Method and apparatus for testing thermal conductivity coefficient of thermal insulation material

Abstract

A method and apparatus for testing a thermal conductivity coefficient of a thermal insulation material. The method for testing a thermal conductivity coefficient of a thermal insulation material comprises: first, on the basis of an experimental theory, determining influencing factors of a thermal conductivity coefficient; second, on the basis of the determined influencing factors of the thermal conductivity coefficient, determining the following experimental parameters to be measured: temperature changes on two side surfaces of a thermal insulation material (2) to be tested, the thickness of said thermal insulation material (2) after a preset pre-tightening force is applied thereto, an ambient temperature, a preset temperature, and a temperature rise time; then, applying different preset pre-tightening forces to an experimental apparatus, heating same to different preset temperatures, and respectively acquiring said experimental parameters; and finally, on the basis of said acquired experimental parameters, calculating the thermal conductivity coefficient of said thermal insulation material (2). The method for testing a thermal conductivity coefficient of a thermal insulation material is designed on the basis of a Fourier heat transfer theory, has a reliable theoretical foundation and design method, and is easy to implement. In addition, the thermal conductivity coefficient of said thermal insulation material (2) is acquired, so that the application of the heat transfer theory in actual engineering is enriched, thereby improving the engineering design accuracy and the engineering simulation accuracy.

Description

A method and apparatus for testing the thermal conductivity of insulation materials Technical Field

[0001] This invention belongs to the field of thermal insulation design technology, and specifically relates to a method and apparatus for testing the thermal conductivity of thermal insulation materials. Background Technology

[0002] Existing thermal design relies heavily on insulation, particularly in aerospace, oil and gas transportation, new energy vehicles, and lithium-ion battery energy storage. Especially in the lithium-ion battery sector, the high energy density of individual cells poses a risk of thermal runaway during use. When a single cell experiences thermal runaway, it can easily lead to system thermal diffusion. The industry commonly uses thermal insulation pads to suppress this diffusion, with foam and aerogel pads being the most prevalent. However, when using thermal insulation pads, most users and manufacturers rely on the thermal conductivity measured at room temperature and pressure as the pad's physical property parameter, neglecting the fact that the thermal conductivity changes with temperature and pressure. Thermal conductivity measured at room temperature and pressure is unsuitable for precise design or calculations. Therefore, accurately measuring the thermal conductivity of insulation materials under different temperatures and preload conditions is becoming an increasingly urgent technical problem to be solved. Summary of the Invention

[0003] To address the above problems, the present invention provides a method and apparatus for testing the thermal conductivity of insulation materials. The method and apparatus are accurate and widely applicable.

[0004] The purpose of this invention is to provide a method for testing the thermal conductivity of insulation materials, including:

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

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

[0007] Based on the identified factors affecting thermal conductivity, the following experimental parameters were determined:

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

[0009] Different preset preload forces were applied to the experimental apparatus, and the apparatus was heated to different preset temperatures. The experimental parameters of the thermal insulation material under test were obtained at different preset temperatures and with different preset preload forces.

[0010] Based on the obtained experimental parameters, the thermal conductivity of the insulation material under test is calculated.

[0011] Furthermore, the experimental theory includes:

[0012] The heat flux density q is calculated according to Fourier's law of heat transfer: q*Δt=∑ρcΔTΔh (1)

[0013] Where: q is the heat flux density, unit: W / m³ 2 Δt is the time of heat flow, in seconds, and ρ is the density of the insulation material being tested, in kg / m³. 3 c represents the specific heat capacity of the insulation material under test, in J / (kg*K); ΔT represents the temperature difference of the insulation material before and after heat flow, in K; Δh represents the thickness of the insulation material under test along the heat flow direction, in meters.

[0014] Transforming equation (1) yields:

[0015] In the formula, ρ is the density of the insulation material to be tested, in kg / m³. 3 c represents the specific heat capacity of the insulation material being tested, in J / (kg*K), and h represents the thickness of the insulation material being tested. The temperature rise rate of the insulation material to be tested;

[0016] The thermal conductivity of the insulation material under test is calculated based on the heat flux density q and the temperature gradient along the thickness direction of the insulation material under test.

[0017] This represents the temperature gradient of the insulation material under test along its thickness.

[0018] Furthermore, different preset preload forces were applied to the experimental apparatus, and it was heated to different preset temperatures to obtain the experimental parameters of the thermal insulation material under different preset temperatures and preset preload forces.

[0019] The experimental device was fixed on the experimental platform, a preset pre-tightening force was applied to the experimental device, and one of the two thermal insulation materials to be tested was selected as the main test object and the other as the auxiliary test object.

[0020] Multiple temperature sensing points were set on both sides of the main test object and connected to a dial gauge;

[0021] To begin the test, a regulated power source is used to heat the two heating plates in the experimental setup simultaneously. After heating the main test object to the preset temperature, it is maintained for a certain period of time until the insulation material under test returns to room temperature, thus completing the test.

[0022] During the test, the ambient temperature, the temperature of multiple temperature sensing points on both sides of the main test object, the thickness of the main test object displayed on the dial gauge, and the temperature rise time were recorded.

[0023] Furthermore, it also includes setting up an insulating environment, whereby the side of the heating plate not attached to the insulation material to be tested is attached to a first insulation material, wherein...

[0024] Both the first insulation material and the insulation material to be tested are larger than the size of the heating plate, so that the four sides of the insulation material to be tested are insulated.

[0025] Furthermore, the two heating plates have the same heating power, causing the two insulation materials to be tested to be heated to the preset temperature simultaneously, so that the insulation material to be tested, which is the auxiliary test object, insulates the side of the insulation material to be tested, which is the main test object.

[0026] Furthermore, it also includes the provision of fastening devices, including,

[0027] Two first insulation materials, two heating plates, and two insulation materials to be tested are fixed between the fastening device and a preset pre-tightening force is applied by fasteners.

[0028] Furthermore, the preset temperatures include 25℃, 50℃, 100℃, 125℃, 150℃, 175℃, 200℃, 225℃, 250℃, 275℃, 300℃, 325℃, 350℃, 375℃, 400℃, 425℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, and 1000℃.

[0029] Furthermore, based on the obtained experimental parameters, the thermal conductivity of the insulation material under test is calculated, including:

[0030] Based on the preset temperature, ambient temperature, and acquired temperature rise time, the temperature rise rate of the main test object during the experiment at the preset temperature is calculated.

[0031] The obtained temperature rise rate Substituting the thickness of the main test object displayed on the dial gauge into formula (2), the heat flux density q is calculated;

[0032] 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.

[0033] In the formula, T a The average temperature measured at all temperature sensing points on the side of the main test object that is in contact with the heating plate at a preset temperature, T.b The average temperature measured at all temperature sensing points on the other side of the main test object at a preset temperature.

[0034] The calculated heat flux density q and the temperature gradient of the main test object at the preset temperature are used. Substitute into formula (3) to calculate the thermal conductivity of the insulation material to be tested.

[0035] Furthermore, it also includes summarizing the thermal conductivity of the insulation material under different preset temperatures and different preset preloads to form a curve of the thermal conductivity of the insulation material under different temperatures under a fixed preload.

[0036] Another object of the present invention is to provide an apparatus for testing the thermal conductivity of insulation materials, comprising a first testing unit and a second testing unit, wherein the first testing unit and the second testing unit are arranged sequentially, wherein...

[0037] Both the first test unit and the second test unit include a first heat insulation material, a heating plate, and a heat insulation material to be tested, which are arranged in a thermally conductive manner and are tightly bonded together in sequence. The heat insulation material to be tested in the first test unit and the heat insulation material to be tested in the second test unit are bonded together.

[0038] Furthermore, it also includes a first clamping plate and a second clamping plate, with the first test unit and the second test unit placed between the first clamping plate and the second clamping plate, wherein...

[0039] The first clamping plate is provided with a connecting hole, and the second clamping plate is provided with fasteners adapted to the connecting hole, for fixing the first test unit and the second test unit and applying preload.

[0040] Furthermore, the dimensions of the first insulation material and the insulation material to be tested in the first test unit and the second test unit are both larger than the dimensions of the heating plate.

[0041] Furthermore, the first test unit and the second side unit are respectively the main test unit and the auxiliary test unit. The insulation material to be tested in the main test unit is the main test object, and the insulation material to be tested in the auxiliary test unit is the auxiliary test object.

[0042] Uniform temperature sensing points are set on both the side of the thermal insulation material to be tested that is attached to the heating plate and the other side of the thermal insulation material that is not attached to the heating plate, which are the main test objects.

[0043] The side of the heat insulation material to be tested, which serves as an auxiliary test object, is fitted with a temperature sensing point. The method of the present invention can accurately measure the thermal conductivity of the heat insulation material under different temperatures and pressures, has strong applicability, and further improves the accuracy of battery thermal safety simulation.

[0044] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 shows a schematic flowchart of a method for testing the thermal conductivity of a thermal insulation material according to an embodiment of the present invention;

[0047] Figure 2 shows a schematic diagram of another method for testing the thermal conductivity of insulation materials in an embodiment of the present invention;

[0048] Figure 3 shows a schematic diagram of another method for testing the thermal conductivity of insulation materials in an embodiment of the present invention;

[0049] Figure 4 shows a schematic diagram of a device for testing the thermal conductivity of insulation materials in an embodiment of the present invention;

[0050] Figure 5a shows a front view of an apparatus for testing the thermal conductivity of a thermal insulation material according to an embodiment of the present invention;

[0051] Figure 5b shows a left view of an apparatus for testing the thermal conductivity of a thermal insulation material according to an embodiment of the present invention;

[0052] Figure 5c shows a top view of an apparatus for testing the thermal conductivity of a thermal insulation material according to an embodiment of the present invention;

[0053] Figure 6 shows a schematic diagram of the setup of the thermal insulation material to be tested in an apparatus for testing the thermal conductivity of thermal insulation material according to an embodiment of the present invention.

[0054] Figure 7 shows a temperature sensor arrangement diagram of a device for testing the thermal conductivity of insulation materials in an embodiment of the present invention;

[0055] Figure 8 shows a temperature sensor arrangement diagram of another device for testing the thermal conductivity of insulation materials in an embodiment of the present invention. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] As shown in Figure 1, this embodiment of the invention introduces a method for testing the thermal conductivity of a thermal insulation material. The method includes, firstly, determining the following factors affecting the thermal conductivity based on experimental theory: the temperature gradient of the thermal insulation material under test in the thickness direction. Temperature rise rate of the insulation material under test The thickness h of the insulation material to be tested is determined first. Then, based on the identified factors affecting thermal conductivity, the following experimental parameters are determined: temperature changes on both sides of the insulation material, thickness of the insulation material after applying a preset preload, ambient temperature, preset temperature, and temperature rise time. Next, different preset preloads are applied to the experimental setup, and the material is heated to different preset temperatures. The experimental parameters of the insulation material under different preset temperatures and preloads are then obtained. Finally, based on the obtained experimental parameters, the thermal conductivity of the insulation material is calculated. This method is applicable to measuring the thermal conductivity of different types of insulation pads (i.e., the insulation material to be tested) and improves the accuracy of design simulation.

[0058] Specifically, the experimental theory includes:

[0059] First, calculate the heat flux density q according to Fourier's heat transfer law: q*Δt=∑ρcΔTΔh (1)

[0060] In the formula: q is the heat flux density, unit: W / m³ 2 (Watts / square meter); Δt is the time of heat flow, in seconds (s); ρ is the density of the insulation material being tested, in kg / m³. 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); By transforming equation (1) using a calculus algorithm, we can obtain:

[0061] In the formula, ρ is the density of the insulation material to be tested, in kg / m³. 3c represents the specific heat capacity of the insulation material under test, in J / (kg*K), and h represents the thickness of the insulation material under test (i.e., the distance between the two sides of the insulation material under test that are respectively attached to the heating plate and another insulation material under test). The temperature rise rate of the insulation material to be tested;

[0062] The thermal conductivity of the insulation material under test is calculated based on the heat flux density q and the temperature gradient along the thickness direction of the insulation material under test.

[0063] This represents the temperature gradient of the insulation material under test along its thickness.

[0064] Therefore, to obtain the thermal conductivity of the insulation material under test, it is necessary to obtain the temperature gradient of the insulation material in the thickness direction. Temperature rise rate of the insulation material under test The thickness h of the insulation material to be tested, where h is the temperature gradient along the thickness direction of the insulation material. The temperature change on both sides of the insulation material under test is calculated by obtaining experimental data. This temperature change includes the temperature on both sides during the experimental process at intervals (e.g., recorded every 30 seconds), as well as the temperature and temperature difference between the two sides when heated to the preset temperature. The temperature rise rate is calculated by obtaining the ambient temperature, the final preset temperature reached, and the time it takes for the insulation material to reach the preset temperature during the experiment. Specifically, the temperature rise rate is calculated as the preset temperature minus the ambient temperature divided by the temperature rise time (i.e., the time to reach the preset temperature). Furthermore, the thickness h of the insulation material under test is obtained using a dial indicator after the experimental apparatus has applied pre-tightening force.

[0065] The experimental method is shown in Figure 2. The insulation material to be tested (referred to as the test sample in the figure) is placed in the insulation device, and the experiment is conducted by heating the test sample. However, the difficulty of testing varies depending on the shape of the test sample. For large-area thin structures, it is difficult to achieve large-area insulation. Therefore, an improved test method is proposed based on the test method in Figure 2, as shown in Figure 3. Two insulation materials to be tested (referred to as test sample 1 and test sample 2 in the figure) are placed in the test device and heated simultaneously. Since the insulation materials to be tested are in contact, the two test samples insulate each other. After heating, the insulation effect of the main test object is better.

[0066] During the experiment, different preset preload forces were applied to the experimental apparatus, and it was heated to different preset temperatures. The experimental parameters of the insulation material under test were obtained at different preset temperatures and with different preset preload forces.

[0067] First, the experimental setup is fixed on the experimental platform, and a preset pre-tightening force is applied. Two insulation materials to be tested are selected as the primary test object and the other as the secondary test object. During the experiment, an insulating environment needs to be set up. The side of the heating plate not attached to the insulation material to be tested is attached to the first insulation material. Both the first insulation material and the insulation material to be tested are larger than the size of the heating plate, ensuring that the four sides of the insulation material to be tested are insulated (the insulation material to be tested has six sides; the four sides are the four sides excluding the two sides attached to the heating plate and the other insulation material to be tested). Preferably, the dimensions of both the first insulation material and the insulation material to be tested are much larger than the size of the heating plate. More preferably, the area of ​​the two sides of the first insulation material and the insulation material to be tested is 4 times, 8 times, or greater than the area of ​​the heating plate, thus ensuring that each side of the insulation material to be tested achieves a near-insulating effect, resulting in better insulation performance, better conforming to the test conditions, and consequently, a more accurate thermal conductivity coefficient of the insulation material. In addition, a fastening device is required to fix the two first heat insulation materials, the two heating plates, and the two heat insulation materials to be tested between the fastening device. A preset pre-tightening force is applied through the fasteners to simulate the working conditions. Specifically, the test device is shown in Figure 4. The fastening device includes at least clamping plates 1 and 2 and fastening bolts (i.e., fasteners). Clamping plates 1 and 2 and fastening bolts serve to fix and tighten the device. Heat insulation materials 1 and 4 are heat insulation sheets (the aforementioned first heat insulation materials), used to block the heat from the heating plates from being conducted to the fixed clamping plates. Heat insulation materials 2 and 3 are heat insulation pads to be tested (the aforementioned heat insulation materials to be tested), serving as the objects for studying the thermal conductivity under dynamic temperature and pressure. If heat insulation material 2 is the main test object, then heat insulation material 3 is the auxiliary test object, and vice versa. The auxiliary test object is used to insulate the sides of the main test object. The side of the main test object that is in contact with the heating plate and the auxiliary test object is called the side surface. Heating plates 1 and 2 provide heat sources for the experiment. Heating plates 1 and 2 have the same power, which makes the temperature rise of insulation materials 2 and 3 the same, so that the auxiliary test object can better insulate the main test object. As shown in Figure 6, the size of insulation materials 1, 2, 3 and 4 is much larger than the size of the heating area. The four sides of the insulation materials form a heat insulation zone to prevent heat from radiating from the insulation materials to the air.

[0068] Secondly, multiple temperature sensing points are set on both sides of the main test object and connected to a dial indicator; wherein, the multiple temperature sensing points are 16 temperature sensing points, but not limited to this, 10 temperature sensing points, etc. are also applicable to this invention.

[0069] Then, the test begins. A regulated power source is used to heat the two heating plates in the experimental device simultaneously. After the main test object is heated to the preset temperature, it is maintained for a certain period of time to wait for the insulation material under test to return to room temperature, thus completing the test. The certain period of time includes, but is not limited to, 5 minutes.

[0070] Finally, during the test, record the temperatures at multiple temperature sensing points on both sides of the main test object, the thickness of the main test object displayed on the dial gauge, and the temperature rise time. Preferably, when recording the preset temperature, record the temperatures of the front and back sides of the insulation material under test and the temperature difference between the front and back sides (two sides) of the insulation material under test. However, the temperature difference during the heating process should also be recorded as a reference, and can be observed during the cooling process.

[0071] In this embodiment of the invention, during the experiment, the heating power of the two heating plates is the same, so that the two heat insulation materials to be tested are heated to the preset temperature simultaneously, so that the heat insulation material to be tested, which is the auxiliary test object, insulates the side of the heat insulation material to be tested, which is the main test object.

[0072] In this embodiment of the invention, the preset temperatures include 25℃ (degrees Celsius), 50℃, 100℃, 125℃, 150℃, 175℃, 200℃, 225℃, 250℃, 275℃, 300℃, 325℃, 350℃, 375℃, 400℃, 425℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, and 1000℃. However, this is not a limitation; other temperature settings are also applicable to this invention. Preferably, the highest temperature is 1000℃.

[0073] In this embodiment of the invention, the calculation of the thermal conductivity of the insulation material to be tested based on the acquired experimental parameters includes:

[0074] Based on the preset temperature, ambient temperature, and acquired temperature rise time, the temperature rise rate of the main test object during the experiment at the preset temperature is calculated.

[0075] The obtained temperature rise rate Substituting the thickness of the main test object displayed on the dial gauge into formula (2), the heat flux density q is calculated;

[0076] 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.

[0077] In the formula, T a The average temperature measured at all temperature sensing points on the side of the main test object that is in contact with the heating plate at a preset temperature, T. b The average temperature measured by all temperature sensing points on the other side of the main test object (i.e. the side that is in contact with the auxiliary test object) at a preset temperature.

[0078] The calculated heat flux density q and the temperature gradient of the main test object at the preset temperature are used. Substitute into formula (3) to calculate the thermal conductivity of the insulation material to be tested.

[0079] For example, 1. Assuming the room temperature is 20℃, calculate the thermal conductivity of the insulation material at a preset temperature of 600℃, with the preset preload remaining unchanged;

[0080] 2. Calculate the heat flux density according to equation (2). The temperature rise rate of the insulation material is the temperature rise rate in this embodiment of the invention. The temperature rise time is 580℃. The other parameters ρ and c are known quantities. The heat flux density q can be calculated by reading the thickness value h from the dial gauge. The temperature rise rate is the ratio of the preset temperature minus the ambient temperature (room temperature) to the temperature rise time.

[0081] 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 side 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 heat insulation sheet as T b =(T 2-1 +T 2-2 +…+T 2-16 ) / 16;

[0082] 4. Calculate the thermal conductivity of the insulation material according to equation (3). The temperature gradient of the primary insulation material is measured. The heat flux density q can be obtained from formula (2), and the thermal conductivity α of the insulation material at this temperature and pressure can be calculated.

[0083] Further, repeat steps 2, 3, and 4 to calculate the thermal conductivity of the insulation material under different preset temperatures and preset preloads. Summarize the calculated data to form a curve of the thermal conductivity of the insulation material at different temperatures under a fixed preload.

[0084] The above method is designed based on Fourier heat transfer theory, and its theoretical foundation and design method are reliable and easy to implement. Furthermore, by obtaining the thermal conductivity of the insulation material under test, it enriches the application of heat transfer theory in practical engineering, improving the accuracy of engineering design and simulation. In addition, the above method also utilizes the following device.

[0085] As shown in Figure 4, this embodiment of the invention introduces an apparatus for testing the thermal conductivity of insulation materials using the aforementioned method. This apparatus is an experimental setup, comprising a first testing unit and a second testing unit arranged sequentially. Each testing unit includes a first insulation material, a heating plate, and the insulation material to be tested, all arranged in a thermally conductive manner and tightly bonded together. The insulation material to be tested in the first testing unit and the second testing unit are bonded together. This apparatus is suitable for measuring the thermal conductivity of different types of insulation pads and improves the accuracy of design simulations.

[0086] Specifically, in Figure 4, the first test unit includes heat insulation material 1, heating plate 1, and heat insulation material 3; the second test unit includes heat insulation material 3, heating plate 2, and heat insulation material 4. Heat insulation material 1 and heat insulation material 4 are both first heat insulation materials, while heat insulation material 2 and heat insulation material 3 are the heat insulation materials to be tested. Further, the device also includes a first clamping plate and a second clamping plate, namely clamping plate 1 and clamping plate 2. The first test unit and the second test unit are placed between clamping plate 1 and clamping plate 2. Clamping plate 1 has connecting holes, and clamping plate 2 has fasteners adapted to the connecting holes for applying pre-tightening force to fix the first test unit and the second test unit, thus forming the device as shown in Figures 5a-5c. The fasteners are bolts, and the device also includes nuts adapted to the bolts. The clamping plates 1 and 2 are tightened by the bolts and nuts, thus applying pre-tightening force to the first test unit and the second test unit in the device to simulate operating conditions. In this embodiment of the invention, fasteners and corresponding connecting holes are provided at both ends of the corresponding clamping plate, with six fasteners in total, but not limited to eight, etc., which are also applicable to this invention. Furthermore, the fasteners are not limited to fastening bolts and their corresponding nuts; other fasteners capable of applying tightening force are also applicable to this invention.

[0087] In this embodiment of the invention, the dimensions of the first insulation material and the insulation material to be tested in the first and second test units are both much larger than the dimensions of the heating plate. Specifically, as shown in Figure 4, the dimensions of insulation materials 1, 2, 3, and 4 are larger than the dimensions of heating plates 1 and 2. This creates a thermal insulation zone around the heating plate on the four sides of the insulation material, preventing heat from radiating from the insulation material into the air and ensuring the accuracy and reliability of the thermal conductivity test of the insulation material under dynamic temperatures. Furthermore, heating plates 1 and 2 provide the heat source for the device, and heating plates 1 and 2 have the same power. Insulation materials 1 and 4 are insulation sheets, which can be aerogel insulation sheets used to block heat conduction from the heating plate to the fixed clamping plate. However, they are not limited to this; other insulation sheets such as foam insulation pads are also suitable for this invention. Insulation material 2 and insulation material 3 in the insulation materials to be tested can be the insulation pads under test, serving as the objects for studying the thermal conductivity of the insulation materials under dynamic temperatures and different preload forces. This also includes determining the main test unit and auxiliary test unit in the first test unit and the second side unit. The insulation material to be tested in the main test unit is the main test object, and the insulation material to be tested in the auxiliary test unit is the auxiliary test object. That is, if insulation material 2 is the main test object, then insulation material 3 is the auxiliary test object, and vice versa.

[0088] In this embodiment of the invention, as shown in Figure 6, the area on the side of the insulation material to be tested that is in contact with the corresponding heating plate is the heating zone, and the area on the side of the insulation material to be tested that is not in contact with the corresponding heating plate is the thermal insulation zone. Further, as shown in Figures 7 and 8, multiple temperature sensing points are evenly distributed on both the heating zone and the corresponding area on the other side of the insulation material to be tested in the main testing unit; in the auxiliary testing unit, one temperature sensing point is provided on the side of the insulation material to be tested that is in contact with the heating plate. Since only one temperature sensing point is provided on the side of the insulation material to be tested that is in contact with the heating plate, the temperature rise of the two insulation materials to be tested can be monitored to ensure consistency, thus guaranteeing the accuracy of the test.

[0089] For example, if the thermal insulation material 2 is the main test object, in order to ensure that the collected temperature reflects the temperature rise of the tested material, as shown in Figure 8, 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 area within the box in the figure), and similarly, 4×4=16 temperature sensing points are arranged at the same position on the back (also called the other side) of the thermal insulation material 2. Only one temperature sensing point is arranged on the side (temperature sensing arrangement area) of the thermal insulation material 3, which serves as the auxiliary test unit, to monitor the temperature rise on the back of the auxiliary test object. Multiple uniform temperature sensing points are evenly arranged in a 4x4 pattern, for a total of 16 temperature sensing points, but this is not limited to this; a 3x3 pattern, for a total of 9 temperature sensing points, is also applicable in this embodiment of the invention.

[0090] The aforementioned device is designed based on Fourier heat transfer theory, and its theoretical foundation 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 accuracy of engineering design and engineering simulation is improved.

[0091] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of testing the thermal conductivity of an insulating material, characterised in that, include, Based on experimental theory, the following factors affecting thermal conductivity have been determined: Temperature gradient in the thickness direction of the insulation material under test Temperature rise rate of the insulation material to be tested The thickness h of the insulation material to be tested; Based on the identified factors affecting thermal conductivity, the following experimental parameters were determined: Temperature changes on both sides of the insulation material under test, thickness of the insulation material under test after a preset preload is applied, ambient temperature, preset temperature, and temperature rise time; Different preset preload forces were applied to the experimental apparatus, and the apparatus was heated to different preset temperatures. The experimental parameters of the thermal insulation material under test were obtained at different preset temperatures and with different preset preload forces. Based on the obtained experimental parameters, the thermal conductivity of the insulation material under test is calculated.

2. The method of testing the thermal conductivity of a thermal insulation material according to claim 1, characterized in that, The experimental theory includes: Calculate the heat flux density q according to Fourier's law of heat transfer: q*Δt=∑ρcΔTΔh (1) Where: q is the heat flux density, unit: W / m³ 2 Δt is the time of heat flow, in seconds, and ρ is the density of the insulation material being tested, in kg / m³. 3 ; c is the specific heat capacity of the insulation material to be tested, in J / (kg*K); ΔT is the temperature difference of the insulation material before and after the test, in K; Δh is the thickness of the insulation material to be tested along the heat flow direction, in m; The formula (1) can be transformed as follows: In the formula, p is the density of the thermal insulation material to be measured, in kg / m 3 c is the specific heat capacity of the thermal insulation material to be measured, in J / (kg*K), h is the thickness of the thermal insulation material to be measured, The temperature rise rate of the insulation material to be tested; Based on the heat flux q and the temperature gradient of the insulation material to be measured in the thickness direction, the thermal conductivity of the insulation material to be measured is calculated: This represents the temperature gradient of the insulation material under test along its thickness.

3. A method of testing the thermal conductivity of a thermal insulation material according to claim 2, characterised in that, Different preset preload forces were applied to the experimental setup, and the device was heated to different preset temperatures. The experimental parameters of the insulation material under test were obtained at different preset temperatures and with different preset preload forces. The experimental device was fixed on the experimental platform, a preset pre-tightening force was applied to the experimental device, and one of the two thermal insulation materials to be tested was selected as the main test object and the other as the auxiliary test object. Multiple temperature sensing points were set on both sides of the main test object and connected to a dial gauge; To begin the test, a regulated power source is used to heat the two heating plates in the experimental setup simultaneously. After heating the main test object to the preset temperature, it is maintained for a certain period of time until the insulation material under test returns to room temperature, thus completing the test. During the test, the ambient temperature, the temperature of multiple temperature sensing points on both sides of the main test object, the thickness of the main test object displayed on the dial gauge, and the temperature rise time were recorded.

4. A method of testing the thermal conductivity of a thermal insulation material according to claim 3, characterised in that, This also includes setting up an insulating environment, whereby the side of the heating plate not attached to the insulation material to be tested is attached to a first insulation material, wherein... Both the first insulation material and the insulation material to be tested are larger than the size of the heating plate, so that the four sides of the insulation material to be tested are insulated.

5. The method of testing the thermal conductivity of thermal insulation according to claim 3, characterized in that, The two heating plates have the same heating power, which allows the two insulation materials to be tested to be heated to the preset temperature simultaneously, so that the insulation material to be tested, which is the auxiliary test object, provides side insulation to the insulation material to be tested, which is the main test object.

6. The method of testing the thermal conductivity of thermal insulation according to claim 3, characterized in that, It also includes the installation of fastening devices, including, Two first insulation materials, two heating plates, and two insulation materials to be tested are fixed between the fastening device and a preset pre-tightening force is applied by fasteners.

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

8. A method of testing the thermal conductivity of a thermal insulation material according to claim 7, characterised in that, Based on the obtained experimental parameters, the thermal conductivity of the insulation material under test is calculated, including: Based on the preset temperature, the ambient temperature, and the acquired temperature rise time, a temperature rise rate of the main test object at the preset temperature is calculated The temperature rise rate obtained Substituting the thickness of the main test object displayed on the dial gauge into formula (2), the heat flux density q is calculated; Based on the temperatures of the multiple temperature sensing points on the two sides of the main test object, a temperature gradient of the main test object at a preset temperature is calculated In the formula, T a is 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 is the average temperature of all temperature sensing points on the other side of the main test object at the preset temperature; The calculated heat flow density q and the temperature gradient of the main test object at the preset temperature are compared Substitute into formula (3) to calculate the thermal conductivity of the insulation material to be tested.

9. A method of testing the thermal conductivity of a thermal insulation material according to claim 8, characterised in that, It also includes summarizing the thermal conductivity of the insulation material under different preset temperatures and different preset preloads, forming curves of the thermal conductivity of the insulation material under different temperatures with a fixed preload.

10. A device for testing the thermal conductivity of an insulating material, characterized in that, It includes a first test unit and a second test unit, which are arranged sequentially. Both the first test unit and the second test unit include a first heat insulation material, a heating plate, and a heat insulation material to be tested, which are arranged in a thermally conductive manner and are tightly bonded together in sequence. The heat insulation material to be tested in the first test unit and the heat insulation material to be tested in the second test unit are bonded together.

11. Apparatus for testing the thermal conductivity of a thermal insulation material according to claim 10, characterised in that It also includes a first clamping plate and a second clamping plate, with the first test unit and the second test unit 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 fasteners adapted to the connecting hole, for fixing the first test unit and the second test unit and applying pre-tightening force.

12. Apparatus for testing the thermal conductivity of a thermal insulation material according to claim 11, characterised in that The dimensions of the first insulation material and the insulation material to be tested in both the first and second test units are larger than the dimensions of the heating plate.

13. Apparatus for testing the thermal conductivity of a thermal insulation material according to claim 12, characterised in that The first test unit and the second side unit are respectively the main test unit and the auxiliary test unit. The insulation material to be tested in the main test unit is the main test object, and the insulation material to be tested in the auxiliary test unit is the auxiliary test object. Uniform temperature sensing points are set on both the side of the thermal insulation material to be tested that is attached to the heating plate and the other side of the thermal insulation material that is not attached to the heating plate, which are the main test objects. A temperature sensing point is set on the side of the heat insulation material to be tested, which is used as an auxiliary test object, and is attached to the heating plate.

Images