A dual heat pipe surface temperature source and its calibration method

Abstract

The application provides a double-heat-pipe surface temperature source calibration device and a calibration method thereof. The calibration device comprises a temperature detector, a platinum resistance thermometer, a heat-pipe surface temperature source, a heating device, a heat-pipe temperature damper, a temperature equalizing block, an insulating layer, a temperature control system, a power meter and a computer. The heat-pipe surface temperature source and the heat-pipe temperature damper adopt high-purity cesium as a heat-pipe working medium, the shell adopts Inconel600 high-temperature alloy, and a high-temperature alloy wire mesh of the same material is welded in the inner cavity of the heat pipe as a liquid absorption core. The device can realize calibration of a surface thermometer in a temperature range of 300 DEG C to 660 DEG C, and can also calibrate various radiation thermometers by spraying a high-temperature-resistant high-emissivity coating on the surface as a blackbody radiation surface source, so that the temperature calibration capability and level of the surface temperature and the radiation bright temperature are significantly improved.

Description

Technical Field

[0001] This invention relates to a dual heat pipe surface temperature source and its calibration method for accurately calibrating surface temperature sensors and radiation thermometers, with an applicable temperature range of 300℃ to 660℃. Background Technology

[0002] A surface temperature source is a metrological standard used to calibrate surface temperature sensors. It typically employs a pure metal isotherm to generate a relatively uniform and stable surface temperature, which is then compared to the sensor's internal temperature for calibration. The stability and uniformity of the surface temperature source are closely related to the thermal properties of the metal material. Higher thermal conductivity results in better surface uniformity, while lower thermal conductivity leads to poorer uniformity. Furthermore, oxidation of the material surface at high temperatures alters its properties, affecting both temperature stability and uniformity. Typically, the temperature of the metal isotherm is used as the surface temperature of the source, neglecting the effects of heat exchange. This introduces greater uncertainty, impacting the accuracy of surface temperature calibration. This error is particularly pronounced above 300°C, leading to greater uncertainty in surface temperature sensor calibration. Therefore, there is an urgent need to develop more effective and novel surface temperature sources to improve calibration accuracy and achieve precise surface temperature measurement.

[0003] Blackbody radiation surface sources are reference temperature sources used to calibrate infrared radiation thermometers by generating a stable and uniform temperature field on a high-emissivity heated surface using the Stefan-Boltzmann law. Surface temperature sources, on the other hand, are temperature reference sources used to calibrate surface temperature sensors attached to their surfaces. Currently, these two temperature reference sources are independent of each other; no single reference source can simultaneously be used for calibrating both infrared radiation thermometers and surface temperature sensors. Heat pipes are highly efficient heat transfer elements that utilize the phase change of a working fluid for heat transfer, and are hailed as thermal superconductors or superconducting heat sources. Their working principle involves removing the gas dissolved in a high-purity working fluid, then filling the sealed heat pipe cavity under high vacuum using gravity. Heat is transferred from the high-temperature section to the low-temperature section using the phase change heat transfer of the working fluid under a small temperature difference. Simultaneously, under the influence of gravity and capillary attraction, the condensed working fluid returns to the high-temperature section. Therefore, heat pipes utilize the circulation of the working fluid to achieve efficient heat transfer and provide a relatively uniform temperature field for temperature calibration. Currently, there are reports of using low-temperature ammonia heat pipes in the -50℃ to 50℃ low-temperature range. However, in the 300℃~660℃ temperature range, due to the increased difficulty in manufacturing alkali metal heat pipes, there are currently no reports of alkali metal heat pipe blackbody radiation surface sources. The heat transfer coefficient λ of a heat pipe is determined by a variety of factors, including its shape design, working medium, internal structure, shell material, and operating temperature. Its calculation model is very complex. If it is simply used as a temperature equalization device, it is difficult to use the internal temperature to deduce the surface temperature by establishing a heat transfer model, making it difficult to simultaneously calibrate the radiation thermometer and the surface temperature sensor.

[0004] Meanwhile, the uniformity and stability of the temperature of the blackbody radiation surface source are key factors affecting its calibration accuracy. The reference source itself also needs to be placed in a highly uniform temperature field. Currently, temperature reference sources use a single temperature equalization block to provide a uniform temperature field for the reference source, but the temperature equalization effect is not ideal, which hinders the further improvement of temperature measurement accuracy.

[0005] In summary, there is currently no blackbody radiation surface temperature source in the 300℃~660℃ temperature range that can simultaneously calibrate surface temperature sensors and radiation thermometers. Summary of the Invention

[0006] To overcome the limitations of existing technologies that lack calibrating surface temperature sensors for heat pipe surface sources and calibrating radiation thermometers for temperatures ranging from 300℃ to 660℃, and to improve the calibration capabilities and levels of surface temperature and radiation temperature, this invention designs a dual heat pipe surface temperature source suitable for both temperature measurement needs. The temperature source includes a thermometer, a platinum resistance thermometer, a heat pipe surface temperature source, a heating device, a heat pipe temperature damper, a temperature equalization block, an insulation layer, a temperature control system, a power meter, and a computer. The heating device contains, from the outside in, a heat insulation layer, a heat pipe temperature damper, a heat spreader, and a heat pipe surface temperature source, arranged coaxially. The heat pipe temperature damper has a generally cylindrical accommodating space in its center for holding the heat pipe surface temperature source and the heat spreader. The heat pipe surface temperature source and the metal heat spreader are coaxially placed within this accommodating space, with the heat pipe surface temperature source positioned above the metal heat spreader. The temperature control system controls the heating power of the heating device, and the power meter measures the heating power and transmits the data to a computer. The upper surface of the heat pipe surface temperature source is coated with a high emissivity coating. A surface temperature sensor to be calibrated is located at the center of the upper surface of the heat pipe surface temperature source. A radiation thermometer to be calibrated is installed above the upper surface of the heat pipe surface temperature source. The thermometer is used to collect the upper surface temperature of the heat pipe surface temperature source obtained by the surface temperature sensor or radiation thermometer as the temperature measurement value to be calibrated. The sidewall of the heat pipe surface temperature source has a first gauge, a second gauge, and a third gauge in sequence from top to bottom along the vertical direction. The first temperature sensor, the second temperature sensor, and the third temperature sensor are respectively inserted into the three horizontal gauges of the heat pipe surface temperature source to obtain the first temperature T1, the second temperature T2, and the third temperature T3 inside the heat pipe surface temperature source and store them in the thermometer. The first temperature T1, the second temperature T2, and the third temperature T3 are located on the same vertical axis.

[0007] The computer establishes a thermal conductivity model based on the first temperature T1, the second temperature T2, the third temperature T3, and the heating power measured by the power meter, calculates the outer wall temperature of the upper surface of the heat pipe surface temperature source housing, and calibrates the temperature measurement value to be calibrated by the surface temperature sensor or radiation thermometer using the outer wall temperature of the upper surface of the heat pipe surface temperature source housing. Specifically, the computer establishes a first thermal conductivity model based on the first temperature T1, the second temperature T2, and the third temperature T3, calculates the inner wall temperature of the upper surface of the heat pipe surface temperature source housing, then establishes a second thermal conductivity model based on the inner wall temperature of the upper surface of the housing and the heating power measured by the power meter, calculates the outer wall temperature of the upper surface of the heat pipe surface temperature source housing, and finally calibrates the temperature measurement value to be calibrated by the surface temperature sensor or radiation thermometer using the outer wall temperature of the upper surface of the heat pipe surface temperature source housing.

[0008] The heating device is a two-stage high-precision heating furnace, which includes a bottom heating element and a side wall heating element. The heating powers of the bottom heating element and the side wall heating element are independently controlled by a temperature control system respectively.

[0009] For the heat pipe surface temperature source and the heat pipe temperature damper of the present application, high-purity cesium is used as the heat pipe working medium. The shells of the heat pipe surface temperature source and the heat pipe temperature damper are made of Inconel600 high-temperature alloy, and a high-temperature alloy wire mesh of the same material is welded inside the heat pipe cavity as the wick.

[0010] The three horizontal gauge wells on the side wall of the heat pipe surface temperature source shell are located in the upper half of the heat pipe surface temperature source. The thickness of the upper surface of the heat pipe surface temperature source shell is H1. The vertical distance between the horizontal axis of the first gauge well and the inner wall of the upper surface of the heat pipe surface temperature source shell is H2. The vertical distance between the horizontal axis of the first gauge well and the horizontal axis of the second gauge well is H3. The vertical distance between the horizontal axis of the second gauge well and the horizontal axis of the third gauge well is H4, where H1 < H2 < H3 = H4.

[0011] The present application also proposes a calibration method for a dual heat pipe surface temperature source. The calibration method includes:

[0012] Step 1: Establish a one-dimensional heat conduction equation set (2), (3) and (4) including the estimated temperature value T of the inner wall of the upper surface of the heat pipe surface temperature source shell interface,n , the first temperature T1, the second temperature T2, and the third temperature T3, that is, the first heat conduction model, specifically as follows:

[0013]

[0014] where n is the number for calculating the estimated temperature value of the inner wall of the upper surface of the heat pipe surface temperature source by the linear method in different one-dimensional heat conduction equations, and the thermal conductivity of the heat pipe surface temperature source is λ;

[0015] Step 2: Calculate the first estimated value T of the inner wall temperature of the upper surface of the heat pipe surface temperature source shell interface,1 , the second estimated value T interface,2 and the third estimated value T interface,3 respectively according to the above equation set;

[0016] Step 3: Calculate the average value of the three estimated values as the temperature value T of the inner wall of the upper surface of the heat pipe surface temperature source shell through the following formula (5) interface ;

[0017]

[0018] Step 4: Establish an equation including the temperature value T of the inner wall of the upper surface of the heat pipe surface temperature source shell interfaceThe outer wall temperature value T of the upper surface of the heat pipe surface temperature source housing surface The one-dimensional heat conduction equations (6), i.e. the second heat conduction model, are as follows:

[0019]

[0020] In equation (6), q is the power converted into heat as measured by the power meter; λsteel is the thermal conductivity of the shell material of the heat pipe surface temperature source 9.

[0021] Step 5: Calculate the outer wall temperature T of the upper surface of the heat pipe surface temperature source shell using the above formula (6). surface The calibration temperature value is compared with the temperature measurement value to be calibrated to complete the calibration of the surface temperature sensor or radiation thermometer.

[0022] This application utilizes heat pipe temperature damping technology to improve the surface source temperature stability of a heat pipe. Specifically, it leverages the efficient heat transfer of a ring-shaped heat pipe to provide a uniform temperature environment. Because the heat pipe absorbs heat through phase change, it mitigates the rise in external temperature; and by utilizing the vacuum within the heat pipe, it mitigates the drop in external temperature. When the external environment experiences fluctuations in temperature, the external ring-shaped heat pipe temperature damper acts as a temperature damper, reducing the amplitude of these fluctuations and thus improving the temperature stability within the external ring-shaped heat pipe cavity. Therefore, this technology is called a "heat pipe temperature damper" and can be used to improve the surface source temperature stability of a heat pipe. Thus, employing dual heat pipe technology can significantly improve the stability and uniformity of the surface source temperature, and enhance the calibration capability of surface temperature and radiation temperature.

[0023] This application designs and develops a dual heat pipe surface temperature source based on cesium heat pipes, which provides a uniform and stable surface temperature. It can be used to calibrate surface temperature sensors and also as a blackbody radiation surface source to calibrate radiation thermometers. Attached image description:

[0024] Figure 1 This is a schematic diagram of the overall surface temperature source of the dual heat pipes;

[0025] Figure 2 This is a schematic diagram of the cross-section of a heat pipe temperature damper;

[0026] Figure 3 This is a schematic diagram of the cross-section of the heat pipe surface source;

[0027] Figure 4 A schematic diagram illustrating the method for determining the surface temperature of a heat pipe;

[0028] Figure reference numerals: 1. Thermometer; 2. High emissivity coating; 3. Platinum resistance thermometer (first, second, and third temperature sensors are 3A, 3B, and 3C, respectively); 4. Heat pipe surface source; 5. Side wall heating element; 6. Heat pipe temperature damper; 7. Temperature distribution block; 8. Bottom heating element; 9. Insulation layer; 10. Temperature control system; 11. Power meter; 12. Computer. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] Figure 1 The diagram shows the overall structure of the dual heat pipe surface temperature source of the present invention. The device includes a thermometer 1, a high emissivity coating 2, first, second, and third temperature sensors 3A, 3B, and 3C, respectively, a heat pipe surface source 4, a heating device, a heat pipe temperature damper 6, a temperature equalization block 7, a temperature control system 9, a power meter 10, and a computer 11. Specifically, the temperature sensor is a platinum resistance thermometer.

[0031] Specifically, the heating device is a two-stage high-precision heating furnace. Inside the furnace chamber, from the outside in, a heat insulation layer 9, a heat pipe temperature damper 6, a metal homogenizing block 7, and a heat pipe surface source 4 are coaxially arranged. The heat pipe temperature damper 6 has a generally cylindrical accommodating space in its middle for placing the heat pipe surface temperature source 4 and the metal homogenizing block 7. The heat pipe surface temperature source 4 and the metal homogenizing block 7 are coaxially placed within the accommodating space, with the heat pipe surface temperature source 4 positioned above the metal homogenizing block 7.

[0032] The electrical power consumed by the heating device is supplied by the temperature control system 10, which uses a Eurotherm 3504 temperature controller and achieves accurate furnace temperature control through PID control. The power consumed is monitored by a power meter 11 and transmitted in real-time to the computer 12. The power meter is a PW-3335 power measuring instrument. The heating device includes a side wall heating unit 5 and a bottom heating unit 8. The heating current of each unit is independently controlled by the temperature control system 10, enabling three heating modes: side wall heating, bottom heating, and side wall / bottom heating. The insulation layer 9 in the furnace is made of non-flammable insulation material, ensuring that heat is not significantly lost from the bottom and sides under calibration conditions, and that only the top remains in contact with air during operation.

[0033] A surface temperature sensor to be calibrated is provided at the center of the upper surface of the heat pipe surface temperature source 4, or a radiation thermometer to be calibrated is provided above the upper surface of the heat pipe surface temperature source 4. The thermometer 1 is used to collect the upper surface temperature of the heat pipe surface temperature source 4 obtained by the surface temperature sensor or the radiation thermometer as the temperature measurement value to be calibrated and send it to the computer.

[0034] Figure 2 This is a schematic diagram of a heat pipe temperature damper 6. The heat pipe temperature damper 6 is a double-layered barrel shape, including a bottom and sidewalls. The shell of the heat pipe temperature damper 6 is a sealed cavity made of Inconel 600 high-temperature alloy steel. The heat pipe temperature damper 6 has a central accommodating space. Inside this sealed cavity, a high-temperature resistant Inconel 600 wire mesh is spot-welded as a liquid wick to increase the capillary attraction of the heat pipe. After welding the heat pipe cavity, it undergoes vacuum leak testing and cleaning. Following high-temperature vacuum degassing in a vacuum degassing furnace, high-purity cesium is filled using a negative pressure method. Because cesium is chemically very reactive, it undergoes a violent chemical reaction upon contact with oxygen or water vapor. Therefore, a high vacuum degree must be maintained inside the heat pipe cavity during filling. After filling, the heat pipe vacuum degree is maintained using a hydraulic cold sealing method. After completion, the heat pipe should be heated in a vacuum degassing furnace to allow the high-purity cesium to be uniformly adsorbed onto the inner wall of the annular heat pipe cavity. When the heat pipe temperature damper 6 is in operation, it can form a temperature field with extremely high temperature uniformity in the accommodating space. Its technical effect is far superior to that of ordinary temperature equalization blocks, which helps to improve the temperature accuracy of the heat pipe surface source 4.

[0035] Figure 3 This is a schematic diagram of the heat pipe surface source 4 of the present invention. To achieve a surface temperature of 300℃ to 660℃, the heat pipe surface source 4 also uses high-purity cesium as the heat pipe working fluid. The shell of the heat pipe surface source 4 in this application is made of Inconel 600 high-temperature alloy steel. A heating vacuum degassing method is used to remove as much gas as possible adsorbed inside the shell of the heat pipe surface source. A wire mesh of the same material is welded to the top of the internal cavity as a liquid wick to increase capillary attraction and ensure that the liquid film can be evenly spread during the operation of the heat pipe, making the surface temperature more uniform. Before filling with high-purity working fluid, the heat pipe shell needs to be heated and vacuum degassed for a long time. Then, high-purity liquid cesium is injected into the heat pipe through the filling tube under gravity. Finally, the filling tube is sealed using hydraulic cold sealing technology, completing the fabrication of the heat pipe surface source 4.

[0036] It is particularly noteworthy that both the heat pipe temperature damper 6 and the heat pipe surface source 4 in this application employ cesium heat pipe technology. Since both the heat pipe temperature damper 6 and the heat pipe surface source 4 can generate a highly uniform temperature field internally during high-temperature operation, and by placing the heat pipe surface source 4 within the accommodating space in the middle of the heat pipe temperature damper 6, the temperature stability of the heat pipe surface source 4 is significantly improved due to this double-nested cesium heat pipe structure. Specifically, compared to a single cesium heat pipe surface source, the heat pipe surface temperature source 4 using the heat pipe temperature damper 6 in this application exhibits at least an order of magnitude improvement in temperature stability between 300℃ and 660℃. Therefore, the dual heat pipe surface temperature source proposed in this application has significant technical advantages.

[0037] The upper surface of the heat pipe surface source 4 is coated with a black high-temperature coating, allowing it to be used not only for calibrating surface temperature sensors but also for calibrating radiation thermometers. With the black high-temperature coating applied, the emissivity of the heat pipe surface source 4 approaches 1, making it suitable as an ideal blackbody radiation surface source for calibrating radiation thermometers. During temperature calibration, the surface temperature sensor to be calibrated is placed on the upper surface of the heat pipe surface source 4, or the surface temperature of the upper surface of the heat pipe surface source 4 is measured using the radiation thermometer to be calibrated. The surface temperature obtained by the surface temperature sensor or radiation thermometer is used as the temperature value to be calibrated. The temperatures of the first, second, and third temperature sensors (3A, 3B, 3C) are then measured using a thermometer 1. A linear extrapolation method is used to determine the surface temperature of the heat pipe surface source, and this temperature is compared with the temperature value to be calibrated to determine the temperature correction values ​​for the surface temperature sensor and the radiation thermometer, thus achieving the calibration of the surface temperature sensor and the radiation thermometer.

[0038] Specifically, the side wall heater 5 and the bottom heater 8 are a two-stage heating device, and the temperature is controlled by a temperature control system 10. A heat pipe temperature damper 6 is placed inside the furnace of the two-stage heating device, and a temperature equalization block 7 is placed inside the heat pipe temperature damper to fix and support the heat pipe surface source 4. The electrical power consumed by the side wall heater 5 and the bottom heater 8 can be measured by a power meter 11 and stored in a computer 12. The two-stage heating device uses a Eurotherm 3504 temperature controller, and accurate furnace temperature control is achieved through PID control.

[0039] The sidewall of the heat pipe surface source 4 has three horizontal thermometer traps arranged vertically from top to bottom: a first thermometer trap, a second thermometer trap, and a third thermometer trap. A first temperature sensor 3A, a second temperature sensor 3B, and a third temperature sensor 3C are respectively inserted into the first, second, and third thermometer traps. The inner diameter of each thermometer trap is 5 mm, and its depth is 80 mm. Three platinum resistance thermometers are used. The first temperature sensor 3A acquires the first temperature T1 inside the heat pipe surface source 4, the second temperature sensor 3B acquires the second temperature T2 inside the heat pipe surface source 4, and the third temperature sensor 3C acquires the third temperature T3 inside the heat pipe surface source 4. Therefore, the first temperature T1, the second temperature T2, and the third temperature T3 are located on the same vertical axis.

[0040] Figure 4Schematic diagram of the method for determining the surface temperature of the heat pipe surface source. Preferably, the three horizontal gauging wells on the side wall of the housing of the heat pipe surface source 4 are located in the upper half of the heat pipe surface source 4. The thickness of the upper surface of the housing of the heat pipe surface source 4 is H1, that is, the vertical distance from the inner wall to the outer wall of the upper surface of the housing of the heat pipe surface source 4 is H1. The vertical distance between the horizontal axis of the first gauging well and the inner wall of the upper surface of the housing of the heat pipe surface source 4 is H2. The vertical distance between the horizontal axis of the first gauging well and the horizontal axis of the second gauging well is H3. The vertical distance between the horizontal axis of the second gauging well and the horizontal axis of the third gauging well is H4. Among them, H1 < H2 < H3 = H4. The purpose of such a setting is to ensure the uniformity of the first temperature T1, the second temperature T2, and the third temperature T3, and at the same time make the first gauging well as close as possible to the inner wall of the upper surface of the housing of the heat pipe surface source 4. In a preferred embodiment, H1 = 5 mm, H2 = 9 mm, H3 = H4 = 10 mm. According to one-dimensional Fourier heat conduction, based on the measured first temperature, second temperature, third temperature and their relative positions, the surface temperature of the surface source can be calculated.

[0041] Figure 4 Schematic diagram of the extrapolation method for the upper surface of the heat pipe surface source 4. According to the one-dimensional heat conduction equation (1):

[0042]

[0043] It can be seen from the above one-dimensional heat conduction equation that the heat flux density is equal in the axial direction of the heat pipe surface source 4. Therefore, for the heat pipe surface source 4, its axial temperature distribution is linearly related to the axial position. The temperature of the inner wall of the upper surface of the housing of the heat pipe surface source is calculated by a linear method; then the temperature of the outer wall of the surface is calculated according to the power measured by the power meter according to the one-dimensional heat conduction equation. Specifically as follows:

[0044] Step 1: Establish a one-dimensional heat conduction equation set (2), (3) and (4) including the estimated temperature value T interface,n of the inner wall of the upper surface of the housing of the heat pipe surface source 4, the first temperature T1, the second temperature T2, and the third temperature T3, that is, the first heat conduction model, specifically as follows:

[0045]

[0046] Where n is the number of the estimated value of the temperature of the inner wall of the upper surface of the housing of the heat pipe surface source 4 calculated by the linear method in different one-dimensional heat conduction equations, and the thermal conductivity of the heat pipe surface source 4 is λ. Since both sides of the equation are multiplied by the thermal conductivity λ in the above equation, it can be canceled out during the calculation process, thus avoiding the modeling and complex calculation of the thermal conductivity of the heat pipe surface source 4.

[0047] Step 2: According to the above equation set, calculate the first estimated value T interface,1 of the temperature of the inner wall of the upper surface of the housing of the heat pipe surface source and the second estimated value T interface,2and the third estimated value T interface,3 .

[0048] Step 3: Calculate the average of the three estimated values ​​using the following formula (5) as the inner wall temperature T of the upper surface of the heat pipe surface source shell. interface .

[0049]

[0050] Step 4: Establish the temperature value T of the inner wall of the upper surface of the heat pipe surface source 4 shell. interface 4. Temperature value T of the outer wall of the upper surface of the heat pipe surface source 4 shell surface The one-dimensional heat conduction equations (6), i.e. the second heat conduction model, are as follows:

[0051]

[0052] In equation (6), q is the power converted into heat as measured by power meter 11; λsteel is the thermal conductivity of the shell material of heat pipe surface source 4, which is the thermal conductivity of Inconel 600 stainless steel in this embodiment.

[0053] Step 5: Calculate the outer wall temperature T of the upper surface of the heat pipe surface source 4 shell using the above formula (6). surface The calibration temperature value is compared with the temperature measurement value to be calibrated on the surface of the heat pipe surface source 4 collected by the surface temperature sensor or radiation thermometer to complete the calibration of the surface temperature sensor or radiation thermometer.

[0054] Those skilled in the art will understand that the above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A dual heat pipe surface temperature source calibration apparatus, characterized by, The calibration device comprises a temperature measuring instrument, a platinum resistance thermometer, a heat pipe surface temperature source, a heating device, a heat pipe temperature damper, a temperature equalizing block, an adiabatic layer, a temperature control system, a power meter and a computer. The heating device is internally provided with, from outside to inside, an adiabatic layer, a heat pipe temperature damper, a temperature equalizing block and a heat pipe surface temperature source in sequence, the heat pipe temperature damper has a cylindrical accommodating space in the middle part for placing the heat pipe surface temperature source and the temperature equalizing block, the heat pipe surface temperature source and the metal temperature equalizing block are coaxially placed in the accommodating space, and the heat pipe surface temperature source is above the metal temperature equalizing block. The temperature control system is used for controlling the heating power of the heating device, and the power meter is used for measuring the heating power of the heating device and sending the heating power to the computer. The upper surface of the heat pipe surface temperature source is sprayed with a high-emissivity coating. A surface temperature sensor to be calibrated is arranged at the center position of the upper surface of the heat pipe surface temperature source, or a radiation thermometer to be calibrated is arranged above the upper surface of the heat pipe surface temperature source, and the temperature measuring instrument is used for collecting the upper surface temperature of the heat pipe surface temperature source obtained by the surface temperature sensor or the radiation thermometer as a to-be-calibrated temperature measurement value. First, second and third temperature sensors are respectively inserted into the three horizontal traps of the heat pipe surface temperature source, and first, second and third temperatures T1, T2 and T3 inside the heat pipe surface temperature source are respectively obtained and saved in the temperature measuring instrument, wherein the first, second and third temperatures T1, T2 and T3 are located on the same vertical axis. The computer establishes a heat conduction model according to the first, second and third temperatures T1, T2 and T3 and the heating power measured by the power meter, calculates the upper surface outer wall temperature of the heat pipe surface temperature source shell, and calibrates the to-be-calibrated temperature measurement value of the surface temperature sensor or the radiation thermometer according to the upper surface outer wall temperature of the heat pipe surface temperature source shell.

2. The dual heat pipe surface temperature source calibration device of claim 1, wherein, The computer establishes a first heat conduction model according to the first, second and third temperatures T1, T2 and T3, calculates the upper surface inner wall temperature of the heat pipe surface temperature source shell, establishes a second heat conduction model according to the upper surface inner wall temperature of the shell and the heating power measured by the power meter, calculates the upper surface outer wall temperature of the heat pipe surface temperature source shell, and finally calibrates the to-be-calibrated temperature measurement value of the surface temperature sensor or the radiation thermometer according to the upper surface outer wall temperature of the heat pipe surface temperature source shell.

3. The dual heat pipe surface temperature source calibration device of claim 1, wherein, The heating device is a two-section high-precision heating furnace, which comprises a bottom heating element and a sidewall surface heating element, and the heating powers of the bottom heating element and the sidewall surface heating element are independently controlled by the temperature control system.

4. The double heat pipe surface temperature source calibration device according to any one of claims 1 to 3, wherein High-purity cesium is used as the working medium of the heat pipe surface temperature source and the heat pipe temperature damper, the shell of the heat pipe surface temperature source and the heat pipe temperature damper is made of Inconel600 high-temperature alloy, and a high-temperature alloy wire mesh of the same material is welded in the inner cavity of the heat pipe as a liquid absorbing core.

5. The dual heat pipe surface temperature source calibration device of claim 1, wherein, The three horizontal meter traps of the heat pipe surface temperature source shell side wall are located in the upper half of the heat pipe surface temperature source.

6. The dual heat pipe surface temperature source calibration device of claim 1, wherein, The thickness of the upper surface of the heat pipe surface temperature source shell is H1, the vertical distance between the first meter trap horizontal axis and the inner wall of the upper surface of the heat pipe surface temperature source shell is H2, the vertical distance between the first meter trap horizontal axis and the second meter trap horizontal axis is H3, and the vertical distance between the second meter trap horizontal axis and the third meter trap horizontal axis is H4, wherein H1 7. A method of calibrating a double heat pipe surface temperature source based on the double heat pipe surface temperature source calibrating apparatus of any one of claims 1 to 6, characterized by, The calibration method comprises: Step one: establish a one-dimensional heat conduction equation group (2), (3) and (4) including the heat pipe surface temperature source shell upper surface inner wall estimated temperature value T interface，n , the first temperature T1, the second temperature T2, the third temperature T3, namely the first heat conduction model, as follows: Wherein n is the number of the calculated value of the temperature of the inner wall of the upper surface of the heat pipe surface temperature source shell using a linear method in different one-dimensional heat conduction equations, and the heat conduction coefficient of the heat pipe surface temperature source is λ; Step two: calculate the first, second and third estimated values of the inner wall temperature of the upper surface of the heat pipe shell surface temperature source according to the above equation set interface，1 , interface，2 and interface，3 ; Step three: Calculate the average of the three extrapolated values as the heat pipe surface temperature source case upper surface inner wall temperature value T by the following formula (5) interface ; Step four: establish one-dimensional heat conduction equation group (6) including the inner wall temperature value T interface of the upper surface of the heat pipe surface temperature source shell and the outer wall temperature value T surface of the upper surface of the heat pipe surface temperature source shell, that is, the second heat conduction model, as follows: In formula (6), q is the power measured by the power meter and converted into heat; and λsteel is the heat conduction coefficient of the heat pipe surface temperature source shell material; Step five: Calculate the heat pipe surface temperature source shell upper surface outer wall temperature value T by the above formula (6) surface As a calibration temperature value, the calibration of the surface temperature sensor or the radiation thermometer is completed by comparing with the temperature measurement value to be calibrated.

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