds, double walls, heat exchangers, or other components that might be impossible or impractical using prior manufacturing methods. Some of these features are described herein.

[0029] Suitable additive manufacturing techniques according to this disclosure include, for example, selective laser melting (SLM), direct metal laser melting (DMLM), fused deposition modeling (FDM), selective laser sintering (SLS), 3D printing such as by inkjet, laser jetting and binder jetting, stereolithography (SLA), direct selective laser sintering (DSLS), electron beam sintering (EBS), electron beam melting (EBM), laser engineered net forming (LENS), laser net forming manufacturing (LNSM), direct metal deposition (DMD), digital light processing (DLP), direct selective laser melting (DSLM) and other known processes.

[0030] Suitable powder materials for manufacturing the structures provided herein as a single, integral structure include metal alloys, polymers, or ceramic powders. Exemplary metal powder materials are stainless steel alloys, cobalt-chromium alloys, aluminum alloys, titanium alloys, nickel-based superalloys, and cobalt-based superalloys. Additionally, suitable alloys may include those designed to have good oxidation resistance, referred to as “superalloys,” which possess acceptable strength at elevated operating temperatures in turbine engines, such as Hastelloy, Inconel alloys (e.g., IN 738, IN 792, IN 939), Rene alloys (e.g., Rene N4, Rene N5, Rene 80, Rene 142, Rene 195), Haynes alloys, Mar M, CM 247, CM 247LC, C263, 718, X-850, ECY 768, 282, X45, PWA 1483, and CMSX (e.g., CMSX-4) single-crystal alloys. The manufactured objects disclosed herein can be formed having one or more selected crystalline microstructures, such as directional solidification (“DS”) or single crystals (“SX”).

[0031] As used herein, the terms "monolithic," "single," or "monolithic" to describe a structure mean that the structure is formed monolithically from a continuous material or group of materials, without seams, joints, etc. The monolithic, single structures described herein can be formed to have the structure by additive manufacturing, or alternatively, by casting or the like.

[0032] This disclosure generally provides systems and methods for monitoring and / or controlling the phase properties of pericritical fluids, including supercritical and near-supercritical fluids. Such pericritical fluids can be used in conjunction with engines (such as turbine engines), for example, as a cooling fluid and / or as fuel. This disclosure provides pericritical fluid systems that can be used to monitor and / or control one or more phase properties of the pericritical fluid, such as its phase state. In some embodiments, the pericritical fluid system may be used by and / or included as part of a thermal management system associated with an engine. The thermal management system may use the pericritical fluid, for example, to cool one or more fluid flows associated with the engine and / or to cool one or more components on the engine. Additionally or alternatively, in some embodiments, the pericritical fluid system may be used by and / or included as part of a fuel system associated with an engine. The fuel system may use the pericritical fluid as a fuel source for the engine. The pericritical fluid system may include one or more sensors configured to generate sensor outputs that the control system may use to perform control operations, such as control operations associated with the pericritical fluid system. The sensor output can be used to monitor one or more phase properties of the pericritical fluid. The control system can provide control commands to one or more controllable components, for example, to control one or more phase properties of the pericritical fluid.

[0033] According to this disclosure, one or more sensors used in a pericritical fluid system may include a phase detection sensor configured to generate a sensor output that can be correlated with one or more phase properties of the pericritical fluid, such as the phase state of the pericritical fluid. In some embodiments, the sensor output from the phase detection sensor can be used to determine one or more phase properties of the fluid. Additionally or alternatively, the sensor output from the phase detection sensor can be used in combination with further sensor outputs from one or more temperature sensors and / or pressure sensors. For example, the sensor output from the phase detection sensor can indicate a change in one or more phase properties of the pericritical fluid, and the sensor outputs from one or more temperature sensors and / or pressure sensors can be used to correlate the change in one or more phase properties of the pericritical fluid with the phase state of the pericritical fluid. In other words, in some embodiments, the sensor output from the phase detection sensor can be used to indicate that some change in one or more phase properties of the pericritical fluid has occurred, and the sensor outputs from one or more temperature sensors and / or pressure sensors can be used to correlate the change with a specific phase state of the pericritical fluid. Additionally or alternatively, in some embodiments, for example, one or more sensor outputs from a phase detection sensor can be used to determine one or more phase properties of the pericritical fluid, such as the phase state of the pericritical fluid, without referencing other sensor outputs such as those from a temperature sensor and / or a pressure sensor.

[0034] As used herein, the term "pericritical fluid" refers to a fluid that has a supercritical or near-supercritical phase. The term "pericritical fluid" includes fluids that constitute supercritical or near-supercritical fluids. A fluid may be described as having a pericritical phase when it possesses the temperature and pressure corresponding to its pericritical phase.

[0035] As used herein, the term "supercritical fluid" refers to a fluid having a temperature and pressure exceeding its critical point. A fluid may be described as having a supercritical phase when it has a temperature exceeding its critical temperature and a pressure exceeding its critical pressure.

[0036] As used herein, the term "near-supercritical fluid" refers to a fluid other than a supercritical fluid that has a temperature at least 70% of the fluid's critical temperature calculated from absolute temperature and a pressure at least 70% of the fluid's critical pressure calculated from absolute pressure. A near-supercritical fluid may have a temperature above the fluid's critical temperature and a pressure below the fluid's critical pressure, or a near-supercritical fluid may have a pressure above the fluid's critical pressure and a temperature below the fluid's critical temperature. When a fluid has the temperature and pressure corresponding to its near-supercritical phase, the fluid may be described as having a near-supercritical phase. A near-supercritical fluid may be in a liquid phase or a gaseous phase.

[0037] As used herein, the term "critical temperature" refers to the temperature above which a gas cannot be liquefied by pressure alone. As used herein, the term "critical pressure" refers to the pressure required to liquefy a gas at its critical temperature. As used herein, the term "critical point" for fluids refers to the point defined by the fluid's critical temperature and critical pressure.

[0038] As used herein, the term "phase property" refers to the phase state of a fluid, or the physical properties of a fluid that depend on the phase state of the fluid, and includes the phase state of a fluid, or the physical properties of a fluid that depend on the phase state of the fluid. The phase properties of a fluid can differ between different phases, for example, between at least two of the following: liquid phase, gas phase, near-supercritical phase, and supercritical phase. Additionally or alternatively, the phase properties of a fluid can differ between different phase states, including differences between different phase states within a given phase. As examples, the physical properties of a fluid that depend on the phase state of the fluid and are covered by the term "phase property" include: density, heat capacity, refractive index, thermal conductivity, viscosity, and coefficient of thermal expansion.

[0039] As used herein, the term "phase" refers to the conditions of a fluid relative to a phase of the fluid and / or a region within a phase of the fluid. As an example, the phase of a fluid may include and refer to the conditions of a fluid relative to a region of a pericritical phase or within a pericritical phase, a supercritical phase or within a supercritical phase, a near-supercritical phase or within a near-supercritical phase, a gas phase or within a gas phase, or a liquid phase or within a liquid phase.

[0040] In some embodiments, the fluid may include a single component. In some embodiments, the fluid may include at least two components. A fluid having two components is sometimes referred to as a bimodal fluid. Such a combination of two fluid components is sometimes referred to as a bimodal combination. A fluid having at least two components is sometimes referred to as a multimodal fluid. The term multimodal fluid includes bimodal fluid. A combination of at least two fluid components is sometimes referred to as a multimodal combination.

[0041] As used herein, the term "multiphase" refers to a fluid comprising multiple components, each having a different phase. As used herein, the term "multiphase region" refers to a region of a phase diagram of a multiphase fluid having multiple phases. For example, a multiphase fluid may include a first fluid component and a second fluid component, and the first and second fluid components may each have: a liquid phase and a gas phase, a liquid phase and a pericritical phase, a gas phase and a pericritical phase, a liquid phase and a supercritical phase, a liquid phase and a near-supercritical phase, a gas phase and a supercritical phase, a gas phase and a near-supercritical phase, or a supercritical phase and a near-supercritical phase.

[0042] As an example, suitable fluids that may be used according to this disclosure include carbon monoxide, carbon dioxide, ammonia, methane, methanol, ethanol, ethylene, propane, propylene, heptane, 1-octanol, 2-octanol, 2-propanol, difluoromethane, ethane, difluoroethane, tetrafluoroethylene, acetone, nitrous oxide, argon, bromine, neon, hydrogen, oxygen, or water, and combinations thereof. In some embodiments, a bimodal or multimodal fluid may include one or more of the exemplary fluids described above, such as at least two of the exemplary fluids described above. As an example, a bimodal or multimodal fluid may include at least one of the following: carbon dioxide and nitrogen; carbon dioxide and hydrogen; carbon dioxide and oxygen; carbon dioxide and methane; carbon dioxide and heptane; carbon dioxide and 1-octanol; carbon dioxide and 2-octanol; carbon dioxide, nitrogen, and ethane; carbon dioxide, hydrogen, and ethane; and carbon dioxide, 2-propanol, and nitrogen.

[0043] As an example, some critical points for exemplary fluids are as follows: carbon monoxide: about 133.2 K and about 3.5 MPa; carbon dioxide: about 304.2 K and about 7.4 MPa; ammonia: about 405.5 K and about 11.3 MPa; methane: about 190.6 K and about 4.6 MPa; methanol: about 512.6 K and about 8.1 MPa; ethanol: about 516.3 K and about 6.4 MPa; ethylene: about 282.4 K and about 5.1 MPa; propane: about 369.9 K and about 4.3 MPa; propylene: about 365.6 K and about 4.7 MPa; heptane: about 540.6 K and about 2.7 MPa; 1-octanol: about 655.1 K and about 2.7 MPa; 2-octanol: about 632.7 K and about 2. 8 MPa; 2-propanol: about 508.8 K and 5.4 MPa; difluoromethane: about 304.1 K and about 7.38 MPa; ethane: about 3.5.5 K and about 4.9 MPa; difluoroethane: about 351 K and about 5.8 MPa; tetrafluoroethylene: about 306.5 K and about 3.8 MPa; acetone: about 508 K and about 4.8 MPa; nitrous oxide: about 309.6 K and about 7.3 MPa; argon: about 150.7 K and about 4.9 MPa; bromine: about 588 K and about 10.3 MPa; neon: about 44.4 K and about 2.8 MPa; hydrogen: about 33.2 K and about 1.3 MPa; oxygen: about 154.6 K and about 5.1 MPa; and water: about 647.1 K and about 22.1 MPa.

[0044] Exemplary embodiments of this disclosure will now be described in more detail. References Figure 1An exemplary power generation system 100 is shown. The exemplary power generation system 100 may include an engine 102, such as a turbine engine. The engine 102 may be mounted to an aircraft, such as a fixed-wing or rotary-wing aircraft. The power generation system 100 may be configured to provide propulsion and / or thrust, such as during flight and / or during ground maneuvers, thereby powering the aircraft. The engine 102 may be mounted to the aircraft, such as in an underwing configuration or a tail-mounted configuration. In other embodiments, the engine 102 may be configured as a rocket engine, a ramjet engine, a turborocket engine comprising a combination of a turbine and a rocket engine, a turboramjet engine comprising a combination of a turbine and a ramjet engine, or a rocket ramjet engine comprising a combination of a rocket engine and a ramjet engine.

[0045] like Figure 1 As shown, in some embodiments, the power generation system 100 and / or the engine 102 may include a thermal management system 200. The thermal management system 200 may be configured to transfer heat from one or more heat sources associated with the engine 102 and / or the power generation system 100. The thermal management system 200 may be configured to circulate cooling fluid through a cooling loop, and heat from the one or more heat sources may be transferred to the cooling fluid. In some embodiments, the cooling fluid may have a pericritical phase state, such as a supercritical phase state and / or a near-supercritical phase state, when circulating through the cooling loop. Further as... Figure 1 As shown, in some embodiments, the power generation system 100 and / or engine 102 may include a fuel system 300. The fuel system 300 may be configured to supply fuel to the engine 102. In some embodiments, the fuel may be a cryogenic fuel. According to this disclosure, the power generation system 100 and / or engine 102 may include a pericritical fluid system 400, such as... Figure 1 As shown. In some embodiments, the peripheral critical fluid system 400 may be used in conjunction with the thermal management system 200. Additionally or alternatively, the peripheral critical fluid system 400 may be used in conjunction with the fuel system 300.

[0046] The currently disclosed subject matter can be implemented in any desired setting (such as land vehicles, ships, power generation facilities, manufacturing facilities, industrial machinery, etc.) including power generation system 100 and / or engines. In the context of aircraft, the currently disclosed subject matter can be implemented in any desired fixed-wing or rotary-wing aircraft, including commercial, military, or civil aircraft and unmanned aerial vehicles (such as unmanned aerial vehicles, drones, etc.). The currently disclosed subject matter can be useful in many other settings and is intended to be implemented in any setting without departing from the intended scope of this disclosure.

[0047] Now for reference Figures 2A-2EThe exemplary thermal management system 200 is further described. Figures 2A-2E As shown, an exemplary thermal management system 200 may include one or more heat exchangers 202, each configured to cool a fluid flow 204 associated with an engine 102 and / or a power generation system 100. The fluid flow 204 flowing through a respective heat exchanger 202 may be cooled by a cooling fluid 206 flowing through a cooling circuit 208. The cooling fluid 206 may be a pericritical fluid, such as a supercritical or near-supercritical fluid. The cooling circuit 208 may include one or more cooling conduits 210. The one or more cooling conduits 210 may be configured to supply the cooling fluid 206 to the one or more heat exchangers 202, for example, the cooling fluid 206 having a pericritical phase, such as a supercritical phase and / or a near-supercritical phase. The one or more cooling conduits 210 may be at least partially defined by the structure of the one or more heat exchangers 202 (such as the overall structure of the one or more heat exchangers 202). The cooling circuit 208 may include one or more cooling conduits 210 and may be configured to receive cooling fluid 206 discharged from the one or more heat exchangers 202.

[0048] During operation, cooling fluid 206 may be supplied to one or more heat exchangers 202 and / or circulated through cooling circuit 208 in a pericritical phase state. Additionally or alternatively, cooling fluid 206 may have a pericritical phase state as it flows through one or more heat exchangers 202 and / or circulates through cooling circuit 208. Cooling circuit 208 may include pump 212 configured to circulate cooling fluid 206 through cooling circuit 208. In some embodiments, thermal management system 200 and / or cooling circuit 208 may include refrigeration system 214 configured to bring cooling fluid 206 into a pericritical phase state and / or maintain cooling fluid 206 in a pericritical phase state, such as a supercritical phase state and / or a near-supercritical phase state. Refrigeration system 214 may include components configured to perform any suitable refrigeration cycle, such as evaporative cooling, absorption refrigeration, thermoelectric refrigeration or mechanical compression refrigeration, cryogenic refrigeration, and combinations thereof. Additionally or alternatively, the refrigeration system 214, such as a refrigeration system 214 configured to perform cryogenic refrigeration, may include a cryogenic cooler, such as a Stirling cooler, a Gifford-McMahon cooler, a pulse tube cooler, or a Joule-Thomson cooler, and combinations thereof. Additionally or alternatively, the cooling circuit 208 may include any other suitable source of the cooling fluid 206, such as a tank or container configured to supply the cooling fluid 206 to the cooling circuit 208, for example, the cooling fluid 206 having a circumcritical phase. The cooling circuit 208 may include one or more cooling fluid control valves 224 configured to control the flow rate of the cooling fluid 206 flowing through the cooling circuit 208. Additionally or alternatively, the thermal management system 200 may include one or more fluid flow control valves 226 configured to control the flow rate of the fluid flow 204 flowing through a respective heat exchanger 202.

[0049] For example, such as Figure 2AAs shown, in some embodiments, the thermal management system 200 may include a plurality of heat exchangers 202. As an example, the thermal management system 200 may include a first heat exchanger 216 configured to cool a first fluid flow 204 passing through a first fluid conduit 218. The first fluid conduit 218 may be at least partially defined by the structure of the first heat exchanger 216 (such as the overall structure of the first heat exchanger 216). The first fluid conduit 218 may include one or more fluid supply lines in fluid communication with the first heat exchanger 216 and configured to supply the first fluid 204 to and / or receive the first fluid 204 flowing out of the first heat exchanger 216. Additionally or alternatively, the thermal management system 200 may include a second heat exchanger 220 configured to cool a second fluid flow 204 passing through a second fluid conduit 222. The second fluid conduit 222 may be at least partially defined by the structure of the second heat exchanger 220 (such as the overall structure of the second heat exchanger 220). The second fluid conduit 222 may include one or more fluid supply lines that are in fluid communication with the second heat exchanger 220 and are configured to supply the second fluid 204 to the second heat exchanger 220 and / or receive the second fluid 204 flowing out of the second heat exchanger 220.

[0050] In some embodiments, such as Figure 2A As shown, the cooling circuit 208 can be configured as a heat transfer bus, which includes a plurality of heat exchangers 202, such as a first heat exchanger 216 and a second heat exchanger 220 respectively configured to transfer heat from the fluid flow 204 to the cooling fluid 206. As an example, a corresponding heat exchanger among the plurality of heat exchangers 202 may include a fuel system heat exchanger, a lubrication system heat exchanger, a reservoir heat exchanger, a bleed air heat exchanger, a compressor cooling air heat exchanger, a thermal gap control heat exchanger, an engine housing heat exchanger, an environmental control system heat exchanger, or an auxiliary system heat exchanger. Additionally or alternatively, the thermal management system 200 may include any other heat exchangers used in conjunction with the power generation system 100, the engine 102, and / or a vehicle powered by the engine 102.

[0051] For example, such as Figure 2BAs shown, in some embodiments, the fluid flow 204 cooled by one or more heat exchangers 202 may include working fluid used by the engine 102 and / or power generation system 100. In some embodiments, the engine 102 may be configured as a turbine engine, and the fluid flow 204 may include intake air 230 flowing into the compressor section of the turbine engine. One or more heat exchangers 202 may include a precooler 232 configured to precool the intake air 230 supplied to the compressor section of the turbine engine. As shown, a fluid flow control valve 226, such as a variable geometry inlet pipe 234, may be configured to control the flow rate of the intake air 230 flowing through the precooler 232. Additionally or alternatively, for example, as Figure 2C As shown, in some embodiments, engine 102 may be configured as a turbine engine, and fluid flow 204 may include compressor bleed air 236 from the compressor section of the turbine engine. Compressor bleed air 236 may be used to cool components of the turbine engine, such as blades, hubs, and / or housings of the turbine section. Compressor bleed air 236 may be used additionally or alternatively by one or more auxiliary systems associated with engine 102 and / or power generation system 100. For example, fluid flow 204 may be used by an environmental control system, which may be configured to provide pressurization and / or temperature control to other areas of the cabin or aircraft. One or more heat exchangers 202 may include bleed air heat exchangers 238 configured to cool the compressor bleed air 236 before use for cooling such components of the turbine engine and / or before use by such an environmental control system. As shown, fluid flow control valve 226, such as bleed air control valve 240, may be configured to control the flow rate of compressor bleed air 236 flowing through bleed air heat exchangers 238.

[0052] For example, such as Figure 2D and 2E As shown, in some embodiments, cooling fluid 206 can be used to cool one or more components 242 of engine 102. In some embodiments, such as Figure 2D As shown, one or more components 242 of engine 102 may define at least a portion of one or more cooling conduits 210 of cooling circuit 208. For example, cooling fluid 206 may flow through one or more cooling conduits 210, which are defined by the structure of one or more components 242 of engine 102 (such as the overall structure of one or more components of engine 102). Additionally or alternatively, one or more components 242 of engine 102 cooled by cooling fluid 206 may define a heat exchanger 202 through which cooling fluid 206 may flow. For example, heat exchanger 202 may be defined by the structure of one or more components 242 of engine 102 (such as the overall structure of one or more components of engine 102).

[0053] In some embodiments, one or more components 242 of the engine cooled by the cooling fluid 206 may include an engine housing. For example, in some embodiments, the engine 102 may be configured as a hybrid electric turbine engine, and one or more components 242 cooled by the cooling fluid 206 may include one or more components of an electric motor, such as a rotor, stator, and / or housing of the electric motor. As another example, the engine 102 may be configured as a turbine engine, and one or more components 242 cooled by the cooling fluid 206 may include a plurality of turbine blades, a plurality of stator blades, a plurality of turbine hubs, and / or one or more housing elements surrounding a turbine section of the turbine engine.

[0054] In some embodiments, such as Figure 2E As shown, the thermal management system 200 may include a primary cooling circuit 244 and an intermediate cooling circuit 246. The primary cooling circuit 244 may be configured to cool one or more components 242 of the engine 102 by transferring heat to a primary cooling fluid 248 flowing through the primary cooling circuit 244. As an example, the primary cooling fluid 248 may include oil, liquid hydrocarbon-based material, dielectric fluid, liquid metal, or any other fluid suitable for use as the primary cooling fluid 248.

[0055] One or more components 242 of engine 102 may define one or more heat exchangers 202 through which primary cooling fluid 248 may flow. For example, heat exchangers 202 may be defined by the structure of one or more components 242 of engine 102 (such as the overall structure of one or more components of engine 102). Additionally or alternatively, primary cooling circuit 244 may include one or more primary cooling conduits 250. One or more primary cooling conduits 250 may be configured to supply primary cooling fluid 248 to one or more heat exchangers 202. One or more primary cooling conduits 250 may be defined at least partially by the structure of one or more heat exchangers 202 (such as the overall structure of one or more heat exchangers 202). One or more primary cooling conduits 250 may be configured to receive primary cooling fluid 248 discharged from one or more heat exchangers 202. In some embodiments, primary cooling circuit 244 may include primary pump 252 configured to circulate primary cooling fluid 248 through primary cooling circuit 244. Additionally or alternatively, the primary cooling circuit 244 may include one or more primary cooling fluid control valves 254 configured to control the flow rate of primary cooling fluid 248 flowing through the primary cooling circuit 244.

[0056] The primary cooling circuit 244 and / or the intermediate cooling circuit 246 may include an intermediate heat exchanger 256 configured to transfer heat from the primary cooling fluid 248 flowing through the primary cooling circuit 244 to the intermediate cooling fluid 258 flowing through the intermediate cooling circuit 246. During operation, the intermediate cooling fluid 258 may be supplied to the intermediate heat exchanger 256 and / or circulated through the intermediate cooling circuit 246 in a pericritical phase state (such as a supercritical phase and / or a near-supercritical phase). Additionally or alternatively, the intermediate cooling fluid 258 may have a pericritical phase state when flowing through the intermediate heat exchanger 256 and / or circulating through the intermediate cooling circuit 246.

[0057] Intermediate cooling circuit 246 may include one or more intermediate cooling conduits 260. The one or more intermediate cooling conduits 260 may be configured to supply intermediate cooling fluid 258 to intermediate heat exchanger 256. The one or more intermediate cooling conduits 260 may be at least partially defined by the structure of intermediate heat exchanger 256 (such as the overall structure of intermediate heat exchanger 256). The one or more intermediate cooling conduits 260 may be configured to receive intermediate cooling fluid 258 discharged from one or more heat exchangers 202.

[0058] In some embodiments, the intercooling circuit 246 may include an intercooling pump 262 configured to circulate intercooling fluid 258 through the intercooling circuit 246. In some embodiments, the thermal management system 200 and / or the intercooling circuit 246 may include a refrigeration system 214 configured to bring the intercooling fluid 258 into a pericritical phase, such as a supercritical phase and / or a near-supercritical phase. Additionally or alternatively, the intercooling circuit 246 may include any other suitable source of the intercooling fluid 258, such as a tank or container configured to supply the intercooling fluid 258 to the intercooling circuit 246, for example, the intercooling fluid 258 having a pericritical phase. The intercooling circuit 246 may include one or more intercooling fluid control valves 264 configured to control the flow rate of the intercooling fluid 258 flowing through the intercooling circuit 246.

[0059] Still referencing Figures 2A-2EAs shown in the figure, cooling circuit 208 or intermediate cooling circuit 246 may include peripheral critical fluid system 400. In some embodiments, peripheral critical fluid system 400 may define a portion of thermal management system 200. Peripheral critical fluid system 400 may be configured to determine one or more phase properties of cooling fluid 206 and / or intermediate cooling fluid 258. One or more phase properties of cooling fluid 206 and / or intermediate cooling fluid 258 may include phase state, transition to or from one phase state to another, and / or one or more physical properties depending on such phase state.

[0060] Now for reference Figure 3A and 3B An exemplary fuel system 300 is further described. Figure 3A and 3B As shown, an exemplary fuel system 300 may include a fuel path 302. Fuel path 302 may include one or more fuel conduits 304. Fuel conduits 304 may be configured to supply fuel 306 to engine 102, for example, fuel 306 having a circumcritical phase, such as a supercritical phase and / or a near-supercritical phase. For example, fuel 306 may be supplied to engine 102 in a circumcritical phase. Additionally or alternatively, fuel path 302 may include a cooling circuit 208 through which fuel 306 can circulate. Figures 2A-2E As an example, exemplary fuel 306 may include hydrogen, methane, liquefied natural gas, kerosene, kerosene-type jet fuels (e.g., Jet A, Jet A-1, JP-5, JP-8), and combinations thereof. In some embodiments, thermal management system 200 may define at least a portion of fuel system 300. Additionally or alternatively, fuel system 300 may include thermal management system 200. In some embodiments, cooling fluid 206 used by thermal management system 200 may include fuel 306. Additionally or alternatively, in some embodiments, power generation system 100 and / or engine 102 may separately include thermal management system 200 and fuel system 300.

[0061] like Figure 3A and 3B As shown, in some embodiments, the fuel system 300 may include a fuel tank 308 configured to store fuel 306 in a pericritical phase (such as a supercritical phase and / or a near-supercritical phase). Additionally or alternatively, the fuel system 300 may include a pump 212. Figures 2A-2E Pump 212 is configured to supply fuel 306 to fuel path 302 in this cyclic critical phase state. Fuel path 302 may include one or more fuel control valves 310 configured to control the flow rate of fuel 306 flowing through fuel path 302.

[0062] For example, such as Figure 3A As shown, in some embodiments, the fuel system 300 may include one or more heat exchangers 202, each configured to cool a fluid flow 204 associated with the engine 102 and / or the power generation system 100. The fluid flow 204 flowing through a respective heat exchanger 202 may be cooled by fuel 306 flowing through a fuel path 302. The fuel path 302 may include one or more fuel conduits 304, configured to supply fuel 306 to the one or more heat exchangers 202, for example, fuel 306 having a periodically critical phase. The one or more fuel conduits 304 may be at least partially defined by the structure of the one or more heat exchangers 202 (such as the overall structure of the one or more heat exchangers 202). Additionally or alternatively, the fuel path 302 may include one or more fuel conduits 304, which may be configured to receive fuel 306 discharged from the one or more heat exchangers 202. In some embodiments, the fuel system 300 may include one or more fluid flow control valves 226 configured to control the flow rate of fluid flow 204 flowing through a respective heat exchanger 202.

[0063] In some embodiments, such as Figure 3B As shown, the fluid flow 204 cooled by one or more heat exchangers 202 may include working fluid used by engine 102 and / or power generation system 100. In some embodiments, engine 102 may be configured as a turbine engine, and fluid flow 204 may include intake air 230 flowing into the compressor section of the turbine engine. One or more heat exchangers 202 may include a precooler 232 configured to precool the intake air 230 supplied to the compressor section of the turbine engine using fuel 306. As shown, a fluid flow control valve 226, such as a variable geometry inlet pipe 234, may be configured to control the flow rate of intake air 230 flowing through precooler 232. Fuel leaving precooler 232 may flow to combustion section 312 of engine 102. At combustion section 312, fuel 306 may combine with intake air 230, and the resulting combination may be combusted to generate thrust.

[0064] Still referencing Figure 3A and 3BAs shown in the figure, fuel system 300 may include a pericritical fluid system 400. In some embodiments, the pericritical fluid system 400 may define a portion of fuel system 300. The pericritical fluid system 400 may be configured to determine one or more phase properties of fuel 306. The one or more phase properties of fuel 306 may include a phase state, a transition to or from one phase state to another, and / or one or more physical properties depending on such phase state.

[0065] Now for reference Figure 4 An exemplary peripheral critical fluid system 400 is further described. The exemplary peripheral critical fluid system 400 may be included in, and / or used by, the thermal management system 200 and / or the fuel system 300. In some embodiments, a first peripheral critical fluid system 400 may define a portion of the thermal management system 200, and a second peripheral critical fluid system 400 may define a portion of the fuel system 300. Figure 4 As shown, the peripheral critical fluid system 400 may include one or more sensors 402 configured to generate sensor outputs 404 corresponding to one or more phase properties of the fluid 401. The fluid 401 may include a cooling fluid 206 associated with the thermal management system 200, such as those referenced herein. Figures 2A-2E As described herein. Additionally or alternatively, fluid 401 may include fuel 306 associated with fuel system 300, such as those referenced herein. Figure 3A and 3B As described. Fluid 401 may include pericritical fluids, such as supercritical fluids and / or near-supercritical fluids. Additionally or alternatively, fluid 401 may include liquids and / or gases. Additionally or alternatively, fluid 401 may include multimodal fluids.

[0066] Sensor output 404 can be transmitted to control system 600. One or more sensors 402 and / or control system 600 can generate fluid monitoring data 406 based at least in part on sensor output 404. Additionally or alternatively, fluid monitoring data 406 may include sensor output 404. Sensor output 404 and / or fluid monitoring data 406 may be used, for example, by control system 600 to determine one or more phase properties of fluid 401. Fluid monitoring data 406 may include one or more phase properties of fluid 401, such as one or more phase properties of fluid 401 determined from sensor output 404. Additionally or alternatively, control system 600 may use fluid monitoring data 406 to control one or more controllable components 408, for example, to adjust and / or maintain desired phase properties of fluid 401.

[0067] like Figure 4As shown, one or more sensors 402 may include one or more phase detection sensors 410. Additionally or alternatively, one or more sensors 402 may include one or more temperature sensors 412. Additionally or alternatively, one or more sensors 402 may include one or more pressure sensors 414. One or more sensors 402 may each be configured to generate sensor outputs 404, which may be transmitted to the control system 600. Sensor outputs 404 from corresponding sensors among the plurality of sensors 402 may be combined, for example, to generate fluid monitoring data 406. Additionally or alternatively, fluid monitoring data 406 may be generated at least partially based on sensor outputs 404 from the plurality of sensors 402. Additionally or alternatively, fluid monitoring data 406 may be generated at least partially based on comparisons of one or more sensor outputs 404 with other data (such as lookup tables, models, etc.), and / or at least partially based on one or more operations performed on one or more sensor outputs 404, for example, at least partially based on such lookup tables, models, etc.

[0068] One or more phase detection sensors 410 may include any suitable sensor configured to generate sensor output 404 from which one or more phase properties of fluid 401 can be determined. In some embodiments, for example, one or more phase properties of fluid 401 may be determined from sensor output 404 generated by phase detection sensor 410 without reference to other data. Additionally or alternatively, one or more phase properties of fluid 401 may be determined based at least in part on sensor output 404 generated by phase detection sensor 410 and at least in part on data from another source, such as additional sensor output 404 from one or more other sensors 402, fluid monitoring data 406, lookup tables, models, etc.

[0069] In some embodiments, when a phase boundary is crossed due to changes in temperature and / or pressure, the sensor output 404 generated by the phase detection sensor 410 may exhibit a change in the sensor output 404 value, such as a sudden change in the sensor output 404 value. The change in the sensor output 404 value exhibited by the sensor output 404 generated by the phase detection sensor 410 may include a sensor output 404 value higher than an upper threshold, a sensor output 404 value lower than a lower threshold, a sensor output 404 value exhibiting a rate of change higher than the upper threshold rate of change, a sensor output 404 value exhibiting a rate of change lower than the upper threshold rate of change, and combinations thereof.

[0070] In some embodiments, the phase detection sensor 410 may include an acoustic sensor, such as a sound velocity sensor or a sound wave sensor. An exemplary sound velocity sensor may be configured to determine the speed of sound waves propagating through fluid 401. The sound velocity sensor may include a transducer (such as an ultrasonic transducer) configured to emit sound waves (such as ultrasound). The sound velocity sensor may include a receiver configured to receive the sound waves and convert them into an electrical signal. The transducer and receiver may be integrated into a common component or may be provided as separate components. The sensor output 404 from the phase detection sensor 410 (such as the sound velocity sensor) may include an electrical signal corresponding to the sound waves received by the sound velocity sensor. In some embodiments, the speed of sound waves (such as ultrasound) propagating through the fluid may depend at least in part on one or more phase properties of the fluid. In some embodiments, the speed of the sound waves may approach a minimum at approximately a critical point of the fluid. One or more phase properties of fluid 401 may be correlated with the sensor output 404 from the phase detection sensor 410 (such as the sound velocity sensor).

[0071] An acoustic wave sensor can be configured to apply an oscillating electric field to generate acoustic waves that propagate through a piezoelectric substrate. Suitable piezoelectric substrates may include quartz, lithium tantalate, lithium niobate, gallium arsenide, silicon carbide, lanthanum gallium silicate, zinc oxide, aluminum nitride, lead zirconium titanate, polyvinylidene fluoride, and combinations thereof. The acoustic waves are converted back into electrical signals. Exemplary acoustic wave sensors include bulk acoustic wave sensors, surface acoustic wave sensors, etc. Exemplary acoustic wave sensors may include a piezoelectric substrate. Sensor output 404 from phase detection sensor 410 (such as an acoustic wave sensor) may include an electrical signal corresponding to the acoustic waves propagating through the piezoelectric substrate. Exemplary acoustic wave sensors include bulk acoustic wave sensors, such as thickness shear mode sensors, horizontal shear acoustic plate mode sensors, and horizontal shear surface acoustic wave sensors. Thickness shear mode sensors are sometimes referred to as quartz crystal microbalance resonators. Advantageously, the acoustic waves generated by such bulk acoustic wave sensors propagate in the horizontal shear direction, which avoids radiating considerable acoustic energy into fluid 401. In some embodiments, the surface acoustic wave sensor can radiate sound waves into fluid 401, causing sound wave attenuation.

[0072] One or more properties of the sound wave propagating through the piezoelectric substrate, such as frequency, amplitude, or phase, and combinations thereof, may depend at least in part on one or more phase properties of the fluid 401. One or more phase properties of the fluid 401 may be correlated with the sensor output 404 from the phase detection sensor 410 (such as an acoustic wave sensor). The minimum impedance of the equivalent circuit of the acoustic wave sensor may be proportional to the density and viscosity of the fluid 401. In some embodiments, the minimum impedance exhibited by the acoustic wave sensor may be proportional to the density and viscosity of the fluid 401 according to the following relationship: Z min ∝(ρη)1 / 2 Z min ρ is the minimum impedance, ρ is the density of fluid 401, and η is the viscosity of the fluid.

[0073] In some embodiments, the impedance value from the phase detection sensor 410 (such as an acoustic sensor) may exhibit different characteristics with respect to vaporization curves (such as the liquid saturation curve and / or vapor saturation curve of fluid 401). For example, when fluid 401 reaches its bubble point (liquid saturation point), the impedance value from the acoustic sensor may exhibit an inflection point indicating a moderate increase. This moderate increase in impedance may be attributed to bubbles forming on the surface of the acoustic sensor (such as on the surface of a piezoelectric substrate). Additionally or alternatively, when fluid 401 reaches its dew point (vapor saturation point), the impedance value from the acoustic sensor may exhibit an inflection point indicating a significant increase. This significant increase in impedance may be attributed to condensation forming on the surface of the acoustic sensor (such as on the surface of a piezoelectric substrate). For bimodal or multimodal fluid 401, the impedance value from the acoustic sensor may exhibit multiple inflection points, each corresponding to a component of the bimodal or multimodal fluid 401.

[0074] An exemplary phase detection sensor 410, such as an acoustic sensor, is sensitive to very small changes in the amount of bubbles or condensate in fluid 401. For example, such bubbles or condensate can accumulate on the surface of the acoustic sensor. This change in the amount of bubbles or condensate can produce a considerable change in the sensor output 404 (such as an impedance value) from the phase detection sensor 410. In some embodiments, the bubble point can be distinguished from the dew point at least in part based on changes in the sensor output 404 value (such as changes in impedance). Additionally or alternatively, a critical point can be determined at least in part based on changes in the sensor output 404 value, such as changes in impedance. Additionally or alternatively, the proximity of the bubble point or dew point to the critical point can be determined at least in part based on changes in the sensor output 404 value, such as changes in impedance. For example, the closer the bubble point or dew point is to the critical point, the smaller the change in the sensor output 404 value at the point of reaching the bubble point or dew point. In some embodiments, the change in the sensor output 404 value at the critical point can be approximately zero.

[0075] In some embodiments, the phase detection sensor 410 may include an optical sensor, such as a fiber optic reflectometer or an infrared spectrometer. An exemplary fiber optic reflectometer may include a light source, an optical fiber, and a photodiode. The light source is configured to generate a probe beam, the optical fiber is configured to guide the probe beam into a measurement chamber, and the photodiode is configured to measure the intensity of the probe beam. The probe beam may pass through a fluid 401 and then be incident on the photodiode. The transmission, reflection, and / or refraction of the probe beam may depend at least in part on one or more phase properties of the fluid 401. The intensity of the probe beam may be compared to a reference value and / or a reference beam emitted by the light source. As an example, the reference beam may be split from the probe beam by a beam splitter and may be incident on the photodiode. The reference beam may be monitored by a reference photodiode, for example, to compensate for intensity variations, etc. In some embodiments, the fiber optic reflectometer may include one or more microstructured optical fibers comprising a core material and multiple channels defined within the core material, through which light may be guided by total internal reflection and / or constructive interference of scattered light. Exemplary microstructured optical fibers include photonic crystal fibers, photonic bandgap fibers, porous fibers, aperture-assisted fibers, and Bragg fibers.

[0076] The sensor response of the phase detection sensor 410 (such as a fiber optic reflectometer) may depend at least in part on one or more phase properties of the fluid 401. The one or more phase properties of the fluid 401 may be correlated with the sensor output 404 from the phase detection sensor 410 (such as a fiber optic reflectometer). In some embodiments, one or more phase properties of the fluid 401 may be determined at least in part based on the value of the sensor output 404 from the phase detection sensor 410 (such as a fiber optic reflectometer). For example, the fluid 401 may exhibit different refractive indices depending on its phase state. For example, the refractive index of the fluid 401 may differ between at least two of the following: liquid phase, gas phase, pericritical phase, supercritical phase, and near-supercritical phase. Additionally or alternatively, the refractive index of the fluid 401 may differ between at least two different phase states within one phase (such as within a liquid phase, gas phase, pericritical phase, supercritical phase, and / or near-supercritical phase). Additionally or alternatively, the refractive index of fluid 401 may depend at least in part on one or more other phase properties of fluid 401, such as the density of fluid 401.

[0077] Additionally or alternatively, one or more phase properties of fluid 401 can be determined at least in part based on the noise or bias level of the sensor output 404 value from phase detection sensor 410 (such as a fiber optic reflectometer). For example, the noise or bias level of the sensor output 404 value may increase due to phase separation. The increase in noise or bias may be attributed, for example, to the refractive index difference between bubbles and condensates in fluid 401, between a phase of fluid 401 and bubbles present in that phase, and / or between a phase of fluid 401 and condensates present in that phase. For fluid 401 having multiple phases, the noise or bias level of the sensor output 404 value may additionally or alternatively increase, for example, due to phase separation of one or more components in fluid 401. In some embodiments, the refractive index of fluid 401 may increase when the phase of fluid 401 reaches a vaporization curve and / or a vapor point on a vaporization curve (such as a bubble point on a liquid saturation curve and / or a liquid saturation curve), such as when the phase of fluid 401 crosses a vaporization curve. Additionally or alternatively, the refractive index of fluid 401 may increase when the phase state of fluid 401 reaches the dew point on the vapor saturation curve and / or the vapor saturation curve, such as when the phase state of fluid 401 crosses the vapor saturation curve from the gaseous state. Advantageously, the noise or bias level of the sensor output 404 value from the phase detection sensor 410 (such as a fiber optic reflectometer) can be used to separately represent the different phase states of a multi-peaked fluid (such as a multi-peaked fluid exhibiting multiple phase states).

[0078] Exemplary infrared spectrometers may include transmission infrared spectrometers or attenuated total reflectance infrared spectrometers. An exemplary infrared spectrometer may include an infrared light source, a measurement window, and an infrared detector. The measurement window is configured to contact fluid 401, and the infrared detector (such as a photodiode) is configured to detect infrared light transmitted through the measurement window. Infrared spectrometers, such as attenuated total reflectance infrared spectrometers, may be configured to detect total internal reflection. The infrared beam generates an evanescent wave at a reflection node, where the infrared beam is reflected from the inner surface of the measurement window in contact with fluid 401. The penetration depth of the evanescent wave may depend at least in part on one or more phase properties of fluid 401. As an example, the penetration depth of fluid 401 in the gas phase may be greater than that of fluid 401 in the liquid phase. Intensity changes detected by the infrared detector may indicate a phase transition. Additionally or alternatively, absorbance intensity may correspond to a wavenumber that depends at least in part on one or more phase properties of fluid 401. For example, different phase states of fluid 401 may exhibit peak absorbance at their respective wavenumbers. Additionally or alternatively, the absorbance intensity may depend at least in part on the proximity of the phase state of fluid 401 to vaporization curves (such as vapor saturation curves and / or liquid saturation curves). For example, the absorbance intensity may increase when the phase state of fluid 401 is close to the vaporization curves (such as vapor saturation curves and / or liquid saturation curves). Additionally or alternatively, fluid combinations such as bimodal and / or multimodal fluids may exhibit different absorbance intensity values ​​and / or peak absorbance at their respective wavenumbers, allowing one or more phase properties of the corresponding portions of bimodal and / or multimodal fluids 401 to be determined from sensor output 404 from phase detection sensor 410 (such as an attenuated total reflectance infrared spectrometer or other infrared spectrometer).

[0079] In some embodiments, the phase detection sensor 410 may include a pressure drop sensor, such as a microchannel pressure drop sensor or a packed bed pressure drop sensor. The pressure drop sensor may include a sample path through which the fluid 401 can flow. The fluid 401 may exhibit a pressure drop due to friction caused by surface interactions between the fluid and the microchannels, packed beds, etc. The pressure drop across the sample path may depend at least in part on one or more phase properties of the fluid 401. One or more phase properties of the fluid 401 may be correlated with a sensor output 404 from the phase detection sensor 410 (such as a pressure drop sensor). In some embodiments, the fluid 401 may exhibit a defined pressure drop change when undergoing a phase transition. For example, a liquid phase may exhibit a larger pressure drop than a gaseous phase. Additionally or alternatively, a supercritical phase may exhibit a relatively low pressure drop, for example, due to the lack of surface tension in the fluid 401. Additionally or alternatively, a multi-peaked fluid may exhibit a larger pressure drop in a multiphase state relative to a single-phase state, for example, due to surface tension interactions between the respective different phase states of the fluid components. Additionally or alternatively, the pressure drop of the fluid 401 may depend at least in part on the density of the fluid 401.

[0080] In some embodiments, one or more phase properties of fluid 401 may be determined at least in part based on sensor outputs 404 from one or more phase detection sensors 410, regardless of the type of phase detection sensors 410 used in the pericritical fluid system 400. For example, control system 600 may be configured to determine one or more phase properties of fluid 401 at least in part based on the correlation between sensor outputs 404 from one or more phase detection sensors 410 and one or more phase properties of fluid 401. As an example, control system 600 may include one or more models, lookup tables, etc., that correlate sensor outputs 404 from one or more phase detection sensors 410 with one or more phase properties of fluid 401. Additionally or alternatively, in some embodiments, sensor outputs 404 from one or more phase detection sensors 410 may be used in combination with sensor outputs 404 from one or more temperature sensors 412 and / or one or more pressure sensors 414. For example, one or more phase properties of fluid 401 may be determined at least in part based on the correlation between sensor outputs 404 from one or more phase detection sensors 410 and sensor outputs 404 from one or more temperature sensors 412 and / or one or more pressure sensors 414. In some embodiments, for example, without relating the sensor outputs 404 from one or more temperature sensors 412 and / or one or more pressure sensors 414 to the determined phase properties of the fluid 401, the sensor outputs 404 from one or more phase sensors 410 may be used in combination with the sensor outputs 404 from one or more phase sensors 410 to determine one or more phase properties of the fluid 401. For example, a change in the value of the sensor output 404 from the phase sensors 410 may indicate the occurrence of a phase transition, and the sensor outputs 404 from one or more temperature sensors 412 and / or one or more pressure sensors 414 may be used to determine the phase state corresponding to the phase transition indicated by the change in the value of the sensor output 404 from the phase sensors 410. In some embodiments, the controller may be configured to determine, at least in part, based on the sensor outputs 404 from one or more temperature sensors 412 and / or one or more pressure sensors 414, whether the phase state corresponding to the phase transition includes a liquid phase, a gas phase, a pericritical phase, a supercritical phase, a near-supercritical phase, or a multiphase phase.As another example, sensor outputs 404 from one or more temperature sensors 412 and / or one or more pressure sensors 414 can be used in combination with sensor outputs 404 from one or more phase detection sensors 410 to distinguish between one or more of the following: vapor saturation curves and liquid saturation curves, dew point and bubble point, critical point and dew point or bubble point, bubble point and critical condensation pressure (cricondenbar), and / or dew point and circumcenter. Additionally or alternatively, in some embodiments, the phase state corresponding to a phase transition indicated by a change in the value of the sensor output 404 from the phase detection sensor 410 can be determined, for example, by the correlation between one or more phase properties of the fluid 401 and the sensor output from the phase detection sensor 410, without reference to the sensor outputs 404 from one or more temperature sensors 412 and / or one or more pressure sensors 414. Additionally or alternatively, in some embodiments, one or more phase properties of fluid 401 may be determined at least in part based on sensor outputs 404 from one or more phase detection sensors 410, without the need for sensor outputs 404 from one or more temperature sensors 412 or from one or more pressure sensors 414.

[0081] Regardless of the specific configuration of the pericritical fluid system 400 according to this disclosure, the control system 600 can be configured to determine one or more phase properties of fluid 401 based at least in part on one or more sensor outputs 404, such as sensor outputs 404 from one or more phase detection sensors 410, and / or at least in part on a combination of sensor outputs 404 from one or more phase detection sensors 410 and sensor outputs 404 from one or more temperature sensors 412 and / or pressure sensors 414. One or more phase properties of fluid 401 can be determined, individually and / or in combination, based at least in part on the correlation between one or more sensor outputs 404 from one or more phase detection sensors 410 and one or more phase properties of fluid 401. One or more phase properties of fluid 401 can be determined at least in part on models, lookup tables, etc., for example, models, lookup tables, etc., using one or more sensor outputs 404 as inputs for determining one or more phase properties of fluid 401.

[0082] In some embodiments, the control system 600 may be configured to determine, at least in part, the phase state of fluid 401 based on sensor output 404, such as whether fluid 401 exhibits a liquid phase, gas phase, pericritical phase, supercritical phase, near-supercritical phase, and / or multiphase phase, and / or the proximity of the phase state of fluid 401 to such a phase. Additionally or alternatively, the control system 600 may be configured to determine the phase state of fluid 401 as consistent with and / or close to one or more of the following: vaporization profile, vapor point, vapor saturation profile, dew point, liquid saturation profile, bubble point, critical point, critical condensation pressure, and / or eccentricity. In some embodiments, the control system 600 may be configured to determine the density of fluid 401 based at least in part on such sensor output 404. In some embodiments, for a bimodal or multimodal fluid 401, the control system 600 may be configured to determine the phase state of a corresponding component of the bimodal or multimodal fluid 401, such as whether one and / or more corresponding components of the fluid 401 exhibit a liquid phase, a gas phase, a pericritical phase, a supercritical phase, a near-supercritical phase, and / or a multiphase phase, and / or the proximity of the phase state of one and / or more corresponding components of the fluid 401 to such a phase state. Additionally or alternatively, for a bimodal or multimodal fluid 401, the control system 600 may be configured to determine the phase state of one and / or more corresponding components of the fluid 401 consistent with and / or close to one or more of the following: vaporization profile, vapor point, vapor saturation profile, dew point, liquid saturation profile, bubble point, critical point, critical condensation pressure, and / or eccentricity. Additionally or alternatively, for bimodal or multimodal fluid 401, control system 600 may be configured to determine, at least in part, the bulk density of such bimodal or multimodal fluid 401 and / or the density of its components based on such sensor output 404.

[0083] In some embodiments, the control system 600 may be configured to control one or more controllable components 408 based at least in part on one or more sensor outputs 404, and / or at least in part on one or more phase properties of fluid 401 determined from values ​​of such sensor outputs 404. For example, controllable components 408 may be configured to control one or more phase properties of fluid 401 based at least in part on control commands 409 from the control system 600. In some embodiments, one or more controllable components 408 may be configured to change the temperature and / or pressure of fluid 401. Additionally or alternatively, one or more controllable components 408 may be configured to change the flow rate of fluid 401. Changes in the temperature, pressure, and / or flow rate of fluid 401 applied by the control system 600 can effectively change and / or maintain the phase state of fluid 401. Additionally or alternatively, changes in the temperature, pressure, and / or flow rate of fluid 401 applied by the control system 600 can, for example, effectively change and / or maintain the density of fluid 401 relative to the corresponding phase state of fluid 401. In some embodiments, the control system 600 may be configured to maintain fluid 401 in a pericritical phase (such as a supercritical phase and / or a near-supercritical phase), for example, by controlling controllable components. Additionally or alternatively, the control system 600 may be configured to maintain the phase of fluid 401 within a specified control range. The specified control range may include an upper control limit and / or a lower control limit. The desired range may be selected at least in part based on a desired density range of the fluid. Additionally or alternatively, the desired range may be selected at least in part based on one or more of the following: vaporization profile, vapor point, vapor saturation profile, dew point, liquid saturation profile, bubble point, critical point, critical condensation pressure, and / or eccentricity. For example, the desired range may be selected at least in part to maintain fluid 401 in a desired phase, such as a phase having a desired closeness to such a vapor saturation profile, dew point, liquid saturation profile, bubble point, critical point, critical condensation pressure, and / or eccentricity. This desired proximity can be selected at least partially to avoid phase change in fluid 401, for example, due to changes in the operating conditions of power generation system 100 and / or engine 102.

[0084] An exemplary controllable component 408 that can be controlled by the control system 600 may include any component that can be controlled to change the temperature, pressure, and / or flow rate of a fluid. For example, controllable component 408 may include one or more of the following: control valves, compressors, pumps, and / or accumulators. In some embodiments, controllable component 408 may include one or more cooling fluid control valves 224 configured to control the flow rate of fluid 401 (such as cooling fluid 206 flowing through cooling circuit 208). Additionally or alternatively, controllable component 408 may include one or more fuel control valves 310 configured to control the flow rate of fuel 306 flowing through fuel path 302. Additionally or alternatively, in some embodiments, controllable component 408 may include a pump 212 configured to circulate fluid 401, such as a pump 212 configured to circulate cooling fluid 206 through cooling circuit 208, and / or a pump 212 configured to supply fuel 306 to fuel path 302. In some embodiments, the controllable component 408 may include one or more components of the refrigeration system 214 configured to bring fuel 306 into a pericritical phase and / or maintain fuel 306 in a pericritical phase, such as a supercritical phase and / or a near-supercritical phase. Additionally or alternatively, in some embodiments, the controllable component 408 may include one or more fluid flow control valves 226 configured to control the flow rate of fluid flow 204 through the heat exchanger 202, such as a variable geometry inlet pipe 234 configured to control the flow rate of intake air 230 through the precooler 232, or a bleed air control valve 240 configured to control the flow rate of compressor bleed air 236 through the bleed air heat exchanger 238, or a primary cooling fluid control valve 254 configured to control the flow rate of primary cooling fluid 248 through the primary cooling circuit 244.

[0085] Now for reference Figures 5A-5E An exemplary phase diagram 500 describes fluid 401. Fluid 401 may be cooling fluid 206 and / or fuel 306. Figures 5A-5D The phase diagram of fluid 401 with respect to temperature and pressure is shown. Figure 5EA phase diagram of the fluid with respect to pressure and density is displayed. As shown, the phase diagram of fluid 401 may include a vaporization curve 502 defined by multiple vapor points 504. At pressures above the vaporization curve, the fluid may have a liquid phase. At pressures below the vaporization curve, the fluid may have a gaseous phase. At temperatures to the right of the vaporization curve, the fluid may have a gaseous phase. At temperatures to the left of the vaporization curve, the fluid may have a liquid phase. Vaporization curve 502 may terminate at a critical point 506. When the fluid has temperatures and pressures exceeding its critical point, fluid 401 may have a supercritical phase. In addition to exhibiting a supercritical phase, fluid 401 may exhibit a near-supercritical phase when it has a temperature at least 70% of its critical temperature and a pressure at least 70% of its critical pressure. When the fluid exhibits a supercritical or near-supercritical phase, fluid 401 may have a pericritical phase.

[0086] Figure 5A The phase diagram shown may correspond to a fluid 401 having a single component (such as a first component). As an example, in some embodiments, the first fluid component may be carbon dioxide. Figure 5B and 5C The phase diagram shown can correspond to a bimodal fluid 401. The bimodal fluid 401 may include a first fluid component and a second fluid component. As an example, in some embodiments, the first fluid component may be carbon dioxide, and the second fluid component may be nitrogen. Figure 5D The phase diagram shown can correspond to a multi-peak fluid 401. The multi-peak fluid 401 may include a first fluid component, a second fluid component, and a third fluid. As an example, in some embodiments, the first fluid component may be carbon dioxide, the second fluid component may be nitrogen, and the third fluid may be ethane. Figures 5B-5D As shown, a bimodal fluid 401 or a multimodal fluid 401 may include a multiphase region 508, within which the fluid 401 may include a liquid phase and a gas phase. The multiphase region may be defined by a liquid saturation curve 510 and a vapor saturation curve 512. The liquid saturation curve 510 may be defined by multiple bubble points representing the transition from liquid to gas. These multiple bubble points may include a critical condensation pressure 514 representing the maximum pressure above which, regardless of temperature, no gas can form. The temperature corresponding to the critical condensation pressure 514 may be referred to as the critical condensation pressure temperature. The vapor saturation curve 512 may be defined by multiple dew points representing the transition from gas to liquid. These multiple dew points may include a critical condensation temperature 516 representing the maximum temperature above which, regardless of pressure, no liquid can form. The pressure corresponding to the critical condensation temperature 516 may be referred to as the critical condensation temperature pressure. For a single-component fluid, for example, such as... Figure 5AAs shown, the liquid saturation curve 510 and the vapor saturation curve 512 can be consistent with the vaporization curve 502, and the multiple vapor points 504 correspond to multiple bubble points and multiple dew points, respectively.

[0087] like Figure 5B As shown, the bimodal fluid 401 may include a first fluid component and a second fluid component. The multiphase region 508 of the bimodal fluid 401 may be defined by a vapor saturation curve 512 and a liquid saturation curve 510. The vapor saturation curve 512 is defined by a plurality of dew points representing the transition of the first fluid component from the gas phase to the liquid phase, and the liquid saturation curve 510 is defined by a plurality of bubble points representing the transition of the second fluid component from the liquid phase to the gas phase. In some embodiments, in Figure 5B Within the multiphase region 508 shown, the first fluid component may be in a liquid phase, and the second fluid component may be in a gaseous phase. Additionally or alternatively, such as... Figure 5C As shown, the bimodal fluid 401 may include a first fluid component and a third fluid. The multiphase region 508 of the bimodal fluid 401 may be defined by a liquid saturation curve 510 and a vapor saturation curve 512. The liquid saturation curve 510 is defined by a plurality of bubble points representing the transition of the first fluid component from the liquid phase to the gas phase, and the vapor saturation curve 512 is defined by a plurality of dew points representing the transition of the third fluid from the gas phase to the liquid phase. In some embodiments, in Figure 5C Within the multiphase region 508 shown, the first fluid component may be in a gaseous state, and the third fluid component may be in a liquid state.

[0088] Additional or alternative land, such as Figure 5D As shown, the multiphase region 508 of the multi-peak fluid 401 can be defined by a liquid saturation curve 510 and a vapor saturation curve 512. The liquid saturation curve 510 is defined by a plurality of bubble points representing the transition of the second fluid component from the liquid phase to the gas phase, and the vapor saturation curve 512 is defined by a plurality of dew points representing the transition of the third fluid from the gas phase to the liquid phase. In some embodiments, the multiphase region 508 of the multi-peak fluid 401 may include a first multiphase region 518 and a second multiphase region 520, for example, as... Figure 5D As shown. The first multiphase region 518 can be defined by a liquid saturation curve 510 and a vaporization curve 502. The liquid saturation curve 510 represents the transition of the second fluid component from the liquid phase to the gas phase, and the vaporization curve 502 represents the transition of the first fluid component from the gas phase to the liquid phase. Figure 5D Within the first multiphase region 518 shown, the first fluid component can be in a liquid phase, the second fluid component can be in a gaseous phase, and the third fluid component can be in a liquid phase. The second multiphase region 520 can be defined by a vaporization curve 502 and a vapor saturation curve 512, where vaporization curve 502 represents the transition of the first fluid component from the liquid phase to the gaseous phase, and vapor saturation curve 512 represents the transition of the third fluid component from the gaseous phase to the liquid phase. Figure 5DWithin the second multiphase region 520 shown, the first fluid component may be in a gaseous state, the second fluid component may be in a gaseous state, and the third fluid component may be in a liquid state.

[0089] In some embodiments, the control system 600 may be configured, for example, to determine one or more phase properties of the bimodal or multimodal fluid 401 corresponding to a multiphase region of the fluid 401, based at least in part on one or more sensor outputs 404 from one or more phase detection sensors 410. For example, refer to Figure 5B and 5D The bimodal or multimodal fluid 401 may include a first fluid component and a second fluid component, and the control system 600 may be configured to determine, for example, one or more phase properties of the second fluid component with respect to a liquid saturation curve 510, such as phase state, which represents the transition of the second fluid component from a liquid phase to a gas phase. In some embodiments, the control system 600 may be configured to determine whether the second fluid component has a liquid phase state and / or whether the second fluid component has a gas phase state. Additionally or alternatively, the control system 600 may be configured to determine whether the phase state of the second fluid component crosses the liquid saturation curve 510 and / or the proximity of the phase state of the second fluid component with respect to the liquid saturation curve 510. Additionally or alternatively, the control system 600 may be configured to determine one or more phase properties of the second fluid component with respect to a critical condensation pressure 514, such as phase state.

[0090] As another example, see Figure 5C and 5D The bimodal or multimodal fluid 401 may additionally or alternatively include a first fluid component and a third fluid component, and the control system 600 may be configured to determine one or more phase properties of the third fluid component, such as phase state, with respect to a vapor saturation curve 512, which represents the transition of the third fluid component from a gaseous phase to a liquid phase. In some embodiments, the control system 600 may be configured to determine whether the third fluid component has a gaseous phase state and / or whether the third fluid component has a liquid phase state. Additionally or alternatively, the control system 600 may be configured to determine whether the phase state of the third fluid component crosses the vapor saturation curve 512 and / or the proximity of the phase state of the third fluid component with respect to the vapor saturation curve 512. Additionally or alternatively, the control system 600 may be configured to determine one or more phase properties of the third fluid component with respect to a critical condensation temperature 516, such as phase state.

[0091] In some embodiments, the control system 600 may be configured to determine one or more phase properties, such as phase state, relative to a first fluid component of the bimodal or multimodal fluid 401, at least in part based on one or more phase properties, such as phase state, of a second and / or third fluid component of the bimodal or multimodal fluid 401. Figure 4 and Figures 5B-5D The control system 600 may be configured to determine one or more phase properties of the first fluid component based at least in part on one or more sensor outputs 404 from one or more phase detection sensors 410 corresponding to one or more phase properties (such as phase state or phase transition) of the second fluid component. For example, the phase state or phase transition of the second fluid component may be related to a liquid saturation curve 510, such as a phase transition of the second fluid component from a liquid phase to a gas phase. In some embodiments, the first fluid component may have a pericritical state, such as a supercritical state or a near-supercritical state, when the second fluid component undergoes a phase transition from a liquid phase to a gas phase. Additionally or alternatively, the control system 600 may determine one or more phase properties of the first fluid component based at least in part on one or more sensor outputs 404 from one or more phase detection sensors 410 indicating one or more phase properties (such as phase state or phase transition) of the third fluid component. For example, the phase state or phase transition of the third fluid component may be related to a vapor saturation curve 512, such as a phase transition of the third fluid component from a gas phase to a liquid phase. In some embodiments, when the third fluid component undergoes a phase transition from the gas phase to the liquid phase, the first fluid component may have a pericritical state, such as a supercritical state or a near-supercritical state.

[0092] In some embodiments, the control system 600 may be configured to determine the phase state of the first fluid component at least in part based on whether the second fluid component has a liquid or gas phase, and / or whether the phase state of the second fluid component crosses the liquid saturation curve 510 and / or the proximity of the phase state of the second fluid component to the liquid saturation curve 510. Additionally or alternatively, the control system 600 may be configured to determine the proximity of the phase state of the first fluid component to the vaporization curve 502 at least in part based on the proximity of the phase state of the second fluid component to the liquid saturation curve 510. For example, the control system 600 may be configured to determine that the first fluid component has a phase state close to the vaporization curve 502 at least in part based on determining that fluid 401 has a multiphase state corresponding to the first multiphase region 518. The control system 600 may determine that fluid 401 has a multiphase state corresponding to the first multiphase region 518 at least in part based on one or more sensor outputs 404 indicating that the second fluid component has a gas phase.

[0093] In some embodiments, the control system 600 may be configured to determine the phase state of the first fluid component at least in part based on whether the third fluid component has a gaseous or liquid phase, and / or whether the phase state of the third fluid component crosses the vapor saturation curve 512 and / or the proximity of the phase state of the third fluid component to the vapor saturation curve 512. Additionally or alternatively, the control system 600 may be configured to determine the proximity of the phase state of the first fluid component to the vaporization curve 502 at least in part based on the proximity of the phase state of the third fluid component to the vapor saturation curve 512. For example, the control system 600 may be configured to determine that the first fluid component has a phase state close to the vaporization curve 502 at least in part based on determining that fluid 401 has a multiphase state corresponding to the second multiphase region 520. The control system 600 may determine that fluid 401 has a multiphase state corresponding to the second multiphase region 520 at least in part based on one or more sensor outputs 404 indicating that the third fluid component has a liquid phase.

[0094] In some embodiments, the control system 600 may use one or more phase properties, such as phase state, of the second and / or third fluid components of the bimodal or multimodal fluid 401 as an indicator or warning of one or more phase properties (such as phase state) of the first fluid component. Figure 5D As shown, a second fluid component and / or a third fluid component can be selected to combine with the first fluid component such that the vaporization curve of the first fluid component can be at least partially surrounded by a liquid saturation curve 510 and / or a vapor saturation curve 512, where the liquid saturation curve 510 represents the transition of the second fluid component from the liquid phase to the gas phase, and the vapor saturation curve 512 represents the transition of the third fluid component from the gas phase to the liquid phase. Additionally or alternatively, a second fluid component and / or a third fluid component can be selected to combine with the first fluid component such that the critical point of the first fluid component is located within the multiphase region 508 of the multi-peak fluid 401.

[0095] For example, the proximity of the phase state of the second fluid component to the liquid saturation curve 510, such as determining that fluid 401 has a multiphase state corresponding to the first multiphase region 518, can serve as an indicator or warning that the first fluid component has a phase state close to the vaporization curve 502. In some embodiments, at their respective corresponding temperatures, a corresponding bubble point among a plurality of bubble points defining at least a portion of the liquid saturation curve 510 of the second fluid component may have a pressure greater than that of a corresponding vapor point among a plurality of vapor points 504 defining at least a portion of the vaporization curve 502 of the first fluid component. Additionally or alternatively, in some embodiments, the critical condensation pressure 514 of the liquid saturation curve 510 may correspond to a pressure greater than that corresponding to the critical point 506 of the first fluid component.

[0096] As another example, the proximity of the phase state of the third fluid component to the vapor saturation curve 512, such as determining that fluid 401 has a multiphase state corresponding to the second multiphase region 520, can serve as an indicator or warning that the first fluid component has a phase state close to the vaporization curve 502. In some embodiments, at their respective corresponding pressures, a corresponding dew point among a plurality of dew points defining at least a portion of the vapor saturation curve 512 of the third fluid component may have a temperature greater than the corresponding vapor point among a plurality of vapor points 504 defining at least a portion of the vaporization curve 502 of the first fluid component. Additionally or alternatively, in some embodiments, the critical condensation temperature 516 of the vapor saturation curve 512 may correspond to a temperature greater than the corresponding temperature of the critical point 506 of the first fluid component.

[0097] The control system 600 may provide one or more control commands 409 to one or more controllable components 408, at least in part, based on one or more sensor outputs 404, which indicate phase states such as relative to a second fluid component and / or a third fluid component. For example, if it is determined that fluid 401 has a multiphase state corresponding to a first multiphase region 518, the control system 600 may provide one or more control commands 409 to one or more controllable components 408, which are configured to increase the temperature and / or pressure of fluid 401. In some embodiments, in response to determining that fluid 401 has a multiphase state corresponding to the first multiphase region 518, one or more control commands 409 may be configured to cause one or more controllable components 408 to increase the pressure of fluid 401 above a critical condensation pressure 514 and / or increase the temperature of fluid 401 above a critical condensation pressure temperature. Additionally or alternatively, the control system 600 may provide one or more control commands 409 to one or more controllable components 408, which are configured to increase the temperature and / or pressure of the fluid 401 upon determining that the fluid 401 has a multiphase state corresponding to the second multiphase region 520. In some embodiments, in response to determining that the fluid 401 has a multiphase state corresponding to the second multiphase region 520, one or more control commands 409 may be configured to cause one or more controllable components 408 to increase the temperature of the fluid 401 above the critical condensation temperature 516 and / or increase the pressure of the fluid 401 above the critical condensation temperature pressure.

[0098] In some embodiments, the concentration of the first fluid component may constitute the vast majority of the total composition of fluid 401. The second and / or third fluid components may constitute a substantially minority of the total composition of fluid 401. In some embodiments, where applicable, the first fluid component may represent the dominant component in fluid 401 used by the thermal management system 200 and / or fuel system 300. In some embodiments, such as when applicable with respect to the purpose of using fluid 401, the second and / or third fluid components may not have a significant effect on the thermal management system 200 and / or fuel system 300. Additionally or alternatively, the second and / or third fluid components may be included in fluid 401 at a concentration sufficient to be used as a tracer, such as a concentration corresponding to trace amounts sufficient to determine one or more of their phase properties (such as phase state). In other embodiments, for purposes other than tracer, such as when suitable as a supplement or replacement for a tracer, the second and / or third fluid components may be included in fluid 401 to have a beneficial effect on the thermal management system 200 and / or fuel system 300. Such second and / or third fluid components may still be used as tracers.

[0099] In some embodiments, the first fluid component may be included in fluid 401 in amounts such as from about 30 mol.% to about 100 mol.%, such as from about 50 mol.% to about 100 mol.%, such as from about 80 mol.% to about 100 mol.%, such as from about 80 mol.% to about 90 mol.%, such as from about 90 mol.% to about 95 mol.%, such as from about 95 mol.% to about 99 mol.%, such as from about 99 mol.% to 99.8 mol.%, such as from about 99 mol.% to 99.9 mol.%, such as from about 99 mol.% to 99.998 mol.%, or such as from about 99 mol.% to 99.999 mol.%. In some embodiments, the second fluid component may be included in fluid 401 in amounts ranging from about 0.001 mol.% to about 50 mol.%, such as from about 1 mol.% to about 20 mol.%, such as from about 1 mol.% to about 10 mol.%, such as from about 1 mol.% to about 5 mol.%, such as from about 0.1 mol.% to about 1 mol.%, or such as from about 0.001 mol.% to about 1 mol.%. In some embodiments, the third fluid component may be included in fluid 401 in amounts ranging from about 0.001 mol.% to about 50 mol.%, such as from about 1 mol.% to about 20 mol.%, such as from about 1 mol.% to about 10 mol.%, such as from about 1 mol.% to about 5 mol.%, such as from about 0.1 mol.% to about 1 mol.%, or such as from about 0.001 mol.% to about 1 mol.%. In some embodiments, the concentration of the second or third fluid component corresponding to a trace amount sufficient to determine one or more phase properties (such as phase state) may be from about 0.001 mol.% to about 5 mol.%, such as from about 0.1 mol.% to about 1 mol.%, or such as from about 0.001 mol.% to about 1 mol.%.

[0100] Further reference Figure 5E This shows another exemplary phase diagram of fluid 401. Figure 5E As shown, the density of fluid 401 can depend on the pressure of fluid 401. In some embodiments, isothermal changes in pressure can produce significant changes in density. Figure 5EThe phase diagram 500 shown includes multiple isotherms (T1, T2, T3, T4, and T5) for the first fluid component of fluid 401. As shown, the first fluid component has a vaporization curve 502 defined by multiple vapor points 504. In some embodiments, such as as indicated by isotherm T3, isothermal changes in the pressure of the first fluid component can produce significant density changes within the pericritical phase, such as within the supercritical phase and / or near the supercritical phase. For example, at the variable density region 522, the first fluid component can exhibit significant density changes due to relative nominal pressure and / or temperature variations. The range of interest for the variable density region 522 can be selected at least in part based on one or more phase properties of fluid 401, and / or at least in part based on one or more desired operating conditions of the thermal management system 200 and / or fuel system 300.

[0101] In some embodiments, it may be desirable to avoid significant changes in the density of fluid 401. In some embodiments, the control system 600 may be configured to determine one or more phase properties of the first fluid component, such as the density of the first fluid component, based at least in part on whether the second fluid component is in a liquid or gaseous phase, and / or whether the second fluid component undergoes a phase transition. In some embodiments, the second fluid component may be used as a tracer to determine one or more phase properties of the first fluid component, such as density. Figure 5E As shown, the first fluid component may have a first vaporization curve 502, and the second fluid component may have a second vaporization curve 524. The second fluid component may be selected based at least in part on the relationship between the pressure and density of the first fluid component, and / or at least in part on the range of interest of the variable density region 522 of the first fluid component. In some embodiments, where applicable, the thermal management system 200 and / or the fuel system 300 may be operated such that fluid 401 exhibits a first phase state 526, and a pressure reduction, such as an isothermal pressure reduction, may cause a phase change in the second fluid component, such as a phase transition. For example, the second fluid component may undergo a phase transition from a liquid phase to a gaseous phase. The phase change of the second fluid component may be determined by the control system 600 based at least in part on one or more sensor outputs 404 from one or more phase detection sensors 410. The phase change of the second fluid component determined by the control system 600 may provide an indicator or warning of further changes in the phase state of fluid 401, such as a further decrease in pressure and / or an increase in temperature, which may lead to a significant change in the density of the first fluid component. For example, a phase change in the second fluid component can provide an indication or warning that the phase of the first fluid component may be approaching the variable density region 522.

[0102] The control system 600 may provide one or more control commands 409 to one or more controllable components 408, at least in part, based on one or more sensor outputs 404, which provide an indication or warning that the phase state of a first fluid component may be approaching a variable density region 522. For example, the control system 600 may provide one or more control commands 409 to one or more controllable components 408 configured to increase the temperature and / or pressure of fluid 401, such as increasing the pressure and / or temperature of fluid 401 above the critical condensation pressure 514 and / or critical condensation temperature 516.

[0103] Still referencing Figures 5A-5E In some embodiments, fluid 401 may include a first fluid component selected from the following: carbon monoxide, carbon dioxide, ammonia, methane, methanol, ethanol, ethylene, propane, propylene, heptane, 1-octanol, 2-octanol, 2-propanol, difluoromethane, ethane, difluoroethane, tetrafluoroethylene, acetone, nitrous oxide, argon, bromine, neon, hydrogen, oxygen, water, liquefied natural gas, kerosene, and kerosene-based jet fuel (e.g., Jet A, Jet A-1, JP-5, JP-8). Additionally or alternatively, in some embodiments, fluid 401 may include a second and / or a third fluid component selected from the above fluids.

[0104] In some embodiments, fluid 401, such as cooling fluid 206, may include a first fluid component and a second and / or a third fluid component, wherein the first fluid component is carbon dioxide, and the second and / or third fluid component may be selected from the following: carbon monoxide, ammonia, methane, methanol, ethanol, ethylene, propane, propylene, heptane, 1-octanol, 2-octanol, 2-propanol, difluoromethane, ethane, difluoroethane, tetrafluoroethylene, acetone, nitrous oxide, argon, bromine, neon, hydrogen, oxygen, and water. As an example, in some embodiments, the first fluid component may be carbon dioxide, and the second fluid component may be hydrogen. As another example, in some embodiments, the first fluid component may be carbon dioxide, the second fluid component may be nitrous oxide, and the third fluid component may be ethane. As another example, the first fluid component may be carbon dioxide, the second fluid component may be 2-propanol, and the third fluid component may be nitrogen. As another example, the first fluid component may be carbon dioxide, the second fluid component may be difluoromethane, and the third fluid component may be tetrafluoroethylene. As another example, the first fluid component may be argon, and the second fluid component may be oxygen.

[0105] As another example, in some embodiments, fluid 401, such as fuel 306, may include a first fluid component and a second and / or a third fluid component, wherein the first fluid component is hydrogen, and the second and / or third fluid component may be selected from: carbon monoxide, carbon dioxide, ammonia, methane, methanol, ethanol, ethylene, propane, propylene, heptane, 1-octanol, 2-octanol, 2-propanol, difluoromethane, ethane, difluoroethane, tetrafluoroethylene, acetone, nitrous oxide, argon, bromine, neon, oxygen, water, hydrogen, methane, liquefied natural gas, kerosene, and kerosene-type jet fuels (e.g., Jet A, Jet A-1, JP-5, JP-8). As an example, the first fluid component may be hydrogen, and the second fluid component may be neon. As another example, the first fluid component may be 1-octanol, and the second fluid component may be 2-octanol. As another example, the first fluid component may be kerosene, and the second fluid component may be 1-octanol. As another example, the first fluid component may be propane, and the second fluid component may be propylene. As another example, the first fluid component may be kerosene, the second fluid component may be 1-octanol, and the third fluid component may be 2-octanol.

[0106] Now for reference Figure 6 The exemplary control system 600 is further described. The exemplary control system 600 can be used to monitor and / or control various characteristics of the power generation system 100, such as various characteristics of the engine 102, thermal management system 200, fuel system 300, and / or pericritical fluid system 400. According to this disclosure, the control system 600 can be configured to perform any desired control operation. Figure 6 As shown, the exemplary control system 600 may include a controller 602, such as an electric motor controller, a full authority digital engine control (FADEC) device, etc.

[0107] The controller 602 may include one or more computing devices 604 configured to perform desired control operations. The one or more computing devices 604 may be located locally or remotely relative to the power generation system 100 and / or the engine 102. Control operations may include determining, generating, transmitting, and / or receiving sensor outputs 404 from one or more sensors 402. Additionally or alternatively, control operations may include, for example, determining, generating, transmitting, and / or receiving fluid monitoring data 406 based at least in part on the sensor outputs 404. Additionally or alternatively, control operations may include, for example, determining, generating, transmitting, and / or receiving one or more control commands 409 based at least in part on the fluid monitoring data 406 and / or the sensor outputs 404. The control commands 409 may be transmitted to one or more controllable components 408.

[0108] The computing device 604 may be communicatively connected to one or more sensors 402 and / or one or more controllable components 408. The computing device 604 may include one or more control modules 606, which are configured to cause the controller 602 to perform one or more control operations, for example, at least in part based on one or more models, lookup tables, etc.

[0109] One or more computing devices 604 may include one or more processors 608 and one or more memory devices 610. The one or more processors 608 may include any suitable processing means, such as a microprocessor, microcontroller, integrated circuit, logic device, and / or other suitable processing means. The one or more memory devices 610 may include one or more computer-readable media, including but not limited to non-transitory computer-readable media, RAM, ROM, hard disk drives, flash drives, and / or other memory devices 610. One or more control modules 606 may be implemented at least in part by one or more processors 608 and / or one or more memory devices 610.

[0110] As used herein, the terms “processor” and “computer,” as well as related terms such as “processing device” and “computing device,” are not limited to those integrated circuits referred to in the art as computers, but broadly refer to microcontrollers, microcomputers, programmable logic controllers (PLCs), application-specific integrated circuits (ASICs), and other programmable circuits, and these terms are used interchangeably herein. Memory device 610 may include, but is not limited to, non-transitory computer-readable media such as random access memory (RAM), and computer-readable non-volatile media such as hard disk drives, flash memory, and other memory devices. Alternatively, floppy disks, read-only optical disc storage (CD-ROM), magneto-optical discs (MOD), and / or digital universal discs (DVDs) may also be used.

[0111] As used herein, the term "non-transitory computer-readable medium" is intended to refer to any tangible computer-based device implemented with any method or technique for short-term and long-term storage of information (such as computer-readable instructions, data structures, program modules and submodules, or other data in any device). The methods described herein can be encoded as executable instructions embodied in a tangible non-transitory computer-readable medium, including but not limited to storage devices and / or memory devices. When executed by a processor, such instructions cause the processor to perform at least a portion of the methods described herein. Furthermore, as used herein, the term "non-transitory computer-readable medium" includes all tangible computer-readable media, including but not limited to non-transitory computer storage devices, including but not limited to volatile and non-volatile media, and removable and non-removable media such as firmware, physical and virtual storage, CD-ROMs, DVDs, and any other digital source such as networks or the Internet, as well as undeveloped digital means, with the sole exception of transient propagation signals.

[0112] One or more memory devices 610 may store information accessible by one or more processors 608, including computer-executable instructions 612 executable by one or more processors 608. Instructions 612 may include any instruction set that, when executed by one or more processors 608, causes one or more processors 608 to perform operations including control operations. One or more memory devices 610 may store data 614 accessible by one or more processors 608, such as data associated with the power generation system 100, engine 102, thermal management system 200, fuel system 300, and / or pericritical fluid system 400. Data 614 may include fluid monitoring data 406. Data 614 may include current or real-time data 614, past data 614, or a combination thereof. Data 614 may be stored in a database 616. Data 614 may also include other datasets, parameters, outputs, and information associated with the power generation system 100, engine 102, thermal management system 200, fuel system 300, and / or pericritical fluid system 400.

[0113] One or more computing devices 604 may also include a communication interface 618 configured to communicate with various nodes on a communication network 620 via a wired or wireless communication line 622. The communication interface 618 may include any suitable components for interfacing with one or more networks, including, for example, a transmitter, receiver, port, controller, antenna, and / or other suitable components. The communication network 620 may include, for example, a local area network (LAN), a wide area network (WAN), a SATCOM network, a VHF network, an HF network, a Wi-Fi network, a WiMAX network, a gatelink network, and / or any other suitable communication network 620 for transmitting messages to and / or from the computing device 604 via the communication line 622. The communication line 622 of the communication network 620 may include a data bus or a combination of wired and / or wireless communication links.

[0114] The control system 600 may include a management system 624, which is located locally or remotely relative to the power generation system 100 and / or the engine 102. The management system 624 may include a server 626 and / or a data warehouse 628. As an example, at least a portion of the data 614 may be stored in the data warehouse 628, and the server 626 may be configured to transmit data 614 from the data warehouse 628 to one or more computing devices 604, and / or receive data 614 from one or more computing devices 604, and store the received data 614 in the data warehouse 628 for further purposes. The server 626 and / or the data warehouse 628 may be implemented as part of one or more computing devices 604 and / or as part of the management system 624. The control system 600 may also include a user interface 630, which is configured to allow a user to interact with various features of the control system 600, for example, via a communication interface 618. The communication interface 618 may allow one or more computing devices 604 to communicate with various nodes associated with the power generation system 100 and / or engine 102, the management system 624 and / or the user interface 630.

[0115] Now for reference Figure 7 The exemplary method according to this disclosure is further described. As an example, exemplary method 700 may include a method for controlling the phase state of a fluid. Exemplary method 700 may be performed in conjunction with thermal management system 200 and / or fuel system 300. Additionally or alternatively, exemplary method 700 may be performed in conjunction with one or more operations of power generation system 100 and / or engine 102 (such as a turbine engine).

[0116] like Figure 7As shown, exemplary method 700 may include, at block 702, determining sensor output 404 generated by one or more sensors 402. The sensor output may correspond to one or more phase properties of fluid 401. Fluid 401 may be a pericritical fluid, such as a supercritical or near-supercritical fluid. In some embodiments, fluid 401 may be cooling fluid 206. Fluid 401, such as cooling fluid 206, may flow through a cooling circuit 208 of a thermal management system 200. Sensor output 404 may be determined relative to fluid 401 (such as cooling fluid 206) as fluid 401 (such as cooling fluid 206) flows through cooling circuit 208, such as when flowing through one or more cooling conduits 210, or in a tank or container configured to supply cooling fluid 206 to cooling circuit 208. Additionally or alternatively, fluid 401 may be fuel 306. Fluid 401, such as fuel 306, may flow through a fuel path 302 of a fuel system 300. The sensor output 404 can be determined relative to the fluid 401 (such as fuel 306) as it flows through the fuel path 302, such as through one or more fuel conduits 304, or in a fuel tank 308 configured to store fuel 306.

[0117] At block 704, exemplary method 700 may include generating a control command 409, at least in part based on sensor output 404, the control command 409 being configured to control one or more controllable components 408. In some embodiments, the controllable component 408 may be associated with a thermal management system 200. In some embodiments, the controllable component 408 may be associated with a fuel system 300. The one or more sensors may include one or more phase detection sensors 410. In some embodiments, the one or more phase detection sensors may include acoustic sensors, such as speed sensors or sound wave sensors. In some embodiments, the one or more phase detection sensors may include optical sensors or pressure drop sensors.

[0118] Therefore, the systems and methods disclosed herein can be used to monitor and / or control the phase state of fluids, such as in pericritical, supercritical, and / or near-supercritical phases. Further aspects of this disclosure are provided by the subject matter of the following provisions:

[0119] A peripheral critical fluid system for a thermal management system associated with a turbine engine, the peripheral critical fluid system comprising: one or more sensors configured to generate sensor outputs corresponding to one or more phase properties of a peripheral critical fluid flowing through a cooling loop of the thermal management system; and a controller communicatively coupled to the one or more sensors, the controller being configured to generate control commands based at least in part on the sensor outputs, the control commands being configured to control one or more controllable components of the thermal management system; wherein the one or more sensors include one or more phase detection sensors, the one or more phase detection sensors including acoustic sensors.

[0120] A peripheral critical fluid system according to any one of the foregoing clauses includes: the one or more controllable components, wherein the one or more controllable components are respectively configured to change one or more of the following: the temperature of the peripheral critical fluid, the pressure of the peripheral critical fluid, and / or the flow rate of the peripheral critical fluid.

[0121] According to any one of the foregoing clauses, in the pericritical fluid system, the acoustic sensor includes a sound velocity sensor, the sound velocity sensor including an ultrasonic transducer and a receiver, the ultrasonic transducer being configured to emit sound waves, and the receiver being configured to receive the sound waves and convert the sound waves into electrical signals.

[0122] The pericritical fluid system according to any one of the foregoing clauses, wherein the acoustic sensor includes an acoustic wave sensor configured to apply an oscillating electric field to generate acoustic waves that propagate through a piezoelectric substrate.

[0123] The peripheral critical fluid system according to any one of the foregoing clauses, wherein the acoustic sensor includes a bulk acoustic sensor.

[0124] The peripheral critical fluid system according to any one of the foregoing clauses, wherein the acoustic wave sensor includes a surface acoustic wave sensor.

[0125] A pericritical fluid system according to any one of the foregoing clauses, wherein the controller is configured to determine one or more phase properties of the pericritical fluid based at least in part on the sensor output.

[0126] According to any one of the foregoing clauses, in a pericritical fluid system, wherein the controller is configured to determine one or more phase properties of the pericritical fluid based at least in part on the correlation between the sensor output and the one or more phase properties of the pericritical fluid.

[0127] According to any one of the foregoing clauses, in a pericritical fluid system, the controller is configured to determine one or more phase properties of the pericritical fluid based at least in part on the noise or bias level of the sensor output.

[0128] In any of the foregoing clauses, the one or more sensors in the circumcritical fluid system include one or more temperature sensors and / or one or more pressure sensors.

[0129] According to any one of the foregoing clauses, the peripheral critical fluid system wherein the sensor output includes a phase detection sensor output generated by the one or more phase detection sensors, and at least one of the following: a temperature sensor output generated by the one or more temperature sensors, and a pressure sensor output generated by the one or more pressure sensors; and wherein the controller is configured to determine one or more phase properties of the peripheral critical fluid based at least in part on the phase detection sensor output combined with at least one of the following: the temperature sensor output and the pressure sensor output.

[0130] According to any one of the foregoing clauses, the peripheral critical fluid system, wherein the one or more phase properties of the peripheral critical fluid include a phase transition and a phase state corresponding to the phase transition, and wherein the controller is configured to determine the occurrence of the phase transition based at least in part on the phase detection sensor output, and wherein the controller is configured to determine the phase state corresponding to the phase transition based at least in part on at least one of the following: the temperature sensor output and the pressure sensor output.

[0131] The pericritical fluid system according to any one of the foregoing clauses, wherein the pericritical fluid comprises at least one of the following: carbon monoxide, carbon dioxide, ammonia, methane, methanol, ethanol, ethylene, propane, propylene, heptane, 1-octanol, 2-octanol, 2-propanol, difluoromethane, ethane, difluoroethane, tetrafluoroethylene, acetone, nitrous oxide, argon, bromine, neon, hydrogen, oxygen, and water.

[0132] The pericritical fluid system according to any one of the foregoing clauses, wherein the pericritical fluid comprises a multi-peaked fluid comprising a first fluid component and a second fluid component, wherein the sensor output corresponds to one or more phase properties relative to the second fluid component, and wherein the controller is configured to determine one or more phase properties relative to the first fluid component based at least in part on the sensor output corresponding to the one or more phase properties relative to the second fluid component.

[0133] According to any one of the foregoing clauses, in a pericritical fluid system, the one or more phase properties relative to the second fluid component include phase states or phase transitions with respect to a liquid saturation curve, the liquid saturation curve representing the transition of the second fluid component from a liquid phase to a gas phase.

[0134] According to any one of the foregoing clauses, in a pericritical fluid system, wherein the multi-peaked fluid comprises a third fluid component, and wherein the sensor output includes an additional sensor output corresponding to one or more phase properties relative to the third fluid component, and wherein the controller is configured to determine one or more phase properties relative to the first fluid component based at least in part on the additional sensor output corresponding to the one or more phase properties relative to the third fluid component; wherein the one or more phase properties relative to the third fluid component include a phase state or phase transition with respect to a vapor saturation curve, the vapor saturation curve representing the transition of the third fluid component from a gas phase to a liquid phase; and wherein the vaporization curve of the first fluid component is at least partially surrounded by the liquid saturation curve and the vapor saturation curve.

[0135] In any of the foregoing clauses, the second fluid component and / or the third fluid component have a concentration corresponding to a trace amount sufficient to determine the properties of the one or more phases.

[0136] The pericritical fluid system according to any one of the foregoing clauses, wherein the first fluid component comprises carbon dioxide, and the second fluid component and / or the third fluid component comprises at least one of the following: carbon monoxide, ammonia, methane, methanol, ethanol, ethylene, propane, propylene, heptane, 1-octanol, 2-octanol, 2-propanol, difluoromethane, ethane, difluoroethane, tetrafluoroethylene, acetone, nitrous oxide, argon, bromine, neon, hydrogen, oxygen, and water.

[0137] A liquid fuel system for a turbine engine, the liquid fuel system comprising: one or more sensors configured to generate sensor outputs corresponding to one or more phase properties of fuel supplied to the turbine engine via a fuel path; and a controller communicatively coupled to the one or more sensors, the controller being configured to generate control commands based at least in part on the sensor outputs, the control commands being configured to control one or more controllable components of the liquid fuel system, wherein the one or more sensors include one or more phase detection sensors; wherein the fuel comprises hydrogen, and wherein the fuel is in a liquid phase.

[0138] In a liquid fuel system according to any one of the foregoing clauses, the one or more phase detection sensors include: acoustic sensors, optical sensors, or pressure drop sensors.

[0139] In a liquid fuel system according to any one of the foregoing clauses, wherein the one or more phase detection sensors include the acoustic sensor, wherein the acoustic sensor includes a sound velocity sensor, the sound velocity sensor including an ultrasonic transducer and a receiver, the ultrasonic transducer being configured to emit sound waves, and the receiver being configured to receive the sound waves and convert the sound waves into electrical signals.

[0140] In a liquid fuel system according to any one of the foregoing clauses, wherein the one or more phase detection sensors include the acoustic sensor, wherein the acoustic sensor includes a sound wave sensor configured to apply an oscillating electric field to generate sound waves that propagate through a piezoelectric substrate.

[0141] In any of the preceding clauses, the liquid fuel system wherein the acoustic sensor comprises a bulk acoustic sensor.

[0142] In any of the preceding clauses, the liquid fuel system wherein the acoustic sensor comprises a surface acoustic wave sensor.

[0143] In a liquid fuel system according to any one of the foregoing clauses, wherein the one or more phase detection sensors include the optical sensor, wherein the optical sensor includes a fiber optic reflector, the fiber optic reflector including a light source, an optical fiber, and a photodiode, the light source being configured to generate a probe beam, the optical fiber being configured to guide the probe beam into a measurement chamber, and the photodiode being configured to measure the intensity of the probe beam.

[0144] In a liquid fuel system according to any one of the foregoing clauses, the fiber optic reflector comprises one or more microstructured optical fibers, each comprising a core material and a plurality of channels defined within the core material, wherein the fiber optic reflector is configured to guide light through the plurality of channels by total internal reflection and / or constructive interference of scattered light.

[0145] In a liquid fuel system according to any one of the foregoing clauses, wherein the one or more phase detection sensors include the optical sensor, wherein the optical sensor includes an infrared spectrometer, the infrared spectrometer including an infrared light source, a measurement window and an infrared detector, the measurement window being configured to contact the fuel, and the infrared detector being configured to detect infrared light transmitted through the measurement window.

[0146] In a liquid fuel system according to any one of the foregoing clauses, the infrared spectrometer includes an attenuated total reflectance infrared spectrometer configured to detect total internal reflection.

[0147] In a liquid fuel system according to any one of the foregoing clauses, the one or more phase detection sensors include the pressure drop sensor, wherein the pressure drop sensor includes a microchannel pressure drop sensor or a packed bed pressure drop sensor.

[0148] A liquid fuel system according to any one of the foregoing clauses includes: the one or more controllable components, wherein the one or more controllable components are respectively configured to change one or more of the following: the temperature of the fuel, the pressure of the fuel, and / or the flow rate of the fuel.

[0149] In a liquid fuel system according to any one of the foregoing clauses, the controller is configured to determine one or more phase properties of the fuel based at least in part on the sensor output.

[0150] In a liquid fuel system according to any one of the foregoing clauses, wherein the controller is configured to determine one or more phase properties of the fuel based at least in part on the correlation between the sensor output and the one or more phase properties of the fuel.

[0151] In a liquid fuel system according to any one of the foregoing clauses, the controller is configured to determine one or more phase properties of the fuel based at least in part on noise or bias levels of sensor outputs.

[0152] In a liquid fuel system according to any one of the foregoing clauses, the one or more sensors include one or more temperature sensors and / or one or more pressure sensors.

[0153] The liquid fuel system according to any one of the foregoing clauses, wherein the sensor output includes a phase detection sensor output generated by the one or more phase detection sensors, and at least one of the following: a temperature sensor output generated by the one or more temperature sensors, and a pressure sensor output generated by the one or more pressure sensors; and wherein the controller is configured to determine one or more phase properties of the fuel based at least in part on the phase detection sensor output in combination with at least one of the following: the temperature sensor output and the pressure sensor output.

[0154] A liquid fuel system according to any one of the foregoing clauses, wherein the one or more phase properties of the fuel include a phase transition and a phase state corresponding to the phase transition, and wherein the controller is configured to determine the occurrence of the phase transition based at least in part on the output of the phase detection sensor, and wherein the controller is configured to determine the phase state corresponding to the phase transition based at least in part on at least one of the following: the output of the temperature sensor and the output of the pressure sensor.

[0155] The liquid fuel system according to any one of the preceding clauses includes: the circumcritical fluid system according to any one of the preceding clauses.

[0156] A turbine engine includes: a thermal management system configured to circulate a peripheral critical fluid through a cooling circuit, the thermal management system including one or more controllable components; one or more sensors configured to generate sensor outputs corresponding to one or more phase properties of the peripheral critical fluid; and a controller communicatively coupled to the one or more sensors, the controller configured to generate control commands based at least in part on the sensor outputs, the control commands being configured to control the one or more controllable components; wherein the one or more sensors include one or more phase detection sensors, the one or more phase detection sensors including acoustic sensors.

[0157] A turbine engine includes: a liquid fuel system configured to supply fuel to the turbine engine via a fuel path, the liquid fuel system including one or more controllable components; one or more sensors configured to generate sensor outputs corresponding to one or more phase properties of the fuel; and a controller communicatively coupled to the one or more sensors, the controller configured to generate control commands based at least in part on the sensor outputs, the control commands being configured to control the one or more controllable components, wherein the one or more sensors include one or more phase detection sensors; wherein the fuel includes hydrogen.

[0158] The turbine engine according to any one of the foregoing clauses, wherein the turbine engine includes the circumcritical fluid system according to any one of the foregoing clauses.

[0159] The turbine engine according to any one of the foregoing clauses, wherein the turbine engine includes a liquid fuel system according to any one of the foregoing clauses.

[0160] A non-transitory computer-readable medium including computer-executable instructions, which, when executed by a processor, cause the processor to perform a method of controlling one or more phase properties of a pericritical fluid associated with a thermal management system of a turbine engine, the method comprising: determining sensor outputs generated by one or more sensors, the sensor outputs corresponding to one or more phase properties of the pericritical fluid flowing through a cooling loop of the thermal management system; and generating control commands, at least in part based on the sensor outputs, the control commands being configured to control one or more controllable components of the thermal management system; wherein the one or more sensors include one or more phase detection sensors, the one or more phase detection sensors including acoustic sensors.

[0161] A non-transitory computer-readable medium including computer-executable instructions, which, when executed by a processor, cause the processor to control one or more phase properties of a fuel associated with a liquid fuel system of a turbine engine, the method comprising: determining sensor outputs generated by one or more sensors corresponding to one or more phase properties of a fuel supplied to the turbine engine via a fuel path; and generating a control command, at least in part based on the sensor outputs, the control command being configured to control one or more controllable components of the liquid fuel system, wherein the one or more sensors include one or more phase detection sensors; wherein the fuel includes hydrogen, and wherein the fuel is in a liquid phase.

[0162] A method for controlling one or more phase properties of a peripheral critical fluid associated with a thermal management system of a turbine engine, the method comprising: determining sensor outputs generated by one or more sensors, the sensor outputs corresponding to one or more phase properties of the peripheral critical fluid flowing through a cooling loop of the thermal management system; and generating a control command based at least in part on the sensor outputs, the control command being configured to control one or more controllable components of the thermal management system; wherein the one or more sensors include one or more phase detection sensors, the one or more phase detection sensors including acoustic sensors.

[0163] A method for controlling one or more phase properties of a fuel associated with a liquid fuel system of a turbine engine, the method comprising: determining sensor outputs generated by one or more sensors, the sensor outputs corresponding to one or more phase properties of a fuel supplied to the turbine engine via a fuel path; and generating a control command based at least in part on the sensor outputs, the control command being configured to control one or more controllable components of the liquid fuel system, wherein the one or more sensors include one or more phase detection sensors; and wherein the fuel comprises hydrogen, and wherein the fuel is in a liquid phase.

[0164] The method according to any one of the foregoing clauses, wherein the method is performed using a circumcritical fluid system according to any one of the foregoing clauses.

[0165] The method according to any one of the foregoing clauses, wherein the method is performed using a liquid fuel system according to any one of the foregoing clauses.

[0166] The method according to any one of the foregoing clauses, wherein the method is performed using a non-transitory computer-readable medium according to any one of the foregoing clauses.

[0167] This written description uses exemplary embodiments to describe the currently disclosed subject matter, including best practices, and also enables any person skilled in the art to practice the subject matter, including making and using any apparatus or system, and methods of making any combination. The patentable scope of the currently disclosed subject matter is defined by the claims, and may include other examples that would occur to a person skilled in the art. These other examples are intended to fall within the scope of the claims if they include structural elements that are not indistinguishable from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

Claims

1. A peri-critical fluid system of a thermal management system associated with a turbine engine, characterized in that, The supercritical fluid system comprises: one or more sensors configured to generate sensor outputs corresponding to one or more phase properties of a supercritical fluid flowing through a cooling loop of the thermal management system; and a controller communicatively coupled to the one or more sensors, the controller configured to generate control commands based at least in part on the sensor outputs, the control commands configured to control one or more controllable components of the thermal management system; wherein the one or more sensors comprise one or more phase detection sensors, the one or more phase detection sensors comprising an acoustic sensor.

2. The peri-critical fluid system of claim 1, wherein, comprises: the one or more controllable components, wherein the one or more controllable components are each configured to change one or more of: a temperature of the supercritical fluid, a pressure of the supercritical fluid, and / or a flow rate of the supercritical fluid.

3. The peri-critical fluid system of claim 1, wherein, wherein the acoustic sensor comprises a sound velocity sensor, the sound velocity sensor comprising an ultrasonic transducer configured to emit sound waves and a receiver configured to receive the sound waves and convert the sound waves into an electrical signal.

4. The near-critical fluid system of claim 1 wherein, wherein the acoustic sensor comprises a sound wave sensor configured to apply an oscillating electric field to generate sound waves that propagate through a piezoelectric substrate.

5. The near-critical fluid system of claim 4 wherein, wherein the sound wave sensor comprises a bulk acoustic wave sensor.

6. The near-critical fluid system of claim 4 wherein, wherein the sound wave sensor comprises a surface acoustic wave sensor.

7. The near-critical fluid system of claim 1 wherein, wherein the controller is configured to determine one or more phase properties of the supercritical fluid based at least in part on the sensor outputs.

8. The near-critical fluid system of claim 7 wherein, wherein the controller is configured to determine one or more phase properties of the supercritical fluid based at least in part on a correlation between the sensor outputs and the one or more phase properties of the supercritical fluid.

9. The near-critical fluid system of claim 7 wherein, wherein the controller is configured to determine one or more phase properties of the supercritical fluid based at least in part on a noise or bias level of sensor outputs.

10. The near-critical fluid system of claim 1 wherein, wherein the one or more sensors comprise one or more temperature sensors and / or one or more pressure sensors.

11. The peri-critical fluid system of claim 10, wherein, wherein the sensor outputs comprise phase detection sensor outputs generated by the one or more phase detection sensors, and at least one of: temperature sensor outputs generated by the one or more temperature sensors, and pressure sensor outputs generated by the one or more pressure sensors; and wherein the controller is configured to determine one or more phase properties of the supercritical fluid based at least in part on the phase detection sensor outputs in combination with at least one of: the temperature sensor outputs and the pressure sensor outputs.

12. The peri-critical fluid system of claim 11, wherein, wherein the one or more phase properties of the supercritical fluid comprise a phase transition and a phase state corresponding to the phase transition, and wherein the controller is configured to determine an occurrence of the phase transition based at least in part on the phase detection sensor outputs, and wherein the controller is configured to determine the phase state corresponding to the phase transition based at least in part on at least one of: the temperature sensor outputs and the pressure sensor outputs.

13. The near-critical fluid system of claim 1 wherein, wherein the near-critical fluid comprises at least one of: carbon monoxide, carbon dioxide, ammonia, methane, methanol, ethanol, ethylene, propane, propylene, heptane, 1-octanol, 2-octanol, 2-propanol, difluoromethane, ethane, difluoroethane, tetrafluoroethylene, acetone, nitrous oxide, argon, bromine, neon, hydrogen, oxygen, and water.

14. The near-critical fluid system of claim 1 wherein, wherein the near-critical fluid comprises a multi-modal fluid, the multi-modal fluid comprising a first fluid component and a second fluid component, and wherein the sensor output corresponds to one or more phase properties with respect to the second fluid component, and wherein the controller is configured to determine one or more phase properties with respect to the first fluid component based at least in part on the sensor output corresponding to the one or more phase properties with respect to the second fluid component.

15. The peri-critical fluid system of claim 14, wherein, wherein the one or more phase properties with respect to the second fluid component include a phase state or phase transition with respect to a liquid saturation curve, the liquid saturation curve representing a transition of the second fluid component from a liquid phase to a gas phase.

16. The near-critical fluid system of claim 15 wherein, wherein the multi-modal fluid comprises a third fluid component, and wherein the sensor output includes an additional sensor output corresponding to one or more phase properties with respect to the third fluid component, and wherein the controller is configured to determine one or more phase properties with respect to the first fluid component based at least in part on the additional sensor output corresponding to the one or more phase properties with respect to the third fluid component; wherein the one or more phase properties with respect to the third fluid component include a phase state or phase transition with respect to a vapor saturation curve, the vapor saturation curve representing a transition of the third fluid component from a gas phase to a liquid phase; and wherein a vaporization curve of the first fluid component is at least partially enclosed by the liquid saturation curve and the vapor saturation curve.

17. The near-critical fluid system of claim 16 wherein, wherein the second fluid component and / or the third fluid component has a concentration corresponding to a trace amount sufficient for determining the one or more phase properties.

18. The near-critical fluid system of claim 16 wherein, wherein the first fluid component comprises carbon dioxide, and the second fluid component and / or the third fluid component comprises at least one of: carbon monoxide, ammonia, methane, methanol, ethanol, ethylene, propane, propylene, heptane, 1-octanol, 2-octanol, 2-propanol, difluoromethane, ethane, difluoroethane, tetrafluoroethylene, acetone, nitrous oxide, argon, bromine, neon, hydrogen, oxygen, water.

19. A turbine engine characterized by, comprising: a thermal management system configured to circulate a near-critical fluid through a cooling loop, the thermal management system comprising one or more controllable components; one or more sensors configured to generate a sensor output corresponding to one or more phase properties of the near-critical fluid; and a controller communicatively coupled to the one or more sensors, the controller configured to generate a control command based at least in part on the sensor output, the control command configured to control the one or more controllable components; wherein the one or more sensors include one or more phase detection sensors, the one or more phase detection sensors including an acoustic sensor.

20. A non-transitory computer-readable medium comprising computer-executable instructions that, when executed by a processor, cause the processor to perform a method of controlling one or more phase properties of a near-critical fluid associated with a thermal management system of a turbine engine, the method comprising: The method includes: determining a sensor output generated by one or more sensors, the sensor output corresponding to one or more phase properties of a supercritical fluid flowing through a cooling loop of the thermal management system; and generating a control command based at least in part on the sensor output, the control command configured to control one or more controllable components of the thermal management system; wherein the one or more sensors include one or more phase detection sensors, the one or more phase detection sensors including an acoustic sensor. The method includes: determining a sensor output generated by one or more sensors, the sensor output corresponding to one or more phase properties of a supercritical fluid flowing through a cooling loop of the thermal management system; and generating a control command based at least in part on the sensor output, the control command configured to control one or more controllable components of the thermal management system; wherein the one or more sensors include one or more phase detection sensors, the one or more phase detection sensors including an acoustic sensor.

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