Method and system for power generation and thermal management with dual cycle architecture

Abstract

Methods and systems related to power generation and thermal management for dual loop architectures. In particular, methods and apparatus for power generation and / or thermal management on a high speed flying vehicle (102) are provided, including circulating a power loop working fluid (122) through a power loop (120) that absorbs heat associated with the flying vehicle (102). A power generator (170) operatively coupled to the power loop (120) generates power. Additionally, a heat transfer loop working fluid (252) can be circulated through a heat transfer loop (250) to provide thermal management through heat transfer.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to high-speed flight vehicles, and more particularly to systems and methods for thermal management and power generation on high-speed flight vehicles. BACKGROUND

[0002] Flight vehicles traveling through the atmosphere at high speeds can experience extremely high temperatures. When traveling at speeds greater than 3 Mach, and more particularly hypersonic speeds greater than 5 Mach, the temperatures can locally exceed 1000 degrees Fahrenheit, forcing the use of high-density materials such as superalloys or expensive non-metallic materials such as ceramic matrix composites. Additionally, turbofan and turbojet engines cannot be used at speeds exceeding 3 Mach without air cooling. Also, as speed increases, a large portion of the total engine airflow is diverted around the turbomachinery into an augmentor, also known as a afterburner, which is essentially a ramjet. As a result, the turbomachinery generates a lower amount of power, thus reducing the ability of the turbomachinery to generate power for the vehicle systems. SUMMARY

[0003] According to one aspect of the present disclosure, a method of providing at least one of cooling and power generation on a flight vehicle using heated inlet air associated with the flight vehicle is provided, the method comprising the steps of: propelling the flight vehicle at a flight speed of at least 3 Mach. circulating a first working fluid through a first fluid circuit, the circulating step comprising in order: compressing the first working fluid through a first compressor; heating the first working fluid through an inlet air heat exchanger, the inlet air heat exchanger comprising an inlet air line in fluid communication with heated inlet air and a first air-circuit line positioned in a thermally coupled relationship to the inlet air line; expanding the first working fluid in a first thermal engine to generate a first work output from the first thermal engine; cooling the first working fluid; and recirculating the first working fluid to the first compressor.

[0004] According to another aspect of the present disclosure, a system for providing at least one of cooling and power generation on a flight vehicle using heated inlet air associated with the flight vehicle, the flight vehicle traveling at a flight speed of at least 3 Mach, is provided, the system comprising a first fluid circuit containing a first working fluid. The first fluid circuit comprises in order: a first compressor for compressing the first working fluid; an inlet air heat exchanger comprising an inlet air line in fluid communication with heated inlet air and a first air-circuit line receiving the first working fluid and positioned in a thermally coupled relationship to the inlet air line; and a first thermal engine for expanding the first working fluid and generating a first work output.

[0005] According to another aspect of the disclosure, there is provided a system for providing cooling and power generation on a flight vehicle using heated incoming air associated with the flight vehicle, the flight vehicle traveling at a flight speed of at least 3 Mach, the system comprising a power generation circuit including a power generation circuit working fluid. The power generation circuit comprises, in order: a power generation circuit compressor for compressing the power generation circuit working fluid; an intake heat exchanger including an intake line in fluid communication with the heated incoming air and a first air-circuit line receiving the power generation circuit working fluid and positioned in a thermal coupling relationship to the intake line; and a power generation circuit heat engine for expanding the power generation circuit working fluid and generating a power generation circuit work output. The system further comprises a heat transport circuit including a heat transport circuit working fluid. The heat transport circuit comprises, in order: a heat transport circuit compressor for compressing the heat transport circuit working fluid; the intake heat exchanger including a second air-circuit line receiving the heat transport circuit working fluid and positioned in a thermal coupling relationship to the intake line; and a heat transport circuit heat engine for expanding the heat transport circuit working fluid and generating a heat transport work output, wherein the heat transport work output is mechanically coupled to the heat transport circuit compressor. An electric generator is operatively coupled to the power generation circuit heat engine and is configured to receive at least a portion of the power generation circuit work output and generate auxiliary electrical power. A controller is operatively coupled to the power generation circuit compressor and the heat transport circuit compressor, wherein the controller is programmed to perform a method comprising the step of initiating operation of the power generation circuit compressor and the heat transport circuit compressor when the flight speed of the flight vehicle is above 3 Mach.

[0006] The features, functions, and advantages that have been discussed can be implemented independently in various examples, or can be combined in yet other examples, further details of which can be appreciated throughout the description and drawings below. BRIEF DESCRIPTION OF DRAWINGS

[0007] The novel features of the example embodiments are set forth with particularity in the claims that follow. A better understanding of the example embodiments, and of their particular

[0008] Figure 1 is a perspective view of a high speed flight vehicle having an integrated cooling and power generation system according to the present disclosure.

[0009] Figure 2 is a schematic illustration of an integrated cooling and power generation system.

[0010] Figure 3 is a plot illustrating exemplary supercritical fluids for use in an integrated cooling and power generation system.

[0011] Figure 4 is a block diagram illustrating a method of using heat associated with a high-speed flight vehicle for at least one of power generation and thermal management on the flight vehicle. Figure 1 is a block diagram illustrating a method of using heat associated with a high-speed flight vehicle for at least one of power generation and thermal management on the flight vehicle. DETAILED DESCRIPTION

[0012] The accompanying drawings and following description illustrate specific examples of the claimed subject matter. Accordingly, it will be apparent to those of ordinary skill in the art that various arrangements can be constructed without departing from the scope of the claimed subject matter as defined by the appended claims and equivalents thereof. Furthermore, the examples described herein are intended to help illustrate the principles of the disclosed subject matter, and are not intended to limit the scope of the claimed subject matter to the specific examples described. As such, the present inventive concept is not intended to be limited to the specific examples described below, but rather is intended to encompass any arrangement that is functionally equivalent to the specific examples described herein and that fall within the scope of the claimed subject matter as defined by the appended claims and equivalents thereof.

[0013] Examples of the integrated cooling and power generation system described herein provide both cooling and power generation to a high-speed flight vehicle. At high speeds, the flight vehicle experiences one or more heat sources. The heat sources can be the incoming air, the vehicle surface, or other sources. The system absorbs heat from the one or more heat sources, provides cooling, and uses the heat to generate mechanical output. The mechanical output can be used directly within the system itself, or can be converted to electrical power that can be used to power components of the integrated cooling and power generation system or subsystems disposed on the flight vehicle. In certain examples, the integrated cooling and power generation system has a dual loop architecture, where a power generation loop is used for power generation and a heat transport loop is used for providing mechanical power. In some implementations, each of the power generation loop and the heat transport loop has a Brayton cycle architecture. In the dual loop implementation, the power generation loop is primarily configured to optimize the conversion of heat to power, while the heat transport loop is primarily configured to optimize heat transfer from the one or more heat sources. Thus, the dual cycle architecture separates power generation from large scale heat transfer, allowing each cycle to have components and operating conditions that are optimized for their respective primary functions. While implementations are disclosed herein having both a power generation loop and a heat transport loop, it should be appreciated that the integrated cooling and power generation system can include only a power generation loop, or alternatively, only a heat transport loop.

[0014] Figure 1Examples of a high-speed flight vehicle 102 are illustrated. The flight vehicle 102 can be piloted or unpiloted as desired. The flight vehicle 102 is merely one configuration of a flight vehicle capable of traveling at speeds of at least 3 Mach, and other configurations not shown can be implemented as desired. For example, the flight vehicle 102 can have different shapes, sizes, aspect ratios, etc. as desired. Thus, the flight vehicle 102 is shown in a particular configuration for purposes of discussion only.

[0015] In this example, the flight vehicle 102 provides one or more heat sources while traveling at high speeds. For example, one heat source can be provided by the first surface 104 of the flight vehicle 102 being aerodynamically heated. In some examples, the first surface 104 is disposed on a leading surface of the flight vehicle 102, such as a wing 106, a tail 108, a nose cap 110, or an inlet duct 112. During operation of the flight vehicle 102 above 3 Mach, or in hypersonic flight (e.g., the flight vehicle 102 moves at hypersonic speeds of 5 Mach and above), the first surface 104 can be aerodynamically heated to 1000 degrees Fahrenheit or more. Additionally or alternatively, another heat source can be incoming air that is introduced into the flight vehicle 102 while traveling at high speeds. This incoming air can include air that travels through the inlet duct 112 or through other structures disposed on the flight vehicle 102.

[0016] The flight vehicle 102 includes an integrated cooling and power generation system 100 that cools and / or generates power from the one or more heat sources. When the first surface 104 is used as a heat source, the system 100 cools the first surface 104, which can enable the first surface 104 to be formed from materials that do not need to be rated for excessively high temperatures, thereby reducing material costs and reducing material weight. Additionally or alternatively, converting heat from the one or more heat sources into electrical power reduces the need for batteries or other conventional power sources, thereby reducing the weight associated with such conventional power sources.

[0017] As Figure 2As best shown, the system 100 includes a power generation loop 120 through which a power generation loop working fluid 122 is circulated. In the illustrated example, the power generation loop 120 is formed as a closed loop having a Brayton cycle architecture. When the flight vehicle 102 is operating at speeds above Mach 3, heat from the one or more heat sources is conducted to the power generation loop working fluid 122 in the power generation loop 120 to maintain the power generation loop working fluid 122 at a temperature and pressure above its critical point. The one or more heat sources can be incoming air, the first surface 104, or other sources. Figure 3 The critical point of a substance is graphically illustrated, where temperatures and pressures above the critical point result in a supercritical state. In some examples, the power generation loop working fluid 122 that circulates through the power generation loop 120 is supercritical carbon dioxide.

[0018] The system 100 includes components disposed in the power generation loop 120 that are used to perform a sequence of thermodynamic processes involving the transfer of heat and work into and out of the system 100 while changing the temperature and pressure of the power generation loop working fluid 122 within the system. As Figure 2 As schematically illustrated in the middle, the system 100 includes a power generation loop compressor 130 that is used to compress the power generation loop working fluid 122 to an increased pressure.

[0019] The power generation loop 120 also includes one or more heat intakes that are used to absorb heat from the one or more heat sources. In the illustrated example, the first heat intake of the power generation loop 120 is an intake heat exchanger 256 that conducts heat from incoming air to the power generation loop working fluid 122. In Figure 2In the illustrated example, intake line 253 passes through intake heat exchanger 256. An upstream end of intake line 253 is fluidly coupled to an intake source, such as intake duct 112. High temperature air system 255 on board flight vehicle 102 is fluidly coupled directly to intake duct 112, thereby bypassing intake heat exchanger 256. Low temperature air system 249 is fluidly coupled to a downstream end of intake line 253. Intake heat exchanger 256 also includes an air-to-power generation loop line 251 positioned in thermal coupling relation to intake line 253 to conduct heat from the incoming air to power generation loop working fluid 122. Additionally or alternatively, power generation loop 120 includes a second heat sink in the form of first surface heat exchanger 140 positioned in thermal coupling relation to first surface 104 of flight vehicle 102.

[0020] A power generation loop heat engine 150 is provided in power generation loop 120 for extracting power generation loop work output 152 from power generation loop working fluid 122 by expanding power generation loop working fluid 122 to a reduced pressure. Although Figure 2 Power generation loop work output 152 is illustrated schematically as a rotating output shaft of a turbine engine, but other types of heat engines that are capable of extracting work output from a heated and pressurized working fluid can be used. In the illustrated example, power generation loop work output 152 takes the form of a rotating output shaft of a turbine engine that is mechanically coupled through shaft 154 to power generation loop compressor 130 to operate it. In an alternative example, power generation loop compressor 130 can be electrically operated, in which case power generation loop work output 152 is mechanically coupled to an electric generator that converts mechanical energy to electrical power to drive power generation loop compressor 130. As discussed in more detail below, this electrical power can also be used to power other vehicle systems.

[0021] Additionally, an electric generator 170 is operatively coupled to the power generation loop heat engine 150. The electric generator 170 receives at least a portion of the power generation loop work output 152 from the power generation loop heat engine 150 and generates an electrical power source 172. In this example, an auxiliary load 180 is operatively coupled to the electric generator 170 and is configured to operate using the electrical power source 172. The auxiliary load 180 can be an environmental control system (ECS), one or more flight control devices (e.g., actuators), avionics systems, a payload, or other devices or systems that require electrical power. Still further, the electrical power source 172 can also be used to power components of the integrated cooling and power generation system 100, such as the power generation loop compressor 130 and / or the heat transfer loop compressor 254. It should be appreciated that the power generation loop compressor 130 and the power generation loop heat engine 150 generally divide the power generation loop 120 into a low pressure leg 124 that extends downstream of the power generation loop heat engine 150 to an inlet of the power generation loop compressor 130 and a high pressure leg 126 that extends upstream of the power generation loop heat engine 150 to an outlet of the power generation loop compressor 130.

[0022] The system 100 also includes a heat transfer loop 250 through which a heat transfer loop working fluid 252 is circulated. In the illustrated example, the heat transfer loop 250 is formed as a closed loop that also has a Brayton cycle architecture. The heat transfer loop working fluid 252 in the heat transfer loop 250 can also be a high temperature working fluid, such as supercritical carbon dioxide.

[0023] A number of components are provided in the heat transfer loop 250 that are used to perform a sequence of thermodynamic processes involving the transfer of heat and work into and out of the system 100 while changing the temperature and pressure of the heat transfer loop working fluid 252 within the system. As Figure 2 As schematically illustrated in FIG. 1, the system 100 includes a heat transfer loop compressor 254 that is used to compress the heat transfer loop working fluid 252 to an increased pressure.

[0024] The heat transfer loop 250 also includes one or more heat absorption sections that are used to absorb heat from the one or more heat sources. In the illustrated example, a first heat absorption section of the heat transfer loop 250 is an intake heat exchanger 256 that conducts heat from the incoming air to the heat transfer loop working fluid 252. In Figure 2In the illustrated example, the intake heat exchanger 256 also includes an air-to-heat loop line 247 positioned in thermal coupling relation to the intake line 253 to conduct heat from the incoming air to the heat loop working fluid 252. Additionally or alternatively, the heat loop 250 includes a second heat sink in the form of a second surface heat exchanger 257 positioned in thermal coupling relation to the second surface 105 of the flight vehicle 102.

[0025] A heat loop heat engine 258 is provided in the heat loop 250 for extracting a heat loop work output 260 from the heat loop working fluid 252 by expanding the heat loop working fluid 252 to a reduced pressure. Although Figure 2 The heat loop heat engine 258 is illustratively shown as a turbine engine, but other types of heat engines capable of extracting a work output from a heated and pressurized working fluid can be used. In the illustrated example, the heat loop work output 260 takes the form of a rotating output shaft of the turbine engine that is mechanically coupled by a shaft 259 to the heat loop compressor 130 to operate the power generation loop compressor 130. Additionally, it will be appreciated that the heat loop compressor 254 and the heat loop heat engine 258 generally divide the heat loop 250 into a low pressure leg 262 extending downstream of the heat loop heat engine 258 to an inlet of the heat loop compressor 254 and a high pressure leg 263 extending upstream of the heat loop heat engine 258 to an outlet of the heat loop compressor 254.

[0026] In Figure 2In the illustrated example, the system 100 also includes a radiator heat exchanger 190 for rejecting excess heat from the power generation circuit working fluid 122 and the heat transfer circuit working fluid 252. The radiator heat exchanger 190 is positioned in the low pressure leg 124 of the power generation circuit 120 and the low pressure leg 262 of the heat transfer circuit 250. By removing heat from the power generation circuit working fluid 122 and the heat transfer circuit working fluid 252, the radiator heat exchanger 190 ensures that the temperature of the power generation circuit working fluid 122 and the temperature of the heat transfer circuit working fluid 252 do not exceed the rated operating temperature range of the power generation circuit compressor 130 and the heat transfer circuit compressor 254. Additionally, the excess heat can be rejected to the ambient atmosphere or conducted to an auxiliary fluid in another system on the flight vehicle 102. In the illustrated example, the radiator heat exchanger 190 also includes a radiator line 191 that passes through the radiator heat exchanger 190. An upstream end of the radiator line 191 is in fluid communication with one or more radiator fluid tanks 192 that carry a radiator fluid (e.g., fuel, water, or other fluid carried on the flight vehicle 102). The upstream end of the radiator line 191 can also be in communication with a subsystem heat load 194. A downstream end of the radiator line 191 can be in fluid communication with a radiator fluid 196 that uses heat and can utilize other vehicle systems that heat the radiator fluid. The radiator heat exchanger 190 includes a radiator-power generation circuit line 187 and a radiator-heat transfer circuit line 189 that are both positioned in a thermally coupled relationship to the radiator line 191 to conduct heat from the incoming air to the power generation circuit working fluid 122 and the heat transfer circuit working fluid 252, respectively.

[0027] In the illustrated example, a controller 200 is provided to control the operation of the system 100. In Figure 2In some examples, the controller 200 is operatively coupled to the power generation circuit compressor 130 and the heat transfer circuit compressor 254, and programmed to perform a method that includes the step of starting operation of the power generation circuit compressor 130 and the heat transfer circuit compressor 254 when one or more operating conditions of the flight vehicle 102 favor maintaining the power generation circuit working fluid 122 and the heat transfer circuit working fluid 252 in a supercritical state. In some examples, the operating condition is a temperature of the one or more heat sources, such as a temperature of the incoming air or the first surface 104 or the second surface 105, in which case the controller 200 receives feedback from the sensor 202 configured to detect the temperature, and is programmed to start the power generation circuit compressor 130 and the heat transfer circuit compressor 254 when the detected temperature exceeds a threshold temperature. Exemplary threshold temperatures include, but are not limited to, 500 degrees Fahrenheit, 600 degrees Fahrenheit, 700 degrees Fahrenheit, 800 degrees Fahrenheit, 900 degrees Fahrenheit, and 1000 degrees Fahrenheit. In other examples, the operating condition is a flight speed of the flight vehicle 102, which is indicative of a temperature of the one or more heat sources. In these examples, the controller 200 receives an indication of the flight speed, such as from an input command or the sensor 202 configured to determine the flight speed, and is programmed to start the power generation circuit compressor 130 and the heat transfer circuit compressor 254 when the flight vehicle 102 reaches a threshold flight speed. Exemplary threshold flight speeds include, but are not limited to, 3 Mach, 3.5 Mach, 4 Mach, and hypersonic (i.e., 5 Mach or greater). Additionally, the controller 200 can be operatively coupled to the power generation circuit heat engine 150 and the heat transfer circuit heat engine 258.

[0028] In Figure 2 In the illustrated examples, the controller 200 is also operatively coupled to the generator 170 and the auxiliary load 180 to control operation or other aspects of those components. Due to the thermal efficiency, compact size, and reduced weight provided by using supercritical working fluids as the power generation circuit working fluid 122 and the heat transfer circuit working fluid 252, the integrated cooling and power generation system 100 achieves a weight and volume power density that is an order of magnitude greater than a battery or other conventional power source.

[0029] While a particular hardware implementation of the controller 200 is subject to design choices, one particular example includes one or more processors coupled with a current driver. The one or more processors can include any electronic and / or optical circuitry capable of performing the functions described herein. For example, the processors can perform any of the functions described herein for the controller 200. The processors can include one or more central processing units (CPUs), microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), programmable logic devices (PLDs), control circuitry, etc. Some examples of processors include: Core TM Processor, Advanced Reduced Instruction Set Computing (RISC) Machine Processor, etc.

[0030] The system 100 is configured to maintain the power generation circuit working fluid 122 and the heat transfer circuit working fluid 252 in a supercritical state throughout the thermodynamic cycle, enabling the use of lighter and more compact turbomachinery. For example, when the power generation circuit working fluid 122 and the heat transfer circuit working fluid 252 are carbon dioxide, the critical temperature is approximately 88 degrees Fahrenheit and the critical pressure is approximately 74 bar. The temperature of the one or more heat sources increases with the speed of the flight vehicle 102. For example, at a speed of 3.5 Mach, the incoming air and / or the first surface 104 and the second surface 105 can reach 750 degrees Fahrenheit or more, which is sufficient to maintain the power generation circuit working fluid 122 and the heat transfer circuit working fluid 252 in a supercritical state. At hypersonic speeds in excess of 5 Mach, the temperature of the one or more heat sources can reach 1000 degrees Fahrenheit. The thermodynamic efficiency of the system 100 increases with the increase in the temperature of the one or more heat sources. Additionally, the power generation circuit compressor 130 and the heat transfer circuit compressor 254 are sized to maintain the pressure of the power generation circuit working fluid 122 and the heat transfer circuit working fluid 252 above the critical pressure throughout the thermodynamic cycle. Because the power generation circuit working fluid 122 and the heat transfer circuit working fluid 252 are in a supercritical state, the power generation circuit compressor 130, the heat transfer circuit compressor 254, the power generation circuit engine 150, and the heat transfer circuit compressor 258 can have reduced size and weight, making the system 100 practical for use on the flight vehicle 102. Additionally, the illustrated system 100 is a closed loop system that is provided independently of the propulsion system of the flight vehicle 102. The operating conditions of the power generation circuit and the heat transfer circuit can be optimized for their respective primary functions. For example, the power generation circuit working fluid 122 can have a higher pressure ratio than the heat transfer circuit working fluid 252. In some examples, using supercritical carbon dioxide as both the power generation circuit working fluid 122 and the heat transfer circuit working fluid 252, the power generation circuit working fluid 122 can have a pressure ratio of approximately 3, while the heat transfer circuit working fluid 252 can have a pressure ratio of approximately 1. As used herein, the term "pressure ratio" refers to the ratio of the inlet to outlet pressure across a compressor (i.e., the power generation circuit compressor 130 and the heat transfer circuit compressor 254).

[0031] Figure 4is a block diagram illustrating a method 300 of power generation and / or thermal management on a flight vehicle 102. The method 300 begins at block 302 with propelling the flight vehicle 102 at a flight speed of at least 3 Mach, during which a temperature of the one or more heat sources increases. At block 304, a first working fluid (such as power generation circuit working fluid 122) is circulated through a first circuit (such as power generation circuit 120). The step of circulating the first working fluid through the first circuit includes, in order: compressing the first working fluid by a first compressor (e.g., power generation circuit working fluid 122 is compressed by power generation circuit compressor 130), as shown at block 306; heating the first working fluid by a first heat sink of the first circuit, where the first heat sink is thermally coupled to the at least one heat source associated with the flight vehicle 102 (e.g., power generation circuit working fluid 122 is heated by the one or more heat sinks of power generation circuit 120), as shown at block 308; and expanding the first working fluid in a first heat engine to generate a first work output from the first heat engine (e.g., power generation circuit working fluid 122 is expanded in power generation circuit heat engine 150, generating power generation circuit work output 152 from power generation circuit heat engine 150), as shown at block 310. The step of circulating the first working fluid through the first circuit 304 also includes, as shown at block 312, cooling the first working fluid (e.g., power generation circuit working fluid 122 is cooled); and, as shown at block 314, recirculating the first working fluid to the first compressor (e.g., power generation circuit working fluid 122 is recirculated to power generation circuit compressor 130).

[0032] Method 300 can also continue at block 330 by circulating a second working fluid through a second circuit (e.g., circulating heat transfer circuit working fluid 252 through heat transfer circuit 250). The step of circulating the second working fluid through the second circuit includes, in order: compressing the second working fluid by a second compressor, as shown at block 332 (e.g., compressing heat transfer circuit working fluid 252 by heat transfer circuit compressor 254); heating the second working fluid by a second heat absorption portion of the second circuit, as shown at block 334, where the second heat absorption portion is thermally coupled to at least one heat source associated with the flying vehicle 102 (e.g., heating heat transfer circuit working fluid 252 by the one or more heat absorption portions of heat transfer circuit 250); and expanding the second working fluid in a second heat engine to generate a second work output from the second heat engine, as shown at block 336 (e.g., expanding heat transfer circuit working fluid 252 in heat transfer circuit heat engine 258 to generate heat transfer work output 260 from heat transfer circuit heat engine 258). The step of circulating the second working fluid through the second circuit also includes, as shown at block 338, cooling the second working fluid (e.g., cooling heat transfer circuit working fluid 252); and recirculating the second working fluid to the second compressor, as shown at block 340 (e.g., recirculating heat transfer circuit working fluid 252 to heat transfer circuit compressor 254).

[0033] In the illustrated example, the method 300 also includes a step of generating power. For example, as Figure 4 As shown schematically in FIG. 1C, the method 300 includes a step of generating power by operatively coupling the first heat engine to a generator, as shown at block 318 (e.g., generating power source 172 by mechanically coupling heat generation circuit work output 152 of heat generation circuit heat engine 150 to generator 170). Power source 172 from generator 170 can be used to operate the heat generation circuit compressor 130 and the heat transfer circuit compressor 254 when these components are driven by electrical power. Additionally or alternatively, power source 172 can be used to power auxiliary load 180. Additionally, the method 300 includes a step of operatively coupling the second work output of the second heat engine to the second compressor, as shown at block 342 (e.g., operatively coupling heat transfer work output 260 of heat transfer circuit heat engine 258 to heat transfer circuit compressor 254).

[0034] Still further, the method 300 can optionally include the additional step of reducing the temperature of the first working fluid and the second working fluid prior to recirculating the first working fluid and the second working fluid back to the first compressor and the second compressor, respectively. More specifically, the method 300 can include the steps of rejecting heat from the first working fluid via a radiator heat exchanger (e.g., rejecting heat from the power generation circuit working fluid 122 using the radiator heat exchanger 190) as shown at block 322, and rejecting heat from the second working fluid via a radiator heat exchanger (e.g., rejecting heat from the heat transfer circuit working fluid 252 using the radiator heat exchanger 190) as shown at block 346.

[0035] In the foregoing examples, it should be appreciated that the terms "first circuit" and "second circuit" are intended to refer to either of the power generation circuit 120 and the heat transfer circuit 250. That is, while the above examples identify the power generation circuit 120 as the "first circuit" and the heat transfer circuit 250 as the "second circuit," in alternative examples, the heat transfer circuit 250 is the "first circuit" and the power generation circuit is the "second circuit."

[0036] Additionally, the terms "first working fluid" and "second working fluid" are intended to refer to either of the power generation circuit working fluid 122 and the heat transfer circuit working fluid 252. That is, while the above examples identify the power generation circuit working fluid 122 as the "first working fluid" and the heat transfer circuit working fluid 252 as the "second working fluid," in alternative examples, the heat transfer circuit working fluid 252 is the "first working fluid" and the power generation circuit working fluid is the "second working fluid."

[0037] Still further, the terms "first compressor" and "second compressor" are intended to refer to either of the power generation circuit compressor 130 and the heat transfer circuit compressor 254. That is, while the above examples identify the power generation circuit compressor 130 as the "first compressor" and the heat transfer circuit compressor 254 as the "second compressor," in alternative examples, the heat transfer circuit compressor 254 is the "first compressor" and the power generation circuit compressor is the "second compressor."

[0038] Still further, the terms "first heat engine" and "second heat engine" are intended to refer to either of the power generation circuit heat engine 150 and the heat transfer circuit heat engine 258. That is, while the above examples identify the power generation circuit heat engine 150 as the "first heat engine" and the heat transfer circuit heat engine 258 as the "second heat engine," in alternative examples, the heat transfer circuit heat engine 258 is the "first heat engine" and the power generation circuit heat engine 150 is the "second heat engine."

[0039] Furthermore, the present disclosure includes the following examples, whereby the scope of protection provided by the claims.

[0040] Example 1. A method of using heated incoming air associated with a flight vehicle to provide at least one of cooling and power generation on the flight vehicle, the method comprising the steps of: propelling the flight vehicle at a flight speed of at least 3 Mach; circulating a first working fluid through a first fluid circuit, the circulating step comprising, in order: compressing the first working fluid through a first compressor; heating the first working fluid through an intake heat exchanger, the intake heat exchanger comprising an intake line in fluid communication with the heated incoming air and a first air-circuit line positioned in a thermally coupled relationship to the intake line; expanding the first working fluid in a first heat engine to generate a first work output from the first heat engine; cooling the first working fluid; and recirculating the first working fluid to the first compressor.

[0041] Example 2. The method of Example 1, wherein the first fluid circuit comprises a power generation circuit, and wherein the method further comprises the step of: generating power by operatively coupling the first work output of the first heat engine to an electrical generator.

[0042] Example 3. The method of any one of Examples 1-2, wherein the first fluid circuit comprises a heat transfer circuit, and wherein the method further comprises the step of: operatively coupling the first work output of the first heat engine to the first compressor.

[0043] Example 4. The method of any one of Examples 1-3, further comprising the step of: circulating a second working fluid through a second fluid circuit, the circulating step comprising, in order: compressing the second working fluid through a second compressor; heating the second working fluid through the intake heat exchanger, the intake heat exchanger comprising a second air-circuit line; expanding the second working fluid in a second heat engine to generate a second work output from the second heat engine; cooling the second working fluid; and recirculating the second working fluid to the second compressor.

[0044] Example 5. The method of Example 4, wherein the first fluid circuit comprises a power generation circuit, the second fluid circuit comprises a heat transfer circuit, the method further comprising the steps of: generating power by operatively coupling the first work output of the first heat engine of the power generation circuit to an electrical generator; and operatively coupling the second work output of the second heat engine to the second compressor.

[0045] Example 6. The method of Example 5, further comprising the step of: using the electrical generator to power an auxiliary load.

[0046] Example 7. The method of any one of examples 4 to 6, wherein the first working fluid comprises a first supercritical working fluid and the second working fluid comprises a second supercritical working fluid.

[0047] Example 8. The method of any one of examples 4 to 7, further comprising the steps of rejecting heat from the first working fluid via a radiator heat exchanger prior to recirculating the first working fluid to the first compressor; and rejecting heat from the second working fluid via the radiator heat exchanger prior to recirculating the second working fluid to the second compressor.

[0048] Example 9. A system for providing at least one of cooling and power generation on a flight vehicle using heated incoming air associated with the flight vehicle, the flight vehicle traveling at a flight speed of at least 3 Mach, the system comprising: a first fluid circuit containing a first working fluid, the first fluid circuit comprising, in order: a first compressor for compressing the first working fluid; an intake heat exchanger comprising an intake line in fluid communication with the heated incoming air, and a first air-circuit line receiving the first working fluid and positioned in thermal coupling relation to the intake line; and a first heat engine for expanding the first working fluid and generating a first work output.

[0049] Example 10. The system of example 9, wherein the first fluid circuit comprises a power generation circuit, the system further comprising a power generator operatively coupled to the first work output and configured to generate power.

[0050] Example 11. The system of example 9, wherein the first fluid circuit comprises a heat transfer circuit, and wherein the first work output of the first heat engine is operatively coupled to the first compressor.

[0051] Example 12. The system of any one of examples 9 to 11, further comprising: a second fluid circuit containing a second working fluid, the second fluid circuit comprising, in order: a second compressor for compressing the second working fluid; the intake heat exchanger comprising a second air-circuit line receiving the second working fluid and positioned in thermal coupling relation to the intake line; and a second heat engine for expanding the second working fluid and generating a second work output.

[0052] Example 13. The system of Example 12, wherein the first fluid circuit comprises a power generation circuit, the second fluid circuit comprises a heat transfer circuit; the system further comprising a power generator operatively coupled to the first work output and configured to generate power; and wherein the second work output of the second heat engine is operatively coupled to the second compressor.

[0053] Example 14. The system of Example 13, the system further comprising a first surface heat exchanger positioned in thermal coupling relation to a first surface of the flying vehicle, the first surface heat exchanger for heating the first working fluid of the power generation circuit.

[0054] Example 15. The system of Example 14, the system further comprising a second surface heat exchanger positioned in thermal coupling relation to a second surface of the flying vehicle, the second surface heat exchanger for heating the second working fluid of the heat transfer circuit.

[0055] Example 16. The system of Example 15, the system further comprising a radiator heat exchanger comprising: a radiator line in fluid communication with a radiator fluid tank; a radiator-power generation circuit line receiving the first working fluid and positioned in thermal coupling relation to the radiator line; and a radiator-heat transfer circuit line receiving the second working fluid and positioned in thermal coupling relation to the radiator line.

[0056] Example 17. The system of any of Examples 9-16, the system further comprising a controller operatively coupled to the first and second compressors, wherein the controller is programmed to perform a method comprising the step of initiating operation of the first and second compressors when a condition of the flying vehicle exceeds an operational threshold.

[0057] Example 18. A system for providing cooling and power generation on a flight vehicle using heated incoming air associated with the flight vehicle, the flight vehicle traveling at a flight speed of at least 3 Mach, the system comprising: a power generation circuit including a power generation circuit working fluid, the power generation circuit including, in order: a power generation circuit compressor for compressing the power generation circuit working fluid; an intake heat exchanger including an intake line in fluid communication with the heated incoming air and a first air-circuit line receiving the power generation circuit working fluid and positioned in thermal coupling relation to the intake line; and a power generation circuit heat engine for expanding the power generation circuit working fluid and generating a power generation circuit work output; a heat transfer circuit including a heat transfer circuit working fluid, the heat transfer circuit including, in order: a heat transfer circuit compressor for compressing the heat transfer circuit working fluid; the intake heat exchanger including a second air-circuit line receiving the heat transfer circuit working fluid and positioned in thermal coupling relation to the intake line; and a heat transfer circuit heat engine for expanding the heat transfer circuit working fluid and generating a heat transfer work output, wherein the heat transfer work output is mechanically coupled to the heat transfer circuit compressor; a power generator operatively coupled to the power generation circuit heat engine and configured to receive at least a portion of the power generation circuit work output and generate auxiliary electrical power; and a controller operatively coupled to the power generation circuit compressor and the heat transfer circuit compressor, wherein the controller is programmed to perform a method including the step of initiating operation of the power generation circuit compressor and the heat transfer circuit compressor when the flight speed of the flight vehicle is above 3 Mach.

[0058] Example 19. The system of Example 18, further comprising an auxiliary load operatively coupled to the power generator.

[0059] Example 20. The system of any of Examples 18-19, further comprising a radiator heat exchanger including: a radiator line in fluid communication with a radiator fluid tank; a radiator-power generation circuit line receiving the power generation circuit working fluid and positioned in thermal coupling relation to the radiator line; and a radiator-heat transfer circuit line receiving the heat transfer circuit working fluid and positioned in thermal coupling relation to the radiator line.

[0060] As used herein, the term "sequence" generally refers to elements (e.g., unit operations) in an order. Such an order can refer to a process order, for example, as the order in which a working fluid flows from one component to another. In an example, a compressor, a regenerator unit, and a turbine are included in a sequence: the compressor upstream of the heat exchange unit and the heat exchange unit upstream of the turbine. In such a case, the working fluid can flow from the compressor to the heat exchange unit and from the heat exchange unit to the turbine. The working fluid flowing through the unit operations in sequence can flow through the unit operations sequentially. A component sequence can include one or more intermediate components. For example, a system including a compressor, a regenerator unit, and a turbine in sequence can include an auxiliary tank between the compressor and the regenerator unit. A component sequence can be cyclic.

[0061] Any of the various elements shown in the figures or described herein can be implemented as hardware, software, firmware, or some combination of these. For example, an element can be implemented as dedicated hardware. A dedicated hardware element can be referred to as a "processor," "controller," or some similar terminology. Where a processor is provided, it can be a single shared processor, a single dedicated processor, or a plurality of individual processors, some of which can be shared or distributed. Also, the term "processor" or "controller" should not be construed to refer exclusively to hardware capable of executing software, but can implicitly include, without limitation, digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), or other circuitry, Field- programmable gate array (FPGA), read-only memory (ROM) for storing software, random access memory (RAM), non-volatile storage, logic, or some other physical hardware component or module.

[0062] Furthermore, an element can be implemented as instructions executable by a processor or a computer to perform the functions of that element. Some examples of instructions are software, program code, and firmware. The instructions are operational when executed by the processor to direct the processor to perform the functions of the element. The instructions can be stored in storage devices, which are computer readable media. Some examples of storage devices are digital or solid-state memories, magnetic storage media such as diskettes and tapes, hard disk drives, or optical storage media.

[0063] Although specific examples were described herein, the scope is not limited to those specific examples. Instead, the scope is defined by the following claims and their equivalents.

Claims

1. A method of using heated incoming air associated with an aircraft to provide at least one of cooling and power generation on the aircraft, the method comprising the steps of: The flight vehicle is propelled at a speed of at least Mach 3; The first working fluid is circulated through the first fluid loop, and the circulation steps include, in sequence: The first working fluid is compressed by the first compressor; The first working fluid is heated by an intake heat exchanger, which includes an intake pipeline in fluid communication with the heated incoming air and a first air-return pipeline located to the intake pipeline in a thermal connection relationship. The first working fluid is expanded in the first heat engine to generate a first work output from the first heat engine; Cooling the first working fluid; and The first working fluid is recirculated to the first compressor; The second working fluid is circulated through the second fluid loop, and the circulation steps include, in sequence: The second working fluid is compressed by the second compressor; The second working fluid is heated by the intake heat exchanger, which includes a second air-return line; The second working fluid expands in the second heat engine to generate a second work output from the second heat engine; Cooling the second working fluid; and The second working fluid is then recirculated to the second compressor.

2. The method of claim 1, wherein, The first fluid circuit includes at least one of the following: A power generation circuit, wherein the method further includes the steps of: generating electricity by connecting the first power output of the first heat engine to a generator; and The heat transfer circuit, wherein the method further includes the step of connecting the first power output of the first heat engine to the first compressor.

3. The method of claim 1, wherein, The first fluid circuit includes a power generation circuit, the second fluid circuit includes a heat transfer circuit, and the method further includes the following steps: Electricity is generated by connecting the first power output of the first heat engine in the power generation circuit to a generator; and The second power output of the second heat engine is connected to the second compressor.

4. The method of claim 3, further comprising the step of: The generator is used to supply power to the auxiliary load.

5. The method of claim 3 or 4, wherein, The first working fluid includes a first supercritical working fluid, and the second working fluid includes a second supercritical working fluid.

6. The method according to claim 3 or 4, further comprising the following step: Before recirculating the first working fluid to the first compressor, heat from the first working fluid is discarded via a radiator-type heat exchanger. as well as Heat from the second working fluid is discarded via the radiator-type heat exchanger before the second working fluid is recirculated to the second compressor.

7. A system that uses heated incoming air associated with an aircraft to provide at least one of cooling and power generation on the aircraft, the aircraft traveling at a speed of at least Mach 3, the system comprising: A first fluid circuit, the first fluid circuit comprising a first working fluid, the first fluid circuit comprising, in sequence: A first compressor is used to compress the first working fluid; An intake heat exchanger, comprising: an intake line in fluid communication with the heated incoming air, and a first air-return line receiving the first working fluid and thermally connected to the intake line; and A first heat engine is used to expand the first working fluid and generate a first work output. A second fluid circuit, the second fluid circuit comprising a second working fluid, the second fluid circuit comprising, in sequence: The second compressor is used to compress the second working fluid; The intake heat exchanger includes a second air-return line that receives the second working fluid and is thermally connected to the intake line; and The second heat engine is used to expand the second working fluid and generate a second work output.

8. The system according to claim 7, wherein, The first fluid circuit includes at least one of the following: The system further includes a power generation circuit, the generator being connected to the first power output and configured to generate electricity; and A heat transfer circuit, wherein the first power output of the first heat engine is connected to the first compressor.

9. The system according to claim 7, wherein, The first fluid circuit includes a power generation circuit, and the second fluid circuit includes a heat transfer circuit; the system further includes a generator connected to the first power output and configured to generate electricity; and wherein the second power output of the second heat engine is connected to the second compressor.

10. The system of claim 9, further comprising a first surface heat exchanger, the first surface heat exchanger being thermally coupled to a first surface of the flight vehicle for heating the first working fluid of the power generation circuit.

11. The system of claim 10, further comprising a second surface heat exchanger, the second surface heat exchanger being thermally coupled to a second surface of the flight vehicle for heating the second working fluid of the heat transfer circuit.

12. The system of claim 11, further comprising a radiator-type heat exchanger, the radiator-type heat exchanger comprising: Radiator piping, wherein the radiator piping is in fluid communication with the radiator fluid tank; A radiator-generator circuit line, wherein the radiator-generator circuit line receives the first working fluid and is located to the radiator line by a thermal connection; as well as A radiator-heat transfer loop line, which receives the second working fluid and is thermally connected to the radiator line.

13. The system of claim 7, further comprising a controller connected to the first compressor and the second compressor, wherein, The controller is programmed to perform a method that includes the step of activating the first compressor and the second compressor when the operating condition of the flight vehicle exceeds an operating threshold.

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