Leaf-shaped bionic pulsating heat pipe loop cooling system

Abstract

The invention discloses a leaf-shaped bionic pulsating heat pipe loop cooling system which comprises a first-stage inner circulation loop and a second-stage outer circulation loop. The first-stage internal circulation loop comprises an evaporation end and a condensation end; the evaporation end comprises an internal circulation evaporator in direct contact with the electronic element; the condensation end comprises an internal circulation condenser, a capillary bend and fins, the capillary bend is partially embedded in the internal circulation condenser, and the inlet end and the outlet end of the internal circulation evaporator are connected with the capillary bend to form an internal circulation heat exchange loop; the fins are welded to the outer wall face of the inner circulation condenser and connected with the second-stage outer circulation loop to form a heat exchange channel. The second-stage outer circulation loop comprises a cooling tower and a mechanical refrigeration module; the mechanical refrigeration module comprises an expansion valve, an evaporator, a condenser and a compressor which are sequentially connected to form a closed loop. According to the invention, shunting dredging and dynamic temperature equalization of a high heat flow area can be realized, stability and safety of electronic junction temperature are ensured, and system energy consumption can be reduced while efficient heat exchange can be provided for server-level equipment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of heat dissipation of high-power electronic equipment, and particularly relates to a leaf-shaped bionic pulsating heat pipe loop cooling system. BACKGROUND

[0002] With the continuous improvement of the integration of high-power electronic components and the sharp increase of heat flux density under operating conditions, developing a heat dissipation device capable of coping with high heat flux density environment has become a key technical challenge.

[0003] The annual power consumption of data centers increases at a rate of 15%-20%, and the energy consumption of the cooling system accounts for more than 40% of the total energy consumption, becoming the core of energy efficiency optimization. The high-density integrated chips in servers lead to heat flux density exceeding 200W / cm², and the traditional heat dissipation scheme is prone to cause local hot spot effect due to insufficient heat flux bearing, increasing the risk of thermal failure of semiconductor devices and the data distortion rate of storage media. The application simulates the design of a blade to achieve high heat flow area shunt and dynamic temperature equalization, ensuring that the electronic junction temperature is stable and within the safety threshold (such as 65℃±2℃), and relying on the pump-free driving and cold source hierarchical utilization mechanism to reduce the cooling energy consumption by more than 40% and optimize the annual average PUE value to below 1.2. This technical breakthrough directly solves the contradiction between high heat flow dissipation and energy efficiency in data centers, providing key technical support for the operation of high-reliability and low-downtime equipment. SUMMARY

[0004] The purpose of the application is to provide a leaf-shaped bionic pulsating heat pipe loop cooling system to achieve high heat flow area shunt and dynamic temperature equalization, ensure electronic junction temperature stability and safety, and provide efficient heat exchange for server-level equipment while reducing system energy consumption.

[0005] To achieve the above purpose, the application provides a leaf-shaped bionic pulsating heat pipe loop cooling system, which comprises a primary internal circulation loop and a secondary external circulation loop. The primary internal circulation loop is a leaf-shaped bionic pulsating heat pipe, which comprises an evaporation end and a condensation end. The evaporation end comprises an internal circulation evaporator in direct contact with electronic components, and the internal circulation evaporator comprises multiple layers of vertically stacked U-shaped capillary heat exchange pipes. The condensation end comprises an internal circulation condenser, a capillary bend, and fins. The capillary bend is partially embedded in the internal circulation condenser, and the capillary bend has a heat exchange working medium flowing inside. The inlet end and outlet end of each layer of the internal circulation evaporator are connected to the two ends of the capillary bend to form an internal circulation heat exchange loop. The fins are vertically welded to the outer wall surface of the internal circulation condenser and are connected to the secondary external circulation loop to form a heat exchange channel connected to the secondary external circulation loop. The secondary external circulation loop comprises a cooling tower and a mechanical refrigeration module. The mechanical refrigeration module comprises an expansion valve, an evaporator, a condenser and a compressor connected in sequence to form a closed loop circuit, wherein the evaporator is connected with the heat exchange channel loop, and the condenser, the heat exchange channel and the cooling tower are connected in sequence to form a loop.

[0006] As a further scheme of the present application: a micro-channel is formed between adjacent U-shaped capillary heat exchange pipes, and a semicircular groove wick is arranged in the micro-channel.

[0007] As a further scheme of the present application: the fins are provided with multiple groups, and are an array of aluminum needle fins.

[0008] As a further scheme of the present application: the heat exchange working medium in the primary internal circulation loop is one of deionized water, a ketone working medium, an alcohol working medium, a micro-nano capsule phase change material emulsion, a nanofluid and a magnetic fluid, the working medium filling rate is 30%-70%, and the filling pressure is 0.8-1.2 times of the standard atmospheric pressure.

[0009] As a further scheme of the present application: the capillary bend is a bionic blade topological structure, which is composed of multiple fractal blade-shaped pipelines, and each loop has a bifurcation angle of 15°-45° and a bifurcation level of 1.

[0010] As a further scheme of the present application: the diameter of the U-shaped capillary heat exchange pipe is 2-3 mm.

[0011] Compared with the prior art, the present application has the following beneficial effects: The present application adopts a blade-shaped bionic pulsating heat pipe system to construct a primary internal circulation loop, adopts a cooling tower, a mechanical refrigeration module and a heat exchange channel to construct a secondary external circulation loop, wherein the blade-shaped bionic pulsating heat pipe system of the primary internal circulation loop adopts a multi-layer U-shaped capillary heat exchange pipe evaporator at the evaporation end, the heat dissipation of the heat generating element is realized through the evaporation heat absorption of the liquid heat exchange working medium, the working medium in a gas-liquid two-phase state enters the condensation end through the capillary heat exchange pipe, the condensation end is a copper condenser with multiple capillary bends that are not directly connected, the circulating condenser forms a heat exchange channel in communication with the secondary external circulation loop through multiple fins, the heat exchange channel is connected with the secondary external circulation loop, and the internal circulation and the external circulation double-loop jointly act to realize the high-efficiency heat dissipation of the server level. The blade-shaped bionic pulsating heat pipe system has superior anti-gravity performance, high freedom and good safety, is suitable for server-level heat dissipation, can directly take heat from high-heat-density elements such as CPUs, improves the cooling system performance, reduces the leakage risk of the liquid cooling system, and has high safety. The present application does not need an additional power system, can fully utilize the outdoor cold source while ensuring the outlet water temperature of the cooling water, has strong energy-saving performance, can provide high-efficiency heat exchange for the server-level equipment, and ensures that the equipment normally works in a suitable temperature range. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a schematic diagram of a leaf-shaped biomimetic pulsating heat pipe loop cooling system of the present application; Figure 2 is a heating mode working principle diagram of a primary internal circulation loop of the present application; Figure 3 is an internal working medium outlet end flow schematic diagram of an internal circulation evaporator of the present application; Figure 4 is an internal working medium inlet end flow schematic diagram of an internal circulation evaporator of the present application.

[0013] In the figure: 1, evaporation end, 2, condensation end, 3, capillary heat exchange pipe, 4, heat exchange channel, 5, cooling tower, 6, mechanical refrigeration module; 101, internal circulation evaporator, 102, wick; 201, internal circulation condenser, 202, capillary bend, 203, fin; 601, expansion valve, 602, evaporator, 603, condenser, 604, compressor. DETAILED DESCRIPTION

[0014] The present application will be further described below in conjunction with the accompanying drawings.

[0015] As shown in Figure 1 and Figure 2 , a leaf-shaped biomimetic pulsating heat pipe loop cooling system includes a primary internal circulation loop and a secondary external circulation loop; The primary internal circulation loop is a leaf-shaped biomimetic pulsating heat pipe, including an evaporation end 1 and a condensation end 2; The evaporation end 1 includes an internal circulation evaporator 101 in direct contact with electronic components, with a curved surface heat conduction substrate on the side, directly coupled to the heat-emitting surface of the electronic components through a thermal interface material, and the internal circulation evaporator 101 includes multiple layers of vertically stacked U-shaped capillary heat exchange pipes 3, preferably with a diameter of 2-3 mm; the internal circulation evaporator 101 can meet the high heat dissipation requirements of small electronic components, and the multiple circuits make the evaporation end 1 have more significant heat absorption and heat exchange effects; Further, micro-channels are formed between adjacent U-shaped capillary heat exchange pipes 3, and there are semi-circular arc-shaped groove wicks 102 in the micro-channels.

[0016] In order to improve the anti-gravity performance of the leaf-shaped biomimetic pulsating heat pipe, the leaf-shaped biomimetic pulsating heat pipe can adjust the number of U-shaped capillary heat exchange pipes 3 in the heat-emitting section according to the heat-emitting power of the electronic components.

[0017] Preferably, the number of internal circulation evaporators 101 matches the number of electronic components in the server.

[0018] The condensing end 2 comprises an inner circulation condenser 201, a capillary bend 202 and a fin 203. Further, the capillary bend 202 is a bionic blade topology structure composed of a plurality of fractal blade-shaped pipelines, each loop has a bifurcation angle of 15-45° and a bifurcation level of 1, and the capillary bend 202 is partially embedded in the inner circulation condenser 201, as shown in Figs. 2 and 3. Figure 3 、 Figure 4 The heat exchange working medium flows in the capillary bend 202. Further, the heat exchange working medium in the first-level inner circulation loop is one of deionized water, a ketone working medium, an alcohol working medium, a micro-nano capsule phase change material emulsion, a nanofluid and a magnetic fluid, and the working medium has a liquid filling rate of 30-70% and a liquid filling pressure of 0.8-1.2 times the standard atmospheric pressure.

[0019] The inlet end and the outlet end of each layer of the inner circulation evaporator 101 are connected with the two ends of the capillary bend 202 to form an inner circulation heat exchange loop. The inlet end and the outlet end of the inner circulation evaporator 101 are located on the two sides of the server internal electronic components, and the contact area with the components is increased, so that the heat absorption effect is better. The fin 203 is vertically welded to the outer wall surface of the inner circulation condenser 201 and is connected with the second-level outer circulation loop to form a heat exchange channel 4 connected with the second-level outer circulation loop. Further, the fin 203 is provided with a plurality of groups and is an aluminum needle fin array.

[0020] The second-level outer circulation loop comprises a cooling tower 5 and a mechanical refrigeration module 6. The mechanical refrigeration module 6 comprises an expansion valve 601, an evaporator 602, a condenser 603 and a compressor 604 connected in sequence to form a closed loop. The evaporator 602 is connected with the heat exchange channel 4, and the condenser 603, the heat exchange channel 4 and the cooling tower 5 are connected in sequence to form a loop.

[0021] Specifically, the outlet of the compressor 604 is connected with the primary side inlet of the condenser 603, the primary side outlet of the condenser 603 is connected with the inlet end of the expansion valve 601, the outlet end of the expansion valve 601 is connected with the primary side inlet of the evaporator 602, and the primary side outlet of the evaporator 602 is connected with the inlet of the compressor 604 to form a closed loop. The secondary side outlet of the evaporator 602 is connected with the secondary side inlet of the heat exchange channel 4, and the secondary side outlet of the heat exchange channel 4 is connected with the secondary side inlet of the evaporator 602.

[0022] The secondary side inlet and the secondary side outlet of the condenser 603 are connected with the outlet of the cooling tower 5 and the primary side inlet of the heat exchange channel 4, respectively, and the primary side outlet of the heat exchange channel 4 is connected with the inlet of the cooling tower 5.

[0023] In the embodiment, the evaporation end 1 of the loop leaf-like pulsating heat pipe in the primary inner circulation loop dissipates heat from the heat generating element by the evaporation heat absorption of the internal liquid heat exchange medium, and the heat exchange medium in gas-liquid two-phase state exchanges heat between the capillary bend 202 and the condensation end 2; The condensation end 2 is connected with the secondary outer circulation loop through the fins 203 arranged in the inner circulation condenser 201, forming a heat exchange channel 4 in communication with the secondary outer circulation loop. The cooling tower 5 in the secondary outer circulation loop uses external air for heat exchange to prepare cooling water, and the prepared cooling water enters the heat exchange channel 4 through a pipeline to flush the fins 203, thereby cooling the heat exchange medium in the capillary bend 202, and the cooled heat exchange medium achieves the purpose of dissipating heat from the heat generating element through the primary inner circulation loop. When the cooling water prepared by the cooling tower 5 cannot meet the heat dissipation requirement in the high temperature and high humidity condition in summer, the mechanical refrigeration module 6 is started, the liquid heat exchange medium is evaporated in the evaporator 602 to become gas, is compressed by the compressor 604 to become high temperature and high pressure gas, enters the condenser 603 to become high pressure liquid, is changed into low temperature and low pressure liquid by the expansion valve 601, and is then sent into the evaporator 602. The low temperature and low pressure liquid from the outlet of the evaporator 602 enters the heat exchange channel 4 through a pipeline to flush the fins 203, thereby cooling the medium in the capillary bend 202, and the cooled medium achieves the purpose of dissipating heat from the heat generating element through the primary inner circulation loop.

Claims

1. A leaf-like biomimetic pulsating heat pipe loop cooling system, characterized in that, The first inner circulation loop and the second outer circulation loop are included. The first inner circulation loop is a leaf-shaped pulsating heat pipe, including an evaporation end (1) and a condensation end (2). The evaporation end (1) includes an inner circulation evaporator (101) in direct contact with the electronic components, and the inner circulation evaporator (101) includes multiple layers of vertically stacked U-shaped capillary heat exchange pipes (3). The condensation end (2) includes an inner circulation condenser (201), a capillary bend (202) and a fin (203), the capillary bend (202) is partially embedded in the inner circulation condenser (201), the capillary bend (202) has heat exchange working fluid flowing inside, the inlet end and the outlet end of each layer of the inner circulation evaporator (101) are connected with the two ends of the capillary bend (202) to form an inner circulation heat exchange loop; the fin (203) is vertically welded to the outer wall surface of the inner circulation condenser (201) and is connected with the second outer circulation loop to form a heat exchange channel (4) connected with the second outer circulation loop. The second outer circulation loop includes a cooling tower (5) and a mechanical refrigeration module (6). The mechanical refrigeration module (6) includes an expansion valve (601), an evaporator (602), a condenser (603) and a compressor (604) connected in sequence to form a closed loop, wherein the evaporator (602) is connected with the heat exchange channel (4), and the condenser (603), the heat exchange channel (4) and the cooling tower (5) are connected in sequence to form a loop.

2. A lobed biomimetic pulsating heat pipe loop cooling system according to claim 1, wherein, Microchannels are formed between adjacent U-shaped capillary heat exchange pipes (3), and semicircular groove wicks (102) are arranged in the microchannels.

3. The leaf-like biomimetic pulsating heat pipe loop cooling system of claim 1, wherein, The fin (203) is provided with multiple groups and is an aluminum needle fin array.

4. The lobed biomimetic pulsating heat pipe loop cooling system of claim 1, wherein, The heat exchange working fluid in the first inner circulation loop is one of deionized water, a ketone working fluid, an alcohol working fluid, a micro-nano capsule phase change material emulsion, a nanofluid and a magnetic fluid, the working fluid has a liquid filling rate of 30%-70% and a liquid filling pressure of 0.8-1.2 times the standard atmospheric pressure.

5. The lobed biomimetic pulsating heat pipe loop cooling system of claim 1, wherein, The capillary bend (202) has a bionic leaf topological structure and is composed of multiple fractal leaf-shaped pipelines, each loop has a bifurcation angle of 15°-45° and a bifurcation level of 1.

6. The lobed biomimetic pulsating heat pipe loop cooling system of claim 1, wherein, The diameter of the U-shaped capillary heat exchange pipe (3) is 2-3 mm.

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