A system for measuring the maximum pore diameter of a porous capillary wick for an evaporator of a loop heat pipe

Abstract

The application discloses a kind of evaporator porous capillary core maximum aperture measurement systems for loop heat pipe, including evaporator porous capillary core soaking pretreatment subsystem, evaporator porous capillary core maximum aperture measurement subsystem and background measurement control system;The measurement system improves the soaking pretreatment process of evaporator porous capillary core, utilizes program control automatic pressurization, automatic identification breakdown pressure in measurement process, and the influence of gravity and temperature is corrected, realizes the efficient, accurate measurement of evaporator porous capillary core maximum aperture for loop heat pipe.

Description

Technical Field

[0001] This invention belongs to the field of high-efficiency heat transfer technology and relates to a system that can efficiently measure the maximum pore diameter of the porous capillary wick of an evaporator for loop heat pipes. Its purpose is to measure the maximum pore diameter of the porous capillary wick inside the evaporator before system installation to determine whether the maximum pore diameter of the porous capillary wick meets the design requirements, thus providing a new type of testing system for the processing, production and application of evaporators for loop heat pipes. Background Technology

[0002] Loop heat pipe technology is an advanced thermal control technology with advantages such as high heat transfer capacity and long heat transfer distance. It has been widely used not only in spacecraft thermal control but also in Earth's gravity environment. Among the basic components of a loop heat pipe, the evaporator is the most important. The maximum capillary driving force provided by the porous capillary wick within the evaporator determines the evaporator's maximum heat transfer capacity and maximum heat transfer distance. The maximum capillary driving force of the porous capillary wick is inversely proportional to its maximum pore size; the larger the maximum pore size, the lower the maximum capillary force it can provide. Therefore, it is necessary to measure the maximum pore size of the porous capillary wick before installing and using the evaporator for a loop heat pipe.

[0003] Currently, the measurement method commonly used in the research and production of loop heat pipes is based on the bubbling method. Chinese invention patent CN200810201460.5 has disclosed a "pore size measuring instrument and its measuring method for porous materials". This method first immerses the porous material in the measuring medium liquid. After soaking for a period of time, pressurize one side of the porous medium. When bubbles are observed to be generated on the other side of the porous capillary, the pressure gauge reading on the other side of the porous capillary is recorded. Then, the maximum pore size of the porous medium is calculated according to the corresponding formula.

[0004] The following problems exist when this method is applied to the measurement of porous capillary wicks in loop heat pipe evaporators: (1) After assembly, a certain length of pipeline is often left on the evaporator, which may cause the porous capillary wick to be insufficiently soaked within the specified time, affecting the measurement results; (2) Data is recorded by observing the generation of bubbles with the naked eye, which may lead to subjective judgment errors; (3) The pressure increase during the measurement process needs to be manually performed by the operator, resulting in poor measurement accuracy and low measurement efficiency; (4) The influence of gravity pressure difference, temperature, etc. on the measurement results is not considered.

[0005] This invention improves the immersion method for porous capillary wicks. A background monitoring and control program automatically identifies the moment the porous capillary wick is punctured and records the pressure value. Based on a preset measurement medium type, and while correcting for the effects of temperature and gravitational pressure difference, the maximum pore size of the porous capillary wick is automatically calculated. This invention can improve the measurement efficiency and accuracy of the maximum pore size of porous capillary wicks used in loop heat pipes, and has significant practical application value. Summary of the Invention

[0006] To achieve the above objectives, the present invention provides a system capable of efficiently and accurately measuring the maximum pore size of a porous capillary wick for an evaporator used in a loop heat pipe. Based on the numerical relationship between capillary force and capillary pore size, the system improves the porous capillary wick soaking pretreatment process and automates the design of related measurement steps to achieve efficient and accurate measurement of the maximum pore size of a porous capillary wick for an evaporator used in a loop heat pipe.

[0007] The present invention adopts the following technical solution:

[0008] This invention provides a system for measuring the maximum pore size of a porous capillary wick for a loop heat pipe evaporator, comprising an evaporator porous capillary wick soaking and pretreatment subsystem, an evaporator porous capillary wick maximum pore size measurement subsystem, and a background measurement and control system.

[0009] The evaporator porous capillary wick soaking pretreatment subsystem includes a measuring medium storage tank (1), a controllable micro-flow injection pump (2), and a low-speed vacuum pump (18), used to inject the measuring medium into the evaporator and remove excess measuring medium from the system. The function of this evaporator porous capillary wick soaking pretreatment subsystem is to complete the porous capillary wick soaking process with high quality and prevent the measurement accuracy from being reduced due to insufficient wick soaking. The method of slowly injecting the measuring medium into the evaporator using a micro-flow injection pump provides sufficient soaking time for the porous capillary wick, while gradually removing air from the evaporator to prevent insufficient wick soaking due to air in the evaporator. Furthermore, the low-speed vacuum pump removes excess measuring medium from the system after the soaking pretreatment process is completed.

[0010] The evaporator porous capillary maximum pore diameter measurement subsystem includes a high-precision pressure generator (3), a sensitive pressure sensor, a temperature sensor (7), and a distance sensor (6), used to measure the maximum pore diameter of the evaporator porous capillary. The function of this evaporator porous capillary maximum pore diameter measurement subsystem is to measure the maximum pore diameter of the evaporator porous capillary. The high-precision pressure generator is used to provide a controllable pressure source. The sensitive pressure sensor is used to measure (or calibrate) the pressure of the high-precision pressure generator and to determine the moment when the porous capillary is punctured. The temperature sensor is used to measure the temperature of the measuring medium. The distance sensor is used to measure the height of the liquid column between the two sensitive pressure sensors.

[0011] The background monitoring and control system is used to read the measurement values ​​from the sensitive pressure sensor, temperature sensor, and distance sensor, automatically determine the moment when the porous capillary wick is punctured, and automatically calculate and display the measurement result of the maximum pore diameter of the porous capillary wick. In addition, the background monitoring and control system can also precisely control the opening / closing of each solenoid valve.

[0012] Furthermore, the measuring medium storage tank (1) contains the measuring medium and is connected to the controllable micro-flow injection pump (2) through pipelines and solenoid valve I (12);

[0013] The evaporator (8) to be tested is installed vertically. Its lower end is connected to the controllable micro-flow injection pump (2) through solenoid valve II (13), to the high-precision pressure generator (3) through solenoid valve III (14), and to the low-speed vacuum pump (18) through solenoid valve VI (17). Its upper end is connected to the atmosphere through solenoid valve IV (15) and to the low-speed vacuum pump (18) through solenoid valve V (16).

[0014] The sensitive pressure sensor includes sensitive pressure sensor A (4) and sensitive pressure sensor B (5). Sensitive pressure sensor A (4) is installed on the connecting pipe between solenoid valve III (14) and high-precision pressure generator (3). Temperature sensor (7) and sensitive pressure sensor B (5) are installed on the connecting pipe between the upper end of the evaporator (8) under test and solenoid valve IV (15). Distance sensor (6) is used to measure the relative height between sensitive pressure sensor A (4) and sensitive pressure sensor B (5).

[0015] Furthermore, the controllable micro-flow injection pump (2), high-precision pressure generator 3, low-speed vacuum pump (18) and all solenoid valves (12-17) are controlled by the background measurement and control system. The data obtained by the distance sensor (6), temperature sensor (7), sensitive pressure sensor A (4), and sensitive pressure sensor B (5) are processed by the background measurement and control system to calculate the measurement results.

[0016] Furthermore, all the connecting pipes are flexible and transparent, which can adapt to the measurement work of evaporators of different sizes and enable the observation of the internal state of the pipes.

[0017] This invention also provides a method for measuring the maximum pore diameter of a porous capillary wick for an evaporator used in a loop heat pipe. The method uses the aforementioned system for measuring the maximum pore diameter of a porous capillary wick for an evaporator used in a loop heat pipe and includes the following steps:

[0018] S1, the loop heat pipe evaporator (8) to be tested is vertically installed on the measurement system, and the porous capillary wick (10) is located inside the evaporator (8) to be tested; the positions of the sensitive pressure sensor B (5) and the sensitive pressure sensor A (4) are adjusted to be at the same height as the upper and lower ends of the evaporator (8) to be tested, and then the distance sensor (6) measures the relative height ΔH between the sensitive pressure sensor A (4) and the sensitive pressure sensor B (5) under the control of the background measurement and control system;

[0019] S2, Select the type of measurement medium on the control interface;

[0020] S3, close solenoid valves Ⅲ (14), ⅙ (16), and Ⅵ (17), open solenoid valves Ⅰ (12), Ⅱ (13), and Ⅳ (15), start the controllable micro-flow injection pump (2), the injection flow rate is 1mL / min, after the measuring medium overflows from solenoid valve Ⅳ (15), the porous capillary wick has been completely wetted by the measuring medium, and close the controllable micro-flow injection pump (2).

[0021] S4, close solenoid valve I (12), solenoid valve II (13), solenoid valve III (14), and solenoid valve IV (15), start the low-speed vacuum pump (18), first open solenoid valve V (16), and close solenoid valve V (16) when there is just no liquid in the transparent pipeline directly connected to the upper end of the evaporator (8) to be tested; open solenoid valve VI (17), and close solenoid valve VI (17) when there is just no liquid in the transparent pipeline directly connected to the lower end of the evaporator (8) to be tested, turn off the low-speed vacuum pump (18) and let it stand for 5 minutes to complete the soaking pretreatment of the porous capillary core;

[0022] S5, close solenoid valve I (12), solenoid valve II (13), and solenoid valve IV (15), open solenoid valve III (14), start the high-precision pressure generator (3), and gradually increase the pressure in steps of 1 kPa under the control of the background measurement and control system, maintaining each pressure condition for 10 seconds; at the same time, continuously collect the measured values ​​of sensitive pressure sensor A (4), sensitive pressure sensor B (5), and temperature sensor (7), and the background measurement and control system judges whether the measured value of pressure sensor B (5) has changed significantly. When the reading of sensitive pressure sensor B (5) increases by more than 1 kPa within 10 seconds, the background measurement and control system judges that the porous capillary core has been broken down, and automatically records the average readings of sensitive pressure sensor A (4), sensitive pressure sensor B (5), and temperature sensor (7) under the previous pressure condition, which are respectively p A p B And T, the background measurement and control system calculates the maximum pore diameter of the porous capillary core of the evaporator under test based on the measured data.

[0023] Furthermore, in step S5, the method for calculating the maximum pore diameter of the porous capillary wick of the evaporator to be tested is as follows:

[0024] The system pressure balance relationship considering gravity and temperature corrections is as follows:

[0025] p A =p B +Δp w +ρ(T)gΔH (1)

[0026] In the formula, Δp w ρ is the capillary force that the porous capillary core being measured can provide, ρ is the density of the measuring medium, ρ is a function of temperature, and g is the acceleration due to gravity.

[0027] According to the Yang-Laplace equation, the surface tension at the gas-liquid interface of a porous medium is...

[0028]

[0029] In the formula, σ is the surface tension coefficient of the measured medium, which is a function of temperature, θ is the contact angle, and d w The maximum pore size of the porous capillary core;

[0030] Substituting equation (2) into equation (1), we can obtain the formula for calculating the maximum pore diameter of the porous capillary core:

[0031]

[0032] The contact angle θ is close to 90°, that is

[0033] cosθ≈1(4)

[0034] Therefore, the maximum pore size of the porous capillary wick of the evaporator under test is...

[0035]

[0036] The beneficial effects of this invention are:

[0037] By improving the porous capillary wick immersion pretreatment method and automatically detecting the breakdown time, while correcting for the effects of gravity pressure difference and temperature, the accuracy of the maximum pore size measurement of the porous capillary wick in the evaporator is improved. At the same time, the invention has a high degree of automation and has the advantages of easy operation, high efficiency and low cost. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the maximum pore diameter measurement system for the porous capillary wick of the evaporator used in the loop heat pipe according to the present invention.

[0039] In the diagram, 1. Measuring medium storage tank; 2. Controllable micro-flow injection pump; 3. High-precision pressure generator; 4. Sensitive pressure sensor A; 5. Sensitive pressure sensor B; 6. Distance sensor; 7. Temperature sensor; 8. Evaporator under test; 9. Evaporator shell; 10. Porous capillary wick; 11. Evaporator connecting pipeline; 12. Solenoid valve I; 13. Solenoid valve II; 14. Solenoid valve III; 15. Solenoid valve IV; 16. Solenoid valve V; 17. Solenoid valve VI; 18. Low-speed vacuum pump. Detailed Implementation

[0040] To make the features and technical solutions of this invention clearer, the operating principle and control logic of this invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific examples described herein are only for explaining this invention and are not intended to limit this invention.

[0041] A system for measuring the maximum pore diameter of a porous capillary wick for an evaporator in a loop heat pipe, such as... Figure 1 As shown, it includes a measuring medium storage tank (1), a controllable micro-flow injection pump (2), a high-precision pressure generator (3), two sensitive pressure sensors (4, 5), a distance sensor (6), a temperature sensor (7), an evaporator to be tested (8), solenoid valves I-VI (12-17), a low-speed vacuum pump (18), a transparent flexible connecting pipeline, and a background measurement and control system.

[0042] The measuring medium storage tank (1) is connected to the controllable micro-flow injection pump (2) through pipelines and solenoid valve I (12); the measuring medium storage tank (1) contains liquids such as acetone, water, and ethanol as measuring media.

[0043] The evaporator (8) under test is installed vertically in space. Its lower end is connected to the controllable micro-flow injection pump (2) through solenoid valve II (13), to the high-precision pressure generator (3) through solenoid valve III (14), and to the low-speed vacuum pump (18) through solenoid valve VI (17). The upper end of the evaporator (8) under test is connected to the atmosphere through solenoid valve IV (15) and to the low-speed vacuum pump (18) through solenoid valve V (16).

[0044] The sensitive pressure sensor A (4) is installed on the connecting pipe between the solenoid valve III (14) and the high-precision pressure generator (3). The temperature sensor (7) and the sensitive pressure sensor B (5) are installed on the connecting pipe between the upper end of the evaporator (8) under test and the solenoid valve IV (15). The function of the distance sensor (6) is to measure the relative height between the sensitive pressure sensor A (4) and the sensitive pressure sensor B (5).

[0045] The outlet of the low-speed vacuum pump (18) is connected to the atmosphere.

[0046] The controllable micro-flow injection pump (2), high-precision pressure generator (3), low-speed vacuum pump (18), and all solenoid valves (12-17) are controlled by the background measurement and control system. The data acquired by the distance sensor (6), temperature sensor (7), sensitive pressure sensor A (4), and sensitive pressure sensor B (5) are processed and the measurement results are calculated by the background measurement and control system. The acquisition of sensor data and the control of related equipment can be achieved through NI modules (in conjunction with LabVIEW programs).

[0047] The measurement of the maximum pore diameter of the porous capillary wick for a loop heat pipe evaporator consists of two parts: the soaking pretreatment of the porous capillary wick to be tested and the measurement of the maximum pore diameter of the porous capillary wick. The measurement steps are as follows:

[0048] S1, the loop heat pipe evaporator (8) to be tested is set up... Figure 1 The device is installed vertically on the measurement system as shown in the diagram. The corresponding connecting pipelines are transparent flexible pipelines to accommodate the needs of evaporators of different sizes and structures. After installation, the positions of the sensitive pressure sensor B (5) and the sensitive pressure sensor A (4) are adjusted to be at the same height as the upper and lower ends of the evaporator (8) under test. Then, the distance sensor (6) measures the relative height ΔH between the sensitive pressure sensor A (4) and the sensitive pressure sensor B (5) under the control of the background measurement and control system.

[0049] S2, select the type of measurement medium on the control interface.

[0050] S3, close solenoid valves Ⅲ (14), ⅙ (16), and Ⅵ (17), and open solenoid valves Ⅰ (12), Ⅱ (13), and Ⅳ (15) to start the controllable micro-flow syringe pump (2), with an injection flow rate of approximately 1 mL / min. After the measuring medium overflows from solenoid valve Ⅳ (15), it indicates that the porous capillary wick has been completely wetted by the measuring medium. At this time, close the controllable micro-flow syringe pump (2).

[0051] S4, close solenoid valves I (12), II (13), III (14), and IV (15), start the low-speed vacuum pump (18), control the pumping speed to not exceed 10 L / min, first open solenoid valve V (16), and close solenoid valve V (16) when there is just no liquid in the transparent pipeline directly connected to the upper end of the evaporator (8) to be tested; open solenoid valve VI (17), and close solenoid valve VI (17) when there is just no liquid in the transparent pipeline directly connected to the lower end of the evaporator (8) to be tested, turn off the low-speed vacuum pump (18) and let it stand for about 5 minutes. At this point, the soaking pretreatment of the porous capillary wick is completed.

[0052] S5, close solenoid valve I (12), solenoid valve II (13), and solenoid valve IV (15), open solenoid valve III (14), start the high-precision pressure generator (3), and gradually increase the pressure in steps of about 1 kPa under the control of the background measurement and control system, maintaining each pressure condition for about 10 seconds. At the same time, continuously collect the measured values ​​of sensitive pressure sensor A (4), sensitive pressure sensor B (5), and temperature sensor (7). The background measurement and control system judges whether there is a significant change in the measured value of pressure sensor B (5). When the reading of sensitive pressure sensor B (5) increases by more than 1 kPa within 10 seconds, the background measurement and control system judges that the porous capillary core is broken down, and automatically records the average readings of sensitive pressure sensor A (4), sensitive pressure sensor B (5), and temperature sensor (7) under the previous pressure condition, which are respectively p A p B And T. The background monitoring and control system calculates the maximum pore diameter of the porous capillary wick of the evaporator under test based on the measured data. The calculation method is as follows:

[0053] The system pressure balance relationship considering gravity and temperature corrections is as follows:

[0054] p A =p B +Δp w +ρ(T)gΔH (1)

[0055] In the formula, Δp w ρ is the capillary force that the porous capillary wick being measured can provide, ρ is the density of the measuring medium, ρ is a function of temperature, and g is the acceleration due to gravity.

[0056] According to the Yang-Laplace equation, the surface tension at the gas-liquid interface of the porous medium (i.e., the capillary force provided by the porous capillary wick under test) is:

[0057]

[0058] In the formula, σ is the surface tension coefficient of the measured medium, which is a function of temperature, θ is the contact angle, and d w This represents the maximum pore size of the porous capillary core.

[0059] Substituting equation (2) into equation (1), we can obtain the formula for calculating the maximum pore diameter of the porous capillary core:

[0060]

[0061] Generally, the contact angle θ is close to 90°, therefore...

[0062] cosθ≈1(4)

[0063] Therefore, the back-end measurement and control system can calculate the maximum pore size of the porous capillary core according to the following formula and display it on the human-machine interface. The measurement and control system has a built-in table of physical property parameters of the measurement medium at different temperatures, and calculations can be performed through interpolation during the calculation process.

[0064]

Claims

1. A system for measuring the maximum pore diameter of a porous capillary wick for an evaporator used in a loop heat pipe, characterized in that, It includes an evaporator porous capillary wick soaking pretreatment subsystem, an evaporator porous capillary wick maximum pore diameter measurement subsystem, and a background measurement and control system; The evaporator porous capillary wick immersion pretreatment subsystem includes a measuring medium storage tank (1), a controllable micro-flow injection pump (2), and a low-speed vacuum pump (18), which are used to inject the measuring medium into the evaporator and remove excess measuring medium from the system. The evaporator porous capillary maximum pore diameter measurement subsystem includes a high-precision pressure generator (3), a sensitive pressure sensor, a temperature sensor (7), and a distance sensor (6), used to measure the maximum pore diameter of the evaporator porous capillary. The sensitive pressure sensor includes a sensitive pressure sensor A (4) and a sensitive pressure sensor B (5), which are used to measure the pressure of the high-precision pressure generator and to determine the moment when the porous capillary wick is punctured. During the measurement, the loop heat pipe evaporator (8) to be measured is vertically installed on the measurement system. The porous capillary wick (10) is located inside the loop heat pipe evaporator (8) to be measured. The positions of the sensitive pressure sensor B (5) and the sensitive pressure sensor A (4) are adjusted to be at the same height as the upper and lower ends of the loop heat pipe evaporator (8) to be measured. The distance sensor (6) is used to measure the relative height between the sensitive pressure sensor A (4) and the sensitive pressure sensor B (5); The background measurement and control system is used to read the measurement values ​​of the sensitive pressure sensor, temperature sensor and distance sensor, automatically determine the moment when the porous capillary is broken, and automatically calculate and display the measurement result of the maximum pore diameter of the porous capillary.

2. The system for measuring the maximum pore diameter of a porous capillary wick for an evaporator in a loop heat pipe according to claim 1, characterized in that, The measuring medium storage tank (1) contains the measuring medium and is connected to the controllable micro-flow injection pump (2) through pipelines and solenoid valve I (12); The loop heat pipe evaporator (8) to be tested is installed vertically. Its lower end is connected to the controllable micro-flow injection pump (2) through solenoid valve II (13), to the high-precision pressure generator (3) through solenoid valve III (14), and to the low-speed vacuum pump (18) through solenoid valve VI (17). Its upper end is connected to the atmosphere through solenoid valve IV (15) and to the low-speed vacuum pump (18) through solenoid valve V (16). The sensitive pressure sensor A (4) is installed on the connecting pipe between the solenoid valve III (14) and the high-precision pressure generator (3), and the temperature sensor (7) and the sensitive pressure sensor B (5) are installed on the connecting pipe between the upper end of the loop heat pipe evaporator (8) to be tested and the solenoid valve IV (15).

3. The system for measuring the maximum pore diameter of a porous capillary wick for an evaporator in a loop heat pipe according to claim 2, characterized in that, The controllable micro-flow injection pump (2), high-precision pressure generator 3, low-speed vacuum pump (18) and all solenoid valves (12-17) are controlled by the background measurement and control system. The data obtained by the distance sensor (6), temperature sensor (7), sensitive pressure sensor A (4), and sensitive pressure sensor B (5) are processed by the background measurement and control system to calculate the measurement results.

4. The system for measuring the maximum pore diameter of a porous capillary wick for an evaporator in a loop heat pipe according to claim 2 or 3, characterized in that, All connecting pipes are flexible and transparent.

5. A method for measuring the maximum pore diameter of a porous capillary wick for an evaporator used in a loop heat pipe, characterized in that, The measurement is performed using the maximum pore diameter measurement system for porous capillary wicks of evaporators for loop heat pipes as described in any one of claims 1-4, comprising the following steps: S1, the loop heat pipe evaporator (8) to be tested is vertically installed on the measurement system, and the porous capillary wick (10) is located inside the loop heat pipe evaporator (8) to be tested; the positions of the sensitive pressure sensor B (5) and the sensitive pressure sensor A (4) are adjusted to be at the same height as the upper and lower ends of the loop heat pipe evaporator (8) to be tested, and then the distance sensor (6) measures the relative height ΔH between the sensitive pressure sensor A (4) and the sensitive pressure sensor B (5) under the control of the background measurement and control system; S2, Select the type of measuring medium on the control interface; S3, close solenoid valves Ⅲ (14), ⅙ (16), and Ⅵ (17), open solenoid valves Ⅰ (12), Ⅱ (13), and Ⅳ (15), start the controllable micro-flow injection pump (2), the injection flow rate is 1mL / min, after the measuring medium overflows from solenoid valve Ⅳ (15), the porous capillary wick has been completely wetted by the measuring medium, and close the controllable micro-flow injection pump (2). S4, close solenoid valve I (12), solenoid valve II (13), solenoid valve III (14), and solenoid valve IV (15), start the low-speed vacuum pump (18), first open solenoid valve V (16), and close solenoid valve V (16) when there is just no liquid in the transparent pipeline directly connected to the upper end of the loop heat pipe evaporator (8) to be tested; open solenoid valve VI (17), and close solenoid valve VI (17) when there is just no liquid in the transparent pipeline directly connected to the lower end of the loop heat pipe evaporator (8) to be tested, turn off the low-speed vacuum pump (18) and let it stand for 5 minutes to complete the soaking pretreatment of the porous capillary core; S5, close solenoid valve I (12), solenoid valve II (13), and solenoid valve IV (15), open solenoid valve III (14), start the high-precision pressure generator (3), and gradually increase the pressure in steps of 1 kPa under the control of the background measurement and control system, maintaining each pressure condition for 10 seconds; at the same time, continuously collect the measured values ​​of sensitive pressure sensor A (4), sensitive pressure sensor B (5), and temperature sensor (7), and the background measurement and control system judges whether the measured value of sensitive pressure sensor B (5) has changed significantly. When the reading of sensitive pressure sensor B (5) increases by more than 1 kPa within 10 seconds, the background measurement and control system judges that the porous capillary core has been punctured, and automatically records the average readings of sensitive pressure sensor A (4), sensitive pressure sensor B (5), and temperature sensor (7) under the previous pressure condition, which are respectively p A p B And T, the background measurement and control system calculates the maximum pore diameter of the porous capillary core of the evaporator under test based on the measured data.

6. The method for measuring the maximum pore diameter of the porous capillary wick for a loop heat pipe evaporator according to claim 5, characterized in that, In step S5, the method for calculating the maximum pore diameter of the porous capillary wick of the evaporator to be tested is as follows: The system pressure balance relationship considering gravity and temperature corrections is as follows: p A =p B +Δp w +ρ(T)gΔH (1) In the formula, Δp w ρ is the capillary force that the porous capillary wick being measured can provide; ρ is the density of the measuring medium, a function of temperature; g is the acceleration due to gravity. According to the Yang-Laplace equation, the surface tension at the gas-liquid interface of a porous medium is... In the formula, σ is the surface tension coefficient of the measuring medium, which is a function of temperature; θ is the contact angle; d w This represents the maximum pore size of the porous capillary core. Substituting equation (2) into equation (1), we can obtain the formula for calculating the maximum pore diameter of the porous capillary core: The contact angle θ is close to 90°, that is cosθ≈1(4) Therefore, the maximum pore size of the porous capillary wick of the evaporator under test is...

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