Closed loop thermal management system

Abstract

A closed loop thermal management system includes a thermal transfer bus configured to circulate a thermal working fluid therein; a heat transfer bus comprising a plurality of fluid conduits configured to circulate a thermal working fluid therein; an energy accumulator includes a housing defining a multi-phase fluid space therein, the multi-phase fluid space configured to contain a multi-phase fluid. The shell defines an opening. The accumulator is fluidly coupled to the heat transfer bus in a closed-loop fluid circuit. The temperature regulator is configured to control a temperature of the multiphase fluid within the multiphase fluid space.

Description

[0001] Federally funded research

[0002] This invention was made with Government support under Contract No. W911W620C0080 awarded by the Department of Defense. The U.S. Government may have certain rights in this invention. Technical Field

[0003] The present disclosure relates generally to closed-loop thermal management systems, and more particularly, to systems for regulating the pressure of a hot working fluid in a closed-loop thermal management system. Background Art

[0004] Thermal management systems may be used in a variety of applications such as aircraft, electric vehicles, generators, electric motors, internal combustion engines, microprocessors, power electronics, and the like. In operation, it may be necessary to cool these various accessory systems via the thermal management system. A thermal management system typically includes a heat transfer bus or fluid loop that facilitates the flow of a hot working fluid through the system at a desired or required average pressure. The hot working fluid interacts with various heat sources and heat sinks to add or remove heat from various operating components or systems. Changing heat loads or the surrounding environment may adversely affect the average pressure of the hot working fluid flowing through the heat transfer bus of the thermal management system. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] A full and enabling disclosure of the present disclosure, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0006] Figure 1 is a perspective view of an exemplary aircraft according to an exemplary embodiment of the present disclosure.

[0007] Figure 2 is a schematic cross-sectional illustration of a ducted turbofan gas turbine engine according to an exemplary embodiment of the present disclosure.

[0008] Figure 3 is a schematic diagram of a closed-loop thermal management system according to an exemplary embodiment of the present disclosure.

[0009] Figure 4 According to an exemplary embodiment of the present disclosure, Figure 3 Schematic diagram of the closed-loop thermal management system shown.

[0010] Figure 5 According to an exemplary embodiment of the present disclosure, Figure 3 Schematic diagram of the closed-loop thermal management system shown.

[0011] Figure 6 is a schematic diagram of an exemplary accumulator and an exemplary temperature regulator according to an embodiment of the present disclosure.

[0012] Figure 7 is a schematic diagram of an exemplary accumulator and an exemplary temperature regulator according to an embodiment of the present disclosure.

[0013] Figure 8 is a schematic diagram of an exemplary accumulator and an exemplary temperature regulator according to an embodiment of the present disclosure.

[0014] Fig. 9 is a schematic diagram of an exemplary accumulator and an exemplary temperature regulator according to an embodiment of the present disclosure.

[0015] Fig.10 is a schematic diagram of an exemplary accumulator and an exemplary temperature regulator according to an embodiment of the present disclosure.

[0016] Fig.11 is a schematic diagram of a closed-loop thermal management system according to an exemplary embodiment of the present disclosure.

[0017] Fig.12 is a schematic diagram of a closed-loop thermal management system according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0018] Reference will now be made in detail to the present embodiments of the present disclosure, one or more examples of which are shown in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the present disclosure.

[0019] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. In addition, unless expressly stated otherwise, all embodiments described herein should be considered exemplary.

[0020] Unless the context clearly dictates otherwise, the singular forms "a," "an," and "the" include plural references. For example, in the context of "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.

[0021] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of each component.

[0022] In addition, the terms "upstream" and "downstream" refer to relative directions relative to the flow of fluid in a fluid path. For example, "upstream" refers to the direction from which the fluid flows, while "downstream" refers to the direction to which the fluid flows.

[0023] In addition, unless otherwise stated, the terms "low", "high" or their corresponding comparatives (e.g., lower, higher, as applicable) refer to relative speeds, pressures, or temperatures within an engine or thermal management system. For example, a "low-pressure turbine" operates at a pressure that is generally lower than a "high-pressure turbine". Alternatively, unless otherwise stated, the above terms may be understood as their highest level. For example, a "low-pressure turbine" may refer to the lowest maximum pressure turbine within a turbine section, while a "high-pressure turbine" may refer to the highest maximum pressure turbine within a turbine section.

[0024] As used herein, the terms "thermal bus" or "heat transfer bus" generally include a fluid circuit or loop formed by various fluid conduits or pipes, fluid couplers, valves, etc. In certain embodiments, these terms may include a fluid circuit or loop, one or more pumps, one or more heat source heat exchangers, and / or one or more heat sink heat exchangers.

[0025] Single-phase, multiphase or supercritical flow loops in aircraft require precise pressure control where compressibility or thermal expansion of the heat transfer bus hot working fluid can be accommodated. Changing heat loads or ambient conditions may affect the average pressure of the compressible hot working fluid in the heat transfer bus. Conventional gas-charged accumulators require an external gas source, pressure regulator and vent line, which increases the complexity of integrating the accumulator into the system. In addition, if a leak occurs between the supply-side gas and the flow loop-side accumulator space, the supply-side gas may contaminate the hot working fluid and may damage the flow loop.

[0026] In general, the present subject matter relates to a closed-loop thermal management system. The closed-loop thermal management system includes a multiphase temperature-controlled accumulator that utilizes a multiphase fluid in a multiphase fluid space in a saturated state, the temperature and subsequent pressure of the multiphase fluid being controlled. A temperature regulator thermally coupled to the multiphase fluid space is used to control the temperature of the multiphase fluid, thereby controlling the baseline pressure of a hot working fluid in a closed-loop flow circuit of a heat transfer bus.

[0027] Temperature control of the multiphase fluid space can be achieved in various ways, such as a temperature controlled fluid jacket or a thermoelectric device. Depending on the target heat transfer bus operating conditions, the multiphase fluid space can contain a multiphase fluid that is used as a hot working fluid flowing through the heat transfer bus. In an alternative, the multiphase fluid space can be fluidically isolated from the heat transfer bus by a deformable diaphragm or piston, and a separate hot working fluid is used for the heat transfer bus. The addition of a non-condensable gas to the multiphase fluid space can allow for adjustment of the temperature and pressure response. In certain configurations, the closed-loop thermal management system includes additional features to ensure orientation independence (dip tubes, paired one-way valves, and gimbal mounting) and embodiments of partial heat recovery.

[0028] The closed-loop thermal management system is applicable to closed-loop two-phase cooling systems for electronic equipment, supercritical heat transfer buses, and power cycles. The closed-loop thermal management system eliminates the weight and volume of external pressure sources and regulators present in current thermal management systems, eliminates the risk of external pressurant contamination, and can suppress flow circuit pressure transients by providing expansion volume. The disclosed closed-loop thermal management system can be integrated into a vehicle, such as but not limited to an aircraft, a ground-based or aircraft gas turbine engine, or any mobile vehicle or machine, for cooling various accessory systems such as electronic equipment and various lubrication systems.

[0029] Now referring to the accompanying drawings, Figure 1 1 is a perspective view of an exemplary vehicle in the form of an aircraft 10 that may include at least one exemplary embodiment of the present disclosure. Figure 1 As shown, the aircraft 10 has a fuselage 12, wings 14 attached to the fuselage 12, and an empennage 16. The aircraft 10 also includes a propulsion system 18 that generates propulsive thrust to propel the aircraft 10 in flight, during taxiing operations, etc. Although the propulsion system 18 is shown as being attached to the wings 14, in other embodiments, it may additionally or alternatively include one or more aspects coupled to other portions of the aircraft 10, such as the empennage 16, the fuselage 12, or both. Figure 1 The configuration of the aircraft 10 shown in FIG. 1 is provided only to place the present subject matter in an exemplary field of use. Therefore, the present subject matter can be easily adapted to any type of aircraft.

[0030] The propulsion system 18 includes at least one engine. In the exemplary embodiment shown, the aircraft 10 includes a pair of gas turbine engines 20. Each gas turbine engine 20 is mounted to the aircraft 10 in an underwing configuration. Each gas turbine engine 20 is capable of selectively generating propulsive thrust for the aircraft 10. The gas turbine engines 20 can be configured to burn various forms of fuel, including but not limited to jet fuel / aviation turbine fuel and hydrogen fuel, unless otherwise specified.

[0031] Figure 2 is a cross-sectional side view of a gas turbine engine 20 according to an exemplary embodiment of the present disclosure. More specifically, Figure 2 In the embodiment of the present invention, the gas turbine engine 20 is a multi-spool high bypass turbofan jet engine, sometimes referred to as a "turbofan engine". Figure 2 As shown, the gas turbine engine 20 defines an axial direction “A” (extending parallel to the longitudinal centerline 22 for reference), a radial direction “R”, and a circumferential direction “C” extending about the longitudinal centerline 22. Generally, the gas turbine engine 20 includes a fan section 24 and a turbine 26 disposed downstream of the fan section 24.

[0032] The illustrated turbine 26 generally includes an engine casing, housing or core shroud 28 defining an annular core inlet 30. The core shroud 28 at least partially surrounds in series flow relationship a compressor section including a supercharger or low-pressure compressor 32 and a high-pressure compressor 34, a combustion section 36, a turbine section including a high-pressure turbine 38 and a low-pressure turbine 40, and at least a portion of a gas jet exhaust nozzle 42. Together, these components or sections comprise a core engine 44 of the turbine 26.

[0033] A high pressure shaft 46 drivingly connects the high pressure turbine 38 to the high pressure compressor 34. A low pressure shaft 48 drivingly connects the low pressure turbine 40 to the low pressure compressor 32. The compressor section, combustion section 36, turbine section, and gas exhaust nozzle 42 together define a working gas flow path 50 through the gas turbine engine 20.

[0034] For the illustrated embodiment, fan section 24 includes a fan 52 having a plurality of fan blades 54 coupled to a disk 56 in a spaced-apart manner. As shown, fan blades 54 extend outwardly from disk 56 generally in a radial direction R. Each fan blade 54 can rotate with disk 56 about pitch axis P by virtue of fan blades 54 being operably coupled to pitch change mechanism 58, which is configured to jointly change the pitch of fan blades 54, e.g., to change the pitch of fan blades 54 in unison. Fan blades 54, disk 56, and pitch change mechanism 58 can rotate together about longitudinal centerline 22 via low-pressure shaft 48.

[0035] In an exemplary embodiment, if Figure 2 As shown, the gas turbine engine 20 also includes a power gearbox or gearbox 60. The gearbox 60 includes a plurality of gears for adjusting the rotational speed of the fan 52 relative to the rotational speed of the low-pressure shaft 48, so that the fan 52 and the low-pressure shaft 48 can rotate at a more efficient relative speed. The gearbox 60 can be any type of gearbox suitable for facilitating the coupling of the low-pressure shaft 48 to the fan 52 while allowing each of the low-pressure turbine 40 and the fan 52 to operate at a desired speed. For example, in some embodiments, the gearbox 60 can be a reduction gearbox. The use of a reduction gearbox allows the low-pressure turbine 40 to operate at a relatively high speed while maintaining a sufficient fan speed to provide an increased air bypass ratio, thereby allowing the gas turbine engine 20 to operate efficiently. In addition, the use of a reduction gearbox allows the reduction of the turbine stage that originally existed (for example, in a direct drive engine configuration), thereby reducing the weight and complexity of the engine.

[0036] Still refer to Figure 2In the exemplary embodiment of the present invention, the disk 56 is connected to the gearbox 60 via a fan shaft 62. The disk 56 is covered by a front hub 64 (sometimes also referred to as a "spinner") of the fan section 24. The front hub 64 has an aerodynamic profile to facilitate airflow through the plurality of fan blades 54. In addition, the fan section 24 includes an annular fan casing or nacelle 66 that circumferentially surrounds at least a portion of the fan 52 and / or the turbine 26. In the illustrated embodiment, the nacelle 66 is supported relative to the turbine 26 by a plurality of circumferentially spaced struts or outlet guide vanes 68. In addition, a downstream section 70 of the nacelle 66 extends over an outer portion of the turbine 26 to define a bypass airflow passage 72 therebetween.

[0037] In addition, if Figure 1 and Figure 2 As shown, the aircraft 10 may include a closed-loop thermal management system 100 for transferring heat between fluids and / or components that support the operation of the aircraft 10. More specifically, the aircraft 10 may include one or more accessory systems configured to support the operation of the aircraft 10. For example, in some embodiments, such accessory systems include a lubrication system that lubricates components of the gas turbine engine 20, a cooling system that provides cooling air to the aircraft 10 and / or electronic components of the gas turbine engine 20, an environmental control system that provides cooling air to the cabin of the aircraft 10, and the like. In such embodiments, the closed-loop thermal management system 100 is configured to transfer heat from one or more fluids that support the operation of the aircraft 10 (e.g., oil of the lubrication system, air of the cooling system and / or environmental control system, and the like) to one or more other fluids that support the operation of the aircraft 10 (e.g., fuel supplied to the gas turbine engine 20). However, in alternative embodiments, the closed-loop thermal management system 100 may be configured to transfer heat between any other suitable fluids that support the operation of the aircraft 10.

[0038] Figure 3 is a schematic diagram of one embodiment of a closed-loop thermal management system 100 or "thermal management system". In general, the closed-loop thermal management system 100 will be described above and respectively as follows Figure 1 and Figure 2 The closed-loop thermal management system 100 is discussed in the context of the aircraft 10 and gas turbine engine 20 shown. However, the disclosed closed-loop thermal management system 100 may be implemented in any aircraft having any other suitable configuration and / or in any turbine engine having any other suitable configuration. Furthermore, it should be understood that the closed-loop thermal management system 100 described and illustrated herein may be integrated into other machines other than aircraft that have high heat flux, two-phase cooling requirements, such as, but not limited to, electronic equipment and computer servers, autonomous vehicle sensors, battery charging, etc., and is not strictly limited to use in an aircraft environment unless otherwise specified.

[0039] like Figure 3As shown, the closed-loop thermal management system 100 includes a heat transfer bus 102. The heat transfer bus 102 is configured as one or more fluid conduits, couplers, valves, etc., which are fluidly coupled together in a closed-loop, recirculating, or closed flow path configuration, and a hot working fluid 104 flows through them. For example, the heat transfer bus 102 may include a plurality of fluid conduits that are configured to circulate the working fluid therein. In an exemplary embodiment, the closed-loop thermal management system 100 includes a pump 106 that is configured to provide power to push or pump the hot working fluid 104 through the heat transfer bus 102. In an exemplary embodiment, the heat transfer bus 102 is fluidly connected to an inlet 108 and an outlet 110 of the pump 106 to provide a continuous flow of a heat exchange fluid through the heat transfer bus 102 in a closed-loop manner during operation.

[0040] exist Figure 3 In the exemplary embodiment shown, the closed-loop thermal management system 100 also includes an accumulator 112. The accumulator 112 is at least partially formed by a pressure vessel or shell 114. The shell 114 includes an inner wall surface 116 and an outer wall surface 118. The accumulator 112 defines a multiphase fluid space 120 within the shell 114. The multiphase fluid space 120 is configured to accommodate a multiphase fluid 122 therein. The shell 114 includes an opening 124. The opening 124 is configured to provide fluid communication between the accumulator 112 (more specifically, the multiphase fluid space 120) and the heat transfer bus 102.

[0041] The heat transfer bus 102, pump 106, and accumulator 112 are configured together as a closed-loop fluid loop or thermal loop. Figure 3 As shown, multiphase fluid space 120 is in fluid communication with heat transfer bus 102 via opening 124, and multiphase fluid 122 and hot working fluid 104 are the same fluid. In another embodiment, multiphase fluid 122 may be fluidly isolated from hot working fluid 104, as will be discussed in detail below.

[0042] like Figure 3 As shown, the closed-loop thermal management system 100 also includes a device for regulating temperature or a temperature regulator 126, generally indicated by a dashed line. The temperature regulator 126 is configured to control the temperature of the multiphase fluid 122 within the multiphase fluid space 120. In certain embodiments, the temperature of the multiphase fluid 122 can be set and regulated or maintained so that the multiphase fluid 122 includes a liquid portion 122 (a).

[0043] In a specific embodiment, if Figure 3As shown, the temperature of the multiphase fluid 122 can be set and adjusted or maintained so that the multiphase fluid 122 includes a liquid portion 122 (a) and a vapor or gas portion 122 (b) within the multiphase fluid space 120. The liquid portion 122 (a) can be in a saturated liquid state, an unsaturated liquid state, a mixture of undissolved gas and unsaturated liquid states, or in a supercooled liquid state (e.g., at a temperature below the saturation temperature of the multiphase fluid 122). The temperature of the multiphase fluid 122 can be set and adjusted or maintained by the temperature regulator 126 so that the gas portion 122 (b) is in a saturated vapor state, a gas state, or a saturated vapor state in which a non-condensable gas is mixed with the saturated vapor within the multiphase fluid space 120. It should be understood that in other embodiments, gravity / buoyancy can be used to drive the hot working fluid 104 to flow around the closed flow loop, and the accumulator 112 can be used to regulate the pressure in the heat transfer bus 102.

[0044] In the exemplary embodiment, the closed-loop thermal management system 100 includes one or more heat source heat exchangers 128 arranged along the heat transfer bus 102 and in thermal communication with the hot working fluid 104. More specifically, the heat source heat exchangers 128 are fluidly coupled to the heat transfer bus 102 such that the hot working fluid 104 flows through the heat source heat exchangers 128. In this regard, the heat source heat exchangers 128 are configured to transfer heat from various accessory systems of the aircraft 10 to the hot working fluid 104. Thus, the heat source heat exchangers 128 add heat to the hot working fluid 104. Although Figure 3 A single heat source heat exchanger 128 is shown, but the closed-loop thermal management system 100 may include multiple heat source heat exchangers 128 arranged along the heat transfer bus 102 .

[0045] In the exemplary embodiment, the closed-loop thermal management system 100 includes a radiator heat exchanger 130 disposed along the heat transfer bus 102 and in thermal communication with the hot working fluid 104. More specifically, the radiator heat exchanger 130 is fluidly coupled to the heat transfer bus 102 such that the hot working fluid 104 flows through the radiator heat exchanger 130. In this regard, the radiator heat exchanger 130 is configured to transfer heat from the hot working fluid 104 to other fluids supporting the operation of the aircraft 10, thereby heating the other fluids supporting the operation of the aircraft 10. Although Figure 3 A single radiator heat exchanger 130 is shown, but the closed-loop thermal management system 100 may include multiple radiator heat exchangers 130 arranged along the heat transfer bus 102 .

[0046] Figure 4 According to an exemplary embodiment of the present disclosure, Figure 3 A schematic diagram of an embodiment of a closed-loop thermal management system 100 is shown. Figure 4As shown, the accumulator 112 may include a siphon or dip tube 132. The dip tube 132 is fluidly coupled to the opening 124 and in fluid communication with the multiphase fluid space 120. In certain embodiments, the opening 134 of the dip tube 132 is in fluid communication with the liquid portion 122(a) of the multiphase fluid 122.

[0047] In an exemplary embodiment, the accumulator 112 is mounted to a gimbal or gimbal assembly 136. The gimbal assembly 136 may be mounted to the aircraft 10 ( Figure 1 ) or gas turbine engine 20 ( Figure 2 ) of the static structure 138. The gimbal assembly 136 maintains the relative orientation of the accumulator 112 with respect to the ground or horizon so that the liquid portion 122(a) remains in fluid communication with the dip tube 132 regardless of the relative orientation between the aircraft 10 and the ground or horizon. In an exemplary embodiment, the dip tube 132 and / or the opening 124 may be fluidly coupled to the heat transfer bus 102 via a flexible tube 140. The dip tube 132 may be rigid, or in an exemplary embodiment, the dip tube 132 may be flexible.

[0048] In certain configurations, particularly configurations where the dip tube 132 is flexible, a weight 142 may be secured or coupled to the end of the flexible tube 140 to maintain the opening 134 of the dip tube 132 within the liquid portion 122(a) of the multiphase fluid 122. The flexible tube 140 may allow or accommodate relative movement between the accumulator 112 and the heat transfer bus 102, and the dip tube 132 may accommodate movement of the accumulator 112 relative to the horizon to maintain fluid contact with the liquid portion 122(a) of the multiphase fluid 122.

[0049] Figure 5 is a schematic diagram of one embodiment of a closed-loop thermal management system 100 according to an exemplary embodiment of the present disclosure. As previously described, in at least one embodiment, the multiphase fluid space 120 and the multiphase fluid 122 are fluidically isolated from the heat transfer bus 102 and the hot working fluid 104. In one embodiment, Figure 5 As shown, the accumulator 112 includes a hot working fluid space 144 and a piston or movable plate 146 disposed within the accumulator 112. The movable plate 146 functions like a piston and fluidly isolates the multiphase fluid space 120 and the multiphase fluid 122 from the hot working fluid space 144 and the hot working fluid 104. The movable plate 146 is configured to move in the direction “M” within the accumulator 112 in response to a change in temperature of the multiphase fluid 122 to increase, decrease, or maintain a constant or substantially constant pressure of the hot working fluid 104 within the heat transfer bus 102.

[0050] Figure 6-10A schematic diagram of accumulators 112 is provided, each having an exemplary temperature regulator 126 according to an embodiment of the present disclosure. Figure 6-10 , the shell 114 of the accumulator 112 includes a wall "W" that defines an inner wall surface 116 and an outer wall surface 118. In one embodiment, as Figure 6 As shown, the temperature regulator 126 includes at least one resistive heater 148. As used herein, the term "resistive heater" includes resistive heating devices or processes whereby an electrical current is passed through a conductive material (resistor) and releases heat.

[0051] In an exemplary embodiment, if Figure 6 As shown, the temperature regulator 126 may include a resistive heater 148 (a) disposed along the outer wall surface 118. Additionally or alternatively, the temperature regulator 126 may include a resistive heater 148 (b) disposed along the inner wall surface 116. In another embodiment, as shown in FIG. Figure 7 As shown, the temperature regulator 126 may include a resistive heater 148 ( c ) disposed between the inner wall surface 116 and the outer wall surface 118 .

[0052] like Figure 8 As shown, the temperature regulator 126 may include a thermoelectric module 150. The thermoelectric module 150 is in thermal contact with the outer wall surface 118 of the shell 114. The thermoelectric module 150 may be configured to provide heating or cooling to the multiphase fluid space 120 via the wall (W) of the shell 114. In certain configurations, the thermoelectric module 150 may include various heat transfer features, such as, but not limited to, a heat sink 152.

[0053] like Fig. 9 As shown, the thermoelectric module 150 is in thermal contact with the outer wall surface 118 of the shell 114. In addition, the thermoelectric module 150 is in thermal communication with the hot working fluid 104 via the heat transfer bus 102. In this configuration, the thermoelectric module 150 can be configured to provide heating or cooling to the multiphase fluid space 120 via the wall (W) of the shell 114.

[0054] In another embodiment, Fig.10 As shown, the temperature regulator 126 includes a thermal fluid jacket 154, which is at least partially disposed along the inner wall surface 116 of the wall (W). The thermal fluid jacket 154 is in fluid communication with a thermal fluid source (not shown) (e.g., a closed-loop coolant system) via an inlet 156 and an outlet 158. In operation, a thermal fluid 160 flows from the inlet 156 through the thermal fluid jacket 154, around at least a portion of the multiphase fluid space 120, and to the outlet 158 ​​to provide heating or cooling to the multiphase fluid 122. Fig. 9 In the exemplary embodiment shown, thermal fluid jacket 154 is fluidly isolated from multiphase fluid space 120 and multiphase fluid 122 .

[0055] Fig.11 FIG. 1 is a schematic diagram of an embodiment of a closed-loop thermal management system 100 according to an exemplary embodiment of the present disclosure. Fig.11 As shown, the closed-loop thermal management system 100 may include a coolant loop 162 in fluid communication with the thermal fluid jacket 154 via an inlet 156 and an outlet 158. The coolant loop 162 may be formed by various fluid conduits, pipes, couplers, valves, etc. that define one or more flow paths of the coolant loop 162.

[0056] exist Fig.11 In the exemplary embodiment shown, coolant circuit 162 includes a main flow loop 164 and a bypass flow loop 166. Bypass flow loop 166 includes a radiator heat exchanger 168 in thermal communication with bypass flow loop 166. It should be appreciated that radiator heat exchanger 168 may be the same as radiator heat exchanger 130 or otherwise incorporated therewith.

[0057] The thermal mixing valve 170 has a first inlet 172 that is fluidly coupled to and in fluid communication with the bypass flow loop 166, a second inlet 174 that is fluidly coupled to and in fluid communication with the main flow loop 164, and an outlet 176 that is fluidly coupled to and in fluid communication with a pump 178. The pump 178 is fluidly coupled to and in fluid communication with the inlet 156 of the thermal fluid jacket 154. The pump 178 provides power for moving the thermal fluid 160 through the thermal fluid jacket 154 and the coolant circuit 162 in a circulating or recirculating manner. The thermal mixing valve 170 may include any valve that can be manipulated to mix the first portion 160 ( a ) of the thermal fluid 160 with the second portion 160 ( b ) of the thermal fluid 160 to heat or cool the thermal fluid 160 to a desired temperature upstream of the inlet 156 of the thermal fluid jacket 154 .

[0058] One or more sensors 179 may be placed at various locations along the coolant loop 162. For example, one or more sensors 179 may be placed upstream of the thermal mixing valve 170, or downstream of the thermal mixing valve 170. The sensors 179 may include, but are not limited to, temperature or pressure sensors. In operation, the sensors 179 may provide a signal to the controller 181 indicating the temperature or pressure in the coolant loop 162. The controller 181 may then manipulate the thermal mixing valve 170 to mix the first portion 160(a) of the thermal fluid 160 with the second portion 160(b) of the thermal fluid 160 to adjust the temperature of the thermal fluid 160 entering the thermal fluid jacket 154 as desired.

[0059] In certain embodiments, the main flow loop 164 is in thermal communication with the heat source heat exchanger 128 at a location between the bypass flow loop 166 and the thermal mixing valve 170. In certain embodiments, a temperature probe 180 may be electrically connected to the thermal mixing valve 170.

[0060] In operation, the thermal fluid 160 flows from the outlet 158 ​​of the thermal fluid jacket 154. A first portion 160(a) of the thermal fluid 160 may be passed through a bypass flow loop 166, where heat is removed via a radiator heat exchanger 168. The cooled first portion 160(a) of the thermal fluid 160 is then passed into the thermal mixing valve 170 via a first inlet 172.

[0061] The second portion 160(b) of the thermal fluid 160 flows through the bypass flow loop 166 and is passed through or near the heat source heat exchanger 128, where heat can be added to the second portion 160(b) of the thermal fluid 160. The heated second portion 160(b) is then passed to the thermal mixing valve 170 via the second inlet 174. The thermal mixing valve 170 mixes the first portion 160(a) and the second portion 160(b) of the thermal fluid 160 to achieve a desired temperature of the thermal fluid 160 before the thermal fluid 160 is passed back to the inlet 156 of the thermal fluid jacket 154 via the pump 178. The desired amount of mixing can be determined at least in part by a temperature reading of the second portion 160(b) of the thermal fluid 160 or the hot working fluid 104 or the multiphase fluid 122 (as measured at the heat source heat exchanger 128).

[0062] The increase in temperature of the thermal fluid 160 flowing through the thermal fluid jacket 154 causes the pressure in the multiphase fluid space 120 to increase, thereby causing the liquid portion 122(a) of the multiphase fluid 122 to flow into the heat transfer bus 102, thereby adjusting the pressure in the heat transfer bus 102. Similarly, the decrease in temperature of the thermal fluid 160 flowing through the thermal fluid jacket 154 causes the pressure in the multiphase fluid space 120 to decrease, thereby causing the liquid portion 122(a) of the multiphase fluid 122 to flow back from the heat transfer bus 102 to the multiphase fluid space 120, thereby adjusting the pressure in the heat transfer bus 102.

[0063] Fig.12 FIG. 1 is a schematic diagram of an embodiment of a closed-loop thermal management system 100 according to an exemplary embodiment of the present disclosure. Fig.12As shown, the heat transfer bus 102, and more specifically, the accumulator 112, includes a multiphase fluid channel 182 defined within the wall (W) between the inner wall surface 116 and the outer wall surface 118. The multiphase fluid channel 182 extends at least partially around the multiphase fluid space 120 and defines a flow path for conveying the multiphase fluid 122 through the shell 114. The multiphase fluid channel 182 includes an inlet 184 and an outlet 186, which are fluidly connected to the multiphase fluid channel 182 and the heat transfer bus 102 and provide fluid communication between the multiphase fluid channel 182 and the heat transfer bus 102. In this configuration, the hot working fluid 104 and / or the multiphase fluid 122 are the same fluid.

[0064] The heat transfer bus 102 includes a bypass flow loop 188 and a main flow loop 190 fluidly coupled to and in fluid communication with the outlet 186. A secondary radiator heat exchanger 192 is in thermal communication with the bypass flow loop 188. A thermal mixing valve 194 is disposed downstream of the bypass flow loop 188 and upstream of the inlet 184. The pump 106 provides power for moving the multiphase fluid 122 through the main flow loop 190, the bypass flow loop 188, the thermal mixing valve 194, and back to the multiphase fluid channel 182. In certain embodiments, a temperature probe 196 may be electrically connected to the thermal mixing valve 194.

[0065] In the exemplary embodiment, the heat transfer bus 102 includes a backpressure valve 198. The backpressure valve 198 is fluidly coupled to the heat transfer bus 102 downstream of the outlet 186 of the multiphase fluid channel 182 and upstream of the fluid connection point 200, wherein the accumulator 112 is connected to the heat transfer bus 102 via the opening 124. In operation, the backpressure valve 198 ensures that the flow pressure of the hot working fluid 104 flowing from the outlet 186 of the multiphase fluid channel 182 to the fluid connection point 200 is higher than the portion of the hot working fluid 104 flowing from the opening 124 of the accumulator 112 to the fluid connection point 200. This further ensures that the portion of the hot working fluid 104 flowing through / out of the multiphase fluid channel 182 is hotter than the portion of the hot working fluid 104 flowing out of the accumulator 112, without boiling.

[0066] In operation, the multiphase fluid 122, and in particular the liquid portion 122(a), flows out of the multiphase fluid passage 182 via the outlet 186, passes through the heat source heat exchanger 128, where heat is added thereto. The liquid portion 122(a) of the multiphase fluid 122 then flows through the radiator heat exchanger 130, where heat is removed from the liquid portion 122(a) of the multiphase fluid 122. The liquid portion 122(a) of the multiphase fluid 122 then flows through the pump 106. A first portion 222(a) of the liquid portion 122(a) of the multiphase fluid 122 is directed through the bypass flow loop 188, where it flows through the secondary radiator heat exchanger 192, thereby further cooling the first portion 222(a) of the liquid portion 122(a) of the multiphase fluid 122. The first portion 222(a) of the multiphase fluid 122 is then delivered to the hot mixing valve 194. It should be understood that the secondary radiator heat exchanger 192 may be the same radiator heat exchanger as the radiator heat exchanger 130 or may be a separate radiator heat exchanger.

[0067] The second portion 322(a) of the liquid portion 122(a) of the multiphase fluid 122 is passed through the bypass flow loop 188 and back through the heat source heat exchanger 128, which adds heat to the second portion 322(a). The second portion 322(a) of the liquid portion 122(a) of the multiphase fluid 122 is then passed to the hot mixing valve 194.

[0068] The thermal mixing valve 194 mixes the first portion 222(a) and the second portion 322(a) of the liquid portion 122(a) of the multiphase fluid 122 to achieve a desired temperature of the liquid portion 122(a) of the multiphase fluid 122 before the liquid portion 122(a) of the multiphase fluid 122 is delivered back to the inlet 184 of the multiphase fluid passage 182, thereby regulating or maintaining the temperature of a portion of the multiphase fluid 122 disposed within the multiphase fluid space 120. The desired amount of mixing may be determined at least in part by a predetermined or desired temperature of the thermal load. For example, if the closed-loop thermal management system 100 is used to cool a CPU, the CPU may need to operate at a specific temperature or within a specific temperature range. Therefore, the temperature probe 196 measures the temperature of the CPU, and the controller controls the thermal mixing valve 194 until the desired CPU temperature is achieved.

[0069] The increase in temperature of the liquid portion 122(a) of the multiphase fluid 122 flowing through the multiphase fluid channel 182 causes the pressure in the multiphase fluid space 120 to increase, thereby causing the liquid portion 122(a) of the multiphase fluid 122 to flow into the heat transfer bus 102, thereby adjusting the pressure in the heat transfer bus 102. Similarly, the decrease in temperature of the gas portion 122(b) of the multiphase fluid 122 causes the pressure in the multiphase fluid space 120 to decrease, thereby causing the liquid portion 122(a) of the multiphase fluid 122 to flow back from the heat transfer bus 102 to the multiphase fluid space 120, thereby adjusting the pressure in the heat transfer bus 102.

[0070] The closed-loop thermal management system disclosed herein can accurately control the pressure within the heat transfer bus loop without being affected by environmental conditions, and has greater simplicity and ease of integration. For example, the pressure response of the accumulator is proportional to the pressure-temperature behavior of the hot working fluid flowing through the heat transfer bus. For example, the pressure response for CO2 is about 22psi / ℃, and the pressure response for R134a is about 3psi / ℃.

[0071] The closed-loop thermal management system can control the pressure of the working fluid of the incompressible and compressible flow loops. By controlling the temperature of the multiphase fluid in the multiphase fluid space, the pressure in the heat transfer bus can be controlled as needed. Temperature control of the multiphase fluid space can also minimize the effects of ambient heat leakage because the temperature of the fluid can be controlled externally via a feedback controller and actuated by an electric heater, thermoelectric or other device, rather than relying on ambient conditions. The use of temperature to control pressure in a closed-loop thermal management system, particularly a heat transfer bus, eliminates the need for external high-pressure gas / vent lines and additional components (such as valves) used in gas-charged accumulators.

[0072] This written description uses examples to disclose the present disclosure, including the best mode, and to enable any person skilled in the art to practice the present disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the present disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims.

[0073] Further aspects are provided by the subject matter of the following clauses:

[0074] A closed-loop thermal management system comprises: a heat transfer bus configured to circulate a hot working fluid therein; an accumulator comprising a shell defining a multiphase fluid space therein, a multiphase fluid at least partially disposed within the multiphase fluid space, and an opening configured to provide fluid communication between the accumulator and the heat transfer bus, wherein the heat transfer bus and the accumulator are configured as a closed-loop fluid circuit; and a temperature regulator configured to control a temperature of the multiphase fluid within the multiphase fluid space, wherein the multiphase fluid regulates a pressure of the hot working fluid flowing through the heat transfer bus based on the temperature of the multiphase fluid.

[0075] A closed-loop thermal management system includes: a heat transfer bus including a plurality of fluid conduits configured to circulate a hot working fluid therein; an accumulator including a shell defining a multiphase fluid space therein, the multiphase fluid space being configured to contain a multiphase fluid, the shell defining an opening, wherein the accumulator is fluidly coupled to the heat transfer bus in a closed-loop fluid circuit; and a temperature regulator configured to control a temperature of the multiphase fluid within the multiphase fluid space.

[0076] A closed-loop thermal management system as described in any preceding or any following clause, wherein the hot working fluid comprises the multiphase fluid.

[0077] A closed-loop thermal management system as described in any preceding or following clause, further comprising a heat source heat exchanger in thermal communication with the hot working fluid.

[0078] The closed-loop thermal management system of any preceding or following clause, further comprising a radiator heat exchanger in thermal communication with the hot working fluid.

[0079] A closed-loop thermal management system according to any preceding or following clause, wherein the multiphase fluid comprises a liquid portion in a saturated liquid state and a gas portion in a saturated vapor state within the multiphase fluid space.

[0080] The closed-loop thermal management system of any preceding or following clause, further comprising a pump having an inlet and an outlet fluidly coupled to the heat transfer bus, wherein the heat transfer bus, the pump, and the accumulator are configured as a closed-loop fluid circuit.

[0081] The closed-loop thermal management system according to any preceding or following clause, wherein the multiphase fluid comprises a liquid portion, a gas portion and a dissolved gas mixed with the liquid portion within the multiphase fluid space.

[0082] A closed-loop thermal management system according to any preceding or following clause, wherein the multiphase fluid comprises a gas portion, a non-condensable gas and a liquid portion within the multiphase fluid space.

[0083] The closed-loop thermal management system according to any preceding or following clause, wherein the multiphase fluid comprises a gas portion in a saturated vapor state, a non-condensable gas mixed with the saturated vapor, and a liquid portion in a saturated liquid state within the multiphase fluid space.

[0084] A closed-loop thermal management system as described in any preceding or following clause, wherein the multiphase fluid is a subcooled liquid within the multiphase fluid space.

[0085] A closed loop thermal management system as described in any preceding or following clause, wherein the accumulator further comprises a dip tube fluidly coupled to the opening.

[0086] A closed-loop thermal management system as described in any preceding or following clause, wherein the multiphase fluid includes a liquid portion in a saturated liquid state and a gas portion in a saturated vapor state, wherein the dip tube is in fluid communication with the liquid portion.

[0087] A closed loop thermal management system as described in any preceding or following clause, further comprising a counterweight coupled to the dip tube.

[0088] A closed loop thermal management system as described in any preceding or following clause, wherein the accumulator is mounted to a gimbal.

[0089] A closed-loop thermal management system according to any preceding or following clause, wherein the housing of the accumulator includes a wall defining an inner wall surface and an outer wall surface, wherein the temperature regulator includes at least one resistive heater disposed along at least one of the outer wall surface and the inner wall surface.

[0090] A closed loop thermal management system as described in any preceding or following clause, wherein the housing of the accumulator includes a wall defining an outer wall surface, wherein the temperature regulator includes a thermoelectric module in thermal contact with the outer wall surface.

[0091] A closed loop thermal management system as described in any preceding or following clause, wherein the thermoelectric module is in thermal contact with the heat transfer bus.

[0092] A closed loop thermal management system as described in any preceding or following clause, wherein the housing of the accumulator includes a wall defining an inner wall surface and an outer wall surface, wherein the temperature regulator includes a thermal fluid jacket disposed at least partially along the inner wall surface.

[0093] A closed loop thermal management system as described in any preceding or following clause, further comprising a coolant circuit in fluid communication with the thermal fluid jacket.

[0094] A closed-loop thermal management system according to any preceding or following clause, wherein the shell defines a fluid passage between the inner wall surface and the outer wall surface, the fluid passage including an inlet and an outlet, wherein the fluid passage is fluidly coupled to the heat transfer bus via the inlet, the outlet and the opening of the accumulator.

[0095] A closed loop thermal management system as described in any preceding or following clause, wherein the accumulator further comprises a hot working fluid space and a movable plate, wherein the movable plate fluidly isolates the multiphase fluid space from the hot working fluid space.

[0096] A closed loop thermal management system as described in any preceding clause, wherein the movable plate is configured to move in response to a change in temperature of the multiphase fluid to increase or decrease pressure within the heat transfer bus.

[0097] The closed-loop thermal management system according to any of the preceding or following clauses further comprises at least one sensor and a controller, further comprising at least one sensor and a controller, wherein the at least one sensor is configured to send a signal indicating the temperature or pressure of the hot working fluid to the controller, wherein the controller is configured to operate the thermal mixing valve in response to the signal.

[0098] A vehicle comprises: a heat transfer bus configured to circulate a hot working fluid therein; an accumulator comprising a shell defining a multiphase fluid space therein, a multiphase fluid at least partially disposed within the multiphase fluid space, and an opening configured to provide fluid communication between the accumulator and the heat transfer bus, wherein the heat transfer bus and the accumulator are configured as a closed-loop fluid circuit; and a temperature regulator configured to control a temperature of the multiphase fluid within the multiphase fluid space, wherein the multiphase fluid regulates a pressure of the hot working fluid flowing through the heat transfer bus based on the temperature of the multiphase fluid.

[0099] A vehicle comprises: a heat transfer bus comprising a plurality of fluid conduits configured to circulate a hot working fluid therein; an accumulator comprising a shell defining a multiphase fluid space therein, the multiphase fluid space being configured to contain a multiphase fluid, the shell defining an opening, wherein the accumulator is fluidly coupled to the heat transfer bus in a closed-loop fluid circuit; and a temperature regulator configured to control a temperature of the multiphase fluid within the multiphase fluid space.

[0100] A vehicle as recited in the preceding clause, further comprising at least one of a heat source heat exchanger and a heat sink heat exchanger in thermal communication with the hot working fluid.

[0101] A vehicle as described in any preceding or following clause, wherein the hot working fluid comprises the multiphase fluid.

[0102] A vehicle according to any preceding or following clause, wherein the multiphase fluid comprises a liquid portion in a saturated liquid state and a gas portion in a saturated vapor state within the multiphase fluid space.

[0103] A vehicle as described in any preceding or following clause, further comprising a pump having an inlet and an outlet fluidly coupled to the heat transfer bus, wherein the heat transfer bus, the pump and the accumulator are configured as a closed-loop fluid circuit.

[0104] A vehicle according to any preceding or following clause, wherein the multiphase fluid comprises a liquid portion, a gas portion and a dissolved gas mixed with the liquid portion within the multiphase fluid space.

[0105] A vehicle as described in any preceding or following clause, wherein the multiphase fluid comprises a gas portion, a non-condensable gas and a liquid portion within the multiphase fluid space.

[0106] A vehicle according to any preceding or following clause, wherein the multiphase fluid comprises a gas portion in a saturated vapor state, a non-condensable gas mixed with the saturated vapor, and a liquid portion in a saturated liquid state within the multiphase fluid space.

[0107] A vehicle as described in any preceding or following clause, wherein the multiphase fluid is a subcooled liquid within the multiphase fluid space.

[0108] A vehicle as described in any preceding or following clause wherein the accumulator further comprises a dip tube fluidly coupled to the opening.

[0109] A vehicle as described in any preceding or following clause, wherein the multiphase fluid comprises a liquid portion in a saturated liquid state and a gas portion in a saturated vapor state, wherein the dip tube is in fluid communication with the liquid portion.

[0110] A vehicle as described in any preceding or following clause, further comprising a counterweight coupled to the dip tube.

[0111] A vehicle as described in any preceding or following clause wherein the accumulator is mounted to a gimbal.

[0112] A vehicle as claimed in any preceding or following clause, wherein the housing of the accumulator comprises a wall defining an inner wall surface and an outer wall surface, wherein the temperature regulator comprises at least one resistive heater disposed along at least one of the outer wall surface and the inner wall surface.

[0113] A vehicle as claimed in any preceding or following clause, wherein the housing of the accumulator comprises a wall defining an outer wall surface, wherein the temperature regulator comprises a thermoelectric module in thermal contact with the outer wall surface.

[0114] A vehicle as described in any preceding or following clause wherein the thermoelectric module is in thermal contact with the heat transfer bus.

[0115] A vehicle as claimed in any preceding or following clause, wherein the housing of the accumulator comprises a wall defining an inner wall surface and an outer wall surface, wherein the temperature regulator comprises a thermal fluid jacket disposed at least partially along the inner wall surface.

[0116] A vehicle as described in any preceding or following clause, further comprising a coolant circuit in fluid communication with the thermal fluid jacket.

[0117] A vehicle as described in any preceding or following clause, wherein the shell defines a fluid channel between the inner wall surface and the outer wall surface, the fluid channel including an inlet and an outlet, wherein the fluid channel is fluidly coupled to the heat transfer bus via the inlet, the outlet and the opening of the accumulator.

[0118] A vehicle as described in any preceding or following clause, wherein the accumulator further comprises a hot working fluid space and a movable plate, wherein the movable plate fluidly isolates the multiphase fluid space from the hot working fluid space.

[0119] A vehicle as claimed in any preceding clause, wherein the movable plate is configured to move in response to changes in temperature of the multiphase fluid to increase or decrease pressure within the heat transfer bus.

[0120] A vehicle as described in any preceding or previous clause, wherein the vehicle comprises a gas turbine engine, wherein the closed loop thermal management system is thermally coupled to the gas turbine engine.

[0121] The vehicle of any preceding or following clause, further comprising at least one sensor and a controller, wherein the at least one sensor is configured to send a signal indicative of the temperature or pressure of the hot working fluid to the controller, wherein the controller is configured to operate the hot mixing valve in response to the signal.

Claims

1. A closed-loop thermal management system, characterized in that: include: a heat transfer bus comprising a plurality of fluid conduits configured to circulate a hot working fluid therein; an accumulator including a shell defining a multiphase fluid space therein, the multiphase fluid space being configured to contain a multiphase fluid, the shell defining an opening, wherein the accumulator is fluidly coupled to the heat transfer bus in a closed-loop fluid circuit; as well as A temperature regulator is configured to control the temperature of the multiphase fluid in the multiphase fluid space.

2. The closed-loop thermal management system according to claim 1, characterized in that: Wherein the hot working fluid comprises the multiphase fluid.

3. The closed-loop thermal management system according to claim 1, characterized in that: Further included is a heat source heat exchanger in thermal communication with the hot working fluid.

4. The closed-loop thermal management system according to claim 1, characterized in that: Further included is a radiator heat exchanger in thermal communication with the hot working fluid.

5. The closed-loop thermal management system according to claim 1, characterized in that: The multiphase fluid includes a liquid portion in a saturated liquid state and a gas portion in a saturated vapor state within the multiphase fluid space.

6. The closed-loop thermal management system according to claim 1, characterized in that: Further included is a pump having an inlet and an outlet fluidly coupled to the heat transfer bus, wherein the closed-loop fluid circuit includes the heat transfer bus, the pump, and the accumulator.

7. The closed-loop thermal management system according to claim 1, characterized in that: Wherein the accumulator further comprises a dip tube fluidly coupled to the opening.

8. The closed-loop thermal management system according to claim 7, characterized in that: The multiphase fluid includes a liquid portion in a saturated liquid state and a gas portion in a saturated vapor state, wherein the dip tube is in fluid communication with the liquid portion.

9. The closed-loop thermal management system according to claim 7, characterized in that: Further included is a counterweight coupled to the dip tube.

10. The closed-loop thermal management system according to claim 7, characterized in that: Further comprising a gimbal, wherein the accumulator is mounted to the gimbal.

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