Systems and methods for heat balance and transport for aircraft hydraulic systems

Patent metadata

Field	Value
Publication number	US-9644898-B2
Application number	US-201414151291-A
Country	US
Kind code	B2
Filing date	Jan 9, 2014
Priority date	Jul 9, 2013
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A thermal management system includes a first hydraulic system for circulating a first hydraulic fluid at a first temperature and a second hydraulic system for circulating a second hydraulic fluid at a second temperature that is higher than the first temperature. The thermal management system also includes a sealed heat transfer device coupled between the first hydraulic system and the second hydraulic system. The sealed heat transfer device is not in flow communication with either of the first hydraulic system and the second hydraulic system. The sealed heat transfer device is configured to transfer heat from the second hydraulic fluid to the first hydraulic fluid.

First claim

What is claimed is:

1. A thermal management system comprising: a first hydraulic system for circulating a first hydraulic fluid to at least a first hydraulically activated component, said first hydraulic system comprising a first pump, a first case drain line, a first reservoir, and a first return line coupled between said first hydraulically activated component and said first reservoir; a second hydraulic system for circulating a second hydraulic fluid to at least a second hydraulically activated component, said second hydraulic system comprising a second pump, a second reservoir, and a second case drain line coupled between said second pump and said second reservoir; and a sealed heat transfer device coupled between said first reservoir and said second case drain line, said sealed heat transfer device is not in flow communication with either of said first reservoir and said second case drain line, wherein said sealed heat transfer device is configured to transfer heat from the second hydraulic fluid to the first hydraulic fluid such that a temperature of the first hydraulic fluid in said first reservoir is stabilized above a threshold temperature that corresponds to a threshold amount of hydraulic power for operation of said first hydraulically operated component, wherein said sealed heat transfer device comprises: a cold interface coupled to said first hydraulic system; a hot interface coupled to said second hydraulic system; a sealed tube extending longitudinally between said cold interface and said hot interface; and a working fluid disposed within said tube in an amount such that said working fluid exists partially in a liquid phase and partially in a vapor phase within said tube throughout an operating temperature range of said sealed heat transfer device, wherein said sealed heat transfer device further comprises a wicking structure extending longitudinally within at least a portion of said tube, said wicking structure configured to induce liquid to flow therethrough due to capillary action.

2. The thermal management system of claim 1 , wherein said sealed heat transfer device extends across a distance of at least three feet such that all components in flow communication with said first hydraulic system are located at least three feet from all components in flow communication with said second hydraulic system.

3. The thermal management system of claim 1 , wherein an elevation of said cold interface relative to said hot interface is sufficient to allow vapor heated by said hot interface to rise toward said cold interface due to natural buoyancy.

4. The thermal management system of claim 1 , wherein said sealed heat transfer device comprises:
a cold interface coupled to said first hydraulic system;
a hot interface coupled to said second hydraulic system;
a surface interface coupled to a structural surface;
a thermostat;
a first tube extending between said hot interface and said thermostat;
a second tube extending between said thermostat and said cold interface; and
a third tube extending between said thermostat and said surface interface, wherein said thermostat is configured to selectively switch said first tube between flow communication with said second tube, such that said first tube and said second tube form a thermosyphon extending between said hot interface and said cold interface, and flow communication with said third tube, such that said first tube and said third tube form a thermosyphon extending between said hot interface and said surface interface.

5. The thermal management system of claim 4 , wherein said thermostat is further configured to selectively switch said first tube from flow communication with said second tube into flow communication with said third tube when a temperature associated with said first hydraulic system exceeds a predetermined threshold value.

6. An aircraft comprising: a first hydraulic system for circulating a first hydraulic fluid to at least a first hydraulically activated component, said first hydraulic system comprising a first pump, a first case drain line, a first reservoir, and a first return line coupled between said first hydraulically activated component and said first reservoir; a second hydraulic system for circulating a second hydraulic fluid to at least a second hydraulically activated component, said second hydraulic system comprising a second pump, a second reservoir, and a second case drain line coupled between said second pump and said second reservoir; and a sealed heat transfer device coupled between said first reservoir and said second case drain line, said sealed heat transfer device is not in flow communication with either of said first reservoir and said second case drain line, wherein said sealed heat transfer device is configured to transfer heat from the second hydraulic fluid to the first hydraulic fluid such that a temperature of the first hydraulic fluid in said first reservoir is stabilized above a threshold temperature that corresponds to a threshold amount of hydraulic power for operation of said first hydraulically operated component, wherein said sealed heat transfer device comprises: a cold interface coupled to said first hydraulic system; a hot interface coupled to said second hydraulic system; a sealed tube extending longitudinally between said cold interface and said hot interface; and a working fluid disposed within said tube in an amount such that said working fluid exists partially in a liquid phase and partially in a vapor phase within said tube throughout an operating temperature range of said sealed heat transfer device, wherein said sealed heat transfer device further comprises a wicking structure extending longitudinally within at least a portion of said tube, said wicking structure configured to induce liquid to flow therethrough due to capillary action.

7. The aircraft of claim 6 , wherein said sealed heat transfer device extends across a distance of at least three feet such that all components in flow communication with said first hydraulic system are located at least three feet from all components in flow communication with said second hydraulic system.

8. The aircraft of claim 6 , wherein an elevation of said cold interface relative to said hot interface is sufficient to allow vapor heated by said hot interface to rise toward said cold interface due to natural buoyancy.

9. The aircraft of claim 6 , wherein said sealed heat transfer device comprises:
a cold interface coupled to said first hydraulic system;
a hot interface coupled to said second hydraulic system;
a surface interface coupled to a structural surface;
a thermostat;
a first tube extending between said hot interface and said thermostat;
a second tube extending between said thermostat and said cold interface; and
a third tube extending between said thermostat and said surface interface, wherein said thermostat is configured to selectively switch said first tube between flow communication with said second tube, such that said first tube and said second tube cooperate to form a thermosyphon extending between said hot interface and said cold interface, and flow communication with said third tube, such that said first tube and said third tube cooperate to form a thermosyphon extending between said hot interface and said surface interface.

10. The aircraft of claim 9 , wherein said thermostat is further configured to selectively switch said first tube from flow communication with said second tube into flow communication with said third tube when a temperature associated with said first hydraulic system exceeds a predetermined threshold value.

11. The aircraft of claim 6 , further comprising at least one engine, wherein said first hydraulic system is c

Assignees

• Boeing Co

Inventors

• Liao Jianmin
• Larsen Ty Aaby
• Drolen Bruce L

Classifications

• F15B18/00

  Parallel arrangements of independent servomotor systems · CPC title

• F15B21/042 Primary

  Controlling the temperature of the fluid · CPC title

• F28D15/0233

  the conduits having a particular shape, e.g. non-circular cross-section, annular (F28D15/0241, F28D15/0266 take precedence) · CPC title

• F28D15/04 Primary

  with tubes having a capillary structure · CPC title

• B64C13/40

  using fluid pressure · CPC title