PASSIVE PUMP SWITCHING

Abstract

A thermal management system includes several normally isolated thermal subsystems, each controlling a specific piece of equipment. These thermal subsystems can be automatically interconnected in response to local pressure within them. When interconnected, one or more components (for example, a pump) of a subsystem can act on the equipment controlled by each of the interconnected subsystems. However, the subsystems can be actively isolated when a leak is detected.

Description

Title of the invention: PASSIVE PUMP SWITCHING

[0001] REFERENCE TO RELATED REQUESTS This application claims the benefit of US Application No. 63 / 704109, filed on October 7, 2025 and entitled "PASSIVE PUMP SWITCHING", disclosure of which is incorporated herein by reference in its entirety. TECHNOLOGICAL BACKGROUND

[0002] Thermal management systems provide cooling for various types of heat-producing equipment. For example, thermal management can be provided for an aircraft propulsion system. In general, a thermal management system includes a cooling fluid (e.g., water, ethylene glycol, etc.) which is circulated by a pump along pipes between a heat exchanger and the equipment to be cooled. SUMMARY

[0003] A thermal management system includes a first thermal subsystem configured to thermally regulate a first piece of equipment and a second thermal subsystem configured to thermally regulate a second piece of equipment that is different from the first. The thermal management system is configured to perform an automatic transition between a normal operating state, a first assistance state, and a second assistance state. The first and second thermal subsystems are isolated from each other when the thermal management system is configured in the normal operating state. The thermal subsystems are connected together to regulate the first and second pieces of equipment in each of the assistance states.In particular, the second thermal subsystem controls the flow of cooling fluid in the first assist state and the first thermal subsystem controls the flow of cooling fluid in the second assist state.

[0004] In certain embodiments, each thermal subsystem includes a pump configured to distribute cooling fluid along a respective local path to the respective equipment. A first transverse path connects the local passages downstream of the pumps, and a second transverse path connects the local passages upstream of the pumps. Consequently, one of the pumps can cycle the cooling fluid through both sets of local passages if the other pump encounters a fault (e.g., stops working, stops working at the required system pressure, etc.). This ability of a certain subsystem to assume the Distributing equipment responsibility across other subsystems provides redundancy, thereby improving system reliability.

[0005] In certain embodiments, a passive valve arrangement allows the thermal management system to automatically switch from normal operating mode to assist mode when the pressure drops within one of the systems. For example, when both thermal subsystems are operating normally, the pressure within the subsystems will apply a relatively equal pressure at the passive valve arrangement. However, when the pressure drops in one thermal subsystem, the passive valve arrangement will allow flow from the higher-pressure subsystem to flow through the lower-pressure subsystem. Similarly, the passive valve arrangement will automatically return the thermal management system to normal operation if the faulty pump is stationary. Transition states without the need for active components further improve the reliability of the thermal management system.

[0006] An active valve arrangement can be added to the thermal management system to isolate local passages in the event of a leak. For example, the active valve arrangement can be controlled by a control device receiving input from one or more sensors in the system to determine the presence of a leak.

[0007] A variety of additional inventive aspects will be set forth in the following description. The inventive aspects may relate to individual features and combinations of features. It should be understood that the preceding general description and the detailed description that follows are merely examples and explanations and are not exhaustive of the general inventive concepts on which the embodiments disclosed herein are based. Brief description of the drawings

[0008] The accompanying drawings, which are incorporated into and form part of the description, illustrate several aspects of this disclosure. A brief description of the drawings is as follows:

[0009] Fig. 1 is a diagram of an example thermal management system configured in a normal operating state, the thermal management system including thermal subsystems interconnected by transverse paths and a passive valve arrangement.

[0010] Fig. 2 represents the thermal management system of Fig. 1 configured in a first assist state in which a pump of the second subsystem drives a fluid between all the interconnected subsystems.

[0011] Fig. 3 represents the thermal management system of Fig. 1 configured in a second assist state in which a pump of the first subsystem drives a fluid between all the interconnected subsystems.

[0012] Fig. 4 represents an example of the implementation of a valve arrangement suitable for use in the passive valve of Figures 1 to 3.

[0013] The [Fig.5] adds an active valve arrangement to the thermal management system of the [Fig.1], the active valve arrangement being configured in an open state.

[0014] Fig. 6 shows the passive valve arrangement of the thermal management system of Fig. 5 configured in the first assist state while the active valve arrangement is configured in the open state.

[0015] Figure 7 represents the thermal management system of Figure 6, while the active valve arrangement is configured in an isolated state. DETAILED DESCRIPTION

[0016] We will now refer in detail to exemplary aspects of this disclosure which are illustrated in the accompanying drawings. Where possible, the same numerical references will be used throughout the drawings to designate identical or similar parts.

[0017] A thermal management system 100 includes multiple thermal subsystems 110, 120, each operating independently to thermally regulate a respective piece of equipment 112, 122. Although two thermal subsystems 110, 120 are shown in the figures, it should be understood that the thermal management system 100 could include additional thermal subsystems. Each thermal subsystem 110, 120 includes a respective pump 114, 124 configured to distribute cooling fluid along a respective passage 115, 125 to the respective piece of equipment 112, 122.

[0018] According to certain aspects of the disclosure, the thermal management system 100 is configured to transition between a normal operating state, a first assist state, and a second assist state. The first and second passes 115, 125 are isolated from each other when the thermal management system 100 is configured in the normal operating state. The first pump 114 supplies coolant to both the first piece of equipment 112 and the second piece of equipment 122 when the thermal management system 100 is configured in the first assist state. The second pump 124 supplies coolant to both the first piece of equipment 112 and the second piece of equipment 122 when the thermal management system 100 is configured in the second assist state.

[0019] In certain embodiments, the transition between states occurs automatically upon a failure in one of the subsystems 110, 120. By For example, the transition is not controlled by active valves. In some embodiments, the transition is implemented using a passive valve arrangement 130. The passive valve arrangement 130 isolates the first and second passages 115, 125 during normal operation. The passive valve arrangement 130 allows flow from a certain higher-pressure passage among the first and second passages 115, 125 to a certain lower-pressure passage among the first and second passages 115, 25 during a component failure, thus leading to a transition to one of the assist states.

[0020] In some examples, the thermal subsystems 110, 120 are interconnected using first and second transverse paths 136, 138. For example, a first transverse path 136 can connect the first passage 115, at a first location 140 downstream of the first pump 114, to the second passage 125 at a second location 142 downstream of the second pump 124. A second transverse path 138 connects the first passage 115, at a third location 144 upstream of the first pump 114, to the second passage 125 at a fourth location 146 upstream of the second pump 124.

[0021] The passive valve arrangement 130 includes a first valve arrangement 132 disposed along the first transverse path 136 and a second valve arrangement disposed along the second transverse path 138. When the pressure in the first and second passages 115, 125 is approximately equal, the flow from either passage 115, 125 to the first valve arrangement 132 will be approximately equal, thus applying an approximately equal pressure to the first valve arrangement 132. As a result, the first valve arrangement 132 will inhibit the flow from any thermal subsystem 110, 120 into the other.When the pressure inside one of the passages 115, 125 is greater than the other, however, as in the case of a pump failure in one of the thermal subsystems 110, 120, the valve arrangements 132, 134 will allow a flow from the higher pressure system to pass along the respective transverse paths 136, 138 into the lower pressure system.

[0022] For example, [Fig. 2] represents the thermal management system 100 configured in the first assist state. In [Fig. 2], the pump 114 of the first thermal subsystem 110 has stopped operating. As a result, the pressure of the coolant inside the first thermal subsystem 110 drops to a level lower than the pressure in the second thermal subsystem 120, which still has an operating pump 124. Consequently, some of the coolant pressurized by the pump 124 in the second thermal subsystem 120 rises above the coolant of the first thermal subsystem 110 at the first valve arrangement 132 and flows along the first transverse path 136 to join the first passage 115. Of course, another part of the cooling fluid pressurized by the pump 124 continues to flow along the second passage 125.

[0023] Furthermore, the second pump 124 draws cooling fluid towards itself along the second passage 125 while the first pump 114 has ceased drawing cooling fluid. Consequently, the second valve arrangement 134 will experience a greater attraction from the second thermal subsystem 120 and will open to allow a flow from location 144 upstream of the first pump 114 to move along the second transverse path 138 towards location 146 upstream of the second pump 124 to form a combined path 148. All the cooling fluid in both subsystems 110, 120 completes a return cycle to the second pump 124 along the combined path 148 in a first direction. As a result, the cooling fluid driven by the second pump 124 passes through all the equipment 112, 122 in the subsystems 110, 120.

[0024] In some examples, the cooling fluid driven by the second pump 124 of [Fig. 2] also passes through the two heat exchangers 116, 126. The inclusion of the two heat exchangers 116, 126 in the combined path 148 helps to compensate for the load produced by the equipment 112, 122. In the illustrated example, the first transverse path 136 connects the first and second passages 115, 125 at locations upstream of the heat exchangers 116, 126. In other examples, however, the first transverse path 136 could connect the first and second passages 115, 125 at locations downstream of the heat exchangers 116, 126.

[0025] Figure 3 represents the thermal management system 100 configured in the second assist state. In particular, Figure 3 shows the second pump 124 in a non-operational state while the first pump 114 remains operational. In such a system, the pressure of the coolant within the second thermal subsystem 120 drops to a level lower than the pressure in the first thermal subsystem 110, with the result that the first and second valve arrangements 132, 134 allow flow in the opposite direction compared to Figure 2. Consequently, the pump 114 of the first thermal subsystem 110 carries a first portion of the coolant along the local passage 115 and a second portion of the coolant over the first transverse path 136 towards the second passage 125.The second transverse path 138 allows the second part of the cooling fluid to complete a return cycle to the first pump 114.

[0026] Figure 4 shows an example of an implementation of a valve arrangement 150 suitable for use as a valve arrangement 132, 134 along the transverse paths 136, 138. In Figure 4, the valve arrangement 150 includes a first check valve 152 and a second check valve 154. The first check valve 152 opens only when the pressure from a first side 156 exceeds the pressure on the opposite second side 158. The second check valve 154 opens only when the pressure from the second side 158 exceeds the pressure on the first side 156. The first and second check valves 152, 154 are arranged parallel to each other. For example, the transverse path 136, 138 can be divided into a first section of path 160 and a second section of path 162 extending parallel to each other before joining again.The first check valve 152 allows flow in one direction from the first side 156 to the second side 158 along the first section of path 160 when it is open. The second check valve 154 allows flow in a second direction from the second side 158 to the first side 156 along the second section of path 162 when it is open. The check valves 152 and 154 remain closed when the pressure on both sides 156 and 158 is equal or nearly equal.

[0027] With reference to Figures 5 to 7, active protection can be added to the thermal management system 100 to prevent the interconnection of subsystems 110, 120 when a local pressure loss is caused by a leak. For example, an active valve arrangement 164 can be arranged along the first and second transverse paths 136, 138. The active valve arrangement 164 is controlled by a system control device 170 to transition between an open state and an isolated state. When in the isolated state, the active valve arrangement 150 isolates the first and second passages 115, 125 independently of any pressure difference between the subsystems 110, 120. However, when in the open state, the active valve arrangement 150 allows the passive valve arrangement 130 to operate as described above.

[0028] In some embodiments, the system control device 170 is configured to receive input from one or more sensors 172 located on the thermal subsystems 110, 120. In some examples, the sensors 172 are located on the pump 114, 124 to determine if the pump 114, 124 is functioning. In other examples, the sensors 172 are located on a respective accumulator located along the local passage 115, 125 to check the volume of coolant stored during normal operation. Other types of sensors are possible. The system control device 170 analyzes the input signals to determine if any of the subsystems 110, 120 has leaked or is otherwise in the process of Losing coolant. System control device 170 issues shutdown instructions when a leak is detected.

[0029] In certain embodiments, the active valve arrangement 150 includes a first shut-off valve 166 located along the first transverse path 136 and a second shut-off valve 168 located along the second transverse path 138. In normal operation, the shut-off valves 166, 168 remain open regardless of the relative pressures of the subsystems 110, 120. For example, [Fig. 6] shows the thermal management system 100 configured in the first assist state while the shut-off valves 166, 168 remain open. Upon receiving shutdown instructions from the system control device 170, however, the shut-off valves 166, 168 close, thus isolating the local passages 115, 125 between the thermal subsystems 110, 120.

[0030] In some examples, shutdown instructions are issued by the control device in the event of a leak L (for example, see [Fig. 7]). Interconnecting subsystems 110, 120 while one subsystem 110, 120 is leaking could lead to a leak in all interconnected subsystems. The active valve arrangement 164 protects against such a scenario by isolating subsystems 110, 120 from each other in the event of a leak, even if one of the thermal subsystems 110, 120 fails otherwise. For example, [Fig. 7] shows the shut-off valves 166, 168 closed while the thermal management system 100 has been configured in the first assist state. In such a configuration, the first equipment 112 is not thermally managed by the first subsystem 110 or the second subsystem 120.However, the leakage L in the first subsystem 110 does not affect the operation of the second subsystem 120, so the second equipment 122 remains thermally managed.

[0031] Certain aspects of disclosure are described in the following examples:

[0032] Aspect 1. A thermal management system, comprising: a first thermal subsystem configured to distribute cooling fluid to a first piece of equipment, the first thermal subsystem including a first pump, a first heat exchanger and first conduits forming a first passage from the first pump to the first heat exchanger and to the first piece of equipment; a second thermal subsystem configured to distribute cooling fluid to a second piece of equipment, the second thermal subsystem including a second pump, a second heat exchanger and second conduits forming a second passage from the second pump to the second heat exchanger and to the second piece of equipment; a first transverse path linking the first passage, at the level of a first location upstream of the first pump, to the second passage at the level of a second location upstream of the second pump; a second transverse path linking the first passage, at a third location downstream of the first pump, to the second passage at a fourth location downstream of the second pump; a passive valve arrangement disposed along the first and second transverse paths, the passive valve arrangement isolating the first and second passages during normal operation, and the passive valve arrangement permitting a flow from a certain higher pressure of the first and second passages to a certain lower pressure of the first and second passages during a component failure.

[0033] Aspect 2. The thermal management system according to aspect 1, in which the passive valve arrangement includes a first valve arrangement disposed along the first transverse path and a second valve arrangement disposed along the second transverse path.

[0034] Aspect 3. The thermal management system according to aspect 2, in which the first valve arrangement includes a first check valve and a second check valve arranged in parallel.

[0035] Aspect 4. The thermal management system according to any one of aspects 1 to 3, further comprising: a system control device; and an active valve arrangement disposed along the first and second cross paths, the active valve arrangement being configured to transition between an open state and an isolated state in response to instructions from the system control device, wherein the active valve arrangement isolates the first and second passes when in the isolated state.

[0036] Aspect 5. The thermal management system according to any one of aspects 1 to 4, in which each of the first and second thermal subsystems includes an internal check valve disposed downstream of the pump and upstream of the second transverse path.

[0037] Aspect 6. The thermal management system according to any one of aspects 1 to 5, wherein the second equipment is substantially the same as the first equipment.

[0038] Aspect 7. The thermal management system according to any one of aspects 1 to 6, in which the second piece of equipment is placed at a different location than the first piece of equipment.

[0039] Aspect 8. The thermal management system according to any one of aspects 1 to 7, wherein the first equipment is part of an aircraft propulsion system.

[0040] Aspect 9. A thermal management system, comprising: a first thermal subsystem including a first pump configured to distribute a first cooling fluid along a first passage to a first piece of equipment; a second thermal subsystem including a second pump configured to distribute a second cooling fluid along a second passage to a second piece of equipment; the thermal management system being configured to perform an automatic transition between a normal operating state, a first assistance state and a second assistance state, the first and second paths being isolated from each other when the thermal management system is configured in the normal operating state, the first pump supplying the first coolant to both the first and second equipment when the thermal management system is configured in the first assistance state, and the second pump supplying the second coolant to both the first and second equipment when the thermal management system is configured in the second assistance state.

[0041] Aspect 10. The thermal management system according to aspect 9, in which the second equipment is substantially the same as the first equipment.

[0042] Aspect 11. The thermal management system according to any one of aspects 9 and 10, wherein the second piece of equipment is arranged at a different location from the first piece of equipment.

[0043] Aspect 12. The thermal management system according to any one of aspects 9 to 11, further comprising: a system control device; and an active valve arrangement, the active valve arrangement being configured to transition between an open state and an isolated state in response to instructions from the system control device, wherein the active valve arrangement isolates the first and second passes when in the isolated state.

[0044] Aspect 13. The thermal management system according to any one of aspects 9 to 12, further comprising: a first transverse path linking the first passage, at a first location upstream of the first pump, to the second passage at a second location upstream of the second pump; and a second transverse path linking the first passage, at a third location downstream of the first pump, to the second passage at a fourth location downstream of the second pump.

[0045] Aspect 14. The thermal management system of aspect 13, further comprising: a first valve arrangement disposed along the first transverse path, the first valve arrangement being configured to permit fluid from a certain higher pressure path among the first and second passages to flow to a certain lower pressure path among the first and second passages; and a second valve arrangement disposed along the second transverse path, the second valve arrangement being configured to permit fluid from a higher pressure path among the first and second passages to flow to a certain lower pressure path among the first and second passages.

[0046] Aspect 15. The thermal management system according to aspect 14, in which the first valve arrangement includes a first check valve and a second check valve arranged in parallel.

[0047] Aspect 16. The thermal management system according to any one of aspects 9 to 15, wherein the first equipment is part of an aircraft propulsion system.

[0048] Having described the preferred aspects and implementations of this disclosure, modifications and equivalents of the disclosed concepts may readily be apparent to a person skilled in the art. However, it is intended that these modifications and equivalents will be included within the scope of the claims annexed hereto.

Claims

Demands

1. Thermal management system, comprising: a first thermal subsystem including a first pump configured to distribute a first cooling fluid along a first passage to the first piece of equipment; a second thermal subsystem including a second pump configured to distribute a second cooling fluid along a second passage to a second piece of equipment;the thermal management system being configured to perform an automatic transition between a normal operating state, a first assistance state and a second assistance state, the first and second paths being isolated from each other when the thermal management system is configured in the normal operating state, the first pump supplying the first coolant to both the first and second equipment when the thermal management system is configured in the first assistance state, and the second pump supplying the second coolant to both the first and second equipment when the thermal management system is configured in the second assistance state.;

2. Thermal management system according to claim 1, wherein the second equipment is substantially the same as the first equipment.

3. Thermal management system according to any one of claims 1 and 2, wherein the second piece of equipment is disposed at a different location from the first piece of equipment.

4. Thermal management system according to any one of claims 1 to 3, further comprising: a system control device; and an active valve arrangement, the active valve arrangement being configured to transition between an open state and an isolated state in response to instructions from the system control device, wherein the active valve arrangement isolates the first and second passes when in the isolated state.

5. Thermal management system according to any one of claims 1 to 4, further comprising: a first transverse path linking the first passage, at the level of a first location upstream of the first pump, to the second passage at the level of a second location upstream of the second pump; and a second transverse path linking the first passage, at the level of a third location downstream of the first pump, to the second passage at the level of a fourth location downstream of the second pump.

6. Thermal management system according to claim 5, further comprising: a passive valve arrangement disposed along the first and second transverse paths, the passive valve arrangement isolating the first and second passages during normal operation, and the passive valve arrangement permitting a flow from a certain higher pressure of the first and second passages to a certain lower pressure of the first and second passages during a component failure.

7. Thermal management system according to claim 6, wherein the passive valve arrangement comprises: a first valve arrangement disposed along the first transverse path, the first valve arrangement being configured to permit fluid from a certain higher pressure path among the first and second passages to flow to a certain lower pressure path among the first and second passages; and a second valve arrangement disposed along the second transverse path, the second valve arrangement being configured to permit fluid from a higher pressure path among the first and second passages to flow to a certain lower pressure path among the first and second passages.

8. Thermal management system according to claim 7, wherein the first valve arrangement comprises a first check valve and a second check valve arranged in parallel.

9. Thermal management system according to any one of claims 1 to 8, wherein the first equipment is part of an aircraft propulsion system.

10. A thermal management system according to any one of claims 1 to 8, wherein the first thermal subsystem includes the first pump, a first heat exchanger, and first conduits forming the first passage from the first pump to the first heat exchanger and the first piece of equipment; and in which the second thermal subsystem includes the second pump, a second heat exchanger and second conduits forming the second passage from the second pump to the second heat exchanger and the second piece of equipment.

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