A pump-driven two-phase flow system microchannel evaporator thermal test device and method

Abstract

A thermal testing apparatus and method for a pump-driven two-phase flow system microchannel evaporator includes a main circuit, a bypass circuit, and a safety circuit. The main circuit consists of a liquid storage tank, a first heat exchanger, a coarse filter, a gear pump, a mass flow meter, a preheating sleeve, a needle valve, a first ball valve, a fine main circuit filter, an evaporator, a second ball valve, and a second heat exchanger, connected sequentially. The outlet of the needle valve is connected to the inlet of a third ball valve, and the outlet of the third ball valve is connected to the inlet of the second heat exchanger. The bypass circuit consists of the liquid storage tank, the first heat exchanger, the coarse filter, the gear pump, the mass flow meter, the preheating sleeve, the needle valve, the third ball valve, and the second heat exchanger, connected sequentially. The outlet of the gear pump is connected to the inlet of a solenoid valve, and the outlet of the solenoid valve is connected to the inlet of the liquid storage tank. The safety circuit consists of the liquid storage tank, the first heat exchanger, the coarse filter, the gear pump, and the solenoid valve, connected sequentially. This invention meets the need for easy replacement of cold plates in microchannel evaporators with different configurations.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation system technology, specifically to a thermal testing experimental apparatus and method for a pump-driven two-phase flow system microchannel evaporator. Background Technology

[0002] With the development of technology, the performance and integration of various electronic devices are constantly improving. Heat dissipation and temperature control have become key issues restricting the development of electronic devices. For example, the heat dissipation requirements of equipment such as computer data centers and avionics equipment reach 500W / cm². 2 (Abdalla Ahmed N, Liu Lei, et al. Two-phase simulation of entropy generation and thermo-hydraulic behavior of atherminol / CuO-diamond nanofluid in a heat exchanger[J]. Engineering Analysis with Boundary Elements, 2023, 146.). To meet the heat dissipation requirements of such high heat flux density applications, researchers at home and abroad have proposed several phase change-based heat dissipation technologies. Among them, two-phase spray cooling and two-phase jet cooling are commonly used two-phase heat dissipation technologies. However, spray cooling and jet cooling systems have limitations such as complex structure and large space occupation. For example, the patent application entitled "Spray cooling system and control method for cold shear machine output roller conveyor for circulating steelmaking" (publication number CN118404385A). For fields such as aerospace that require compact structures, researchers at home and abroad have proposed pump-driven two-phase flow technology based on microchannel evaporators to achieve heat dissipation of high heat flux density devices in a limited space.

[0003] However, existing research on pump-driven two-phase flow systems based on microchannel evaporators mainly focuses on the cold plates of rectangular microchannel evaporators, such as patent applications titled "A Pump-Driven Two-Phase Flow Thermal Control System and Its Control Method" (publication number CN117042413A) and "An Integrated Preheating Pump-Driven Two-Phase Flow System" (publication number CN118274491A). There is little attention paid to the structural optimization of the cold plates of microchannel evaporators, and little attention paid to the need for easy replacement of the cold plates in the thermal testing of pump-driven two-phase flow systems. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention aims to provide a thermal testing apparatus and method for a pump-driven two-phase flow system microchannel evaporator. By constructing a bypass circuit, the pump-driven two-phase flow system can be kept running during the replacement of the microchannel evaporator cold plate. By modularly designing the microchannel evaporator, the need for easy replacement of cold plates of different configurations of microchannel evaporators can be met, thereby improving the efficiency of microchannel evaporator cold plate structure optimization.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A thermal testing apparatus for a pump-driven two-phase flow system microchannel evaporator includes a main circuit, a bypass circuit, and a safety circuit.

[0007] The main circuit is formed by sequentially connecting the following components: liquid storage tank 1, first heat exchanger 2, coarse filter 3, gear pump 4, mass flow meter 5, preheating sleeve 6, needle valve 7, first ball valve 8, fine main circuit filter 9, evaporator 10, second ball valve 11, and second heat exchanger 12.

[0008] The outlet of needle valve 7 is connected to the inlet of third ball valve 13, and the outlet of third ball valve 13 is connected to the inlet of second heat exchanger 12. The liquid storage tank 1, first heat exchanger 2, coarse filter 3, gear pump 4, mass flow meter 5, preheating sleeve 6, needle valve 7, third ball valve 13, and second heat exchanger 12 are connected in sequence to form a bypass circuit.

[0009] The outlet of gear pump 4 is connected to the inlet of solenoid valve 14, and the outlet of solenoid valve 14 is connected to the inlet of liquid storage tank 1. Liquid storage tank 1, first heat exchanger 2, coarse filter 3, gear pump 4 and solenoid valve 14 are connected in sequence to form a safety circuit.

[0010] The evaporator 10 includes an upper cover plate 101, an observation mirror 102, a microchannel evaporator cold plate 103, and a heat source 104. The upper cover plate 101, the observation mirror 102, and the microchannel evaporator cold plate 103 are connected by bolts in a top-to-bottom order. During thermal testing, only the microchannel evaporator cold plate 103 needs to be replaced to test the heat flow characteristics of microchannels with different configurations.

[0011] The microchannel evaporator cold plate 103 includes a rectangular microchannel 1031, a rhomboid microchannel 1032, and a cylindrical microchannel 1033.

[0012] The method for using the aforementioned pump-driven two-phase flow system microchannel evaporator thermal testing experimental apparatus includes:

[0013] Thermal test mode: The working fluid circulates in the main loop. When the pressure in the storage tank 1 is within the normal range, the gear pump 4 starts, the third ball valve 13 closes, and the solenoid valve 14 closes. The gas-liquid mixed working fluid flows out of the storage tank 1 and into the first heat exchanger 2. In the first heat exchanger 2, the working fluid temperature drops and it condenses completely into a liquid state. Then, the working fluid flows out of the first heat exchanger 2 and passes through the coarse filter 3, gear pump 4, and mass flow meter 5 in sequence. Subsequently, the working fluid flows into the preheating sleeve 6. In the preheating sleeve 6, the working fluid temperature rises but remains in a liquid state. The working fluid flows out of the preheating sleeve 6 and passes through the needle valve 7, the first ball valve 8, and the fine filter 9 in sequence. Finally, the working fluid flows into the evaporator 10. The working fluid is heated in evaporator 10 and becomes a gas-liquid mixture. Then, the working fluid flows out of evaporator 10 and flows into second heat exchanger 12 through second ball valve 11. The working fluid temperature drops in second heat exchanger 12 and condenses completely into liquid. Then, the working fluid flows into storage tank 1. The saturation temperature of the working fluid is set by adjusting the pressure value in storage tank 1. The flow resistance of microchannel evaporator cold plate 103 under this condition is determined by measuring the pressure difference between the outlet and inlet of evaporator 10. The heat exchange performance of microchannel evaporator cold plate 103 under this condition is analyzed by measuring the temperature of microchannel evaporator cold plate 103. The intensity of boiling of working fluid in evaporator 10 is evaluated by calculating the outlet dryness of evaporator 10.

[0014] Bypass loop mode: The working fluid circulates in the bypass loop. When the microchannel evaporator cold plate 103 needs to be replaced during the thermal test, the first ball valve 8 and the second ball valve 11 are closed, the third ball valve 13 is opened, and the solenoid valve 14 is closed. The gas-liquid mixed working fluid flows out of the storage tank 1 and into the first heat exchanger 2. In the first heat exchanger 2, the temperature of the working fluid drops and it all condenses into a liquid state. Then the working fluid flows out of the first heat exchanger 2 and passes through the coarse filter 3, gear pump 4, and mass flow meter 5 in sequence. Then the working fluid flows into the preheating sleeve 6. The temperature of the working fluid rises in the preheating sleeve 6, but it remains liquid. The working fluid flows out of the preheating sleeve 6 and passes through the needle valve 7 and the third ball valve 13 in sequence. Then the working fluid flows into the second heat exchanger 12. The temperature of the working fluid drops in the second heat exchanger 12 and it all condenses into a liquid state. Then the working fluid flows into the storage tank 1.

[0015] Safety loop mode: The working fluid circulates in the safety loop. When blockage or dry burning occurs in the evaporator 10, the pressure value in the liquid storage tank 1 exceeds the normal range. The solenoid valve 14 opens, and the working fluid flows out of the liquid storage tank 1, passing through the first heat exchanger 2, the coarse filter 3, the gear pump 4, and the solenoid valve 14 in sequence. Then the working fluid returns to the liquid storage tank 1.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] This invention provides a modular design for microchannel evaporators, meeting the need for easy replacement of cold plates in microchannel evaporators with different configurations, and supporting the optimization of microchannel evaporator cold plate structure and heat dissipation performance testing.

[0018] This invention adopts a design scheme combining a main circuit, a bypass circuit, and a safety circuit. The main circuit enables the function of thermal testing of the microchannel evaporator in the pump-driven two-phase flow system (testing parameters such as temperature, flow resistance, and outlet dryness of the microchannel evaporator under specific operating conditions); the bypass circuit enables the pump-driven two-phase flow system to continue operating when the microchannel evaporator cold plate is replaced, thus improving the efficiency of thermal testing; and the safety circuit can prevent local high pressure caused by blockage or dry burning of the microchannel evaporator, thus improving the safety of thermal testing. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the experimental apparatus structure according to an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the microchannel evaporator structure according to an embodiment of the present invention.

[0021] Figure 3 This is a flowchart of the method according to an embodiment of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] like Figure 1 As shown, a thermal testing apparatus for a pump-driven two-phase flow system microchannel evaporator includes a storage tank 1, a first heat exchanger 2, a coarse filter 3, a gear pump 4, a mass flow meter 5, a preheating sleeve 6, a needle valve 7, a first ball valve 8, a fine filter 9, an evaporator 10, a second ball valve 11, a second heat exchanger 12, a third ball valve 13, and a solenoid valve 14. The storage tank 1 has a volume of 5L, the first and second heat exchangers 2 and 12 have a heat exchange power of 0.5P, the gear pump 4 has a head of 2bar, the preheating sleeve 6 has a heating power of 50W, and the evaporator 10 has a heat exchange area of ​​8cm². 2 .

[0024] This embodiment of a pump-driven two-phase flow system microchannel evaporator thermal testing experimental device includes a main circuit, a bypass circuit, and a safety circuit. The main circuit is composed of a liquid storage tank 1, a first heat exchanger 2, a coarse filter 3, a gear pump 4, a mass flow meter 5, a preheating sleeve 6, a needle valve 7, a first ball valve 8, a fine filter 9, an evaporator 10, a second ball valve 11, and a second heat exchanger 12 connected in sequence. The outlet of the liquid storage tank 1 is connected to the inlet of the first heat exchanger 2, the outlet of the first heat exchanger 2 is connected to the inlet of the coarse filter 3, and the outlet of the coarse filter 3 is connected to the inlet of the gear pump 4. The outlet of gear pump 4 is connected to the inlet of mass flow meter 5. The outlet of mass flow meter 5 is connected to the inlet of preheating sleeve 6. The outlet of preheating sleeve 6 is connected to the inlet of needle valve 7. The outlet of needle valve 7 is connected to the inlet of first ball valve 8. The outlet of first ball valve 8 is connected to the inlet of fine filter 9. The outlet of fine filter 9 is connected to the inlet of evaporator 10. The outlet of evaporator 10 is connected to the inlet of second ball valve 11. The outlet of second ball valve 11 is connected to the inlet of second heat exchanger 12. The outlet of second heat exchanger 12 is connected to the inlet of liquid storage tank 1.

[0025] The bypass circuit is composed of a storage tank 1, a first heat exchanger 2, a coarse filter 3, a gear pump 4, a mass flow meter 5, a preheating sleeve 6, a needle valve 7, a third ball valve 13, and a second heat exchanger 12 connected in sequence. The outlet of the storage tank 1 is connected to the inlet of the first heat exchanger 2, the outlet of the first heat exchanger 2 is connected to the inlet of the coarse filter 3, the outlet of the coarse filter 3 is connected to the inlet of the gear pump 4, the outlet of the gear pump 4 is connected to the inlet of the mass flow meter 5, the outlet of the mass flow meter 5 is connected to the inlet of the preheating sleeve 6, the outlet of the preheating sleeve 6 is connected to the inlet of the needle valve 7, the outlet of the needle valve 7 is connected to the inlet of the third ball valve 13, the outlet of the third ball valve 13 is connected to the inlet of the second heat exchanger 12, and the outlet of the second heat exchanger 12 is connected to the inlet of the storage tank 1.

[0026] The safety circuit consists of a liquid storage tank 1, a first heat exchanger 2, a coarse filter 3, a gear pump 4, and a solenoid valve 14 connected in sequence: the outlet of the liquid storage tank 1 is connected to the inlet of the first heat exchanger 2, the outlet of the first heat exchanger 2 is connected to the inlet of the coarse filter 3, the outlet of the coarse filter 3 is connected to the inlet of the gear pump 4, the outlet of the gear pump 4 is connected to the inlet of the solenoid valve 14, and the outlet of the solenoid valve 14 is connected to the inlet of the liquid storage tank 1.

[0027] like Figure 2As shown, the evaporator 10 includes an upper cover plate 101, an observation mirror 102, a microchannel evaporator cold plate 103, and a heat source 104. The upper cover plate 101, the observation mirror 102, and the microchannel evaporator cold plate 103 are connected by bolts in a top-to-bottom order. The microchannel evaporator cold plate 103 has a relatively simple structure and is easy to manufacture. Therefore, microchannel evaporator cold plates 103 with different microchannel configurations can be manufactured and replaced in the evaporator 10 to test the heat transfer performance of different microchannel configurations, for example... Figure 2 The rectangular microchannel 1031, the rhomboid microchannel 1032, and the cylindrical microchannel 1033 are shown in the figure.

[0028] The method for using the aforementioned pump-driven two-phase flow system microchannel evaporator thermal testing experimental device, such as... Figure 3 As shown, the working fluid is selected as R134a, and the saturation temperature is set to 30 degrees Celsius, including:

[0029] The working fluid circulates in the main loop. Specifically, when the pressure in the storage tank 1 is less than 1.5 MPa, the gear pump 4 starts at 200 r / min, the third ball valve 13 closes, and the solenoid valve 14 closes. The gas-liquid mixture of working fluid flows out of the storage tank 1 and into the first heat exchanger 2. In the first heat exchanger 2, the working fluid temperature drops to 15 degrees Celsius and condenses completely into a liquid state. Then, the working fluid flows out of the first heat exchanger 2, passing sequentially through the coarse filter 3, the gear pump 4, and the mass flow meter 5. The working fluid then flows into the preheating sleeve 6, where the temperature rises to 25 degrees Celsius, remaining liquid. The working fluid then flows out of the preheating sleeve 6, passing sequentially through the needle valve 7, the first ball valve 8, and the fine filter 9. Finally, the working fluid flows into the evaporator 10, where the heat source 104 is added. The heat output is 200W. The working fluid is heated in the evaporator 10 and becomes a gas-liquid mixture. Then the working fluid flows out of the evaporator 10 and flows into the second heat exchanger 12 through the second ball valve 11. The working fluid temperature drops to 15 degrees Celsius in the second heat exchanger 12 and condenses completely into a liquid. Then the working fluid flows into the storage tank 1. The saturation temperature of the working fluid can be set to 30 degrees Celsius by adjusting the pressure value in the storage tank 1 to 0.77 MPa. The flow resistance of the microchannel evaporator cold plate 103 under this condition can be evaluated by measuring the pressure difference between the outlet and inlet of the evaporator 10. The heat exchange performance of the microchannel evaporator cold plate 103 under this condition can be analyzed by measuring the temperature of the microchannel evaporator cold plate 103. The intensity of boiling of the working fluid in the evaporator 10 can be evaluated by calculating the outlet dryness of the evaporator 10.

[0030] Bypass loop mode: The working fluid circulates in the bypass loop. The specific process is as follows: When the microchannel evaporator cold plate 103 needs to be replaced during the thermal test, the first ball valve 8 and the second ball valve 11 are closed, the third ball valve 13 is opened, and the solenoid valve 14 is closed. The gas-liquid mixed working fluid flows out from the storage tank 1 and into the first heat exchanger 2. In the first heat exchanger 2, the temperature of the working fluid drops and it all condenses into a liquid state. Subsequently, the working fluid flows out of the first heat exchanger 2 and passes sequentially through the coarse filter 3, the gear pump 4, and the mass flow meter 5. The working fluid then flows into the preheating sleeve 6, where its temperature rises while remaining liquid. It then flows out of the preheating sleeve 6, passing sequentially through the needle valve 7 and the second ball valve 13 before flowing into the second heat exchanger 12. There, its temperature drops, and it condenses completely into a liquid state. Finally, it flows into the storage tank 1. When replacing the microchannel evaporator cold plate 103, the working fluid circulates in the bypass loop, preventing pressure spikes and energy losses caused by the shutdown of the gear pump 4.

[0031] Safety loop mode: The working fluid circulates in the safety loop. The specific process is as follows: When blockage or dry burning occurs in the evaporator 10, the pressure value in the liquid storage tank 1 exceeds 1.5 MPa. The solenoid valve 14 opens, and the working fluid flows out of the liquid storage tank 1, passing through the first heat exchanger 2, the coarse filter 3, the gear pump 4, and the solenoid valve 14 in sequence. Then the working fluid returns to the liquid storage tank 1, thus avoiding excessive pressure in the liquid storage tank 1.

[0032] Experimental analysis shows that when the heating power of the heat source 104 is 200W, the heat exchange performance of the evaporator 10 with different microchannel configurations varies. The rectangular microchannel 1031 can reduce flow resistance, but the heat exchange efficiency is low; the rhomboid microchannel 1032 has higher heat exchange efficiency but also higher flow resistance; the cylindrical microchannel 1033 can have both high heat exchange efficiency and low flow resistance.

[0033] Although the invention has been described above with reference to specific embodiments, those skilled in the art will understand that many modifications can be made to the configurations and details disclosed herein within the principles and scope of the invention. The scope of protection of the invention is determined by the appended claims, which are intended to cover all modifications included in the literal meaning or scope of equivalents of the technical features in the claims.

Claims

1. A thermal testing experimental apparatus for a pump-driven two-phase flow system microchannel evaporator, characterized in that, Includes main circuit, bypass circuit and safety circuit; The main circuit is formed by connecting the liquid storage tank (1), the first heat exchanger (2), the coarse filter (3), the gear pump (4), the mass flow meter (5), the preheating sleeve (6), the needle valve (7), the first ball valve (8), the fine filter (9), the evaporator (10), the second ball valve (11), and the second heat exchanger (12) in sequence. The outlet of the needle valve (7) is connected to the inlet of the third ball valve (13), and the outlet of the third ball valve (13) is connected to the inlet of the second heat exchanger (12). The liquid storage tank (1), the first heat exchanger (2), the coarse filter (3), the gear pump (4), the mass flow meter (5), the preheating sleeve (6), the needle valve (7), the third ball valve (13), and the second heat exchanger (12) are connected in sequence to form a bypass circuit. The outlet of the gear pump (4) is connected to the inlet of the solenoid valve (14), and the outlet of the solenoid valve (14) is connected to the inlet of the storage tank (1). The storage tank (1), the first heat exchanger (2), the coarse filter (3), the gear pump (4), and the solenoid valve (14) are connected in sequence to form a safety circuit. The evaporator (10) includes an upper cover plate (101), an observation mirror (102), a microchannel evaporator cold plate (103), and a heat source (104). The upper cover plate (101), the observation mirror (102), and the microchannel evaporator cold plate (103) are connected by bolts in order from top to bottom. During thermal testing, only the microchannel evaporator cold plate (103) needs to be replaced to test the heat flow characteristics of microchannels with different configurations.

2. The apparatus according to claim 1, characterized in that: The microchannel evaporator cold plate (103) includes rectangular microchannels (1031), rhomboid microchannels (1032) and cylindrical microchannels (1033).

3. A method for thermal testing experimental apparatus of a pump-driven two-phase flow system microchannel evaporator according to any one of claims 1-2, characterized in that, include: Thermal test mode: The working fluid circulates in the main loop. When the pressure value in the storage tank (1) is within the normal range, the gear pump (4) starts, the third ball valve (13) closes, the solenoid valve (14) closes, and the gas-liquid mixed working fluid flows out of the storage tank (1) and into the first heat exchanger (2). In the first heat exchanger (2), the temperature of the working fluid drops and it all condenses into a liquid state. Then the working fluid flows out of the first heat exchanger (2) and passes through the coarse filter (3), gear pump (4), and mass flow meter (5) in sequence. Then the working fluid flows into the preheating sleeve (6). The temperature of the working fluid rises in the preheating sleeve (6) and remains liquid. The working fluid flows out of the preheating sleeve (6) and passes through the needle valve (7), first ball valve (8), and fine filter (9) in sequence. Then the working fluid flows into the evaporator (10). The working fluid is heated in the evaporator (10) and becomes a gas-liquid mixture. Then the working fluid flows out of the evaporator (10) and flows into the second heat exchanger (12) through the second ball valve (11). The working fluid temperature drops in the second heat exchanger (12) and condenses into a liquid. Then the working fluid flows into the storage tank (1). The saturation temperature of the working fluid is set by adjusting the pressure value in the storage tank (1). The flow resistance of the microchannel evaporator cold plate (103) under this working condition is determined by measuring the pressure difference between the outlet and inlet of the evaporator (10). The heat exchange performance of the microchannel evaporator cold plate (103) under this working condition is analyzed by measuring the temperature of the microchannel evaporator cold plate (103). The intensity of boiling of the working fluid in the evaporator (10) is evaluated by calculating the outlet dryness of the evaporator (10). Bypass loop mode: The working fluid circulates in the bypass loop. When the microchannel evaporator cold plate (103) needs to be replaced during the thermal test, the first ball valve (8) and the second ball valve (11) are closed, the third ball valve (13) is opened, and the solenoid valve (14) is closed. The gas-liquid mixed working fluid flows out from the storage tank (1) and into the first heat exchanger (2). In the first heat exchanger (2), the temperature of the working fluid drops and it all condenses into liquid. Then the working fluid flows out of the first heat exchanger (2) and passes through the coarse filter (3), gear pump (4), and mass flow meter (5) in sequence. Then the working fluid flows into the preheating sleeve (6). The temperature of the working fluid rises in the preheating sleeve (6) and remains liquid. The working fluid flows out of the preheating sleeve (6) and passes through the needle valve (7) and the third ball valve (13) in sequence. Then the working fluid flows into the second heat exchanger (12). The temperature of the working fluid drops in the second heat exchanger (12) and it all condenses into liquid. Then the working fluid flows into the storage tank (1). Safety loop mode: The working fluid circulates in the safety loop. When blockage or dry burning occurs in the evaporator (10), the pressure value in the storage tank (1) exceeds the normal range. The solenoid valve (14) opens, and the working fluid flows out from the storage tank (1) and passes through the first heat exchanger (2), coarse filter (3), gear pump (4), and solenoid valve (14) in sequence. Then the working fluid returns to the storage tank (1).

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