Closed-loop temperature and pressure feedback high-precision interface thermal resistance testing device and method

Abstract

The invention relates to the technical field of thermal resistance testing, and discloses a closed-loop temperature and pressure feedback high-precision interface thermal resistance testing device and method. The upper heat insulation cylinder and the lower heat insulation cylinder are stacked and arranged on the weighing sensor, and heat flow meters are arranged in the upper heat insulation cylinder and the lower heat insulation cylinder; the first heat sink block is arranged between the bottom of the lower heat insulation cylinder and the weighing sensor, the second heat sink block is arranged on the top of the upper heat insulation cylinder, and the two TEC units are arranged on the faces, away from the heat flow meter, of the first heat sink block and the second heat sink block respectively. The multiple supporting columns are longitudinally arranged on the base in the circumferential direction of the weighing sensor, the clamping plate is arranged on the top of the second heat sink block, and the clamping plate is provided with multiple adjusting screws in threaded connection with the supporting columns. The device solves the problems of non-uniform pressure, large temperature fluctuation, remarkable heat loss and the like in the prior art, can accurately simulate the actual working condition during the ground test of the space camera, and remarkably improves the thermal resistance test precision.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal resistance testing, and particularly to a high-precision interfacial thermal resistance testing device and method with closed-loop temperature and pressure feedback, which is especially applicable to the coupled heat transfer analysis between the heat sink surface of a space camera and the cold surface of the main payload in a spacecraft. Background Art

[0002] With the rapid development of aerospace technology, the thermal management requirements of spacecraft and aircraft have become increasingly prominent. In an environment of extreme temperature, vacuum, and high heat flux density, the thermal stability of electronic devices and other key components has become a key factor in ensuring mission success. As a core parameter in the heat conduction path, interfacial thermal resistance directly affects the heat dissipation efficiency and reliability of devices. Therefore, the development of high-precision and high-reliability interfacial thermal resistance testing devices has become an important direction for thermal design and technological innovation in the aerospace field.

[0003] Common steady-state interfacial thermal resistance testing devices are based on the ASTM D-5470 standard and are mainly used to measure the thermal conductivity and contact thermal resistance of thermal interface materials (TIM). During the testing process, the sample is clamped between two constant-temperature blocks using mechanical screws or hydraulic pressure to ensure unidirectional heat flow. At the same time, temperature and heat flow data are monitored through sensors, and the thermal conductivity and interfacial thermal resistance are calculated in combination with the thickness and contact area of the sample.

[0004] However, in practical applications, interfacial thermal resistance is affected by various complex factors, such as contact pressure and extreme temperature environments. During the thermal management process, the heat transfer between different material interfaces is affected by the interfacial contact thermal resistance, which is due to the heat transfer hindrance caused by microscopic unevenness and gaps on the contact surface. Traditional testing methods (steady-state methods based on the ASTM D-5470 standard) use mechanical screws or hydraulic pressure to apply pressure to the interface material, which easily leads to excessive deviation in the pressure distribution on the contact surface of the interface material, cannot accurately simulate the actual crimping conditions, and are difficult to meet the measurement requirements under high-temperature (such as the surface of a supersonic aircraft) and low-temperature (such as a space vacuum environment) conditions. Summary of the Invention

[0005] The present invention proposes a high-precision interfacial thermal resistance testing device with closed-loop temperature and pressure feedback to solve the deficiencies in the above-mentioned prior art. This high-precision interfacial thermal resistance testing device solves the problem of uneven pressure in traditional technologies and can meet the measurement requirements under high-temperature and low-temperature conditions.

[0006] The technical solution of the present invention is: A high-precision interfacial thermal resistance testing device with closed-loop temperature and pressure feedback for testing the interfacial thermal resistance of a to-be-tested interface material, including a base, and further including:

[0007] A load cell, which is annular, and the load cell is arranged on the base; the load cell is used to monitor the pressure distribution on the contact surface.

[0008] The heat insulation cylinder includes an upper heat insulation cylinder and a lower heat insulation cylinder which are stacked and arranged on the load cell; heat flux meters are installed in the upper heat insulation cylinder and the lower heat insulation cylinder, and the interface material to be measured is clamped between the two heat flux meters;

[0009] The high and low temperature module includes a first heat sink, a second heat sink and two TEC units. The first heat sink is arranged between the bottom of the lower heat insulation cylinder and the load cell, and the first heat sink is located inside the annular space of the load cell. The second heat sink is arranged on the top of the upper heat insulation cylinder, and the two TEC units are respectively arranged on the sides of the first heat sink and the second heat sink away from the heat flux meters;

[0010] The pressure adjusting member includes: a plurality of support columns and a clamping plate. The plurality of support columns are all longitudinally arranged on the circumference of the load cell on the base, the clamping plate is arranged on the top of the second heat sink, and a plurality of adjusting screws threadedly connected to the support columns are provided on the clamping plate.

[0011] In at least one embodiment of the present invention, both the upper heat insulation cylinder and the lower heat insulation cylinder are of a double-layer structure. The inner layer of the upper heat insulation cylinder and the lower heat insulation cylinder is porous vacuum silica heat insulation cotton, the outer layer of the upper heat insulation cylinder and the lower heat insulation cylinder is polytetrafluoroethylene, and the surface of the polytetrafluoroethylene is coated with aluminum foil.

[0012] In at least one embodiment of the present invention, multiple pairs of thermocouples are provided in both of the two heat flux meters. Each pair of thermocouples is located in the same plane, the multiple pairs of thermocouples are longitudinally distributed in the heat flux meters, and the multiple thermocouples are signal-connected to a temperature inspection instrument.

[0013] In at least one embodiment of the present invention, a temperature control module is further included. NTC sensors are provided in both the first heat sink and the second heat sink, and the two NTC sensors and the two TEC units are all signal-connected to the temperature control module.

[0014] In at least one embodiment of the present invention, a first heat insulation ring is provided between the first heat sink and the load cell, and a second heat insulation ring is provided between the second heat sink and the clamping plate.

[0015] In at least one embodiment of the present invention, the base is in a Π shape. A first mounting hole is provided on the base below the load cell, a second mounting hole is provided on the clamping plate, radiators passing through the first mounting hole and the second mounting hole are respectively provided on the sides of the two TEC units away from the first heat sink and the second heat sink, and a heat conducting block is provided between the radiator in the first mounting hole and the TEC unit.

[0016] In at least one embodiment of the present invention, a plurality of first threaded holes are provided circumferentially on the weighing sensor on the base, and a plurality of the support columns are respectively threadedly connected in the first threaded holes. Second threaded holes are provided at the tops of the plurality of support columns. Through holes corresponding to the plurality of support columns are provided on the clamping plate, and a plurality of adjusting screws respectively pass through the through holes and are threadedly connected to the second threaded holes.

[0017] The present invention also discloses a high-precision interfacial thermal resistance testing method based on closed-loop temperature control and pressure feedback, including the following steps:

[0018] S1: Device assembly. Bond the porous vacuum silica thermal insulation cotton to the inner walls of the upper thermal insulation cylinder and the lower thermal insulation cylinder through epoxy resin; place the two heat flux meters sandwiching the material of the interface to be measured on the first heat sink, and then sequentially sleeve the lower thermal insulation cylinder and the upper thermal insulation cylinder outside the two heat flux meters; then assemble the second heat sink and the clamping plate; and connect the plurality of thermocouples to the temperature inspection instrument.

[0019] S2: Pressure system debugging. During the process of rotating the adjusting screw, the pressure distribution is real-time feedback through the weighing sensor, and the torque of the adjusting screw is adjusted until the pressure distribution on the contact surface of the material of the interface to be measured is uniform.

[0020] S3: Device startup. Start the two TEC units and respectively set the target temperatures of the two TEC units.

[0021] S4: Data acquisition and thermal resistance calculation. After the system reaches a steady state, data is acquired through the temperature inspection instrument, and the temperature curve is fitted by the least squares method, and then the interfacial thermal resistance is calculated according to R = ΔT / Q.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. The present invention is provided with an annular weighing sensor on the base; an upper heat insulation barrel and a lower heat insulation barrel equipped with heat flux meters; a high and low temperature module composed of a first heat sink, a second heat sink and two TEC units; and a pressure adjusting member composed of a plurality of support columns, clamping plates and screws. When assembling the interface thermal resistance test device before testing, two heat flux meters sandwiching the interface material to be tested are placed on the first heat sink, and then the lower heat insulation cylinder and the upper heat insulation cylinder are sequentially sleeved outside the two heat flux meters. Subsequently, the second heat sink and the clamping plate are assembled. During the process of rotating and adjusting the screws, the corresponding screw torque is adjusted through the pressure distribution real-time feedback by the weighing sensor, so that the pressure distribution on the contact surface of the interface material to be tested is more uniform. Through relevant experiments, the present invention realizes quantitative feedback through the weighing sensor, and the pressure uniformity is improved by 50%. And the present invention realizes two-way temperature control by arranging TEC units on the top and bottom of the upper heat insulation barrel and the lower heat insulation barrel. And because the TEC supports two-way switching of heating / cooling, it can meet the measurement requirements of the interface material under high temperature and low temperature conditions. It is experimentally verified that the device can reach a steady state within 10 minutes, meeting the transient test requirements of space cameras.

[0024] 2. The present invention is provided with a temperature control module, and NTC sensors are arranged in both the first heat sink and the second heat sink. And the two NTC sensors and the two TEC units are all signal-connected to the temperature control module, thereby forming a closed-loop temperature control system. It is experimentally verified that different from the prior art with a temperature fluctuation > ±0.1 °C, the present invention can reduce the temperature fluctuation to ±0.05 °C through the TEC and closed-loop control.

[0025] 3. The present invention adopts an upper heat insulation barrel and a lower heat insulation barrel composed of an inner layer of porous vacuum silicon heat insulation cotton and an outer layer of polytetrafluoroethylene with an aluminized foil surface. During the temperature measurement process of the device, the one-dimensionality of heat flow is ensured, and the lateral heat loss is significantly reduced. It is experimentally verified that the lateral heat loss rate < 5%, and compared with the traditional single-layer heat insulation scheme, the lateral heat loss rate is reduced by 80%.

[0026] 4. The present invention is provided with multiple pairs of thermocouples in the two heat flux meters above and below the interface material to be tested. Compared with the traditional temperature measurement point layout method, it is experimentally verified that the thermal resistance calculation error is reduced from the traditional 5% to within 3.8%.

[0027] 5. The present invention uses a TEC module for temperature control, integrates the most space-consuming high and low temperature module into the device, realizes miniaturized design, and can be integrated into a ground test platform or a constant temperature vacuum test chamber. It supports the replacement of rectangular and circular fixtures and adapts to different shapes of thermal interface materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a three-dimensional structural schematic diagram of the present invention;

[0029] Figure 2Schematic diagram of the front view cross-section of the present invention;

[0030] Figure 3 Schematic diagram of the three-dimensional structure of the high and low temperature module of the present invention;

[0031] Figure 4 Schematic diagram of the cross-section structure of the high and low temperature module of the present invention;

[0032] Figure 5 Logic block diagram of the temperature control closed loop of the present invention;

[0033] Figure 6 Schematic diagram of the top view structure of the second heat sink and the TEC unit of the present invention;

[0034] Figure 7 Schematic diagram of the cross-section structure of the second heat sink and the TEC unit of the present invention;

[0035] Figure 8 Schematic diagram of the three-dimensional structure of the heat insulation cylinder and the heat insulation ring of the present invention;

[0036] Figure 9 Schematic diagram of the cross-section structure of the three-dimensional structure of the heat insulation cylinder and the heat insulation ring of the present invention.

[0037] Explanation of reference numerals:

[0038] 1. Base; 11. First mounting hole; 12. Second threaded hole; 2. Weighing sensor; 3. Heat insulation cylinder; 31. Upper heat insulation cylinder; 32. Lower heat insulation cylinder; 4. Interface material to be measured; 41. Heat flux meter; 42. Thermocouple; 51. First heat sink; 511. First heat insulation ring; 52. Second heat sink; 521. Second heat insulation ring; 53. TEC unit; 54. Radiator; 541. Heat conduction block; 6. Pressure regulating member; 61. Support column; 611. Second threaded hole; 62. Clamping plate; 621. Mounting hole; 63. Adjusting screw. Detailed implementation manners

[0039] The drawings in the present invention are not strictly drawn according to the actual ratio, and the specific dimensions and quantities of each structure can be determined according to actual needs. The drawings described in the present invention are only schematic diagrams of the structure.

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings as understood by those of ordinary skill in the art to which the present invention pertains. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. "Inside", "outside", "above", "below", "far", "near", "front", "rear", etc. are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0042] In the spacecraft thermal control system, the interfacial thermal resistance between the heat sink surface of the space camera and the cold surface of the main payload is a key parameter affecting the heat dissipation performance of the equipment. The traditional thermal resistance test method (steady-state method based on ASTM D-5470 standard) has the following technical defects:

[0043] Uneven pressure control: The mechanical screws or hydraulic pressurization lack real-time feedback, resulting in a deviation of the contact surface pressure distribution exceeding 20%, and it is impossible to accurately simulate the actual crimping condition.

[0044] Insufficient temperature stability: The traditional temperature control system (such as resistance heating) has low precision (above ±0.5°C), and the temperature fluctuation under PID control is ≥±0.1°C, making it difficult to meet the high-precision test requirements.

[0045] Significant lateral heat loss: The single-layer thermal insulation material cannot play an efficient heat insulation function, and has a high thermal conductivity (for fiberglass wool it is (0.04 W·m-1·K-1)), with a high lateral heat loss rate, which destroys the one-dimensionality of the heat flow.

[0046] Poor system adaptability: The existing device is bulky and cannot be adapted to small-scale test scenarios such as space cameras, and the temperature measurement points are sparse (4 - 6), with a thermal resistance calculation error of up to 5%.

[0047] In view of this, the present invention proposes a high-precision interfacial thermal resistance test device with closed-loop temperature and pressure feedback. This high-precision interfacial thermal resistance test device solves the problems of uneven pressure, large temperature fluctuations, significant heat loss, etc. in the traditional technology, can accurately simulate the actual conditions during the ground test of the space camera, and significantly improves the thermal resistance test accuracy.

[0048] Combined with Figures 1 to 9 As shown, a high-precision interfacial thermal resistance test device with closed-loop temperature and pressure feedback is used for testing the interfacial thermal resistance of the interfacial material 4 to be tested, and includes a base 1, and further includes:

[0049] The load cell 2 is annular and is arranged on the base 1; the range of the load cell 2 is: 0 kg - 500 kg, with an accuracy of ±0.1%, and the load cell 2 is used to monitor the pressure distribution on the contact surface in real time.

[0050] The heat insulation cylinder 3 includes an upper heat insulation cylinder 31 and a lower heat insulation cylinder 32 that are stacked and arranged on the load cell 2; heat flux meters 41 are installed in the upper heat insulation cylinder 31 and the lower heat insulation cylinder 32, and the interface material 4 to be measured is sandwiched between the two heat flux meters 41.

[0051] The high and low temperature module includes a first heat sink 51, a second heat sink 52 and two TEC units 53. The first heat sink 51 is arranged between the bottom of the lower heat insulation cylinder 32 and the load cell 2, and the first heat sink 51 is located inside the annular space of the load cell 2. The second heat sink 52 is arranged on the top of the upper heat insulation cylinder 31; the materials of the first heat sink 51 and the second heat sink 52 are copper (thermal conductivity 401 W·m -1 ·K -1 ); the thicknesses of the first heat sink 51 and the second heat sink 52 are 10 mm / 16 mm to ensure uniformity during temperature input; the two TEC units 53 are respectively arranged on the side of the first heat sink 51 and the second heat sink 52 away from the heat flux meter 41; specifically, the model of the TEC unit 53 is: Same Sky CP110, which supports ±12V bidirectional voltage, with a maximum temperature difference of 75 °C and a power of 82 W;

[0052] The pressure adjusting member 6 includes: a plurality of support columns 61 and a clamping plate 62. The plurality of support columns 61 are all longitudinally arranged on the circumference of the load cell 2 on the base 1, and the clamping plate 62 is arranged on the top of the second heat sink 52. A plurality of adjusting screws 63 that are threadedly connected to the support columns 61 are provided on the clamping plate 62; specifically, the torque accuracy of the adjusting screw 63 is ±1%, and the material of the adjusting screw 63 is high-strength alloy steel; when adjusting the pressure, pressure is evenly applied through a torque wrench.

[0053] As an alternative embodiment, both the upper heat insulation cylinder 31 and the lower heat insulation cylinder 32 are of double-layer structure. The inner layer of the upper heat insulation cylinder 31 and the lower heat insulation cylinder 32 is porous vacuum silicon insulation cotton with a thickness of 2 mm and a thermal conductivity of 0.012 W·m -1 ·K -1 ), whose function is to inhibit lateral heat conduction; the outer layer of the upper heat insulation cylinder 31 and the lower heat insulation cylinder 32 is polytetrafluoroethylene with a thickness of 5 mm and a thermal conductivity of 0.25 W·m -1 ·K -1 , and the surface of the polytetrafluoroethylene is aluminized (reflectivity ≥ 95%) to reduce radiant heat loss.

[0054] As an alternative embodiment, multiple pairs of thermocouples 42 are provided in each of the two heat flow meters 41. Each pair of thermocouples 42 is located in the same plane, and multiple pairs of thermocouples 42 are longitudinally distributed in the heat flow meter 41. Multiple thermocouples 42 are signal-connected to a temperature inspection instrument. Specifically, the number of thermocouples 42 is 12. The thermocouples 42 are K-type thermocouples (temperature measurement range -50 to +1300 °C, accuracy ±0.02 °C), and the hole pitch is regularly distributed at 30 mm, with key coverage of the area near the test interface. The height and diameter of each heat flow meter 41 are 100 mm and 50 mm respectively. To improve the temperature measurement accuracy and reduce the measurement error, each heat flow meter 41 is axially machined with three groups of temperature measurement holes, each group containing two holes, and the average value of the temperatures measured at the two holes at the same axial position is taken as the temperature value at that position.

[0055] As an alternative embodiment, it further includes a temperature control module. NTC sensors are provided in both the first heat sink 51 and the second heat sink 52. The two NTC sensors and the two TEC units 53 are all signal-connected to the temperature control module. Specifically, the temperature control module is a PID controller. The NTC sensors (-40 to +105 °C) collect the heat sink temperature in real time, and the PID controller dynamically adjusts the TEC power. It reaches a steady state within 10 minutes, and the temperature fluctuation ≤0.05 °C, with the response speed increased by 3 times compared to the traditional solution.

[0056] As an alternative embodiment, a first heat insulation ring 511 is provided between the first heat sink 51 and the weighing sensor 2, and a second heat insulation ring 521 is provided between the second heat sink 52 and the clamping plate 62.

[0057] As an alternative embodiment, the base 1 is in a Π shape. A first mounting hole 11 is provided on the base 1 below the weighing sensor 2, and a second mounting hole 621 is provided on the clamping plate 62. Radiators 54 passing through the first mounting hole 11 and the second mounting hole 621 are respectively provided on the sides of the two TEC units 53 away from the first heat sink 51 and the second heat sink 52. The radiator 54 is an adjustable-speed fan (rotation speed 500 rpm - 3000 rpm). A heat conduction block 541 is provided between the radiator 54 and the TEC unit 53 in the first mounting hole 11.

[0058] As an alternative embodiment, a plurality of first threaded holes 12 are provided circumferentially on the base 1 around the weighing sensor 2. A plurality of support columns 61 are distributed and threadedly connected in the first threaded holes 12. Second threaded holes 611 are provided at the tops of the plurality of support columns 61. Through holes corresponding to the plurality of support columns 61 are provided on the clamping plate 62. A plurality of adjusting screws 63 are distributed and pass through the through holes and are threadedly connected to the second threaded holes 611.

[0059] As an alternative embodiment, the overall dimensions of the device are 300mm×200mm×150mm, and the weight is 5.8kg. It can be integrated into a ground test platform or a constant-temperature vacuum experimental chamber; Quick-change interface: Supports the replacement of rectangular and circular fixtures, and adapts to different shapes of thermal interface materials.

[0060] The present invention also proposes a high-precision interfacial thermal resistance testing method based on closed-loop temperature control and pressure feedback, including the following steps:

[0061] S1: Device assembly. Bond the porous vacuum silica insulation cotton to the inner walls of the upper heat insulation cylinder 31 and the lower heat insulation cylinder 32 through epoxy resin. Bond the double-layer material through epoxy resin, and the lateral heat loss rate <5%, which is 80% lower than the single-layer insulation scheme; Place the two heat flux meters 41 sandwiching the interface material 4 to be measured on the first heat sink 51, and then sequentially sleeve the lower heat insulation cylinder 32 and the upper heat insulation cylinder 31 outside the two heat flux meters 41; Subsequently, assemble the second heat sink 52 and the clamping plate 62; And connect multiple thermocouples 42 to the temperature patrol instrument.

[0062] S2: Pressurization system debugging. During the process of rotating the adjusting screw 63, the pressure distribution is real-time feedback through the load cell 2, and the screw torque is adjusted so that the pressure deviation of the contact surface of the interface material 4 to be measured ≤5%.

[0063] S3: Device startup. Start the two TEC units 53, and set the target temperatures of the two TEC units 53 respectively (such as -20°C or +85°C), and adjust the power through the PID controller; The cooling fan (5) automatically adjusts the speed according to the temperature rise, and the system reaches a steady state within 10 minutes (temperature fluctuation ≤0.02°C);

[0064] S4: Data acquisition and thermal resistance calculation. After the system reaches a steady state, use the MEASUREFINE TCP-16 multi-channel temperature patrol instrument (sampling frequency 10Hz), and the upper computer fits the temperature curve by the least square method, and calculates the interfacial thermal resistance in real time through the preset function R = ΔT / Q, and generates a test report (error <1%).

[0065] Compared with the prior art, the beneficial effects of the present invention and the data sources are described

[0066] 1. The pressure uniformity is increased by 50%

[0067] Experimental method:

[0068] Control group: A traditional manual screw-adjusting pressurizing device (without load cell feedback) was used to apply a pressure of 500 N. The Fujifilm Prescale pressure distribution film was used to measure the contact surface pressure distribution, and the calculated standard deviation was σ1 = 18.68 N; Experimental group: The closed-loop pressure feedback system of the present invention was used to apply the same pressure, and the measured standard deviation σ2 = 9.36 N; Improvement ratio: Uniformity improvement rate

[0069] Data source: Test instrument: Fujifilm Prescale pressure distribution film (accuracy ±5%).

[0070] Test conditions: Room temperature 25°C, and the experiment was repeated 10 times and the average value was taken.

[0071] 2. The temperature fluctuation is reduced to ±0.05°C

[0072] Experimental method:

[0073] Control group: Traditional resistance heating + PID control (without TEC), the target temperature was set at 50°C, and a Keysight 34972A temperature recorder was used to collect data. The temperature fluctuation range was ±0.2°C; Experimental group: TEC + PID closed-loop control of the present invention, and the temperature fluctuation range was ±0.05°C under the same conditions.

[0074] Verification standard: According to JJF 1049-2024 "Temperature Sensor Calibration Specification", continuous sampling was carried out for 1 hour under steady state, and the peak-to-peak value of the fluctuation ≤ 0.05°C.

[0075] Data source: Test instrument: Keysight 34972A (accuracy ±0.01°C), sampling interval 1 second.

[0076] Test environment: Constant temperature laboratory (temperature fluctuation ±0.5°C).

[0077] 3. The lateral heat loss rate is reduced by 80%

[0078] Calculation method:

[0079] Control group: Single-layer glass fiber cotton (thermal conductivity 0.04 W·m -1 ·K -1 ), heat flux density Q1 = 1000 W / m 2 , lateral heat loss rate η1 = 30%; Experimental group: The double-layer heat insulation structure of the present invention (porous vacuum silicon heat insulation cotton + polytetrafluoroethylene, equivalent thermal conductivity 0.035 W·m -1 ·K -1 ), under the same heat flux density, the lateral heat loss rate η2 = 5%; Reduction ratio: (rounded to 80%).

[0080] Verification experiment: Measure the axial and transverse heat flux components using a heat flux meter and calculate the loss rate;

[0081] Test conditions: Temperature difference ΔT = 50 °C, and maintain the steady state for 2 hours.

[0082] 4. Reduce the calculation error of thermal resistance to 3.8%

[0083] The calculation of interfacial thermal resistance is based on the steady-state heat flux method, and the formula is: The calculation error of thermal resistance is mainly caused by the following factors: Temperature difference measurement error (δΔT): Affected by the accuracy of thermocouples, the layout of temperature measurement points, and the fitting algorithm; Heat flux density calculation error (δQ): Measurement error of heating power, calibration error of heat transfer area; Systematic error: Heat loss, incomplete elimination of contact thermal resistance, etc.

[0084] Experimental verification and error calculation steps:

[0085] Step 1: Calibrate using a standard sample. Select a standard thermal interface material certified by ASTM D5470 (nominal thermal resistance R ref = 0.025 K·cm 2 / W); Fix the heat flux density (Q = 1000 W / m 2 ), and measure the temperature difference ΔT under steady state.

[0086] Step 2: Compare the measured value with the nominal value. Measure the temperature difference ΔT 实测 through 12 temperature measurement points, and calculate Error calculation:

[0087] Step 3: Repeatability test and statistics. Conduct 10 independent tests on the same standard sample, and calculate the average error and standard deviation.

[0088]

[0089] Average error: 3.7%;

[0090] Standard deviation: 0.18%;

[0091] Final statement: Error ≤ 3.8% (take the maximum value).

[0092] Data source: Calibration sample: ASTM D5470 standard thermal interface material (nominal thermal resistance 0.025 K·cm 2 / W); Test instrument: MEASUREFINE TCP-16 multi-channel temperature inspection instrument (sampling error ±0.02 °C).

[0093] 5. Miniaturized design is adapted to multiple scenarios

[0094] Measured data: Volume of the traditional device: 500×400×300 mm, weight 20 kg; Volume of the present invention: 300×200×150 mm, weight 8 kg, with a 60% reduction in volume.

[0095] Adaptability verification: Integrated testing was carried out in the ground test platform of the space camera (size limit 400×300×200 mm), and the measurement of the thermal resistance of the heat sink surface was successfully completed.

[0096] The above embodiments are only specific implementation manners of the present invention patent, which are used to illustrate the technical solutions of the present invention patent, rather than to limit it. The protection scope of the present invention patent is not limited thereto. Although the present invention patent has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: Any person skilled in the art within the technical scope disclosed by the present invention can still modify the technical solutions recorded in the foregoing embodiments, or can easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions implemented by the present invention patent, and should all be covered by the protection scope of the present invention.

Claims

1. A high-precision interface thermal resistance testing device with closed-loop temperature and pressure feedback, used for testing the interface thermal resistance of an interface material (4) to be tested, comprising a base (1), characterized in that: Also includes: The weighing sensor (2) is annular and is arranged on a base (1); the weighing sensor (2) is used to monitor the pressure distribution on the contact surface. The heat-insulating cylinder (3) comprises an upper heat-insulating cylinder (31) and a lower heat-insulating cylinder (32) which are stacked on each other and arranged on the weighing sensor (2); a heat flow meter (41) is installed in the upper heat-insulating cylinder (31) and the lower heat-insulating cylinder (32), and the interface material (4) to be measured is sandwiched between the two heat flow meters (41); A high and low temperature module, comprising a first heat sink block (51), a second heat sink block (52) and two TEC units (53), wherein the first heat sink block (51) is arranged between the bottom of a lower heat insulation tube (32) and a weighing sensor (2), the first heat sink block (51) is located inside the annular space of the weighing sensor (2), the second heat sink block (52) is arranged on the top of an upper heat insulation tube (31), and the two TEC units (53) are respectively arranged on a side of the first heat sink block (51) and a side of the second heat sink block (52) away from a heat flow meter (41); The pressure regulating member (6) comprises: a plurality of supporting columns (61) and a clamping plate (62), wherein the plurality of supporting columns (61) are longitudinally arranged on the base (1) in the circumference of the weighing sensor (2), the clamping plate (62) is arranged on the top of the second heat sink block (52), and the clamping plate (62) is provided with a plurality of adjusting screws (63) threadedly connected to the supporting columns (61).

2. A high-precision interface thermal resistance testing device with closed-loop temperature and pressure feedback as claimed in claim 1, characterized in that: It also comprises a temperature control module, wherein the first heat sink block (51) and the second heat sink block (52) are both provided with NTC sensors, and the two NTC sensors and the two TEC units (53) are both connected to the temperature control module signals.

3. A high-precision interface thermal resistance testing device with closed-loop temperature and pressure feedback as claimed in claim 1, characterized in that: The upper insulation tube (31) and the lower insulation tube (32) are both double-layer structures, the inner layers of the upper insulation tube (31) and the lower insulation tube (32) are porous vacuum silicon insulation cotton, and the outer layers of the upper insulation tube (31) and the lower insulation tube (32) are polytetrafluoroethylene, and the surface of the polytetrafluoroethylene is plated with aluminum foil.

4. A high-precision interface thermal resistance testing device with closed-loop temperature and pressure feedback as claimed in claim 1, characterized in that: Both of the heat flow meters (41) are provided with a plurality of pairs of thermocouples (42), each pair of the thermocouples (42) is located in the same plane, the plurality of pairs of the thermocouples (42) are longitudinally distributed in the heat flow meter (41), and the plurality of thermocouples (42) are connected to the temperature patrol meter signal.

5. A high-precision interface thermal resistance testing device with closed-loop temperature and pressure feedback as claimed in claim 1, characterized in that: A first heat insulating ring (511) is provided between the first heat sink block (51) and the weighing sensor (2), and a second heat insulating ring (521) is provided between the second heat sink block (52) and the clamping plate (62).

6. A high-precision interface thermal resistance testing device with closed-loop temperature and pressure feedback as claimed in claim 1, characterized in that: The base (1) is ∏-shaped, a first mounting hole (11) is provided on the base (1) below the weighing sensor (2), a second mounting hole (621) is provided on the clamping plate (62), a heat sink (54) passing through the first mounting hole (11) and the second mounting hole (621) is provided on one side of the two TEC units (53) away from the first heat sink block (51) and the second heat sink block (52), respectively, and a heat conduction block (541) is provided between the heat sink (54) and the TEC unit (53) in the first mounting hole (11).

7. A high-precision interface thermal resistance testing device with closed-loop temperature and pressure feedback as claimed in claim 1, characterized in that: A plurality of first threaded holes (12) are provided in the circumference of the weighing sensor (2) on the base (1), a plurality of the support columns (61) are distributed and threadedly connected in the first threaded holes (12), a second threaded hole (611) is provided at the top of each of the plurality of the support columns (61), a through hole corresponding to the plurality of the support columns (61) is provided on the clamping plate (62), and a plurality of the adjusting screws (63) are distributed and pass through the through holes and are threadedly connected to the second threaded holes (611).

8. A high-precision interface thermal resistance test method based on closed-loop temperature control and pressure feedback, based on the high-precision interface thermal resistance test device of closed-loop temperature and pressure feedback as claimed in claim 1, characterized in that: The following steps are involved: S1: assembling the device, placing the two heat flow meters (41) sandwiching the interface material (4) to be measured on the first heat sink block (51), and then sleeve the lower heat insulation tube (32) and the upper heat insulation tube (31) on the outer sides of the two heat flow meters (41) in sequence; then assembling the second heat sink block (52) and the clamping plate (62); A plurality of thermocouples (42) connected to a temperature inspection instrument are installed in the heat flow meter (41); S2: Debugging the pressurizing system. During the process of rotating the adjusting screw (63), the pressure distribution is fed back in real time by the weighing sensor (2), and the torque of the adjusting screw (63) is adjusted until the pressure distribution on the contact surface of the interface material (4) to be tested is uniform. S3: the device is started, the two TEC units (53) are started, and the target temperatures of the two TEC units (53) are respectively set; S4: Data collection and thermal resistance calculation. After the system reaches a steady state, data is collected through a temperature patrol meter, and the temperature curve is fitted by the least squares method. The interface thermal resistance is then calculated based on R=ΔT / Q.

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