A high-temperature thermal conductivity testing system and testing method for medium thermal conductive materials

Abstract

The application discloses a high-temperature thermal conductivity testing system and testing method for medium thermal conductive materials, and belongs to the technical field of measurement, which comprises: a sample area to be tested; a heating area and a detection area are oppositely arranged at two ends of the sample area to be tested; a first heat insulation layer is arranged around the outside of the sample area to be tested; one end of the first heat insulation layer is connected with the heating area, the other end is provided with a second heat insulation layer, and the second heat insulation layer is connected with the detection area. The first heat insulation layer is arranged to slow down the transverse heat dissipation of the sample area to be tested, on the one hand, the temperature change gradient of each area near the heating area and the detection area is reduced, and the sample area to be tested is heated more uniformly; on the other hand, the temperature difference between the inner side and the outer side of the first heat insulation layer is reduced by the uniform temperature layer, the transverse temperature loss of the sample area to be tested is reduced, and the problems that it is difficult to obtain the thermal conductivity data of the medium thermal conductive material at high temperature and the measurement data is inaccurate are solved.

Description

Technical Field

[0001] This invention relates to the field of measurement technology, and in particular to a high-temperature thermal conductivity testing system and method applicable to medium-thermal-conductivity materials. Background Technology

[0002] High-temperature thermal conductivity is an important thermophysical property parameter for evaluating the thermal insulation performance of high-temperature resistant materials such as aerogels, thermal insulation tiles, quartz composites, metal honeycomb, and C / SiC composites. It is also a key parameter for thermal simulation and structural design. Currently, the methods for testing the high-temperature thermal conductivity of materials can be categorized as follows:

[0003] For high thermal conductivity materials (thermal conductivity greater than 10), due to their good thermal response, the flash method is usually used to measure the temperature change on the back of the sample after laser irradiation to calculate the thermal conductivity. Commercial equipment is available that can measure thermal conductivity up to 2800℃. For low thermal conductivity materials (thermal conductivity less than 0.1), due to their high thermal resistance, these materials are prone to large temperature differences. Temperature measurement deviations and side heat dissipation have little impact on the measurement results. The protective hot plate method (up to 600℃) or the heat flow meter method (up to 90℃) is usually used.

[0004] Materials with thermal conductivity between the two types mentioned above, such as quartz / quartz composites and alloy honeycomb materials, exhibit poor thermal response and low thermal resistance, making them unsuitable for thermal conductivity testing using the methods described above. Testing is generally performed using the standard ASTM E1530, but this method only reaches a maximum temperature of 300℃. Existing medium-conductivity materials are already used at temperatures exceeding 600℃. Compared to testing environments below 300℃, existing testing methods struggle to obtain thermal conductivity data for medium-conductivity materials at high temperatures, severely impacting the design of related thermal simulation structures.

[0005] In addition, existing measurement methods cannot completely suppress heat dissipation around the sample, resulting in significant deviations between the measurement results and the true values.

[0006] To meet the demand for high-temperature thermal conductivity testing data of medium thermal conductivity materials, the market urgently needs a testing system and method for measuring the high-temperature thermal conductivity of medium thermal conductivity materials, in order to improve the inaccuracy of thermal conductivity data and measurement data of medium thermal conductivity materials at high temperatures. Summary of the Invention

[0007] In view of the above analysis and in view of the shortcomings of the prior art, the present invention aims to provide a high-temperature thermal conductivity testing system and method applicable to medium thermal conductivity materials, which solves at least one of the problems in the prior art, such as the difficulty in obtaining thermal conductivity data of medium thermal conductivity materials at high temperatures and the inaccuracy of measurement data.

[0008] The objective of this invention is mainly achieved through the following technical solutions:

[0009] A high-temperature thermal conductivity testing system applicable to medium thermal conductivity materials includes:

[0010] Sample area to be tested;

[0011] A heating zone and a detection zone are provided at opposite ends of the sample area to be tested;

[0012] A first heat insulation layer is provided around the outer side of the sample area to be tested;

[0013] One end of the first heat insulation layer is connected to the heating zone, and the other end is provided with a second heat insulation layer, which is connected to the detection zone.

[0014] Preferably, the detection area uses a heat flow meter.

[0015] Preferably, the thickness of the sample area to be tested is ≤ 20% of the side length or diameter of the bottom surface of the sample area to be tested.

[0016] Preferably, the thermal conductivity of the first insulation layer ranges from 0.02 W / mK to 0.05 W / mK.

[0017] Preferably, a temperature equalization layer is provided outside the first heat insulation layer, and the temperature equalization layer is arranged in the form of a hollow column surrounding the first heat insulation layer;

[0018] One end of the temperature equalization layer is connected to the heating zone 0, and the other end is connected to the second heat insulation layer.

[0019] Preferably, the thermal conductivity of the temperature equalization layer is ≥2 times the thermal conductivity of the sample to be tested.

[0020] Preferably, a third heat insulation layer is provided on the outer side of the temperature equalization layer.

[0021] Preferably, the first heat insulation layer extends into the detection area, dividing the detection area into a central detection area and an edge heat exchange area.

[0022] A method for testing the high-temperature thermal conductivity of a medium-thermal-conductivity material, the testing system comprising:

[0023] Based on the adjustment of the thermal resistance between the sample area and the detection area, the heat flow meter can measure the sample under the environment of 0-600℃.

[0024] Based on the temperature difference adjustment in the first direction from the heating end of the sample area to the other end away from the heating area, and the heat dissipation gradient adjustment of the sample area perpendicular to the first direction, the measurement accuracy of the sample under test is improved in an environment of 0-600℃.

[0025] Preferably, the measurement of the sample under test by the heat flow meter in an environment of 0–600℃ includes:

[0026] A second heat insulation layer is installed between the sample area and the detection area;

[0027] Adjusting the thickness and thermal conductivity of the second insulation layer adjusts the thermal resistance between the sample area and the detection area.

[0028] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0029] (1) By setting a first heat insulation layer between the detection area and the sample area to be tested, the present invention reduces the amount of heat entering the detection area from the sample area to be tested and lowers the temperature of the detection area. Compared with the prior art, the present invention enables the measurement of high temperature sample (≥600℃) by medium and low temperature detection equipment, and overcomes the defects of the prior art in that the testing method is difficult to obtain thermal conductivity data of medium thermal conductivity material at high temperature and the measurement data is inaccurate.

[0030] (2) By setting a first heat insulation layer, the present invention reduces the lateral heat dissipation of the sample area to be tested. On the one hand, it reduces the temperature change gradient of each area near the heating zone and near the detection zone of the sample area to be tested, so as to achieve more uniform heating of the sample area to be tested. On the other hand, by setting a uniform temperature layer, the present invention reduces the temperature difference between the inner and outer sides of the first heat insulation layer, which greatly reduces the lateral temperature loss of the sample area to be tested and helps to improve the detection accuracy of the thin film heat flow meter.

[0031] (3) By extending the first heat insulation layer into the detection area, the detection area is divided into a central detection area and an edge heat exchange area. The portion of the first heat insulation layer extending into the detection area isolates the heat of the temperature equalization layer in the edge heat exchange area, reducing the heat entry and temperature of the detection area. At the same time, the above design can prevent other heat flows above from being transferred within the thermally conductive pad surface, thus affecting the measurement results. Attached Figure Description

[0032] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0033] Figure 1 This is an external three-dimensional view of the high-temperature thermal conductivity testing system;

[0034] Figure 2 A cross-sectional view of the high-temperature thermal conductivity testing system (AA surface).

[0035] Figure 3 This is a cross-sectional view of the BB surface of the high-temperature thermal conductivity testing system.

[0036] Figure label:

[0037] Sample area 01 and heating area 02;

[0038] Testing area 03, central testing area 031, edge heat exchange area 032, medium and low temperature testing equipment 033;

[0039] First insulation layer 04, second insulation layer 05, temperature equalization layer 06, third insulation layer 07, fourth insulation layer 08, cooling plate 09, temperature equalization plate 10;

[0040] The thickness of the first insulation layer is h1, the thickness of the second insulation layer is h2, the thickness of the third insulation layer is h3, and the thickness of the temperature equalization layer is h4. Detailed Implementation

[0041] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0042] On the one hand, such as Figures 1-3 As shown, the present invention discloses a high-temperature thermal conductivity testing system applicable to medium thermal conductivity materials, comprising: a sample area 01 to be tested;

[0043] A heating zone 02 and a detection zone 03 are provided at opposite ends of the sample area 01 to be tested;

[0044] A first heat insulation layer 04 is provided around the outside of the sample area to be tested between the heating zone 02 and the detection zone 03;

[0045] One end of the first heat insulation layer 04 is connected to the heating zone 02, and the other end is provided with a second heat insulation layer 05, which is connected to the detection zone 03 through the second heat insulation layer 05.

[0046] During implementation, the heating zone 02 heats the sample area 01 to be tested, causing the sample area 01 to be heated in a gradient from one end near the heating zone 02 to the one end near the detection zone 03. The first insulation layer 04 uses a highly insulating material to reduce or avoid the transfer of heat from the sample area 01 to the outside, forming a lateral temperature gradient. At the same time, the second insulation layer 05 inhibits the transfer of heat from the sample area 01 to the detection zone 03, reducing the temperature of the detection zone 03, so that the detection zone 03 can use a medium-low temperature detection device 033.

[0047] Preferably, the low-temperature detection device 033 can be a thin-film heat flow meter.

[0048] It should be noted that in order to use low-temperature detection equipment (such as a thin-film heat flow meter) to detect the sample area 01 at high temperature (about 600°C), the heating area 02 can only be set on the side away from the detection area 03 to avoid the influence of high temperature on the low-temperature detection equipment. Although the influence of high temperature on the low-temperature detection equipment can be suppressed by increasing the thickness of the second heat insulation layer 05, an excessively thick second heat insulation layer 05 will also cause the insulation of heat radiation to affect the measurement of the detection area 03.

[0049] Compared with the prior art, the present invention reduces the amount of heat entering the detection zone from the sample zone by setting a first heat insulation layer between the detection zone and the sample zone, thereby lowering the temperature of the detection zone. This enables the measurement of high-temperature samples (≥600℃) by a medium-low temperature detection device compared with the prior art.

[0050] In addition, the temperature difference between the heated end of the sample area 01 and the other end away from the heated area will also affect the detection accuracy of low-temperature detection equipment (such as thin-film heat flow meters):

[0051] If the temperature difference between the heating end and the end furthest from the heating zone is too small, the temperature measurement error at both ends will be amplified, making the thermal conductivity calculation result unstable. If the temperature difference between the heating end and the end furthest from the heating zone is too large, the measured thermal conductivity is the average effect over a large temperature gradient range between the hot and cold surfaces, rather than using the average temperature of the hot and cold surfaces as the temperature value corresponding to the measured thermal conductivity value. At the same time, under large temperature differences, the thermal radiation transmission phenomenon inside some materials will also cause the measured value of the thin-film heat flow meter to be too large.

[0052] Preferably, the temperature difference between the heating end of the sample area 01 and the other end away from the heating area 02 should be controlled within the range of 20℃ to 100℃.

[0053] Specifically, the thickness h2 of the second insulation layer 05 ranges from 5mm to 15mm, and the room temperature thermal conductivity ranges from 0.02W / mK to 0.05W / mK. Within this range, it is possible to ensure that the low-temperature testing equipment (such as a thin-film heat flow meter) in the testing area 03 has a suitable operating temperature and good testing effect.

[0054] It should also be noted that the thin-film heat flow meter can measure the thermal radiation that enters the detection surface vertically. The average temperature of the hot and cold surfaces is used as the temperature value corresponding to the measured thermal conductivity value. Therefore, the detection of the thin-film heat flow meter is directional. The present invention reduces the lateral heat dissipation of the sample area 01 under test by setting the first heat insulation layer 04, and reduces the lateral temperature gradient distribution of the sample area 01 under test, which helps to improve the detection accuracy of the thin-film heat flow meter.

[0055] Preferably, the sample area 01 to be tested can be a cylinder or a cuboid. The larger the ratio of the side length of the bottom surface of the cuboid or the diameter of the bottom surface of the cylinder to the thickness, the smaller the proportion of heat dissipation from the side. However, the increase in size will also lead to an increase in sample preparation cost and equipment size. The size relationship range satisfies: the thickness of the sample area 01 to be tested is ≤ 20% of the side length or diameter of the bottom surface of the sample area 01 to be tested.

[0056] Specifically, the bottom diameter or bottom side length of the sample area 01 to be tested can vary between 20mm and 200mm.

[0057] Commonly used dimensions can be a base diameter of 50.8 mm, a base side length of 100×100 mm, or a base side length of 300×300 mm, etc. The dimensions depend on the sample production cost, the sample size of other equipment that can be used for comparison, and the size of the standard sample, etc.

[0058] It should be further noted that the temperature difference between the hot and cold surfaces of the sample needs to be within a reasonable range: on the one hand, since the thermocouple itself may have a fluctuation error of about 1℃, in order to ensure that the influence of the thermocouple's own measurement error on the measurement results is as small as possible, the temperature difference between the hot and cold surfaces of the sample should be at least 10℃; on the other hand, the temperature difference between the hot and cold surfaces cannot be increased indefinitely. When the temperature difference exceeds 100℃, the internal temperature gradient of the sample is large, and the thermal conductivity from the hot surface to the cold surface may change significantly. The measured thermal conductivity is the apparent thermal conductivity under the temperature difference condition, and multiple measurements are required to deduce the true thermal conductivity of the sample at a certain temperature.

[0059] Specifically, the temperature difference between the hot and cold surfaces of the sample depends on the ratio of the sample's own thermal resistance to the thermal resistance below the sample. By dividing the hot surface temperature and the water-cooled plate temperature using this ratio, the proportion of the temperature difference that the sample's thermal resistance should receive can be calculated.

[0060] The formula for thermal resistance R satisfies:

[0061] Where λ is the thermal conductivity and d is the sample thickness. The above formula must be satisfied so that the temperature difference between the heated end and the other end of the sample area being tested is 20℃~100℃. When the thermal conductivity λ is determined, the thickness range of the sample area 01 can be determined. Simultaneously, the bottom diameter or bottom side length of the sample area 01 needs to vary between 20mm and 200mm, i.e., the thickness of the sample area 01 is ≤4mm~40mm. The thickness of the sample area 01 is determined based on these rules.

[0062] As an example, assuming the thermal conductivity λ of the thermal resistance is 0.02, d is the sample thickness, and the thermal conductivity λ of the sample is approximately 1, from the above formula, when the thickness of the sample area 01 to be tested is 5mm, the hot surface is 100℃; the temperature below the thermal resistance is room temperature 23℃. At this time, the thickness of the sample area 01 to be tested is 15mm, and the temperature difference between the hot and cold surfaces of the sample is 4.3℃. After reducing the thickness of the sample area 01 to be tested to 2mm, the temperature difference between the hot and cold surfaces increases to 10℃.

[0063] Preferably, the thickness h1 of the first heat insulation layer 04 satisfies: h1 = 0.1 to 0.5 × the bottom diameter or bottom side length of the sample area 01 to be tested.

[0064] The thermal conductivity of the first insulation layer 04 ranges from 0.02 W / mK to 0.05 W / mK.

[0065] Preferably, a temperature equalization layer 06 is provided outside the first heat insulation layer 04, and the temperature equalization layer 06 is arranged in the form of a hollow column surrounding the first heat insulation layer 04;

[0066] One end of the temperature equalization layer 06 is connected to the heating zone 02, and the other end is connected to the second heat insulation layer 05. It can transfer the heat from the heating zone 02 along the outside of the sample area 01 to the side near the detection zone 03, while simultaneously heating the outside of the sample area 01. On the one hand, it reduces the temperature gradient between the areas near the heating zone 02 and the detection zone 03 of the sample area 01, achieving more uniform heating of the sample area 01. On the other hand, the presence of the temperature equalization layer 06 reduces the temperature difference between the inside and outside of the first heat insulation layer 04, greatly reducing the lateral temperature loss of the sample area 01, which helps to improve the detection accuracy of the thin-film heat flow meter.

[0067] Preferably, the thickness h4 of the temperature equalization layer 06 satisfies: h4 = 0.1 to 0.2 × the bottom diameter or bottom side length of the sample area 01 to be tested.

[0068] Preferably, the thermal conductivity of the temperature equalization layer 06 is ≥ 2 times the thermal conductivity of the sample to be tested.

[0069] Preferably, a third heat insulation layer 07 is provided on the outer side of the temperature equalization layer 06, which can further reduce the lateral temperature loss of the sample area 01 to be tested and help improve the detection accuracy of the thin film heat flow meter.

[0070] Specifically, the thickness h3 of the third insulation layer 07 satisfies that the third insulation layer 07 is flush with the heating zone 02, and the thermal conductivity ranges from 0.02W / mK to 0.05W / mK.

[0071] Preferably, the heating zone 02, the detection zone 03, and the third insulation layer 07 are covered with a fourth insulation layer 08, which can further reduce heat loss in each area and reduce energy consumption in the heating zone.

[0072] Preferably, the first heat insulation layer 04 extends into the detection area 03, dividing the detection area 03 into a central detection area 031 and an edge heat exchange area 032.

[0073] During implementation, the portion of the first heat insulation layer 04 that extends into the detection area 03 isolates the heat from the temperature equalization layer 06 in the edge heat exchange area 032, reducing the heat entering and temperature of the detection area 03. At the same time, the above design can prevent other heat flows above from being transferred within the thermally conductive adhesive pad surface, thus affecting the measurement results.

[0074] Compared with the prior art, the present invention divides the detection area into a central detection area and an edge heat exchange area by extending the first heat insulation layer into the detection area; the portion of the first heat insulation layer extending into the detection area isolates the heat of the temperature equalization layer in the edge heat exchange area, reducing the heat entry and temperature of the detection area; at the same time, the above design can prevent other heat flows above from being transferred within the thermally conductive adhesive pad surface, thus affecting the measurement results.

[0075] Specifically, such as Figure 1 As shown, the detection area 03 is provided with two stacked thermal conductive strips. The upper thermal conductive strip is connected to the bottom of the second heat insulation layer 05, and the thin film heat flow meter is placed between the two thermal conductive strips.

[0076] The first insulation layer 04 extends into the interior of the detection area 03, dividing the detection area 03 into a central detection area 031 and an edge heat exchange area 032.

[0077] A cooling plate 09 is also provided at the bottom of the lower heat-conducting adhesive strip to further accelerate the heat dissipation and cooling of the detection area 03.

[0078] Preferably, a heat spreader 10 is provided between the sample area 01 to be tested and the heating area 02, so that the heat from the heating area 02 is evenly transferred to the sample area 01 to be tested.

[0079] On the other hand, such as Figure 1 As shown, this invention discloses a high-temperature thermal conductivity testing method applicable to medium-thermal-conductivity materials, using the aforementioned testing system, including:

[0080] S1: Based on the adjustment of the thermal resistance between the sample area and the detection area, the heat flow meter can measure the sample under the environment of 0-600℃.

[0081] S2: Based on the temperature difference adjustment from the heating end of the sample area to the other end away from the heating area in the first direction, and the heat dissipation gradient adjustment of the sample area perpendicular to the first direction, the measurement accuracy of the sample under test is improved in the 0-600℃ environment.

[0082] Specifically, S1 includes:

[0083] S101: A second heat insulation layer 05 is provided between the sample area 01 and the detection area 03;

[0084] S102: Adjust the thickness and thermal conductivity of the second insulation layer 05 to adjust the thermal resistance between the sample area and the detection area.

[0085] Specifically, S2 includes:

[0086] S201: A first heat insulation layer 04 is provided on the outside of the sample area 01 to be tested, a temperature equalization layer 06 is provided outside the first heat insulation layer 04, and a third heat insulation layer 07 is provided outside the temperature equalization layer 06.

[0087] S202: Adjust the size of the sample area 01 to be tested and the thickness and thermal conductivity of the first insulation layer 04, the temperature equalization layer 06, and the third insulation layer 07 to adjust the thermal resistance between the sample area to be tested and the detection area.

[0088] To better illustrate the present invention, the following embodiments and comparative examples are further disclosed:

[0089] Example 1

[0090] This embodiment discloses a high-temperature thermal conductivity testing system applicable to medium thermal conductivity materials, including:

[0091] Sample area 01; The sample to be tested is a commercially available titanium alloy honeycomb material. The sample was prepared according to the space of the sample area to be tested. The thermal conductivity data is obtained from the table when the average temperature of the hot and cold surfaces is 300℃:

[0092]

[0093] A heating zone 02 and a detection zone 03 are provided at opposite ends of the sample area 01 to be tested;

[0094] A first heat insulation layer 04 is provided around the outside of the sample area to be tested between the heating zone 02 and the detection zone 03;

[0095] One end of the first heat insulation layer 04 is connected to the heating zone 02, and the other end is provided with a second heat insulation layer 05, which is connected to the detection zone 03 through the second heat insulation layer 05.

[0096] Heating zone 02 heats the sample area 01 to be tested, causing the sample area 01 to be heated in a gradient from one end near heating zone 02 to the other end near detection zone 03. The first insulation layer 04 uses a highly insulating material to reduce or avoid the transfer of heat from the inside to the outside of the sample area 01 to form a lateral temperature gradient. At the same time, the second insulation layer 05 inhibits the transfer of heat from the sample area 01 to the detection zone 03, reducing the temperature of the detection zone 03, so that the detection zone 03 can use medium and low temperature detection equipment.

[0097] The low-temperature detection device is a thin-film heat flow meter.

[0098] The thickness h2 of the second insulation layer 05 is 7mm, and the thermal conductivity is 0.03. Within this range, it can simultaneously ensure that the low-temperature detection equipment (such as thin-film heat flow meter) in the detection area 03 has a suitable operating temperature and a good detection effect.

[0099] The temperature difference between the heating end of the sample area 01 and the other end away from the heating area should be controlled within the range of 20℃-100℃.

[0100] The sample area 01 to be tested is a cylinder with a bottom diameter of 50 mm and a thickness of 16 mm;

[0101] The thickness h1 of the first insulation layer 04 is 10mm, and the thermal conductivity is 0.025.

[0102] A temperature equalization layer 06 is provided outside the first heat insulation layer 04. The temperature equalization layer 06 is arranged in the form of a hollow column surrounding the first heat insulation layer 04.

[0103] One end of the temperature equalization layer 06 is connected to the heating zone 02, and the other end is connected to the second heat insulation layer 05. It can transfer the heat from the heating zone 02 along the outside of the sample area 01 to the side near the detection zone 03, while simultaneously heating the outside of the sample area 01. On the one hand, it reduces the temperature gradient between the areas near the heating zone 02 and the detection zone 03 of the sample area 01, achieving more uniform heating of the sample area 01. On the other hand, the presence of the temperature equalization layer 06 reduces the temperature difference between the inside and outside of the first heat insulation layer 04, greatly reducing the lateral temperature loss of the sample area 01, which helps to improve the detection accuracy of the thin-film heat flow meter.

[0104] The thickness of the temperature homogenization layer 06, h4, is 5mm, and the thermal conductivity is 16.

[0105] A third heat insulation layer 07 is provided on the outside of the temperature equalization layer 06, which can further reduce the lateral temperature loss of the sample area 01 under test and help improve the detection accuracy of the thin film heat flow meter.

[0106] The thermal conductivity of the third insulation layer 07 is taken as 0.03.

[0107] The heating zone 02, the detection zone 03, and the third insulation layer 07 are covered with a fourth insulation layer 08, which can further reduce heat loss in each area and reduce energy consumption in the heating zone.

[0108] The first insulation layer 04 extends into the interior of the detection area 03, dividing the detection area 03 into a central detection area 031 and an edge heat exchange area 032.

[0109] The detection area 03 is provided with two stacked thermal conductive strips. The upper thermal conductive strip is connected to the bottom of the second heat insulation layer 05, and the thin film heat flow meter is placed between the two thermal conductive strips.

[0110] The first insulation layer 04 extends into the interior of the detection area 03, dividing the detection area 03 into a central detection area 031 and an edge heat exchange area 032.

[0111] A cooling plate is also provided at the bottom of the lower heat-conducting strip to further accelerate the heat dissipation and cooling of the detection area 03.

[0112] This embodiment discloses a high-temperature thermal conductivity testing method applicable to medium-thermal-conductivity materials, using the aforementioned testing system, including:

[0113] Based on the thermal resistance adjustment between the sample area and the detection area, the heat flow meter can measure the sample under the environment of 0-600℃.

[0114] Based on the temperature difference adjustment in the first direction from the heating end of the sample area to the other end away from the heating area, and the heat dissipation gradient adjustment in the sample area perpendicular to the first direction, the measurement accuracy of the sample under test is improved in an environment of 0-600℃.

[0115] Based on the adjustment of the thermal resistance between the sample area and the detection area, the heat flow meter can measure the sample under test in an environment of 0–600℃, including:

[0116] S101: A second heat insulation layer 05 is provided between the sample area 01 and the detection area 03;

[0117] S102: Adjust the thickness and thermal conductivity of the second insulation layer 05 to adjust the thermal resistance between the sample area and the detection area.

[0118] The temperature difference between the heating end of the sample area 01 and the other end away from the heating area was measured to be 40℃.

[0119] S201: A first heat insulation layer 04 is provided on the outside of the sample area 01 to be tested, a temperature equalization layer 06 is provided on the outside of the first heat insulation layer 04, and a third heat insulation layer 07 is provided on the outside of the temperature equalization layer 06.

[0120] S202: Adjust the size of the sample area 01 to be tested and the thickness and thermal conductivity of the first insulation layer 04, the temperature equalization layer 06, and the third insulation layer 07 to adjust the thermal resistance between the sample area to be tested and the detection area.

[0121] The heating zone was heated from 325°C to 640°C, and the thermal conductivity data λ of the standard samples at at least three temperatures were measured. i The nominal data λ of the standard sample at the same temperature 0i By performing linear fitting, a functional relationship between the actual thermal conductivity and the measured thermal conductivity is obtained, λ. i =k×λ 0i +b; the closer k is to 1, the better the heat dissipation control effect around the perimeter. The parameter detection results before and after the heating is completed are shown in Table 1 below:

[0122] Table 1. Parameter detection results before and after heating.

[0123]

[0124] Example 2

[0125] The difference from Example 1 is that: no uniform temperature layer 06 is set, while in Example 1, the position of uniform temperature layer 06 is filled with a third heat insulation layer 07.

[0126] The heating zone was heated from 325℃ to 640℃, and the parameter test results before and after the heating was completed are shown in Table 2 below:

[0127] Table 2. Parameter detection results before and after heating.

[0128]

[0129] Comparative Example 1

[0130] The difference from Example 2 is that the thickness h2 of the second insulation layer 05 is reduced from 7mm to 2mm, while the rest are the same.

[0131] The heating zone was heated from 325℃ to 640℃, and the parameter test results before and after the heating was completed are shown in Table 3 below:

[0132] Table 3. Parameter detection results before and after heating.

[0133]

[0134] Comparing the data from the examples and comparative examples, it can be seen that the thickness h2 of the second insulation layer 05 in comparative example 1 is lower than that in example 2. The temperature difference 1 between the hot and cold surfaces at 640°C in comparative example 1 is significantly greater than that in example 2, indicating that the increased thermal resistance can significantly improve the temperature difference between the hot and cold surfaces and improve the detection accuracy.

[0135] Comparing the data from Example 1 and Example 2, it can be seen that the coefficient k in Example 1 is significantly smaller than that in Example 2, and is closer to 1, indicating that the heat dissipation control effect around the perimeter is better and the detection accuracy is higher.

[0136] Comparing the average temperature of the hot and cold surfaces at approximately 300℃, and the standard thermal conductivity of the honeycomb titanium alloy sample, it can be seen that the thermal conductivity of Example 2 and Comparative Example 1 is significantly lower than the standard thermal conductivity of the honeycomb titanium alloy sample, at 0.432 W·m. -1 • K, the measured thermal conductivity of Example 1 is 0.461 W·m -1 The standard thermal conductivity of K and the honeycomb titanium alloy sample are quite close, indicating that the thermal conductivity value measured in Example 1 is more accurate.

[0137] It should be noted that existing technologies lack a standard method for measuring the thermal conductivity of thermally conductive materials at temperatures above 300°C, and there is no corresponding standard data to evaluate the measurement accuracy. In Example 1 of this invention, the coefficient k is significantly smaller than that in Example 2, and closer to 1, indicating better heat dissipation control around the perimeter, which is beneficial for obtaining higher detection accuracy. Furthermore, Example 1 of this invention measures the thermal conductivity of the hot and cold surfaces of the sample near 300°C and compares it with the standard thermal conductivity of the sample at that temperature, showing good measurement accuracy.

[0138] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-temperature thermal conductivity testing system applicable to medium-thermal-conductivity materials, characterized in that, include: Sample area to be tested; A heating zone and a detection zone are provided at opposite ends of the sample area to be tested; A first heat insulation layer is provided around the outer side of the sample area to be tested; One end of the first heat insulation layer is connected to the heating zone, and the other end is provided with a second heat insulation layer, which is connected to the detection zone.

2. The high-temperature thermal conductivity testing system for applicable medium-thermal-conductivity materials according to claim 1, characterized in that, The detection area uses a heat flow meter.

3. The high-temperature thermal conductivity testing system for applicable medium-thermal-conductivity materials according to claim 2, characterized in that, The thickness of the sample area to be tested is ≤ 20% of the side length or diameter of the bottom surface of the sample area to be tested.

4. The high-temperature thermal conductivity testing system for applicable medium-thermal-conductivity materials according to claim 3, characterized in that, The thermal conductivity of the first insulation layer ranges from 0.02 W / mK to 0.05 W / mK.

5. A high-temperature thermal conductivity testing system for applicable medium-thermal-conductivity materials according to claim 4, characterized in that, A temperature equalization layer is provided outside the first heat insulation layer, and the temperature equalization layer is arranged in the form of a hollow column surrounding the first heat insulation layer; One end of the temperature equalization layer is connected to the heating zone 0, and the other end is connected to the second heat insulation layer.

6. The high-temperature thermal conductivity testing system for applicable medium-thermal-conductivity materials according to claim 5, characterized in that, The thermal conductivity of the temperature equalization layer is ≥ 2 times the thermal conductivity of the sample to be tested.

7. A high-temperature thermal conductivity testing system for applicable medium-thermal-conductivity materials according to claim 6, characterized in that, A third heat insulation layer is provided on the outside of the temperature equalization layer.

8. A high-temperature thermal conductivity testing system for applicable medium-thermal-conductivity materials according to claim 6, characterized in that, The first insulation layer extends deep into the detection area, dividing the detection area into a central detection area and an edge heat exchange area.

9. A method for testing the high-temperature thermal conductivity of a medium-thermal-conductivity material, characterized in that, Using the test system according to any one of claims 2-7, comprising: Based on the adjustment of the thermal resistance between the sample area and the detection area, the heat flow meter can measure the sample under the environment of 0-600℃. Based on the temperature difference adjustment in the first direction from the heating end of the sample area to the other end away from the heating area, and the heat dissipation gradient adjustment of the sample area perpendicular to the first direction, the measurement accuracy of the sample under test is improved in an environment of 0-600℃.

10. A method for testing the high-temperature thermal conductivity of a suitable medium-thermal-conductivity material according to claim 9, characterized in that, The process of using a heat flow meter to measure samples in an environment of 0–600℃ includes: A second heat insulation layer is installed between the sample area and the detection area; Adjusting the thickness and thermal conductivity of the second insulation layer adjusts the thermal resistance between the sample area and the detection area.

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