Oscillating heat pipe with phase change material

Abstract

An oscillating heat pipe includes an evaporator section, a condenser section, and a plurality of fluid channels extending between the evaporator section and the condenser section. The plurality of fluid channels are at least partially filled with a phase change material in a solid state. A method of transferring thermal energy from a component includes thermally connecting an oscillating heat pipe to the component. The oscillating heat pipe includes an evaporator section in thermal contact with the component, a condenser section, and a plurality of fluid channels extending between the evaporator section and the condenser section. The plurality of fluid channels are at least partially filled with a phase change material in a solid state. A heat load is applied to the component, and the phase change material is melted to absorb thermal energy from the component. The thermal energy is transferred to the condenser section via the fluid channels.

Description

BACKGROUND

[0001] Exemplary embodiments pertain to the art of thermal energy removal from, for example, electronics, and more particularly to oscillating heat pipe configurations for removal of such thermal energy.

[0002] Oscillating heat pipes typically include two main sections, a condenser section and an evaporator section that are interconnected by looping channels. The channels are filled with a two-phase mixture, which acts as the heat transfer medium for the system. Instabilities caused by the intermittent evaporation and condensation of working fluid transfers the vapor from the evaporator to condenser and return liquid from condenser back to the evaporator section.

[0003] Oscillating heat pipes can achieve 10× equivalent thermal conductivity of a solid material through passive phase-change heat spreading. In current configurations, oscillating heat pipes are partially filled with a liquid that changes phase between vapor and liquid during operation of the oscillating heat pipe.BRIEF DESCRIPTION

[0004] In one exemplary embodiment, an oscillating heat pipe includes an evaporator section, a condenser section, and a plurality of fluid channels extending between the evaporator section and the condenser section. The plurality of fluid channels are at least partially filled with a phase change material in a solid state.

[0005] Additionally or alternatively, in this or other embodiments the phase change material in solid state is initially positioned at the evaporator section.

[0006] Additionally or alternatively, in this or other embodiments the plurality of fluid channels contain the phase change material in a range of 30 percent to 70 percent of a total volume of the plurality of fluid channels.

[0007] Additionally or alternatively, in this or other embodiments the phase change material includes one or more molten salts.

[0008] Additionally or alternatively, in this or other embodiments the one or more molten salts includes one or more of NaNO3, KNO3, LiNO3 and LiCl.

[0009] Additionally or alternatively, in this or other embodiments the plurality of fluid channels are arranged into a plurality of closed channel loops.

[0010] Additionally or alternatively, in this or other embodiments the evaporator section is positioned at a first end of the oscillating heat pipe, and the condenser section is positioned at a second end of the oscillating heat pipe opposite the first end.

[0011] Additionally or alternatively, in this or other embodiments the condenser section surrounds the evaporator section.

[0012] In another exemplary embodiment, a thermal energy dissipation system includes a component and an oscillating heat pipe positioned at the component configured to remove thermal energy from the component. The oscillating heat pipe includes an evaporator section, a condenser section, and a plurality of fluid channels extending between the evaporator section and the condenser section. The plurality of fluid channels are at least partially filled with a phase change material in a solid state.

[0013] Additionally or alternatively, in this or other embodiments the phase change material in solid state is initially located at the evaporator section.

[0014] Additionally or alternatively, in this or other embodiments the plurality of fluid channels contain the phase change material in a range of 30 percent to 70 percent of a total volume of the plurality of fluid channels.

[0015] Additionally or alternatively, in this or other embodiments the phase change material includes one or more molten salts.

[0016] Additionally or alternatively, in this or other embodiments the one or more molten salts includes one or more of NaNO3, KNO3, LiNO3 and LiCl.

[0017] Additionally or alternatively, in this or other embodiments the plurality of fluid channels are arranged into a plurality of closed channel loops.

[0018] Additionally or alternatively, in this or other embodiments the evaporator section is located at a first end of the oscillating heat pipe, and the condenser section is located at a second end of the oscillating heat pipe opposite the first end.

[0019] Additionally or alternatively, in this or other embodiments the condenser section surrounds the evaporator section.

[0020] Additionally or alternatively, in this or other embodiments a heat sink is in thermal communication with the condenser section to remove thermal energy from the oscillating heat pipe.

[0021] In yet another exemplary embodiment, a method of transferring thermal energy from a component includes thermally connecting an oscillating heat pipe to the component. The oscillating heat pipe includes an evaporator section in thermal contact with the component, a condenser section, and a plurality of fluid channels extending between the evaporator section and the condenser section. The plurality of fluid channels are at least partially filled with a phase change material in a solid state. A heat load is applied to the component, and the phase change material is melted to absorb thermal energy from the component. The thermal energy is transferred to the condenser section via the plurality of fluid channels.

[0022] Additionally or alternatively, in this or other embodiments the thermal energy is transferred to one or more heat sinks at the condenser section.

[0023] Additionally or alternatively, in this or other embodiments the phase change material in solid state is initially located at the evaporator section.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

[0025] FIG. 1 is a schematic illustration of an embodiment of a thermal energy dissipation system;

[0026] FIG. 2 is a schematic illustration of an exemplary embodiment of an oscillating heat pipe of a thermal energy dissipation system; and

[0027] FIG. 3 is a schematic illustration of another exemplary embodiment of an oscillating heat pipe of a thermal energy dissipation system,DETAILED DESCRIPTION

[0028] A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

[0029] Illustrated in FIG. 1 is an exemplary embodiment of an assembly 10. The assembly 10 includes a component 12, for example, an airfoil or control surface or other component of an aerospace system. A heat exchanger 16 is operably connected to the component 12 to remove thermal energy generated by, for example, a high speed flow 13 across the component 12 and / or the heat exchanger to thereby cool the heat generating component 12. In some embodiments, the heat exchanger 16 is embedded in the component 12, at least partially defining an outer surface 14 of the component 12.

[0030] Referring now to FIG. 2, the heat exchanger is configured as an oscillating heat pipe (OHP) 16. The OHP 16 includes an evaporator section 18 at which thermal energy is absorbed from the component 12, and a condenser section 20 at which the thermal energy is rejected from the OHP 16 to, for example, one or more heat sinks 21. In the embodiment of FIG. 2, the OHP 16 is configured as a linear OHP 16, in which the condenser section 20 is located at a first end 22 of the OHP 16, and the evaporator section 18 is located at a second end 24 of the OHP 16, opposite the first end 22. In other embodiments, such as shown in FIG. 3 for example, the OHP 16 is configured as a radial OHP 16, where in the condenser section 20 surrounds the evaporator section 18.

[0031] A plurality of fluid channels 26 extend substantially radially outwardly from the evaporator section 18 to the condenser section 20. In some embodiments, the plurality of fluid channels 26 are arranged into one or more closed fluid loops 28 that are arranged between the evaporator section 18 and the condenser section 20. The fluid channels 26 are initially at least partially filled with a volume of phase change material (PCM), which is installed into the OHP 16 in liquid phase then solidified. PCM's have a high latent heat of fusion, allowing the PCM to absorb and store a large amount of thermal energy with a relatively low temperature rise.

[0032] In some embodiments, the PCM may include one or more of the molten salts, such as NaNO3, KNO3, NaCl, LiNO3, LiCl, or combinations thereof. In some embodiments, the PCM is concentrated at the evaporator section 18, with the fluid channels 26 being filled with PCM in a ratio of 30 percent to 70 percent of the total volume of the fluid channels 26. In some embodiments, the PCM is the only material installed into the plurality of fluid channels 26, with the partial fill of the fluid channels 26 with the PCM allowing for expansion of the PCM during phase change of the PCM.

[0033] While in some embodiments, each of the closed fluid loops 28 has the PCM installed therein, in other embodiments only select fluid loops 28 are provided with solid PCM, while other fluid loops 28 are provided with another fluid, such as a liquid glycol, refrigerant material or the like, thus adjusting or tuning performance of the OHP 16, depending on the configuration of the component 12.

[0034] In operation, the heating profile of the component 12 is transient. When operation is begun, the component 12 absorbs thermal energy, which is transferred to the evaporator portion 18 of the OHP 16. This causes the PCM located or concentrated at the evaporator portion 18 to melt when the PCM absorbs the thermal energy. Once the PCM is melted, the OHP 16 transfers the thermal energy to the condenser portion 20 via the plurality of fluid channels 26. The thermal energy is removed from the condenser portion 20 via the one or more heat sinks 21.

[0035] The configurations of OHP's 16 with the PCM installed therein are particularly useful to address transient heat loads for a predetermined length of time, with the amount of PCM or type of PCM determined by the duration of the predetermined length of time.

[0036] The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application.

[0037] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and / or groups thereof.

[0038] While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.

Examples

Embodiment Construction

[0028]A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

[0029]Illustrated in FIG. 1 is an exemplary embodiment of an assembly 10. The assembly 10 includes a component 12, for example, an airfoil or control surface or other component of an aerospace system. A heat exchanger 16 is operably connected to the component 12 to remove thermal energy generated by, for example, a high speed flow 13 across the component 12 and / or the heat exchanger to thereby cool the heat generating component 12. In some embodiments, the heat exchanger 16 is embedded in the component 12, at least partially defining an outer surface 14 of the component 12.

[0030]Referring now to FIG. 2, the heat exchanger is configured as an oscillating heat pipe (OHP) 16. The OHP 16 includes an evaporator section 18 at which thermal energy is absorbed from the component 12, and a condenser secti...

BACKGROUND

[0001] Exemplary embodiments pertain to the art of thermal energy removal from, for example, electronics, and more particularly to oscillating heat pipe configurations for removal of such thermal energy.

[0002] Oscillating heat pipes typically include two main sections, a condenser section and an evaporator section that are interconnected by looping channels. The channels are filled with a two-phase mixture, which acts as the heat transfer medium for the system. Instabilities caused by the intermittent evaporation and condensation of working fluid transfers the vapor from the evaporator to condenser and return liquid from condenser back to the evaporator section.

[0003] Oscillating heat pipes can achieve 10× equivalent thermal conductivity of a solid material through passive phase-change heat spreading. In current configurations, oscillating heat pipes are partially filled with a liquid that changes phase between vapor and liquid during operation of the oscillating heat pipe.BRIEF DESCRIPTION

[0004] In one exemplary embodiment, an oscillating heat pipe includes an evaporator section, a condenser section, and a plurality of fluid channels extending between the evaporator section and the condenser section. The plurality of fluid channels are at least partially filled with a phase change material in a solid state.

[0005] Additionally or alternatively, in this or other embodiments the phase change material in solid state is initially positioned at the evaporator section.

[0006] Additionally or alternatively, in this or other embodiments the plurality of fluid channels contain the phase change material in a range of 30 percent to 70 percent of a total volume of the plurality of fluid channels.

[0007] Additionally or alternatively, in this or other embodiments the phase change material includes one or more molten salts.

[0008] Additionally or alternatively, in this or other embodiments the one or more molten salts includes one or more of NaNO3, KNO3, LiNO3 and LiCl.

[0009] Additionally or alternatively, in this or other embodiments the plurality of fluid channels are arranged into a plurality of closed channel loops.

[0010] Additionally or alternatively, in this or other embodiments the evaporator section is positioned at a first end of the oscillating heat pipe, and the condenser section is positioned at a second end of the oscillating heat pipe opposite the first end.

[0011] Additionally or alternatively, in this or other embodiments the condenser section surrounds the evaporator section.

[0012] In another exemplary embodiment, a thermal energy dissipation system includes a component and an oscillating heat pipe positioned at the component configured to remove thermal energy from the component. The oscillating heat pipe includes an evaporator section, a condenser section, and a plurality of fluid channels extending between the evaporator section and the condenser section. The plurality of fluid channels are at least partially filled with a phase change material in a solid state.

[0013] Additionally or alternatively, in this or other embodiments the phase change material in solid state is initially located at the evaporator section.

[0014] Additionally or alternatively, in this or other embodiments the plurality of fluid channels contain the phase change material in a range of 30 percent to 70 percent of a total volume of the plurality of fluid channels.

[0015] Additionally or alternatively, in this or other embodiments the phase change material includes one or more molten salts.

[0016] Additionally or alternatively, in this or other embodiments the one or more molten salts includes one or more of NaNO3, KNO3, LiNO3 and LiCl.

[0017] Additionally or alternatively, in this or other embodiments the plurality of fluid channels are arranged into a plurality of closed channel loops.

[0018] Additionally or alternatively, in this or other embodiments the evaporator section is located at a first end of the oscillating heat pipe, and the condenser section is located at a second end of the oscillating heat pipe opposite the first end.

[0019] Additionally or alternatively, in this or other embodiments the condenser section surrounds the evaporator section.

[0020] Additionally or alternatively, in this or other embodiments a heat sink is in thermal communication with the condenser section to remove thermal energy from the oscillating heat pipe.

[0021] In yet another exemplary embodiment, a method of transferring thermal energy from a component includes thermally connecting an oscillating heat pipe to the component. The oscillating heat pipe includes an evaporator section in thermal contact with the component, a condenser section, and a plurality of fluid channels extending between the evaporator section and the condenser section. The plurality of fluid channels are at least partially filled with a phase change material in a solid state. A heat load is applied to the component, and the phase change material is melted to absorb thermal energy from the component. The thermal energy is transferred to the condenser section via the plurality of fluid channels.

[0022] Additionally or alternatively, in this or other embodiments the thermal energy is transferred to one or more heat sinks at the condenser section.

[0023] Additionally or alternatively, in this or other embodiments the phase change material in solid state is initially located at the evaporator section.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

[0025] FIG. 1 is a schematic illustration of an embodiment of a thermal energy dissipation system;

[0026] FIG. 2 is a schematic illustration of an exemplary embodiment of an oscillating heat pipe of a thermal energy dissipation system; and

[0027] FIG. 3 is a schematic illustration of another exemplary embodiment of an oscillating heat pipe of a thermal energy dissipation system,DETAILED DESCRIPTION

[0028] A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

[0029] Illustrated in FIG. 1 is an exemplary embodiment of an assembly 10. The assembly 10 includes a component 12, for example, an airfoil or control surface or other component of an aerospace system. A heat exchanger 16 is operably connected to the component 12 to remove thermal energy generated by, for example, a high speed flow 13 across the component 12 and / or the heat exchanger to thereby cool the heat generating component 12. In some embodiments, the heat exchanger 16 is embedded in the component 12, at least partially defining an outer surface 14 of the component 12.

[0030] Referring now to FIG. 2, the heat exchanger is configured as an oscillating heat pipe (OHP) 16. The OHP 16 includes an evaporator section 18 at which thermal energy is absorbed from the component 12, and a condenser section 20 at which the thermal energy is rejected from the OHP 16 to, for example, one or more heat sinks 21. In the embodiment of FIG. 2, the OHP 16 is configured as a linear OHP 16, in which the condenser section 20 is located at a first end 22 of the OHP 16, and the evaporator section 18 is located at a second end 24 of the OHP 16, opposite the first end 22. In other embodiments, such as shown in FIG. 3 for example, the OHP 16 is configured as a radial OHP 16, where in the condenser section 20 surrounds the evaporator section 18.

[0031] A plurality of fluid channels 26 extend substantially radially outwardly from the evaporator section 18 to the condenser section 20. In some embodiments, the plurality of fluid channels 26 are arranged into one or more closed fluid loops 28 that are arranged between the evaporator section 18 and the condenser section 20. The fluid channels 26 are initially at least partially filled with a volume of phase change material (PCM), which is installed into the OHP 16 in liquid phase then solidified. PCM's have a high latent heat of fusion, allowing the PCM to absorb and store a large amount of thermal energy with a relatively low temperature rise.

[0032] In some embodiments, the PCM may include one or more of the molten salts, such as NaNO3, KNO3, NaCl, LiNO3, LiCl, or combinations thereof. In some embodiments, the PCM is concentrated at the evaporator section 18, with the fluid channels 26 being filled with PCM in a ratio of 30 percent to 70 percent of the total volume of the fluid channels 26. In some embodiments, the PCM is the only material installed into the plurality of fluid channels 26, with the partial fill of the fluid channels 26 with the PCM allowing for expansion of the PCM during phase change of the PCM.

[0033] While in some embodiments, each of the closed fluid loops 28 has the PCM installed therein, in other embodiments only select fluid loops 28 are provided with solid PCM, while other fluid loops 28 are provided with another fluid, such as a liquid glycol, refrigerant material or the like, thus adjusting or tuning performance of the OHP 16, depending on the configuration of the component 12.

[0034] In operation, the heating profile of the component 12 is transient. When operation is begun, the component 12 absorbs thermal energy, which is transferred to the evaporator portion 18 of the OHP 16. This causes the PCM located or concentrated at the evaporator portion 18 to melt when the PCM absorbs the thermal energy. Once the PCM is melted, the OHP 16 transfers the thermal energy to the condenser portion 20 via the plurality of fluid channels 26. The thermal energy is removed from the condenser portion 20 via the one or more heat sinks 21.

[0035] The configurations of OHP's 16 with the PCM installed therein are particularly useful to address transient heat loads for a predetermined length of time, with the amount of PCM or type of PCM determined by the duration of the predetermined length of time.

[0036] The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application.

[0037] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and / or groups thereof.

[0038] While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.

Examples

Embodiment Construction

[0028]A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

[0029]Illustrated in FIG. 1 is an exemplary embodiment of an assembly 10. The assembly 10 includes a component 12, for example, an airfoil or control surface or other component of an aerospace system. A heat exchanger 16 is operably connected to the component 12 to remove thermal energy generated by, for example, a high speed flow 13 across the component 12 and / or the heat exchanger to thereby cool the heat generating component 12. In some embodiments, the heat exchanger 16 is embedded in the component 12, at least partially defining an outer surface 14 of the component 12.

[0030]Referring now to FIG. 2, the heat exchanger is configured as an oscillating heat pipe (OHP) 16. The OHP 16 includes an evaporator section 18 at which thermal energy is absorbed from the component 12, and a condenser secti...

Claims

1. An oscillating heat pipe, comprising:an evaporator section;a condenser section; anda plurality of fluid channels extending between the evaporator section and the condenser section, the plurality of fluid channels at least partially filled with a phase change material in a solid state.

2. The oscillating heat pipe of claim 1, wherein the phase change material in solid state is initially disposed at the evaporator section.

3. The oscillating heat pipe of claim 1, wherein the plurality of fluid channels contain the phase change material in a range of 30 percent to 70 percent of a total volume of the plurality of fluid channels.

4. The oscillating heat pipe of claim 1, wherein the phase change material includes one or more molten salts.

5. The oscillating heat pipe of claim 4, wherein the one or more molten salts includes one or more of NaNO3, KNO3, LiNO3 and LiCl.

6. The oscillating heat pipe of claim 1, wherein the plurality of fluid channels are arranged into a plurality of closed channel loops.

7. The oscillating heat pipe of claim 1, wherein the evaporator section is disposed at a first end of the oscillating heat pipe, and the condenser section is disposed at a second end of the oscillating heat pipe opposite the first end.

8. The oscillating heat pipe of claim 1, wherein the condenser section surrounds the evaporator section.

9. A thermal energy dissipation system, comprising:a component; andan oscillating heat pipe disposed at the component configured to remove thermal energy from the component, the oscillating heat pipe including:an evaporator section;a condenser section; anda plurality of fluid channels extending between the evaporator section and the condenser section, the plurality of fluid channels at least partially filled with a phase change material in a solid state.

10. The thermal energy dissipation system of claim 9, wherein the phase change material in solid state is initially disposed at the evaporator section.

11. The thermal energy dissipation system of claim 9, wherein the plurality of fluid channels contain the phase change material in a range of 30 percent to 70 percent of a total volume of the plurality of fluid channels.

12. The thermal energy dissipation system of claim 9, wherein the phase change material includes one or more molten salts.

13. The thermal energy dissipation system of claim 12, wherein the one or more molten salts includes one or more of NaNO3, KNO3, LiNO3 and LiCl.

14. The thermal energy dissipation system of claim 9, wherein the plurality of fluid channels are arranged into a plurality of closed channel loops.

15. The thermal energy dissipation system of claim 9, wherein the evaporator section is disposed at a first end of the oscillating heat pipe, and the condenser section is disposed at a second end of the oscillating heat pipe opposite the first end.

16. The thermal energy dissipation system of claim 9, wherein the condenser section surrounds the evaporator section.

17. The thermal energy dissipation system of claim 9, further comprising a heat sink in thermal communication with the condenser section to remove thermal energy from the oscillating heat pipe.

18. A method of transferring thermal energy from a component, comprising:thermally connecting an oscillating heat pipe to the component, the oscillating heat pipe including:an evaporator section in thermal contact with the component;a condenser section; anda plurality of fluid channels extending between the evaporator section and the condenser section, the plurality of fluid channels at least partially filled with a phase change material in a solid state;applying a heat load to the component;melting the phase change material to absorb thermal energy from the component; andtransferring the thermal energy to the condenser section via the plurality of fluid channels.

19. The method of claim 18, further comprising transferring the thermal energy to one or more heat sinks at the condenser section.

20. The method of claim 18, wherein the phase change material in solid state is initially disposed at the evaporator section.

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