Double pipe multistage pulsating heat pipe

Abstract

The application discloses a multi-stage double-pipe pulsating heat pipe, which comprises a heat source area, a high-temperature pulsating heat pipe, a low-temperature pulsating heat pipe and a heat sink area, wherein the heat source area is connected with an evaporation section of the high-temperature pulsating heat pipe, a condensation section of the high-temperature pulsating heat pipe is connected with an evaporation section of the low-temperature pulsating heat pipe, and a condensation section of the low-temperature pulsating heat pipe is connected with the heat sink area; and the evaporation section and the condensation section between different stages of the pulsating heat pipes are connected through a double-pipe structure. The application can be applied to occasions with a large temperature difference between a cold source and a heat source, ensures that each stage of the pulsating heat pipes works in a high-performance temperature range, and reduces the heat transfer thermal resistance between different stages of the pulsating heat pipes through the double-pipe structure connection.

Description

Technical Field

[0001] This invention relates to the field of thermal management technology for electronic devices. Background Technology

[0002] Pulsating heat pipes rely on the pressure difference generated by the phase change of the internal working fluid to drive the unidirectional flow of the working fluid inside the pipe. Heat is transferred from the heat source to the heat sink through sensible and latent heat, exhibiting significant advantages such as high heat transfer capacity and reliability. They are widely used in fields such as thermal control of electronic equipment and energy utilization. However, due to the limitations of the pulsating heat pipe's working principle, a single pulsating heat pipe can generally only operate within a narrow temperature range. Within a wider temperature range, pulsating heat pipes suffer from poor start-up characteristics and low heat transfer capacity.

[0003] Chinese invention patent CN107947638A discloses a solar thermoelectric power generation device based on dual-pulsating heat pipes, comprising a solar collector, a phase change heat storage cavity, a high-temperature pulsating heat pipe, a low-temperature pulsating heat pipe, and a thermoelectric generator. The phase change heat storage cavity is filled with phase change heat storage material. The evaporation end of the high-temperature pulsating heat pipe extends into the phase change heat storage material, and its condensation end is embedded in the channel of the high-temperature heat-conducting plate. The evaporation end of the low-temperature pulsating heat pipe is embedded in the channel of the low-temperature heat-conducting plate, and its condensation end is placed in the external environment. The thermoelectric generator is placed between the low-temperature heat-conducting plate and the high-temperature heat-conducting plate. This invention uses dual-pulsating heat pipes, which can ensure that there is always a high temperature difference on both sides of the thermoelectric generator, resulting in fast thermal response and high heat transfer efficiency. By using phase change heat storage material to store the heat energy absorbed by the solar collector, it avoids problems such as uneven temperature distribution and small contact area during heat export. However, it also has the following drawbacks: the condensation section of the high-temperature pulsating heat pipe and the evaporation section of the low-temperature pulsating heat pipe are embedded with heat-conducting plates, and heat is transferred through the heat-conducting plates. This connection method results in high thermal resistance of the pulsating heat pipe and large size and weight. Summary of the Invention

[0004] This invention provides a sleeve-type multi-stage pulsating heat pipe that can be applied to situations with large temperature differences between cold and heat sources. It ensures that each stage of the pulsating heat pipe operates within a high-performance temperature range. Different stages of the pulsating heat pipe are connected by a sleeve structure to reduce the thermal resistance between them.

[0005] The proposed invention provides a shell-and-tube multi-stage pulsating heat pipe, comprising a heat source region, a high-temperature pulsating heat pipe, a low-temperature pulsating heat pipe, and a heat sink region. Its structure is such that the heat source region is connected to the evaporation section of the high-temperature pulsating heat pipe, the condensation section of the high-temperature pulsating heat pipe is connected to the evaporation section of the low-temperature pulsating heat pipe, and the condensation section of the low-temperature pulsating heat pipe is connected to the heat sink region. Its characteristic feature is that the evaporation sections and condensation sections of different stages of pulsating heat pipes are connected by a shell-and-tube structure.

[0006] Preferably, in the coaxial multi-stage pulsating heat pipe, the high-temperature pulsating heat pipe has a circular tube structure, filled with a high-temperature working fluid, and the inner diameter d1 of the pipe meets the following requirements. In the formula, g is the acceleration due to gravity, σ is the surface tension of the high-temperature working fluid, and ρ l ρ is the liquid density of the working fluid at high temperature. v This is the gaseous density of the working fluid at high temperatures.

[0007] Preferably, the wall thickness b of the inner layer of the sleeve structure is 0.2 to 0.6 mm.

[0008] Preferably, the outer layer of the sleeve-type multi-stage pulsating heat pipe is filled with a low-temperature working fluid, and the inner diameter d2 of the outer layer satisfies... In the formula, g is the acceleration due to gravity, σ′ is the surface tension of the high-temperature working fluid, ρ′1 is the liquid density of the high-temperature working fluid, and ρ′ v This is the gaseous density of the working fluid at high temperatures.

[0009] Compared with the prior art, the present invention has the following advantages:

[0010] This invention introduces a sheath structure to connect different stages of a multi-stage pulsating heat pipe. By optimizing the dimensions of the sheath structure, the stability of the pulsating heat pipe operation is improved, the thermal resistance between different stages of the pulsating heat pipe is reduced, and the overall performance of the pulsating heat pipe is enhanced. Simultaneously, using a sheath structure instead of a metal heat conduction structure reduces the volume and weight of the connecting components between different stages of the pulsating heat pipe, facilitating the miniaturization and weight reduction of the pulsating heat pipe. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the device of the present invention.

[0012] Figure 2 This is a schematic diagram of the sleeve structure of the device of the present invention.

[0013] Figure 3 This is a schematic diagram of the sleeve structure dimensions of the device of the present invention.

[0014] The diagram shows heat source area 1, high-temperature pulsating heat pipe 2, low-temperature pulsating heat pipe 3, heat sink area 4, high-temperature pulsating heat pipe shell 11, and low-temperature pulsating heat pipe shell 21. Detailed Implementation

[0015] The invention will now be further described with reference to the accompanying drawings:

[0016] Figure 1 A schematic diagram of the device of the present invention is provided, including a heat source region 1, a high-temperature pulsating heat pipe 2, a low-temperature pulsating heat pipe 3, and a heat sink region 4. The heat source region 1 is connected to the evaporation section of the high-temperature pulsating heat pipe 2, the condensation section of the high-temperature pulsating heat pipe 2 is connected to the evaporation section of the low-temperature pulsating heat pipe 3, and the condensation section of the low-temperature pulsating heat pipe 3 is connected to the heat sink region. The heat source region 1 and the cold source region 2 can be thermally conductive metals or can be in direct contact with the working fluid requiring heat exchange.

[0017] Figure 2 A schematic diagram of the sleeve structure of the device of the present invention is provided. The high-temperature pulsating heat pipe 2 and the low-temperature pulsating heat pipe 3 adopt a multi-loop structure, possessing independent and non-interconnected cavity structures. A portion of the condensation section loop of the high-temperature pulsating heat pipe 2 and a portion of the evaporation section of the low-temperature pulsating heat pipe 3 are connected by a sleeve structure. The working fluid inside the high-temperature pulsating heat pipe undergoes efficient indirect heat exchange with the working fluid inside the low-temperature pulsating heat pipe through the shell of the high-temperature pulsating heat pipe's condensation section. The sleeve structure may or may not contain elbows. The flow cross-section of the high-temperature pulsating heat pipe remains constant along the direction of the working fluid circulation, while the low-temperature pulsating heat pipe, after flowing through the sleeve structure, narrows its diameter via a tapered tube, maintaining a flow cross-section similar to that inside the sleeve.

[0018] Figure 3 A schematic diagram of the sleeve structure of the device of the present invention is provided. In the sleeve structure, the inner diameter of the high-temperature pulsating heat pipe shell 11 is d1, the wall thickness is b, and the inner diameter of the low-temperature pulsating heat pipe shell 21 is d2.

[0019] In one embodiment, heat source zone 1 is a cold plate equipped with high-power electronic devices, with an operating temperature range of 50°C to 120°C; heat sink zone 4 is the upper atmosphere, with a temperature range of -40°C to 10°C; the high-temperature pulsating heat pipe 2 uses deionized water as the working fluid, the low-temperature pulsating heat pipe 3 uses R134a as the working fluid, the inner diameter of the high-temperature pulsating heat pipe is d1, which is 3mm, the wall thickness of the high-temperature pulsating heat pipe shell is b, which is 0.4mm, and the inner diameter of the low-temperature pulsating heat pipe is d2, which is 5.6mm.

Claims

1. A sleeve-type multi-stage pulsating heat pipe, characterized in that: It includes a heat source area, a high-temperature pulsating heat pipe, a low-temperature pulsating heat pipe, and a heat sink area. The heat source area is connected to the evaporation section of the high-temperature pulsating heat pipe, the condensation section of the high-temperature pulsating heat pipe is connected to the evaporation section of the low-temperature pulsating heat pipe, and the condensation section of the low-temperature pulsating heat pipe is connected to the heat sink area. The evaporation sections and condensation sections of different levels of pulsating heat pipes are connected by a sleeve structure.

2. The sleeve-type multi-stage pulsating heat pipe according to claim 1, characterized in that: The high-temperature pulsating heat pipe has a circular tube structure and is filled with a high-temperature working fluid. The inner diameter d1 of the pipe meets the following requirements. In the formula g Let σ be the acceleration due to gravity, σ be the surface tension of the high-temperature working fluid, ρ1 be the liquid density of the high-temperature working fluid, and ρ be the surface tension of the high-temperature working fluid. v This is the gaseous density of the working fluid at high temperatures.

3. The sleeve-type multi-stage pulsating heat pipe according to claim 2, characterized in that: The wall thickness of the inner layer of the sleeve structure b The thickness ranges from 0.2 to 0.6 mm.

4. The sleeve-type multi-stage pulsating heat pipe according to claim 3, characterized in that, The outer layer of the sleeve structure is filled with a cryogenic working fluid, and the inner diameter d2 of the outer layer satisfies: ； In the formula g It is the acceleration due to gravity. For the surface tension of the high-temperature working fluid, The density of the working fluid in its liquid state at high temperatures. This is the gaseous density of the working fluid at high temperatures.

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