A method and apparatus for measuring the thermal resistance of a non-uniform composite structure.

Abstract

This invention discloses a device for measuring the thermal resistance of a non-uniform composite structure, comprising a high-temperature detection unit. The high-temperature detection unit is adsorbed onto the heating side of the composite structure under test via a high-temperature adsorption structure. The high-temperature detection unit includes a calculation and control unit, a heating wire, a temperature sensor, and a vacuum insulation plate. The vacuum insulation plate is located behind the high-temperature adsorption structure, the heating wire is located inside the vacuum insulation plate, and the temperature sensor is located at the contact point between the high-temperature adsorption structure and the composite structure under test. The calculation and control unit is located behind the vacuum insulation plate and connected to the temperature sensor and the heating wire. By utilizing the detection device and method proposed in this invention, the problem of difficult thermal resistance detection in non-uniform composite structures due to the diversity of their internal materials can be solved. Furthermore, the adsorption structure eliminates the need to disassemble the composite structure, preventing damage to the tested material and simplifying the operation process.

Description

Technical Field

[0001] This invention relates to the field of heat transfer detection, specifically to a method and apparatus for measuring the thermal resistance of a non-uniform composite structure. Background Technology

[0002] The non-uniform composite structure contains a variety of materials. For example, the insulation layer consists of an outer sheet metal, an inner ABS board, and a foam layer sandwiched in between. The thermal resistance of the iron and ABS board can be calculated using a one-dimensional expression of Fourier's law.

[0003]

[0004] Where: Φ is the heat flux (W), R is the thermal resistance, and ΔT is the temperature gradient.

[0005] However, due to the varying densities and shapes of the foamed layers located in the middle of the insulation layer, their thermal resistance can only be estimated based on a given range of thermal conductivity. Therefore, a measuring device and method are proposed to quantitatively study and measure the thermal resistance of the foamed layers.

[0006] Traditional methods for measuring the thermal resistance of composite structures, such as the insulation layer of a refrigerator, require destructive disassembly of the refrigerator casing when using traditional thermal resistance testing devices. This damages the original product and is too costly. Furthermore, even composite structures manufactured using the same method may have variations in their foaming process. Measuring the thermal resistance of one composite structure does not represent the thermal resistance of other composite structures and offers no reference value. Therefore, the aim is to design a non-destructive testing device for the thermal resistance of composite structures that does not damage the sample itself.

[0007] Traditional methods for measuring thermal resistance have another drawback: theoretically, thermal resistance measurement must be performed on an infinitely large plane, which implies that heat transfer only occurs between the two surfaces, with no heat dissipation. With traditional measurement methods, regardless of the area and wall thickness of the material being measured, the contact area between the instrument and the material is fixed. If the material is thick and has a small area, heat transfer between the two surfaces will inevitably result in heat loss, leading to a significant error in the measured thermal resistance value.

[0008] Therefore, the current problem to be solved is how to provide a testing device that does not have many restrictions on the size and specifications of composite structural materials, does not require destructive disassembly of the composite structural materials, does not require complicated fixing and installation of the composite structural materials to be tested, and has a simple operation process and small measurement error. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a method and apparatus for measuring the thermal resistance of non-uniform composite structures, thus solving the problems in the background technology.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a measuring device for the thermal resistance of a non-uniform composite structure, comprising:

[0011] A high-temperature detection unit is attached to the heating side of the composite structure under test via a high-temperature adsorption structure. The high-temperature detection unit includes a calculation and control unit, a heating wire, a temperature sensor, and a vacuum insulation plate. The vacuum insulation plate is located behind the high-temperature adsorption structure, the heating wire is located inside the vacuum insulation plate, the temperature sensor is located at the contact point between the high-temperature adsorption structure and the composite structure under test, and the calculation and control unit is located behind the vacuum insulation plate and connected to the temperature sensor and the heating wire.

[0012] The low-temperature detection unit is adsorbed on the other side of the composite structure under test through a low-temperature end adsorption structure. The low-temperature detection unit includes a measurement and control unit 2 and a temperature sensor group connected to the measurement and control unit 2. The temperature sensor group includes temperature sensors 2 that are uniformly distributed.

[0013] Further specifying, the temperature sensor group includes nine temperature sensors, and the low temperature detection unit also includes a moving mechanism for controlling the movement of the nine temperature sensors.

[0014] A method for measuring the thermal resistance of a non-uniform composite structure includes the following steps:

[0015] At the high-temperature end, the wall surface of the composite structure under test is uniformly divided into m regions. One region is selected, and its center point is heated using a heating wire. The other regions are covered by vacuum insulation panels. The temperature of this region is detected by a temperature sensor. After the high-temperature gas raises the temperature of this region by 10°C and stabilizes, the heating temperature data T is collected by the high-temperature detection unit. w1 ;

[0016] At the low-temperature end, the wall surface of the composite structure under test is uniformly divided into n regions, and nine temperature sensors are installed. These temperature sensors are dynamically movable, with each sensor capturing the temperature of n / 9 regions. In this way, the nine sensors can completely monitor the temperature distribution of these n regions. The low-temperature detection unit can collect the temperatures T1 to T2 at each part of the entire low-temperature end. n The heat flux density q through the axis can be calculated by observing the temperature distribution of the material at different heights. m The temperature curve on this axis is then fitted using the least squares method, and the slope K of the temperature curve is obtained. T ;

[0017] The heat transfer temperature of the tested material is deduced from the temperature curve. Combined with the heating temperature data and the heat transfer temperature data, the thermal resistance R1 of the tested composite material in the selected high-temperature region is finally calculated using Fourier's law of thermal conductivity.

[0018] Further defining the process, the heating area at the high-temperature end is moved, and each of the m areas is heated sequentially. The above steps are repeated to obtain the thermal resistance corresponding to each of the m areas at the high-temperature end: R1-R... m .

[0019] Further specifying the thermal resistance, the overall thermal resistance of this composite material is calculated by fitting the thermal resistance of m regions:

[0020]

[0021] The present invention has the following advantages: by using the detection device and detection method proposed in the present invention, the problem of difficult detection of thermal resistance of non-uniform composite structures due to the diversity of internal materials can be solved; and by adopting an adsorption structure, there is no need to disassemble the composite structure, which will not damage the material being tested, and the operation process is simple. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention;

[0023] Figure 2 This is a regional division diagram for the present invention.

[0024] In the diagram: 1. Composite structure under test; 2. High-temperature end adsorption structure; 3. Vacuum insulation panel one; 4. Temperature sensor one; 5. Heating wire; 6. Calculation and control unit one; 7. Low-temperature end wall of the material under test; 8. High-temperature detection unit; 9. Low-temperature end adsorption structure; 10. Temperature sensor group; 11. Calculation and control unit two; 12. Low-temperature detection unit; 13. Measurement area of ​​one temperature sensor two at the low-temperature end. Detailed Implementation

[0025] 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, and 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.

[0026] Please see Figure 1-2 This invention provides a technical solution: a measuring device for the thermal resistance of a non-uniform composite structure, comprising:

[0027] The high-temperature detection unit 8 is attached to the heating side of the composite structure 1 under test via a high-temperature adsorption structure 2. Both the high-temperature adsorption structure 2 and the low-temperature adsorption structure 9 are vacuum adsorption platforms, employing negative pressure adsorption to adsorb onto both sides of the composite structure 1 under test through pressure difference. The high-temperature detection unit 8 includes a measurement and control unit 6, a heating wire 5, a temperature sensor 4, and a vacuum insulation plate 3. The vacuum insulation plate 3 is located behind the high-temperature adsorption structure 2, and the heating wire 5 is located inside the vacuum insulation plate 3 and is in close contact with a point on the high-temperature end plane of the composite structure 1 under test for heating. In the high-temperature region, when the heating wire 5 is turned on to heat the composite structure 1 under test, the vacuum insulation plate 3 ensures the direction of heat transfer and prevents heat transfer to the high-temperature end, so that the heat transfer direction is fixed from the high-temperature end to the heat transfer end. In this way, the temperature data collected at the heat transfer end has a small error in the thermal resistance calculation. The temperature sensor 4 is located at the contact point between the high-temperature adsorption structure 2 and the composite structure 1 under test, and is used to obtain the temperature data of the high-temperature region under the heating wire 5. The measurement and control unit 6 is located behind the vacuum insulation plate 3 and is connected to the temperature sensor 4 and the heating wire 5.

[0028] The low-temperature detection unit 12 is adsorbed onto the other side of the composite structure 1 under test via the low-temperature end adsorption structure 9. The low-temperature detection unit 12 includes a measurement and control unit 2 11 and a temperature sensor group 10 connected to the measurement and control unit 2. The temperature sensor group 10 includes nine evenly distributed temperature sensors 2 for acquiring heat transfer temperature data of the wall at the low-temperature end. The low-temperature detection unit 12 also includes a moving mechanism for controlling the movement of the nine temperature sensors 2. The moving mechanism is a cross-shaped moving mechanism, such as a ball screw cross slide. The measurement and control unit 2 controls the cross-shaped moving mechanism to move the temperature sensors 2, making the collected low-temperature end temperature data more accurate.

[0029] The measurement and control unit 6 controls the high temperature detection unit 8 and is configured to: receive heating temperature data from the high temperature detection unit 8; and determine the thermal resistance of the composite structure 1 under test based on the heating temperature data and the heat transfer temperature data.

[0030] Measurement and control unit 2 11 controls the low temperature detection unit 12 and is configured to receive heat transfer temperature data from the low temperature detection unit 12.

[0031] Based on the heating temperature data and heat transfer temperature data, the thermal resistance of the non-uniform composite material under test can be calculated using Fourier's law of thermal conductivity.

[0032] A method for measuring the thermal resistance of a non-uniform composite structure includes the following steps:

[0033] At the high-temperature end, the wall surface of the composite structure 1 under test is uniformly divided into m regions. One region is selected, and its center point is heated using a heating wire 5. The other regions are covered by a vacuum insulation panel 3. The temperature of this region is detected by a temperature sensor 4. After the high-temperature gas raises the temperature of this region by 10°C and the temperature stabilizes, the heating temperature data T is collected by the high-temperature detection unit 8. w1 ;

[0034] At the low-temperature end, the wall surface of the composite structure 1 under test is uniformly divided into n regions, and nine temperature sensors are set up. These temperature sensors are dynamically movable, and each probe captures the temperature of n / 9 regions. In this way, the nine probes can completely monitor the temperature distribution of these n regions. The low-temperature detection unit 12 can collect the temperature T1 to T2 of each part of the entire low-temperature end. n Nine temperature sensors, evenly distributed on the wall, are positioned so that their distances from the high-temperature heating point can be equated to a single axis. Thus, these nine sensors can be approximated as temperature sensors at different heights on the same axis. Because each sensor's area is small, the longitudinal heat transfer at the low-temperature end is minimal. The heat flux density q across this axis can be calculated from the temperature distribution of the measured material at different heights. m The temperature curve on this axis is then fitted using the least squares method, and the slope K of the temperature curve is obtained. T :

[0035]

[0036] The heat transfer temperature of the tested material is deduced from the temperature curve. Combined with the heating temperature data and the heat transfer temperature data, the thermal resistance R1 of the tested composite structure 1 material in the selected high-temperature region is finally calculated using Fourier's law of thermal conductivity.

[0037] Move the heating area at the high-temperature end and heat each of the m areas one by one. Repeat the above steps to obtain the thermal resistance corresponding to each of the m areas at the high-temperature end: R1-R m .

[0038] The overall thermal resistance of this composite material is calculated by fitting the thermal resistance of m regions:

[0039]

[0040] Calculation process:

[0041] The slope K can be obtained from the temperature curve fitted by the low-temperature detection unit 12. T :

[0042]

[0043] Among them, TW1 The temperature data obtained by temperature sensor 4 at the high-temperature end of the non-uniform composite material under test, T W2 To measure the theoretical heat transfer temperature at the low-temperature end of the non-uniform composite structure material, ι is its thickness.

[0044] The heat flux density q of the material m :

[0045]

[0046]

[0047] Where, λ m The coefficient of thermal conductivity is the measured non-uniform composite material.

[0048] By Fourier's Law: We can obtain:

[0049]

[0050]

[0051] In summary, the formula for calculating the thermal resistance R1 of this non-uniform composite structure is:

[0052]

[0053] Since the thermal resistance varies in different regions of the composite structure, the heating area at the high-temperature end needs to be moved to heat each of the m regions one by one. This process is repeated to obtain the thermal resistances corresponding to these m regions at the high-temperature end: R1-R... m .

[0054] The overall thermal resistance R of this composite material is calculated by fitting the thermal resistance of these m regions. A :

[0055]

[0056] Theoretically, thermal resistance measurement should be performed on an infinitely large plane, assuming heat transfer only between the two surfaces and no heat dissipation. However, in reality, an infinitely large plane is impossible to measure, inevitably introducing errors. Traditional measurement methods maintain a fixed contact area between the instrument and the material regardless of its area and wall thickness. If the material is thick and has a small area, heat dissipation will occur during heat transfer between the two surfaces, resulting in a large error in the measured thermal resistance value. The measurement device and method used in this invention, as shown above, approximate the temperature data at both ends of the composite structure 1 measured on an infinitely large plane, minimizing error and leading to a more accurate thermal resistance reading.

[0057] By utilizing the detection device and method proposed in this invention, the problem of difficulty in detecting thermal resistance of non-uniform composite structures due to the diversity of their internal materials can be solved; moreover, the adsorption structure eliminates the need to disassemble the composite structure, preventing damage to the tested material and simplifying the operation process; it also provides a method to solve the problem of inaccurate thermal resistance measurement caused by the size and specifications of the tested material, thereby improving the detection accuracy.

[0058] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for measuring thermal resistance of a non-uniform composite structure, characterized by, The application relates to a heat resistance testing device for a non-uniform composite structure material. The high-temperature detection unit is adsorbed on the heating side of the measured composite structure through a high-temperature end adsorption structure, and comprises a calculation control unit I, an electric heating wire, a temperature sensor I and a vacuum heat insulation plate; the vacuum heat insulation plate is located at the back of the high-temperature end adsorption structure; the electric heating wire is located in the vacuum heat insulation plate and closely adheres to a point on the high-temperature end plane of the measured composite structure, so that the heat transfer direction is ensured to be from the high-temperature end to the heat transfer end; the temperature sensor I is located at the adhering position of the high-temperature end adsorption structure and the measured composite structure; and the calculation control unit I is located at the back of the vacuum heat insulation plate and is connected with the temperature sensor I and the electric heating wire. The low-temperature detection unit is adsorbed on the other side of the measured composite structure through a low-temperature end adsorption structure, and comprises a calculation control unit II, a temperature sensor group connected with the calculation control unit II and a moving mechanism for controlling the temperature sensor group. The calculation control unit I controls the high-temperature detection unit and receives the heating temperature data from the high-temperature detection unit; the calculation control unit II controls the low-temperature detection unit and receives the heat transfer temperature data from the low-temperature detection unit; and according to the heating temperature data and the heat transfer temperature data, the heat resistance of the measured non-uniform composite structure material can be calculated by the Fourier heat conduction law.

2. The apparatus for measuring thermal resistance of a non-uniform composite structure according to claim 1, wherein: The temperature sensor group comprises nine temperature sensors II, and the low-temperature detection unit further comprises a moving mechanism for controlling the nine temperature sensors II.

3. A method of measuring thermal resistance of a non-uniform composite structure, applied to the measuring apparatus of thermal resistance of a non-uniform composite structure according to any one of claims 1 to 2, characterized by, The application further relates to a heat resistance testing method for a non-uniform composite structure material. At the high temperature end, the wall of the composite structure to be measured is evenly divided into m regions, one of the m regions is selected, a center point of the region is heated by an electric heating wire, other regions are covered by vacuum insulation panels, the temperature of the region is detected by a temperature sensor, after the high temperature gas makes the temperature of the region rise by 10°C and stabilizes, the heating temperature data T is collected by a high temperature detection unit w1 ; At the low temperature end, the wall surface of the composite structure to be measured is evenly divided into n regions, and 9 temperature sensors II are arranged, which are all dynamically movable, wherein each probe captures the temperature condition of n / 9 regions, so that the 9 probes can completely monitor the temperature distribution of the n regions, and the low temperature detection unit can collect the temperatures T1 to T9 of each part of the entire low temperature end n , the 9 temperature sensors II are evenly distributed on the wall surface, and the distances of the 9 temperature sensors II to the heating point of the high temperature end can be equivalent to an axis, so that the 9 temperature sensors II can be approximately regarded as temperature sensors at different heights on the same axis, and the heat flow density q passing through the axis can be calculated through the temperature distribution of the measured material at different heights m , and the temperature curve on the axis is fitted through the least square method to obtain the slope K of the temperature curve T ; The heat transfer temperature of the measured material is calculated from the temperature curve, and the thermal resistance R of the measured composite structure material in the selected region at the high temperature end is finally calculated from the Fourier heat conduction law by combining the heating temperature data and the heat transfer temperature data 1。 4. The method of measuring thermal resistance of a non-uniform composite structure according to claim 3, wherein: The heating area of the high temperature end is moved, and the m areas are heated one by one, and the above steps are repeated to obtain the thermal resistance corresponding to the m areas of the high temperature end: R1-Rm m .

5. The method of measuring thermal resistance of a non-uniform composite structure according to claim 4, wherein: The heat resistance of the whole composite structure material is calculated by fitting according to the heat resistance of m regions. 。

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