A device and method suitable for performance testing of micro-flow cold plate heat exchangers

Abstract

This invention belongs to the field of heat dissipation technology for high heat flux density devices, specifically relating to an apparatus and method for performance testing of low-flow-rate cold plate heat exchangers. The apparatus includes a heat exchanger platform and a platform temperature measuring instrument disposed inside a test chamber, a working fluid pipeline connecting a working fluid storage tank, the heat exchanger under test within the heat exchanger platform, and a working fluid recovery tank, with the working fluid recovery tank connected to a weight measuring device, and the heat exchanger platform connected to an adjustable heat transfer simulator. The apparatus and method provided by this invention can accurately measure the working fluid flow rate, main and auxiliary side heat exchange capacity, and latent heat of vaporization utilization rate of low-flow-rate cold plate heat exchangers, meeting the measurement and evaluation needs of the heat exchange capacity of low-flow-rate cold plate heat exchangers.

Description

Technical Field

[0001] This invention belongs to the field of heat dissipation technology for high heat flux density devices, and specifically relates to an apparatus and method for performance testing of low-flow-rate cold plate heat exchangers. Background Technology

[0002] Miniature flow cold plate heat exchangers utilize the two-phase flow and boiling of the cooling medium to remove heat from the object being cooled, representing a highly promising heat dissipation solution for high heat flux density devices. Due to their advantages such as small internal microchannel heat sink size, low working fluid requirement, high heat transfer coefficient, and small device size and weight, they have broad application prospects in fields such as chip heat dissipation in the electronics industry.

[0003] However, during the operation of low-flow-rate cold plate heat exchangers, the flow rate of the cooling medium is extremely low. Existing heat exchanger testing devices and methods make it difficult to accurately measure performance indicators such as working fluid flow rate, heat exchange capacity, and latent heat of vaporization utilization, thus hindering effective measurement and evaluation of the heat exchanger's performance. How to accurately measure the working fluid flow rate, main and auxiliary side heat exchange capacity, and latent heat of vaporization utilization of low-flow-rate cold plate heat exchangers to meet the measurement and evaluation requirements of their heat exchange capacity remains a technical problem to be solved. Summary of the Invention

[0004] To address the aforementioned technical problems, one objective of this invention is to provide a device suitable for performance testing of low-flow cold plate heat exchangers.

[0005] The present invention adopts the following technical solution:

[0006] An apparatus suitable for performance testing of low-flow-rate cold plate heat exchangers, comprising:

[0007] Test section: includes a test chamber for forming a closed test environment, a heat exchanger platform set inside the chamber and a platform temperature measuring instrument for measuring the temperature of the inner wall surface of the heat exchanger platform. The heat exchanger platform is provided with space for accommodating the heat exchanger to be tested, and the heat exchanger platform is also connected to an adjustable heat load simulator.

[0008] Measurement Unit: Includes a working fluid pipeline and a working fluid storage tank and a working fluid recovery storage tank respectively installed at both ends of the working fluid pipeline. The working fluid recovery storage tank is connected to a weight measuring device. A proportional unloading valve is also installed on the side of the working fluid pipeline near the working fluid recovery storage tank.

[0009] The working fluid pipeline runs through the test chamber and is connected to the inlet and outlet of the heat exchanger under test, so that the heat exchanger under test forms a flow section of the working fluid pipeline; a working fluid inlet temperature gauge, a working fluid inlet pressure gauge, a working fluid outlet temperature gauge, and a working fluid outlet pressure gauge are respectively installed on the working fluid pipeline connected to the inlet and outlet of the heat exchanger under test.

[0010] Preferably, it also includes a control unit for adjusting the temperature of the test environment. The control unit includes an air duct, which is connected to the test chamber through an air inlet and an air outlet. Inside the test chamber, a test chamber temperature measuring instrument is also provided.

[0011] Preferably, the air inlet is connected to an air temperature control unit for adjusting the temperature of the test environment inside the test chamber.

[0012] Preferably, at the location between the proportional unloading valve and the working fluid recovery tank, the working fluid pipeline is also connected to the air inlet of the air pipeline via a cooling heat exchanger for heat exchange between the working fluid and the air.

[0013] Preferably, a working fluid recovery pipeline is also provided between the working fluid recovery tanks, and a working fluid pump is installed on the working fluid recovery pipeline to enable the working fluid to be recycled.

[0014] The second objective of this invention is to provide a testing method for the apparatus described above suitable for performance testing of low-flow-rate cold plate heat exchangers, comprising the following steps:

[0015] S1. Temperature control: The temperature of the test environment inside the test chamber is brought to the set value by the air temperature control unit, and the working fluid pipeline and the heat exchanger under test are filled with working fluid;

[0016] S2. Test: Adjust the power of the adjustable heat load simulator to the set value and start heating; when the working fluid outlet pressure gauge reading reaches the discharge pressure set by the proportional unloading valve, open the proportional unloading valve, adjust the opening of the first working fluid pump to discharge the working fluid from the working fluid storage tank, flow through the heat exchanger under test, condense in the cooling heat exchanger, and enter the working fluid recovery storage tank, and record the weight by the weight measuring device; when the surface temperature of the adjustable heat load simulator is constant and stable for at least 10 minutes, the working fluid is in the stable discharge stage, and record the initial time and the weight of the working fluid recovery storage tank at this time. After heating for time T using an adjustable heat-load simulator, the weight of the working fluid recovery tank is recorded. ;

[0017] S3. Data Acquisition: During the heating time T of the adjustable heat load simulator, continuously monitor the readings of the working fluid inlet temperature gauge and calculate the average inlet temperature of the heat exchanger under test. The average inlet pressure of the heat exchanger under test is calculated from the pressure gauge reading of the working fluid inlet. The average outlet temperature of the heat exchanger under test is calculated from the reading of the working fluid outlet temperature gauge. The average outlet pressure of the heat exchanger under test is calculated from the pressure gauge reading at the outlet of the working fluid. The average temperature of the test environment was obtained by measuring the temperature of the test chamber. The readings from the stage temperature measuring instrument yield the average wall temperature of each inner wall surface of the heat exchanger stage and the average heating power of the adjustable heat load simulator. ;

[0018] S4. Calculation: Calculate the heat transfer on the working fluid side of the heat exchanger under test based on the data obtained in S3. The heat transfer rate on the heat source side of the heat exchanger under test ,according to and The average outlet pressure of the heat exchanger under test was calculated. The heat carried away per unit time after the cooling medium has completely vaporized. And the effective utilization rate of latent heat of gasification .

[0019] Preferably, the continuous monitoring refers to monitoring at a frequency of 15 times / min or more during the heating time T of the adjustable heat load simulator.

[0020] Preferably, for the heat exchanger platform, let the first... The average temperature of each inner wall surface is , No. The surface area of ​​each inner wall surface is , No. The surface area of ​​each outer wall surface is The heat transfer capacity on the heat source side of the heat exchanger under test The specific formula is:

[0021]

[0022] In the formula The heat leakage coefficient per unit area of ​​the heat exchanger platform wall; the average temperature refers to the average temperature obtained from continuous monitoring.

[0023] Preferably, the heat transfer capacity on the working fluid side of the heat exchanger under test is... The calculation formula is as follows:

[0024]

[0025] In the formula, This refers to the enthalpy of the working fluid at the outlet of the heat exchanger during the test, expressed in joules per kilogram. The enthalpy of the working fluid at the inlet of the heat exchanger under test during the experiment is expressed in joules per kilogram; the average pressure at the outlet of the heat exchanger under test is... The heat carried away per unit time after the cooling medium has completely vaporized. And the effective utilization rate of latent heat of gasification The calculation formula is as follows:

[0026]

[0027]

[0028] In the formula: For the medium under pressure The saturated steam temperature, expressed in degrees Celsius. The average pressure of the medium at the outlet of the heat exchanger under test. The saturated vapor enthalpy value, expressed in joules per kilogram.

[0029] Preferably, the heat transfer coefficient per unit area of ​​the heat exchanger platform wall is... The calculation method is as follows: Before the experiment begins, turn on the air temperature control unit and the adjustable heat load simulator to ensure that the reading of the heat exchanger platform temperature meter is at least 20°C higher than the reading of the test chamber temperature meter, and keep the reading of the heat exchanger platform temperature meter stable for at least 2 hours. Record and calculate the average temperature of the inner wall of the heat exchanger platform within time t. Average temperature of the test environment and the average heating power of the adjustable heat load simulator The heat leakage coefficient per unit area of ​​the heat exchanger platform (20) wall is calculated according to the following formula. :

[0030]

[0031] Preferably, if the measured heat transfer rate of the working fluid side of the heat exchanger under test is... Heat exchange with the working fluid side of the heat exchanger under test If the error value exceeds ±5%, adjust the settings between the heat exchanger under test, the adjustable heat load simulator, and the heat exchanger platform to ensure they are in full contact and / or change the test temperature, and then retest.

[0032] The beneficial effects of this invention are as follows:

[0033] The present invention provides a performance testing device and method for low-flow-rate cold plate heat exchangers. Utilizing the heat balance theory of the heat source and working fluid sides, it separately tests the heat exchange capacity on the working fluid side (main side) and the heat source side (auxiliary material side), improving measurement accuracy. This allows for precise measurement of the working fluid flow rate, the heat exchange capacity on both the main and auxiliary sides, and the latent heat of vaporization utilization rate of the low-flow-rate cold plate heat exchanger, meeting the requirements for accurate measurement and evaluation of the heat exchange capacity of low-flow-rate cold plate heat exchangers. Simultaneously, the testing device is equipped with a working fluid recovery system, enabling the recycling and reuse of the working fluid and improving the system's operational economy. Attached Figure Description

[0034] Figure 1 A schematic diagram of the performance testing device for a low-flow-rate cold plate heat exchanger;

[0035] Figure 2This is a schematic diagram of the internal structure of the test chamber;

[0036] Figure 3 This is a schematic diagram of the structure of the scheme in Example 3.

[0037] The meanings of the symbols marked in the figure are as follows:

[0038] 10-Test chamber 11-Test chamber temperature measuring instrument

[0039] 20 - Heat exchanger platform; 21 - Heat exchanger under test

[0040] 30-Stage temperature measuring instrument; 31-Adjustable thermal load simulator

[0041] 40 - Working medium pipeline; 41 - Working medium storage tank; 411 - First working medium pump; 412 - First valve; 42 - Working medium recovery storage tank; 43 - Working medium recovery pipeline; 431 - Second working medium pump; 432 - Second valve

[0042] 51-Working fluid inlet temperature gauge; 52-Working fluid inlet pressure gauge; 53-Working fluid outlet temperature gauge; 54-Working fluid outlet pressure gauge

[0043] 60 - Weight measuring device; 70 - Proportional unloading valve

[0044] 80 - Air duct; 81 - Air inlet; 82 - Air outlet; 821 - Air temperature control unit

[0045] 90-Cooling heat exchanger

[0046] 100 - High-pressure nitrogen tank; 101 - Pressure reducing valve; 102 - Inlet valve Detailed Implementation

[0047] The technical solution of the present invention will be described in more detail below with reference to the embodiments and accompanying drawings:

[0048] Example 1

[0049] like Figure 1 and Figure 2 As shown, an apparatus suitable for performance testing of low-flow cold plate heat exchangers includes a testing section and a measuring section.

[0050] The test section includes a test chamber 10 for forming a closed test environment, a heat exchanger platform 20 disposed inside the chamber, and a platform temperature measuring instrument 30 for measuring the temperature of the inner wall surface of the heat exchanger platform 20. The heat exchanger platform 20 is provided with space for accommodating the heat exchanger 21 to be tested. The heat exchanger platform 20 is connected to an adjustable heat load simulator 31, which is set in close contact with the heat exchanger 21 to be tested and the two are kept in close contact by thermally conductive silicone. The adjustable heat load simulator 31 is used to provide heat input to the heat exchanger 21 to be tested inside the heat exchanger platform 20.

[0051] The measuring unit includes a working fluid pipeline 40 that runs through the test chamber 10, a working fluid storage tank 41 and a first valve 412 located at one end of the working fluid pipeline 40, and a working fluid recovery storage tank 42 located at the other end of the working fluid pipeline 40. The working fluid storage tank 41 stores the working fluid used as a cooling medium for testing the heat exchanger 21 under test. The working fluid storage tank 41 is also connected to a first working fluid pump 411 to achieve stable discharge of the working fluid. The working fluid temperature during the test is set according to the test requirements and can be adjusted by existing means; this invention does not impose any limitations on this.

[0052] The working fluid recovery storage tank 42 is connected to a weight measuring device 60 for real-time measurement of the total weight of the working fluid recovery storage tank 42, including the working fluid. A proportional unloading valve 70 is also provided on the side of the working fluid pipeline 40 near the working fluid recovery storage tank 42.

[0053] The inlet and outlet of the heat exchanger under test 21 are connected to the working fluid pipeline 40, so that the internal flow channel of the heat exchanger under test 21 forms a flow section of the working fluid pipeline 40. A working fluid inlet temperature gauge 51, a working fluid inlet pressure gauge 52, a working fluid outlet temperature gauge 53, and a working fluid outlet pressure gauge 54 are respectively installed on the working fluid pipeline 40 connected to the inlet and outlet of the heat exchanger under test 21; wherein, the working fluid inlet temperature gauge 51 is used to measure the inlet temperature of the heat exchanger, the working fluid inlet pressure gauge 52 is used to measure the inlet pressure of the heat exchanger, the working fluid outlet temperature gauge 53 is used to measure the outlet temperature of the heat exchanger, and the working fluid outlet pressure gauge 54 is used to measure the outlet pressure of the heat exchanger.

[0054] For accurate measurement, the device also includes a control unit for adjusting the test environment temperature. The control unit includes an air duct 80, which is connected to the test chamber 10 via an air inlet 81 and an air outlet 82. The air inlet 81 is equipped with an air temperature control unit 821 for adjusting the temperature of the test environment inside the test chamber 10. A test chamber temperature sensor 11 is also installed inside the test chamber 10.

[0055] In order to recover the heat of the working fluid, the working fluid pipeline 40 is also connected to the air inlet of the air pipeline 80 through the cooling heat exchanger 90 at the location between the proportional unloading valve 70 and the working fluid recovery storage tank 42, for the heat exchange between the working fluid and the air.

[0056] Once the test begins, the working medium in the working medium storage tank 41 flows to the working medium recovery storage tank 42. At this time, the cooling heat exchanger 90 can also be used to regulate the working medium temperature. In order to recycle the working medium, a working medium recovery pipeline 43 and a second valve 432 are also provided between the working medium recovery storage tank 42 and the working medium storage tank 41. A second working medium pump 431 is installed on the working medium recovery pipeline 43 so that the working medium can be pumped back to the working medium storage tank 41 after the test.

[0057] Example 2

[0058] The present invention provides a testing method for an apparatus suitable for performance testing of low-flow-rate cold plate heat exchangers, comprising the following steps:

[0059] S1. Temperature control: The temperature of the test environment inside the test chamber 10 is brought to the set value by the air temperature control unit 821, and the working fluid pipe 40 and the space of the heat exchanger 21 under test are filled with working fluid.

[0060] S2. Test: Adjust the power of the adjustable heat load simulator 31 to the set value and start heating; when the working fluid outlet pressure gauge 54 reaches the discharge pressure set by the proportional unloading valve 70, open the proportional unloading valve 70, adjust the opening of the first working fluid pump 411 to discharge the working fluid from the working fluid storage tank 41, flow through the heat exchanger 21 under test for heat exchange, condense by the cooling heat exchanger 90 and enter the working fluid recovery storage tank 42, and then the weight is recorded by the weight measuring device 60; when the surface temperature of the adjustable heat load simulator 31 is constant and stable for at least 10 minutes, record this stable moment as the initial time and record the weight of the working fluid recovery storage tank 42 at this time. After the adjustable heat load simulator 31 heats for time T, the weight of the working fluid recovery storage tank 42 is recorded. ;

[0061] S3. Data Acquisition: During the heating time T of the adjustable heat load simulator 31, continuously monitor the readings of the working fluid inlet temperature gauge 51, and calculate the average inlet temperature of the heat exchanger 21 under test. The average inlet pressure of the heat exchanger 21 was calculated by reading the pressure gauge at the working fluid inlet pressure gauge 52. The average outlet temperature of the heat exchanger 21 was calculated from the reading of the working fluid outlet temperature gauge 53. The average outlet pressure of the heat exchanger 21 under test was calculated from the reading of the working fluid outlet pressure gauge 54. The average temperature of the test environment was obtained by reading the temperature of the test chamber using the temperature measuring instrument 11. The readings from the platform temperature measuring instrument 30 are used to obtain the average wall temperature of each inner wall surface of the heat exchanger platform 20 and the average heating power of the adjustable heat load simulator 31. The aforementioned continuous monitoring refers to monitoring at a frequency of 15 times / min or more during the heating time T of the adjustable heat load simulator 31. In actual experiments, the frequency can be set according to specific needs. The higher the monitoring frequency, the higher the accuracy of the test.

[0062] S4. Calculation: Calculate the heat transfer on the working fluid side of the heat exchanger 21 under test based on the data obtained in S3. The heat exchange rate on the heat source side of the heat exchanger 21 under test ,according to and The average outlet pressure of the heat exchanger 21 under test was calculated. The heat carried away per unit time after the cooling medium has completely vaporized. And the effective utilization rate of latent heat of gasification .

[0063] Specifically, for the heat exchanger platform 20, the temperature values ​​of its six internal planes may differ during the test. To accurately measure the heat leakage of each wall surface, the temperature of each of the six planes must be measured separately. First, the heat leakage of each surface is calculated, and then the values ​​are added together to obtain the total heat leakage: Let the first plane be the heat exchanger platform 20. The average temperature of each inner wall surface is , No. The surface area of ​​each inner wall surface is , No. The surface area of ​​each outer wall surface is The heat exchange capacity on the heat source side of the heat exchanger 21 under test The specific formula is:

[0064]

[0065] In the formula The heat leakage coefficient per unit area of ​​the heat exchanger platform wall 20 is expressed in W / ℃ / m². 2 ; The average heating power of the adjustable heat load simulator 31 is expressed in W. A n,i For the heat exchanger platform i The surface area of ​​each inner wall, in m² 2 ; A w,i For the heat exchanger platform i The surface area of ​​the outer wall, in m² 2 ; t n,i For the heat exchanger platform i The average temperature of each inner wall surface, in °C; The average temperature of the test environment is expressed in °C.

[0066] The average temperature mentioned above refers to the average temperature obtained from continuous monitoring.

[0067] The heat exchange capacity on the working fluid side of the heat exchanger 21 under test The calculation formula is as follows:

[0068]

[0069] In the formula, Q M The unit is watts (W); The average inlet pressure of the heat exchanger during the steady-state test is expressed in Pascals (Pa). t i The average inlet temperature of the heat exchanger during the steady-state test is expressed in degrees Celsius (°C). The average outlet pressure of the heat exchanger during the steady-state test is expressed in Pascals (Pa). t o The average outlet temperature of the heat exchanger during the steady-state test is expressed in degrees Celsius (°C). The value represents the enthalpy of the working fluid at the outlet of heat exchanger 21 during the test, expressed in joules per kilogram (J / kg). The value of the working fluid at the inlet of heat exchanger 21 during the test is expressed in joules per kilogram (J / kg). m o The weight of the working fluid recovery tank after the steady-state test ， The unit is kilogram (kg); m i The weight of the working fluid recovery tank before the steady-state test. ， The unit is kilogram (kg); T Steady-state test time ， The unit is seconds (s).

[0070] The heat exchanger under test 21 has an average outlet pressure The heat carried away per unit time after the cooling medium has completely vaporized. And the effective utilization rate of latent heat of gasification The calculation formula is as follows:

[0071]

[0072]

[0073] In the formula Q s The average pressure of the cooling medium at the outlet in the heat exchanger The amount of heat carried away per unit time after all vaporization, expressed in watts (W). For the medium under pressure The saturated steam temperature, expressed in degrees Celsius (°C). The average pressure of the medium at the outlet of the heat exchanger under test. The saturated vapor enthalpy value, expressed in joules per kilogram (J / kg).

[0074] when When the value is ≥1, it indicates that the outlet state of the cooling medium is saturated or superheated steam, the cooling medium is completely vaporized, and the effective utilization rate of the latent heat of vaporization of the heat exchanger is 100%.

[0075] The heat leakage coefficient per unit area of ​​the wall surface of the heat exchanger platform 20 mentioned above The calculation method is as follows: Before the test begins, turn on the air temperature control unit 821 and the adjustable heat transfer simulator 31, so that the reading of the heat exchanger platform temperature measuring instrument 30 is at least 20°C higher than the reading of the test chamber temperature measuring instrument 11, and maintain this reading stable for at least 2 hours. Record and calculate the average temperature of the inner wall surface of the heat exchanger platform 20 within time t. Average temperature of the test environment and the average heating power of the adjustable heat load simulator 31 The heat leakage coefficient per unit area of ​​the heat exchanger platform 20 wall is calculated according to the following formula. :

[0076]

[0077] It should be emphasized that in actual testing, maintaining a constant surface temperature for the adjustable heat load simulator 31 in step S2 requires ensuring that its surface temperature is lower than the maximum allowable design temperature of the heat exchanger 21 under test. Additionally, in the above experiment, if the measured heat transfer on the working fluid side of the heat exchanger 21 under test... Heat exchange with the working fluid side of the heat exchanger under test If the error value exceeds ±5%, adjust the setting position between the heat exchanger under test 21, the adjustable heat load simulator 31 and the heat exchanger platform 20 to make them fit together fully and / or change the test temperature, and retest.

[0078] After the test is completed, the second working medium pump 431 and the second valve 432 are turned on to transport the working medium in the working medium recovery tank 42 to the working medium storage tank 41 to realize the recycling of the cooling medium.

[0079] Example 3

[0080] According to the method in Example 2, the heat transfer capacity and latent heat of vaporization utilization rate of a certain type of low-flow cold plate heat exchanger were tested. This cold plate heat exchanger is used to meet a heat flux density of 10 kW / m³. 2 The heat dissipation requirements of the electronic heat transfer device are as follows: the structural dimensions are 500 mm × 200 mm × 10 mm (length × width × height); the target control temperature of the heat transfer device surface is ≤200℃; the cooling medium is water; and the effective utilization rate of the target latent heat of vaporization is ≥95%.

[0081] according to Figure 1The apparatus shown places the heat exchanger under test on the heat exchanger platform 20, which is made of 60mm insulation board. The adjustable heat load simulator 31 has dimensions of 520 mm × 200 mm × 20 mm.

[0082] (1) Heat leakage coefficient test

[0083] The test environment temperature inside the test chamber was set to 25℃. The air temperature control unit 821 and the adjustable heat transfer simulator 31 were turned on, ensuring the reading of the platform temperature meter 30 was at least 20℃ higher than the reading of the test chamber temperature meter 11. The system was operated and maintained under this condition for at least 2 hours. Once the readings of the test chamber temperature meter 11 (i.e., the test environment temperature inside the test chamber, outer surface) and the platform temperature meter 30 (including the inner surface temperatures of the six walls) reached a stable state, the readings of the test chamber temperature meter 11 and the platform temperature meter 30, as well as the areas of the inner and outer surfaces of the heat exchanger platform 20, were measured and recorded, as shown in Table 1 below. During the experiment, the total input power consumption of the adjustable heat transfer simulator 31 was 138.6W. Using the calculation formula provided in Example 2, the heat leakage coefficient per unit area of ​​the test chamber walls was determined. C h It is 17.037 W / ℃ / m 2 .

[0084] Table 1. Relevant test data of the heat exchanger platform

[0085]

[0086] (2) Heat exchange test

[0087] After the experiment reached a steady state, the average surface temperature of the adjustable thermal load simulator 31 was measured to be 188.6℃, which meets the requirement of a target control temperature of ≤200℃ for the thermal load surface. The test parameters recorded and calculated at each measuring point are shown in Table 2 below.

[0088] Table 2. Relevant test data of the heat exchanger under test

[0089]

[0090] The average temperatures of the six inner wall surfaces of the heat exchanger platform are shown in Table 3 below:

[0091] Table 3. Average temperature data of each inner wall surface of the heat exchanger platform

[0092]

[0093] Based on the above method, the heat exchange capacity on the working fluid side of the heat exchanger was determined to be 1126.47W, and the heat exchange capacity on the heat source side of the heat exchanger was determined to be 1171.3W. The deviation between the main and auxiliary sides of the heat exchange capacity was 3.98%, which meets the test requirement of keeping the error within ±5%. Therefore, the test results are acceptable.

[0094] (3) Effective utilization rate of latent heat of vaporization of heat exchanger

[0095] According to the formula in Example 2, the average pressure of the cooling medium at the outlet of the heat exchanger is... When all vaporization occurs, the heat removed per unit time is 1117.982 W. The effective utilization rate of the latent heat of vaporization of the heat exchanger is... 102.76%. ≥1 indicates that the outlet state of the cooling medium is saturated or superheated steam, the cooling medium is completely vaporized, and the effective utilization rate of the latent heat of vaporization of the heat exchanger is 100%, which meets the design target of effective utilization rate of latent heat of vaporization of cooling medium ≥95%.

[0096] Example 4

[0097] Because the working fluid flow rate of the micro-flow cold plate heat exchanger is very small, and in order to ensure that the working fluid can be smoothly discharged after evaporation during the experiment, the first working fluid pump 411 requires a small flow rate and high pressure. If a suitable first working fluid pump 411 cannot be selected during the experiment, the present invention provides an improved device structure based on Embodiment 1, such as... Figure 3 As shown, the working medium storage tank 41 is pressurized by the high-pressure nitrogen tank 100 connected to the working medium storage tank 41 and the air inlet valve 102, so as to realize the operation of the system process. The connection section between the high-pressure nitrogen tank 100 and the working medium storage tank 41 is also equipped with a pressure reducing valve 101.

[0098] The testing method for this device is the same as in Example 2, except that in step S2, when the pressure reading on the working fluid outlet pressure gauge 54 reaches the discharge pressure set by the proportional unloading valve 70, the proportional unloading valve 70 is opened, and the pressure reducing valve 101 is adjusted to the set pressure value. The inlet valve 102 is then opened, allowing the high-pressure nitrogen tank 100 to provide a certain discharge pressure to the working fluid storage tank 41, thus enabling the working fluid to be discharged from the working fluid storage tank 41. The stable discharge of the working fluid is regulated by adjusting the set pressure value of the pressure reducing valve 101.

[0099] In this scheme, the high-pressure nitrogen tank 100 can also be a device containing other safe gases, such as a gas cylinder containing argon or other inert high-pressure gases, as long as the gas used is safe for the system and the high pressure can overcome the resistance of the system.

[0100] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device suitable for performance testing of low-flow-rate cold plate heat exchangers, characterized in that, include: Test section: includes a test chamber (10) for forming a closed test environment, a heat exchanger platform (20) set inside the chamber and a platform temperature measuring instrument (30) for measuring the temperature of the inner wall surface of the heat exchanger platform (20). The heat exchanger platform (20) is provided with space for accommodating the heat exchanger (21) to be tested. The heat exchanger platform (20) is also connected to an adjustable heat load simulator (31). Measurement Unit: Includes a working fluid pipeline (40) and a working fluid storage tank (41) and a working fluid recovery storage tank (42) respectively installed at both ends of the working fluid pipeline (40). The working fluid storage tank (41) is connected to a first working fluid pump (411) to achieve stable discharge of the working fluid. The working fluid recovery storage tank (42) is connected to a weight measuring device (60). A proportional unloading valve (70) is also installed on the side of the working fluid pipeline (40) near the working fluid recovery storage tank (42). The working fluid pipeline (40) runs through the test chamber (10) and is connected to the inlet and outlet of the heat exchanger (21) under test, so that the heat exchanger (21) under test forms a flow section of the working fluid pipeline (40); a working fluid inlet temperature gauge (51), a working fluid inlet pressure gauge (52), a working fluid outlet temperature gauge (53) and a working fluid outlet pressure gauge (54) are respectively installed on the working fluid pipeline (40) connected to the inlet and outlet of the heat exchanger (21) under test. It also includes a control unit for adjusting the temperature of the test environment. The control unit includes an air duct (80), which is connected to the test chamber (10) through an air inlet (81) and an air outlet (82) provided on the test chamber (10). Inside the test chamber (10), there is also a test chamber temperature measuring instrument (11). The air inlet (81) is connected to the air temperature control unit (821) for adjusting the temperature of the test environment inside the test chamber (10); At the location between the proportional unloading valve (70) and the working fluid recovery tank (42), the working fluid pipeline (40) is also connected to the air inlet of the air pipeline (80) through a cooling heat exchanger (90) for heat exchange between the working fluid and the air. A working fluid recovery pipeline (43) is also provided between the working fluid recovery storage tank (42) and the working fluid storage tank (41), and a second working fluid pump (431) is provided on the working fluid recovery pipeline (43) so that the working fluid can be recycled.

2. A test method for the apparatus as described in claim 1, suitable for performance testing of low-flow-rate cold plate heat exchangers, characterized in that, Includes the following steps: S1. Temperature control: The temperature of the test environment inside the test chamber (10) is brought to the set value by the air temperature control unit (821), and the working fluid pipeline (40) and the heat exchanger under test (21) are filled with working fluid; S2. Test: Adjust the power of the adjustable heat load simulator (31) to the set value and start heating; when the value of the working fluid outlet pressure gauge (54) reaches the discharge pressure set by the proportional unloading valve (70), open the proportional unloading valve (70), adjust the opening of the first working fluid pump (411) to discharge the working fluid from the working fluid storage tank (41), flow through the heat exchanger to be tested (21), condense by the cooling heat exchanger (90) and enter the working fluid recovery storage tank (42), and record the weight by the weight measuring device (60); when the surface temperature of the adjustable heat load simulator (31) is constant and stable for at least 10 minutes, the working fluid is in the stable discharge stage, and record the initial time and the weight of the working fluid recovery storage tank (42) at this time. After heating for time T using the adjustable heat load simulator (31), the weight of the working fluid recovery tank (42) is recorded. ; S3. Data Acquisition: During the heating time T of the adjustable heat load simulator (31), continuously monitor the reading of the working fluid inlet temperature gauge (51) and calculate the average inlet temperature of the heat exchanger (21) under test. The average inlet pressure of the heat exchanger (21) under test is calculated by reading the pressure gauge (52) at the inlet of the working fluid. The average outlet temperature of the heat exchanger (21) under test is calculated by reading the working fluid outlet temperature gauge (53). The average outlet pressure of the heat exchanger (21) under test is calculated from the reading of the working fluid outlet pressure gauge (54). The average temperature of the test environment was obtained by reading the temperature of the test chamber using the temperature measuring instrument (11). The readings from the stage temperature measuring instrument (30) are used to obtain the average wall temperature of each inner wall surface of the heat exchanger stage (20) and the average heating power of the adjustable heat load simulator (31). ; S4. Calculation: Calculate the heat transfer capacity on the working fluid side of the heat exchanger (21) under test based on the data obtained in S3. The heat exchange capacity of the heat exchanger under test (21) on the heat source side ,according to and The calculated average outlet pressure of the heat exchanger under test (21) was obtained. The heat carried away per unit time after the cooling medium has completely vaporized. And the effective utilization rate of latent heat of gasification .

3. The test method as described in claim 2, characterized in that, The continuous monitoring refers to monitoring at a frequency of 15 times / min or more during the heating time T of the adjustable heat load simulator (31).

4. The test method as described in claim 3, characterized in that, For the heat exchanger platform (20), let the first... The average temperature of each inner wall surface is , No. The surface area of ​​each inner wall surface is , No. The surface area of ​​each outer wall surface is The heat exchange capacity of the heat exchanger (21) on the heat source side under test The specific formula is: In the formula The heat leakage coefficient per unit area of ​​the wall surface of the heat exchanger platform (20); The average temperature refers to the average temperature obtained from continuous monitoring.

5. The test method as described in claim 2, characterized in that, The heat exchange capacity on the working fluid side of the heat exchanger (21) under test The calculation formula is as follows: In the formula, The value of the working fluid at the outlet of the heat exchanger (21) during the test is expressed in joules per kilogram. The enthalpy of the working fluid at the inlet of the heat exchanger (21) during the test is expressed in joules per kilogram; the average outlet pressure of the heat exchanger (21) during the test is... The heat carried away per unit time after the cooling medium has completely vaporized. And the effective utilization rate of latent heat of gasification The calculation formula is as follows: In the formula: For the medium under pressure The saturated steam temperature, expressed in degrees Celsius (°C). The average pressure of the medium at the outlet of the heat exchanger under test (21) The saturated vapor enthalpy value, expressed in joules per kilogram (J / kg).

6. The test method as described in claim 5, characterized in that, The heat leakage coefficient per unit area of ​​the wall surface of the heat exchanger platform (20) The calculation method is as follows: Before the test begins, turn on the air temperature control unit (821) and the adjustable heat transfer simulator (31) to make the reading of the platform temperature measuring instrument (30) at least 20°C higher than the reading of the test chamber temperature measuring instrument (11) and keep the reading of the platform temperature measuring instrument (30) stable for at least 2 hours. Record and calculate the average temperature of the inner wall of the heat exchanger platform (20) within time t. Average temperature of the test environment and the average heating power of the adjustable heat load simulator (31) The heat leakage coefficient per unit area of ​​the heat exchanger platform (20) wall is calculated according to the following formula. : 。 7. The test method as described in claim 2, characterized in that, If the heat exchange rate of the working fluid side of the heat exchanger under test (21) is measured... The heat exchange with the working fluid side of the heat exchanger under test (21) If the error value exceeds ±5%, adjust the setting position between the heat exchanger (21), the adjustable heat load simulator (31) and the heat exchanger platform (20) to make them fit together fully and / or change the test temperature, and retest.

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