Method and device for testing heat conductivity coefficient of thermal insulation material

Abstract

The invention discloses a method and device for testing the heat conductivity coefficient of a heat insulation material, and the method comprises the steps: firstly, determining the following heat conductivity coefficient influence factors based on an experimental theory; secondly, on the basis of the determined heat conductivity coefficient influence factors, determining the following experimental parameters to be measured: temperature changes of two side surfaces of the heat insulation material to be measured, the thickness of the heat insulation material to be measured after the preset pre-tightening force is applied, the environment temperature, the preset temperature and the temperature rise time; then, different preset pre-tightening forces are applied to the experimental device, the experimental device is heated to different preset temperatures, and to-be-tested experimental parameters are obtained respectively; and finally, based on the obtained experimental parameters to be measured, calculating the heat conductivity coefficient of the thermal insulation material to be measured. The method is designed on the basis of the Fourier heat transfer theory, and the theoretical basis and the design method are reliable and easy to implement; in addition, the application of the heat transfer theory in practical engineering is enriched by obtaining the heat conductivity coefficient of the heat insulation material to be tested, and the engineering design precision and the engineering simulation precision are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal insulation design, and in particular relates to a method and a device for testing the thermal conductivity of a thermal insulation material. Background Art

[0002] Existing thermal energy designs are inseparable from thermal insulation design, especially in the fields of aerospace, oil and gas transportation, new energy vehicles, and lithium battery energy storage. Especially in the field of lithium battery new energy, the energy density of single cells is high. During use, single cells are at risk of thermal runaway. Among them, when a single cell has thermal runaway, it is also easy to cause system thermal diffusion. Insulation pads are often used in the industry to suppress system thermal diffusion. Foam insulation pads and aerogel insulation pads are the most common. However, when using insulation pads, the vast majority of users and manufacturers use the thermal conductivity measured at room temperature and pressure as the physical property parameter of the insulation pad for use or even research, ignoring that the thermal conductivity of the insulation pad will change with changes in temperature and pressure. The thermal conductivity measured at room temperature and pressure is not suitable for use in precise design or calculation. Therefore, how to accurately measure the thermal conductivity of insulation materials under different temperatures and preload forces is becoming an increasingly urgent technical problem to be solved. Summary of the invention

[0003] In view of the above problems, the present invention provides a method and device for testing the thermal conductivity of thermal insulation materials. The method and device are accurate in testing and have strong applicability.

[0004] The object of the present invention is to provide a method for testing the thermal conductivity of a thermal insulation material, comprising:

[0005] Based on experimental theory, the following factors affecting thermal conductivity are determined:

[0006] Temperature gradient of the insulation material to be tested in the thickness direction Temperature rise rate of the insulation material to be tested The thickness of the thermal insulation material to be tested h;

[0007] Based on the determined factors affecting thermal conductivity, the following experimental parameters to be tested are determined:

[0008] Temperature changes on both sides of the insulation material to be tested, thickness of the insulation material to be tested after a preset preload is applied, ambient temperature, preset temperature, and temperature rise time;

[0009] Apply different preset preload forces to the experimental device and heat it to different preset temperatures to obtain the experimental parameters of the thermal insulation material to be tested at different preset temperatures and different preset preload forces;

[0010] Based on the obtained experimental parameters to be tested, the thermal conductivity of the thermal insulation material to be tested is calculated.

[0011] Furthermore, the experimental theory includes:

[0012] Calculate the heat flux q according to Fourier's heat transfer law:

[0013] q*Δt=∑ρcΔTΔh (1)

[0014] Where: q is the heat flux, unit: W / m 2 , Δt is the time of heat flow, unit: s, ρ is the density of the insulation material to be tested, unit: kg / m 3 ; c is the specific heat capacity of the insulation material to be tested, unit: J / (kg*K); ΔT is the temperature difference before and after the insulation material to be tested, unit: K; Δh is the thickness of the insulation material to be tested along the heat flow direction, m;

[0015] By transforming formula (1), we can get:

[0016]

[0017] Where ρ is the density of the insulation material to be tested, in kg / m 3 , c is the specific heat capacity of the insulation material to be tested, unit J / (kg*K), h is the thickness of the insulation material to be tested, is the temperature rise rate of the thermal insulation material to be tested;

[0018] Based on the heat flux density q and the temperature gradient of the insulation material to be tested in the thickness direction, the thermal conductivity of the insulation material to be tested is calculated:

[0019]

[0020] is the temperature gradient of the thermal insulation material to be tested in the thickness direction.

[0021] Furthermore, different preset preload forces are applied to the experimental device, and the device is heated to different preset temperatures, and the experimental parameters of the thermal insulation material to be tested under different preset temperatures and different preset preload forces are obtained respectively, including:

[0022] Fix the experimental device on the experimental platform, apply a preset preload force to the experimental device, and select one of the two thermal insulation materials to be tested as a main test object and the other as a secondary test object;

[0023] Set up multiple temperature sensing points on two sides of the main test object and connect a dial gauge;

[0024] Start the test, use the voltage stabilizer to heat the two heating plates in the experimental device at the same time, heat the main test object to the preset temperature, maintain it for a certain period of time, wait for the insulation material to return to normal temperature, and complete the test;

[0025] During the test, record the ambient temperature, the temperatures of multiple temperature sensing points on both sides of the main test object, the thickness of the main test object displayed on the micrometer, and the temperature rise time.

[0026] Furthermore, it also includes setting up an insulating environment, and setting up a first insulating material on the side of the heating plate that is not in contact with the insulating material to be tested, wherein:

[0027] The sizes of the first thermal insulation material and the thermal insulation material to be tested are both larger than the size of the heating plate, so that the four sides of the thermal insulation material to be tested are thermally insulated.

[0028] Furthermore, the heating power of the two heating plates is the same, so that the two thermal insulation materials to be tested are heated to a preset temperature synchronously, so that the thermal insulation material to be tested as the auxiliary test object insulates the side of the thermal insulation material to be tested as the main test object.

[0029] Furthermore, it also includes setting a fastening device, including,

[0030] The two first thermal insulation materials, the two heating plates and the two thermal insulation materials to be tested are fixed between the fastening devices, and a preset pre-tightening force is applied to fix them through fasteners.

[0031] Furthermore, the preset temperatures include 25°C, 50°C, 100°C, 125°C, 150°C, 175°C, 200°C, 225°C, 250°C, 275°C, 300°C, 325°C, 350°C, 375°C, 400°C, 425°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, and 1000°C.

[0032] Further, based on the obtained experimental parameters to be tested, the thermal conductivity of the thermal insulation material to be tested is calculated,

[0033] Based on the preset temperature, ambient temperature and the obtained temperature rise time, calculate the temperature rise rate of the main test object under the preset temperature

[0034] The obtained temperature rise rate and the thickness of the main test object shown on the micrometer are substituted into formula (2) to calculate the heat flux density q;

[0035] Based on the temperatures of multiple temperature sensing points on both sides of the main test object, the temperature gradient of the main test object at the preset temperature is calculated.

[0036]

[0037] Where, T aThe average temperature of all temperature sensing points on the side of the main test object attached to the heating plate at the preset temperature, T b The average temperature of all temperature sensing points on the other side of the main test object at the preset temperature;

[0038] The calculated heat flux q and the temperature gradient of the main test object at the preset temperature are Substitute into formula (3) and calculate the thermal conductivity of the insulation material to be tested.

[0039] Furthermore, it also includes summarizing the thermal conductivity of the thermal insulation material to be tested under different preset temperatures and different preset preloads to form a curve of the thermal conductivity of the thermal insulation material to be tested under a fixed preload and at different temperatures.

[0040] Another object of the present invention is to provide a device for testing the thermal conductivity of a thermal insulation material, comprising a first testing unit and a second testing unit, wherein the first testing unit and the second testing unit are arranged in sequence, wherein:

[0041] The first test unit and the second test unit both include a first thermal insulation material, a heating plate and a thermal insulation material to be tested which are arranged in a heat-conductive manner and are tightly fitted in sequence, wherein the thermal insulation material to be tested of the first test unit and the thermal insulation material to be tested of the second test unit are fitted together.

[0042] Furthermore, it also includes a first clamping plate and a second clamping plate, and the first test unit and the second test unit are placed between the first clamping plate and the second clamping plate, wherein:

[0043] The first clamping plate is provided with a connecting hole, and the second clamping plate is provided with a fastener adapted to the connecting hole, which is used to fix the first test unit and the second test unit and apply a pre-tightening force.

[0044] Furthermore, the sizes of the first thermal insulation material and the thermal insulation material to be tested in the first test unit and the second test unit are both larger than the size of the heating plate.

[0045] Furthermore, the first test unit and the second side unit are respectively a main test unit and an auxiliary test unit, the insulation material to be tested in the main test unit is a main test object, and the insulation material to be tested in the auxiliary test unit is an auxiliary test object, wherein,

[0046] The side of the insulation material to be tested that is attached to the heating plate and the other side of the insulation material to be tested that is not attached to the heating plate as the main test object are both provided with uniform temperature sensing points;

[0047] A temperature sensing point is set on the side of the heating plate of the thermal insulation material to be tested as an auxiliary test object. The method of the present invention can accurately measure the thermal conductivity of the thermal insulation material to be tested under different temperatures and pressures, has strong applicability, and further improves the accuracy of battery thermal safety simulation.

[0048] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0050] Figure 1 A schematic flow chart of a method for testing thermal conductivity of a thermal insulation material according to an embodiment of the present invention is shown;

[0051] Figure 2 A schematic diagram of another method for testing the thermal conductivity of a thermal insulation material according to an embodiment of the present invention is shown;

[0052] Figure 3 A schematic diagram of another method for testing the thermal conductivity of a thermal insulation material according to an embodiment of the present invention is shown;

[0053] Figure 4 A schematic diagram of the structure of a device for testing the thermal conductivity of a thermal insulation material in an embodiment of the present invention is shown;

[0054] Figure 5a A front view of a device for testing thermal conductivity of a thermal insulation material according to an embodiment of the present invention is shown;

[0055] Figure 5b A left view of a device for testing thermal conductivity of a thermal insulation material according to an embodiment of the present invention is shown;

[0056] Figure 5c A top view of a device for testing thermal conductivity of a thermal insulation material according to an embodiment of the present invention is shown;

[0057] Figure 6 A schematic diagram of the arrangement of the thermal insulation material to be tested in a device for testing the thermal conductivity of the thermal insulation material according to an embodiment of the present invention is shown;

[0058] Figure 7 A temperature sensing arrangement diagram of a device for testing thermal conductivity of thermal insulation materials according to an embodiment of the present invention is shown;

[0059] Figure 8 A temperature sensing arrangement diagram of another device for testing the thermal conductivity of thermal insulation materials in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] like Figure 1 As shown, the embodiment of the present invention introduces a method for testing the thermal conductivity of a thermal insulation material. The method includes, firstly, determining the following thermal conductivity influencing factors based on experimental theory: the temperature gradient of the thermal insulation material to be tested in the thickness direction; Temperature rise rate of the insulation material to be tested The thickness h of the thermal insulation material to be tested; secondly, based on the determined factors affecting the thermal conductivity, determine the following experimental parameters to be tested: temperature changes on the two sides of the thermal insulation material to be tested, thickness of the thermal insulation material to be tested after the preset preload is applied, ambient temperature, preset temperature, and temperature rise time; then, apply different preset preloads to the experimental device and heat it to different preset temperatures to obtain the experimental parameters of the thermal insulation material to be tested at different preset temperatures and different preset preloads; finally, based on the obtained experimental parameters to be tested, calculate the thermal conductivity of the thermal insulation material to be tested. The above method is suitable for measuring the thermal conductivity of different types of thermal insulation pads (i.e., the thermal insulation material to be tested), and has the function of improving the accuracy of design simulation.

[0062] Specifically, the experimental theory includes:

[0063] First, the heat flux q is calculated according to Fourier's heat transfer law:

[0064] q*Δt=∑ρcΔTΔh (1)

[0065] Where: q is the heat flux, unit: W / m 2 (W / m2); Δt is the time of heat flow, unit: s (seconds); ρ is the density of the insulation material to be tested, unit: kg / m 3 (kg / m3); c is the specific heat capacity of the insulation material to be tested, unit: J / (kg*K); ΔT is the temperature difference before and after the insulation material to be tested, unit: K (Kelvin); Δh is the thickness of the insulation material to be tested along the heat flow direction, m (meter); Using the calculus algorithm to transform formula (1), we can get:

[0066]

[0067] Where ρ is the density of the insulation material to be tested, in kg / m 3, c is the specific heat capacity of the thermal insulation material to be tested, in J / (kg*K), h is the thickness of the thermal insulation material to be tested (i.e., the distance between the two sides of the thermal insulation material to be tested that are respectively attached to the heating plate and the other thermal insulation material to be tested), is the temperature rise rate of the thermal insulation material to be tested;

[0068] Based on the heat flux density q and the temperature gradient of the insulation material to be tested in the thickness direction, the thermal conductivity of the insulation material to be tested is calculated:

[0069]

[0070] is the temperature gradient of the thermal insulation material to be tested in the thickness direction.

[0071] Therefore, if you want to obtain the thermal conductivity of the insulation material to be tested, you need to obtain the temperature gradient of the insulation material to be tested in the thickness direction. Temperature rise rate of the insulation material to be tested The thickness h of the thermal insulation material to be tested, where the temperature gradient in the thickness direction of the thermal insulation material to be tested is The temperature change on the two sides of the thermal insulation material to be tested is calculated through the experiment. The temperature change on the two sides of the thermal insulation material to be tested includes the temperature of the two sides within the interval time during the experiment (for example, recorded once every 30 seconds) and the temperature, temperature difference, etc. of the two sides of the thermal insulation material to be tested when heated to the preset temperature. The temperature rise rate needs to be calculated by obtaining the ambient temperature, the preset temperature finally reached, and the time for the thermal insulation material to be tested to reach the preset temperature during the experiment, that is, the preset temperature minus the ambient temperature divided by the temperature rise time (that is, the time to heat up to the preset temperature) is equal to the temperature rise rate. Furthermore, the thickness h of the thermal insulation material to be tested needs to be the thickness of the thermal insulation material to be tested obtained by a micrometer after the preload force is applied in the experimental device.

[0072] So the experimental method is as follows Figure 2 As shown in the figure, the insulation material to be tested (called the test sample in the figure) is placed in the insulation device, and the test is conducted by heating the test sample. However, the difficulty of implementing the test varies with the shape of the test sample. For a large thin structure, it is difficult to achieve large surface insulation. Figure 2 Improve the test method based on the test method, such as Figure 3 As shown, two thermal insulation materials to be tested (referred to as test sample 1 and test sample 2 in the figure) are arranged in the test device and heated at the same time. Since the thermal insulation materials to be tested are insulated from each other due to the close proximity of the two test samples, the thermal insulation effect of the main test object is better after heating.

[0073] During the experiment, different preset preload forces are applied to the experimental device and heated to different preset temperatures to obtain the experimental parameters of the thermal insulation material under different preset temperatures and different preset preload forces, including:

[0074] First, fix the experimental device on the experimental platform, apply a preset preload to the experimental device, and select one of the two thermal insulation materials to be tested in the experimental device as the main test object and the other as the auxiliary test object. During the experiment, it is necessary to set up an insulating environment, and set the first thermal insulation material on the side of the heating plate that is not in contact with the thermal insulation material to be tested, wherein the sizes of the first thermal insulation material and the thermal insulation material to be tested are both larger than the size of the heating plate, so that the four sides of the thermal insulation material to be tested are insulated (the four sides of the six sides of the thermal insulation material to be tested are the four sides except for the two side surfaces that are in contact with the heating plate and the other thermal insulation material to be tested). Preferably, the sizes of the first thermal insulation material and the thermal insulation material to be tested are much larger than the size of the heating plate, and further preferably, the area of ​​the two side surfaces of the first thermal insulation material and the thermal insulation material to be tested is 4 times or 8 times or more of the area of ​​the heating plate, so that each side of the thermal insulation material to be tested can achieve an approximate insulation effect, so that the insulation effect is better and more in line with the test conditions, and the thermal conductivity of the thermal insulation material obtained is more accurate. In addition, a fastening device is required to fix the two first thermal insulation materials, the two heating plates and the two thermal insulation materials to be tested between the fastening devices, and fasten them with fasteners to apply a preset preload to simulate the use condition. Figure 4 As shown, the fastening device at least includes clamps 1, 2 and fastening bolts (i.e. fasteners), and the clamps 1, 2 and the fastening bolts play the role of fixing and fastening, and the thermal insulation materials 1, 4 are thermal insulation sheets (the above-mentioned first thermal insulation materials) used to block the heat of the heating plate from being conducted to the fixed clamps; the thermal insulation materials 2, 3 are thermal insulation pads to be tested (the above-mentioned thermal insulation materials to be tested), which are used as objects for studying thermal conductivity under dynamic temperature and pressure. If the thermal insulation material 2 is used as the main test object, then the thermal insulation material 3 is the auxiliary test object, and vice versa, wherein the auxiliary test object is to insulate the side of the main test object, wherein the surface of the main test object that is in contact with the heating plate and the auxiliary test object is the side. The heating plates 1 and 2 provide heat sources for the experiment, and the power of the heating plates 1 and 2 is the same, so that the temperature rise of the thermal insulation materials 2 and 3 is the same, so that the auxiliary test object can better achieve thermal insulation of the main test object; as shown Figure 6 The size of the heat insulating materials 1, 2, 3, 4 shown is much larger than the size of the heating zone, and the four sides around the heat insulating materials form a heat preservation and insulation zone to prevent heat from radiating from the heat insulating materials to the air.

[0075] Secondly, multiple temperature sensing points are set on the two sides of the main test object and connected to a micrometer; wherein the multiple temperature sensing points are 16 temperature sensing points, but not limited thereto, and 10 temperature sensing points are also applicable to the present invention.

[0076] Then, start the test, use a voltage stabilizer to heat the two heating plates in the experimental device at the same time, heat the main test object to the preset temperature, maintain it for a certain period of time, wait for the insulation material to be tested to return to room temperature, and complete the test; the certain period of time includes but is not limited to 5 minutes.

[0077] Finally, during the test, record the temperature of multiple temperature-sensitive points on the two sides of the main test object, the thickness of the main test object displayed on the micrometer, and the temperature rise time. Preferably, when recording the preset temperature, it includes recording the temperature of the front and back sides of the thermal insulation material to be tested and the temperature difference between the front and back sides (two sides) of the thermal insulation material to be tested, but the temperature difference during the heating process also needs to be recorded as a reference, and it can be observed during the cooling process.

[0078] In the embodiment of the present invention, during the experiment, the heating power of the two heating plates is the same, so that the two thermal insulation materials to be tested are heated synchronously to a preset temperature, so that the thermal insulation material to be tested as the auxiliary test object insulates the side of the thermal insulation material to be tested as the main test object.

[0079] In the embodiment of the present invention, the preset temperature includes 25°C (degrees Celsius), 50°C, 100°C, 125°C, 150°C, 175°C, 200°C, 225°C, 250°C, 275°C, 300°C, 325°C, 350°C, 375°C, 400°C, 425°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, and 1000°C. However, it is not limited thereto, and a series of other temperature settings are applicable to the present invention. Preferably, the maximum temperature is 1000°C.

[0080] In the embodiment of the present invention, based on the obtained experimental parameters to be tested, calculating the thermal conductivity of the thermal insulation material to be tested includes:

[0081] Based on the preset temperature, ambient temperature and the obtained temperature rise time, calculate the temperature rise rate of the main test object under the preset temperature

[0082] The obtained temperature rise rate and the thickness of the main test object shown on the micrometer are substituted into formula (2) to calculate the heat flux density q;

[0083] Based on the temperatures of multiple temperature sensing points on both sides of the main test object, the temperature gradient of the main test object at the preset temperature is calculated.

[0084]

[0085] Where, T aThe average temperature of all temperature sensing points on the side of the main test object attached to the heating plate at the preset temperature, T b The average temperature of all temperature sensing points at the preset temperature on the other side of the main test object (i.e., the side attached to the auxiliary test object);

[0086] The calculated heat flux q and the temperature gradient of the main test object at the preset temperature are Substitute into formula (3) and calculate the thermal conductivity of the insulation material to be tested.

[0087] For example, 1. Assuming that the room temperature is 20°C, calculate the thermal conductivity of the insulation material at a preset temperature of 600°C, and the preset preload force remains unchanged;

[0088] 2. Calculate the heat flux density according to formula (2) is the temperature rise rate of the thermal insulation material. In the embodiment of the present invention, the temperature rise rate The temperature rise rate is 580℃ / temperature rise time, and the other parameters ρ and c are known quantities. The heat flux q can be calculated by reading the thickness value h from the micrometer. Among them, the temperature rise rate is the ratio of the preset temperature minus the ambient temperature (room temperature) to the temperature rise time.

[0089] 3. Assume that 16 temperature sensing points are set on both sides of the insulation material to be tested. The average temperature of the 16 temperature sensing points on the front of the main test object is taken as T a =(T 1-1 +T 1-2 +…+T 1-16 ) / 16, take the average temperature of 16 temperature sensing points on the back of the main insulation sheet as T b =(T 2-1 +T 2-2 +…+T 2-16 ) / 16;

[0090] 4. Calculate the thermal conductivity of the insulation material according to formula (3) is the temperature gradient of the main insulation material, that is The heat flux density q is obtained by formula (2), and the thermal conductivity coefficient α of the insulation material at this temperature and pressure can be calculated;

[0091] Further, steps 2, 3, and 4 are repeated to calculate the thermal conductivity of the insulation material at different preset temperatures and preset preloads, and the calculated data are summarized to form a curve of the thermal conductivity of the insulation material at different temperatures under a fixed preload.

[0092] The above method is designed on the basis of Fourier heat transfer theory, and the theoretical basis and design method are reliable and easy to implement; in addition, by obtaining the thermal conductivity of the insulation material to be tested, the application of heat transfer theory in practical engineering is enriched, and the engineering design accuracy and engineering simulation accuracy are improved. Furthermore, the above method also applies the following device.

[0093] like Figure 4 As shown, an apparatus for testing the thermal conductivity of thermal insulation materials capable of executing the above method is introduced in an embodiment of the present invention, and the apparatus is an experimental apparatus, and the apparatus comprises a first test unit and a second test unit, and the first test unit and the second test unit are arranged in sequence, wherein the first test unit and the second test unit both comprise a first thermal insulation material, a heating plate and a thermal insulation material to be tested, which are arranged in sequence and closely fit with thermal conductivity, wherein the thermal insulation material to be tested of the first test unit and the thermal insulation material to be tested of the second test unit fit. The apparatus is suitable for measuring the thermal conductivity of different types of thermal insulation pads, and has the function of improving the accuracy of design simulation.

[0094] Specifically, Figure 4 In the embodiment, the first test unit includes thermal insulation material 1, heating plate 1 and thermal insulation material 3, and the second test unit includes thermal insulation material 3, heating plate 2 and thermal insulation material 4, that is, thermal insulation material 1 and thermal insulation material 4 are both first thermal insulation materials, and thermal insulation material 2 and thermal insulation material 3 are both thermal insulation materials to be tested. Further, the device also includes a first clamp and a second clamp, that is, clamp 1 and clamp 2, and the first test unit and the second test unit are placed between clamp 1 and clamp 2, wherein clamp 1 is provided with a connecting hole, and clamp 2 is provided with a fastener adapted to the connecting hole, which is used to fix the first test unit and the second test unit and apply a pre-tightening force, thereby forming a device such as Figure 5a-5c As shown. Among them, the fastener is a fastening bolt, and the device also includes a nut compatible with the fastening bolt. The clamps 1 and 2 are fastened by the fastening bolt and the nut, that is, a pre-tightening force is applied to the first test unit and the second test unit in the device to simulate the use condition. In the embodiment of the present invention, the fasteners and the corresponding connecting holes are arranged at both ends of the corresponding clamps, and there are 6 of them respectively, but there is no limit to the number, and it can be 8, etc., which is also applicable to the present invention. In addition, the fasteners are not limited to the fastening bolts and the nuts compatible therewith, and other fasteners that can apply the tightening force are also applicable to the present invention.

[0095] In the embodiment of the present invention, the sizes of the first thermal insulation material and the thermal insulation material to be tested in the first test unit and the second test unit are much larger than the size of the heating plate. Figure 4In the invention, the sizes of the thermal insulation materials 1, 2, 3 and 4 are larger than the sizes of the heating plates 1 and 2, so that the four surfaces around the thermal insulation materials form a heat preservation and insulation zone around the heating plates to prevent heat from radiating from the surrounding of the thermal insulation materials to the air, thereby ensuring the accuracy and reliability of the thermal conductivity test of the thermal insulation materials at dynamic temperatures. Further, the heating plates 1 and 2 provide a test heat source for the device, and the heating plates 1 and 2 have the same power. The thermal insulation materials 1 and 4 are thermal insulation sheets, which can be aerogel thermal insulation sheets, used to block the heat of the heating plates from being conducted to the fixed splints, but are not limited to this, and other thermal insulation sheets such as foam insulation pads are also suitable for the present invention. The thermal insulation materials 2 and 3 in the thermal insulation materials to be tested can be the thermal insulation pads to be tested, as the objects for studying the thermal conductivity of the thermal insulation materials under dynamic temperatures and different preload forces, and also include determining the main test unit and the auxiliary test unit in the first test unit and the second side unit, the thermal insulation material to be tested in the main test unit is the main test object, and the thermal insulation material to be tested in the auxiliary test unit is the auxiliary test object. That is, if the thermal insulation material 2 is used as the main test object, the thermal insulation material 3 is used as the auxiliary test object, and vice versa.

[0096] In the embodiment of the present invention, Figure 6 As shown, the area on the side of the thermal insulation material to be tested that is in contact with the corresponding heating plate is the heating area, and the area on the side of the thermal insulation material to be tested that is not in contact with the corresponding heating plate is the heat preservation and insulation area. Figure 7 , 8 As shown in the figure, the heating area of ​​the insulation material to be tested as the main test unit and the area on the other side corresponding to the heating area are evenly set with multiple temperature sensing points; the side of the insulation material to be tested in the auxiliary test unit that is in contact with the heating plate is set with a temperature sensing point. As the auxiliary test object, only one temperature sensing point is set on the side of the insulation material to be tested that is in contact with the heating plate, so that it is possible to monitor whether the temperature rise of the two insulation materials to be tested is consistent, ensuring the accuracy of the test.

[0097] For example, if the thermal insulation material 2 is the main test object, in order to ensure that the collected temperature can reflect the temperature rise of the tested material, Figure 8 As shown, 4×4=16 temperature sensing points are evenly arranged on the front (also called the side) of the heating area of ​​the thermal insulation material 2 (the box in the figure is the heating area), and 4×4=16 temperature sensing points are also arranged at the same position on the back (also called the other side) of the thermal insulation material 2. As an auxiliary test unit, one temperature sensing point is arranged on the side (temperature sensing arrangement area) of the thermal insulation material 3 to be tested to monitor the temperature rise on the back of the auxiliary test object. Multiple uniform temperature sensing points are 4x4 uniformly arranged, with a total of 16 temperature sensing points, but are not limited to this. 3x3 uniformly arranged, with a total of 9 temperature sensing lights, are all applicable to the embodiments of the present invention.

[0098] The above device is designed on the basis of Fourier heat transfer theory, and the theoretical basis and design method are reliable and easy to implement. In addition, by obtaining the thermal conductivity of the thermal insulation material to be tested, the application of heat transfer theory in practical engineering is enriched, and the engineering design accuracy and engineering simulation accuracy are improved.

[0099] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for testing the thermal conductivity of an insulation material, characterized in that: include, Based on experimental theory, the following factors affecting thermal conductivity are determined: Temperature gradient of the insulation material to be tested in the thickness direction Temperature rise rate of the insulation material to be tested The thickness of the thermal insulation material to be tested h; Based on the determined factors affecting thermal conductivity, the following experimental parameters to be tested are determined: Temperature changes on both sides of the insulation material to be tested, thickness of the insulation material to be tested after a preset preload is applied, ambient temperature, preset temperature, and temperature rise time; Apply different preset preload forces to the experimental device and heat it to different preset temperatures to obtain the experimental parameters of the thermal insulation material to be tested at different preset temperatures and different preset preload forces; Based on the obtained experimental parameters to be tested, the thermal conductivity of the thermal insulation material to be tested is calculated.

2. The method for testing thermal conductivity of thermal insulation materials according to claim 1, characterized in that: The experimental theory includes: Calculate the heat flux q according to Fourier's heat transfer law: q*Δt=∑ρcΔTΔh (1) Where: q is the heat flux, unit: W / m 2 , Δt is the time of heat flow, unit: s, ρ is the density of the insulation material to be tested, unit: kg / m 3 ; c is the specific heat capacity of the insulation material to be tested, unit: J / (kg*K); ΔT is the temperature difference before and after the insulation material to be tested, unit: K; Δh is the thickness of the insulation material to be tested along the heat flow direction, m; By transforming formula (1), we can get: Where ρ is the density of the insulation material to be tested, in kg / m 3 , c is the specific heat capacity of the thermal insulation material to be tested, unit J / (kg*K), h is the thickness of the thermal insulation material to be tested, is the temperature rise rate of the thermal insulation material to be tested; Based on the heat flux density q and the temperature gradient of the insulation material to be tested in the thickness direction, the thermal conductivity of the insulation material to be tested is calculated: is the temperature gradient of the thermal insulation material to be tested in the thickness direction.

3. The method for testing thermal conductivity of thermal insulation materials according to claim 2, characterized in that: Apply different preset preload forces to the experimental device and heat it to different preset temperatures to obtain the experimental parameters of the thermal insulation material to be tested under different preset temperatures and different preset preload forces, including: Fix the experimental device on the experimental platform, apply a preset preload force to the experimental device, and select one of the two thermal insulation materials to be tested as a main test object and the other as a secondary test object; Set up multiple temperature sensing points on two sides of the main test object and connect a dial gauge; Start the test, use the voltage stabilizer to heat the two heating plates in the experimental device at the same time, heat the main test object to the preset temperature, maintain it for a certain period of time, wait for the insulation material to return to normal temperature, and complete the test; During the test, record the ambient temperature, the temperatures of multiple temperature sensing points on both sides of the main test object, the thickness of the main test object displayed on the micrometer, and the temperature rise time.

4. The method for testing thermal conductivity of thermal insulation materials according to claim 3, characterized in that: The method further includes setting up a heat-insulating environment, and placing a first heat-insulating material on the side of the heating plate that is not in contact with the heat-insulating material to be tested, wherein: The sizes of the first thermal insulation material and the thermal insulation material to be tested are both larger than the size of the heating plate, so that the four sides of the thermal insulation material to be tested are thermally insulated.

5. The method for testing thermal conductivity of thermal insulation materials according to claim 3, characterized in that: The two heating plates have the same heating power, so that the two insulation materials to be tested are heated to a preset temperature synchronously, so that the insulation material to be tested as the auxiliary test object insulates the side of the insulation material to be tested as the main test object.

6. The method for testing thermal conductivity of thermal insulation materials according to claim 3, characterized in that: Also included is a fastening device, including, The two first thermal insulation materials, the two heating plates and the two thermal insulation materials to be tested are fixed between the fastening devices, and a preset pre-tightening force is applied to fix them through fasteners.

7. The method for testing thermal conductivity of thermal insulation materials according to claim 5, characterized in that: The preset temperatures include 25°C, 50°C, 100°C, 125°C, 150°C, 175°C, 200°C, 225°C, 250°C, 275°C, 300°C, 325°C, 350°C, 375°C, 400°C, 425°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, and 1000°C.

8. The method for testing thermal conductivity of thermal insulation materials according to claim 7, characterized in that: Based on the obtained experimental parameters to be tested, the thermal conductivity of the insulation material to be tested is calculated including: Based on the preset temperature, ambient temperature and the obtained temperature rise time, calculate the temperature rise rate of the main test object under the preset temperature The obtained temperature rise rate and the thickness of the main test object shown on the micrometer are substituted into formula (2) to calculate the heat flux density q; Based on the temperatures of multiple temperature sensing points on both sides of the main test object, the temperature gradient of the main test object at the preset temperature is calculated. Where, T a The average temperature of all temperature sensing points on the side of the main test object attached to the heating plate at the preset temperature, T b The average temperature of all temperature sensing points on the other side of the main test object at the preset temperature; The calculated heat flux q and the temperature gradient of the main test object at the preset temperature are Substitute into formula (3) and calculate the thermal conductivity of the insulation material to be tested.

9. The method for testing thermal conductivity of thermal insulation materials according to claim 8, characterized in that: It also includes summarizing the thermal conductivity of the thermal insulation material to be tested under different preset temperatures and different preset preloads to form a curve of the thermal conductivity of the thermal insulation material to be tested under a fixed preload and at different temperatures.

10. A device for testing thermal conductivity of thermal insulation materials, characterized in that: It includes a first test unit and a second test unit, the first test unit and the second test unit are arranged in sequence, wherein: The first test unit and the second test unit both include a first thermal insulation material, a heating plate and a thermal insulation material to be tested which are arranged in a heat-conductive manner and are tightly fitted in sequence, wherein the thermal insulation material to be tested of the first test unit and the thermal insulation material to be tested of the second test unit are fitted together.

11. The device for testing thermal conductivity of thermal insulation materials according to claim 10, characterized in that: It also includes a first clamping plate and a second clamping plate, and the first test unit and the second test unit are placed between the first clamping plate and the second clamping plate, wherein: The first clamping plate is provided with a connecting hole, and the second clamping plate is provided with a fastener adapted to the connecting hole, which is used to fix the first test unit and the second test unit and apply a pre-tightening force.

12. The device for testing thermal conductivity of thermal insulation materials according to claim 11, characterized in that: The sizes of the first thermal insulation material and the thermal insulation material to be tested in the first test unit and the second test unit are both larger than the size of the heating plate.

13. The device for testing thermal conductivity of thermal insulation materials according to claim 12, characterized in that: The first test unit and the second side unit are respectively a main test unit and an auxiliary test unit, the insulation material to be tested in the main test unit is a main test object, and the insulation material to be tested in the auxiliary test unit is an auxiliary test object, wherein, The side of the insulation material to be tested that is attached to the heating plate and the other side of the insulation material to be tested that is not attached to the heating plate as the main test object are both provided with uniform temperature sensing points; A temperature sensing point is arranged on the side of the heat insulation material to be tested which is attached to the heating plate as an auxiliary test object.

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