A device for measuring thermal conductivity of irregular block solid and a measuring method thereof

Abstract

The application provides an irregular block solid thermal conductivity measuring device and a measuring method thereof, and belongs to the technical field of irregular block solid thermal conductivity measurement. The device solves the problem that the existing measuring device has randomness when selecting a heating point, and sometimes the temperature rise signal of the selected measuring point is not obvious, leading to a large measurement error. The device comprises a CT detector, a three-dimensional scanner, a computing system, a pulse light source system, a temperature detection device, a rocker arm, a rotary table, a rotary guide rail and a horizontal moving mechanism arranged on a test table. The rotary table is installed on the horizontal moving mechanism, the three-dimensional scanner is installed on the side of the horizontal moving mechanism, the CT detector is located above one end of the horizontal moving mechanism and is installed on the test table, the rotary guide rail is installed on the other end of the horizontal moving mechanism, the temperature detection device is installed on the rotary guide rail, the pulse light source system is installed on the rocker arm, and the rotary table is provided with a sample to be detected. The device is mainly used for non-destructive measurement of porous materials.

Description

Technical Field

[0001] The invention belongs to the technical field of irregular block solid thermal conductivity measurement, and in particular relates to an irregular block solid thermal conductivity measurement device and a measurement method thereof. Background Art

[0002] Thermal conductivity is one of the basic parameters for measuring the thermal properties of an object. Heterogeneous bulk materials are commonly found in aerospace, oil extraction, rock excavation, geothermal development, permafrost engineering and other related fields. Accurate thermal conductivity measurement can better analyze the evolution history of rocks, the cyclic characteristics of permafrost, and simulate the distribution characteristics of the temperature field around the rock and soil during oil extraction and thereby provide thermal protection. Therefore, accurate and efficient measurement of the thermal conductivity of heterogeneous bulk materials has important practical and theoretical significance.

[0003] The measurement of thermal conductivity can be generally divided into steady-state method and non-steady-state method. The steady-state method is to compress the sample to be tested into a standardized material plate and calculate the thermal conductivity using a balanced heat flux meter under a constant temperature gradient. Since the material needs to be changed into a standard shape, this type of measurement is destructive and cannot be applied to porous materials. For the non-steady-state method, thermal conductivity scanning and line source technology are two commonly used methods. The heat source and thermal sensor are moved at the same speed and maintained at a constant distance from each other. The thermal conductivity is obtained by measuring the change in the temperature signal of the thermal sensor with distance. This type of method usually takes a long time to measure, and for materials with low thermal conductivity, the temperature signal of the thermal sensor is weak, which will cause large errors.

[0004] However, the above-mentioned thermal conductivity measurement method has more or less the following problems: there is randomness in the selection of heating points, and sometimes the temperature rise signal of the selected measurement point is not obvious, resulting in large measurement errors; for porous materials, it is impossible to accurately obtain the law between its thermal conductivity and pore distribution. Summary of the Invention

[0005] In view of this, the present invention aims to propose a device and method for measuring the thermal conductivity of irregular block solids, so as to solve the problems that the existing measuring devices are random when selecting heating points, sometimes the temperature rise signal of the selected measuring points is not obvious, resulting in large measurement errors, and for porous materials, it is impossible to accurately obtain the law between their thermal conductivity and pore distribution.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A device for measuring the thermal conductivity of irregular block solids includes a CT detector, a three-dimensional scanner, a computing system, a pulse light source system, a temperature detection device, a rocker arm, a turntable, a rotating guide rail, and a horizontal moving mechanism. The horizontal moving mechanism is arranged on a test bench, the turntable is mounted on the horizontal moving mechanism, the three-dimensional scanner is mounted on the side of the horizontal moving mechanism, the CT detector is located above one end of the horizontal moving mechanism and is mounted on the test bench, the rotating guide rail is mounted on the other end of the horizontal moving mechanism, the temperature detection device is mounted on the rotating guide rail, the rocker arm is mounted on the test bench and is arranged in contact with the side of the horizontal moving mechanism, the pulse light source system is mounted on the rocker arm, and the CT detector, three-dimensional scanner, pulse light source system, temperature detection device, rocker arm, turntable, rotating guide rail, and horizontal moving mechanism are all connected to the computing system via control lines, and a sample to be tested is placed on the turntable.

[0008] Furthermore, the horizontal moving mechanism includes a moving guide rail and a moving slider, the moving slider is slidably mounted on the moving guide rail, the moving guide rail is mounted on the test bench, and the turntable is mounted on the moving slider.

[0009] Furthermore, the control modules of the movable guide rail and the turntable are both connected to the computing system via control lines.

[0010] Furthermore, the control modules of the rotating guide rail and the rocker arm are connected to the computing system via control lines.

[0011] Furthermore, the scanning direction of the three-dimensional scanner is facing the sample to be inspected.

[0012] A method for measuring thermal conductivity of an irregular block solid, comprising the following steps:

[0013] Step 1: Place the sample to be tested on the turntable;

[0014] Step 2: Move the sample to be tested to the detection area of ​​the 3D scanner by moving the slider and scan it with the 3D scanner;

[0015] Step 3: Determine whether the computing system obtains a three-dimensional scanning signal;

[0016] Step 4: After obtaining the 3D scanning signal, move the slider to the CT detector detection area and perform detection with the CT detector;

[0017] Step 5: Determine whether the computing system obtains the signal from the CT detector;

[0018] Step 6: After obtaining the signal from the CT detector, the computing system calculates the optimal incident position of the pulse light source system and the optimal detection position of the temperature detection device;

[0019] Step 7: Then control the turntable, rocker arm and rotating guide rail to move to corresponding positions respectively;

[0020] Step 8: The pulse light source system emits energy, and the temperature detection device detects and transmits the temperature rise information to the calculation system;

[0021] Step 9: The computing system performs data analysis to obtain the thermal conductivity.

[0022] Furthermore, if no three-dimensional scanning signal is obtained in step 3, the three-dimensional scanner needs to be used to scan again.

[0023] Furthermore, the signal of the CT detector that is not obtained in step 5 needs to be detected again by the CT detector.

[0024] Furthermore, in step 6, the computing system calculates the optimal incident position of the light source of the pulse light source system and the optimal detection position of the temperature detection device through genetic algorithm optimization.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention can obtain the three-dimensional morphology of the sample to be detected by collecting images with a three-dimensional scanner and controlling the rotation of the sample to be detected above the turntable by a computing system.

[0027] 2. The present invention can obtain defects inside the sample to be tested through the CT detector.

[0028] 3. The present invention obtains an irregular three-dimensional structure with pores in the form of nodes and node connections through a CT detector, takes the best incident point and the best measurement point as optimization variables, and uses a genetic algorithm to optimize the best incident point and the best measurement point with the best thermal response as the goal.

[0029] 3. The present invention combines the surface morphology obtained by a three-dimensional scanner with the internal defects obtained by a CT detector to obtain the three-dimensional structure of the sample to be tested, and transmits the data into a computing system. The computing system converts the imported three-dimensional structure into a data format of nodes and node connections, and optimizes and calculates the optimal light source position and temperature measurement position through genetic algorithm optimization, thereby solving the problem of large measurement errors caused by the traditional heat source method due to the randomness of line selection, resulting in unclear temperature rise signals.

[0030] 4. The present invention optimizes the optimal light source incident point and temperature measurement point of the device through a genetic algorithm, establishes a transient thermal diffusion model to measure the temperature difference between the heat source excitation point and the temperature measurement under constant heat flux density boundary conditions, and inversely obtains the thermal conductivity of the heterogeneous material. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0032] Figure 1 This is a schematic structural diagram of a device for measuring thermal conductivity of irregular block solids according to the present invention;

[0033] Figure 2 This is a measurement flow chart of the device for measuring thermal conductivity of irregular block solids described in the present invention.

[0034] 1-CT detector, 2-3D scanner, 3-computing system, 4-pulsed light source system, 5-temperature detection device, 6-rocker arm, 7-turntable, 8-rotating guide rail, 9-moving guide rail, 9-1: moving slider, 10-sample to be tested. DETAILED DESCRIPTION

[0035] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features therein can be combined with each other in the absence of conflict, and the embodiments described are only part of the embodiments of the present invention, not all of the embodiments.

[0036] See also Figure 1-2 This embodiment describes a device for measuring the thermal conductivity of irregular block solids, including a CT detector 1, a three-dimensional scanner 2, a computing system 3, a pulse light source system 4, a temperature detection device 5, a rocker arm 6, a turntable 7, a rotating guide rail 8, and a horizontal moving mechanism. The horizontal moving mechanism is arranged on a test bench, the turntable 7 is mounted on the horizontal moving mechanism, the three-dimensional scanner 2 is mounted on the side of the horizontal moving mechanism, the CT detector 1 is located above one end of the horizontal moving mechanism and is mounted on the test bench, the rotating guide rail 8 is mounted on the other end of the horizontal moving mechanism, the temperature detection device 5 is mounted on the rotating guide rail 8, the rocker arm 6 is mounted on the test bench and is arranged in contact with the side of the horizontal moving mechanism, the pulse light source system 4 is mounted on the rocker arm 6, the CT detector 1, three-dimensional scanner 2, pulse light source system 4, temperature detection device 5, rocker arm 6, turntable 7, rotating guide rail 8, and horizontal moving mechanism are all connected to the computing system 3 through a control line, and a sample 10 to be tested is placed on the turntable 7.

[0037] The horizontal moving mechanism includes a moving guide rail 9 and a moving slider 9 - 1 . The moving slider 9 - 1 is slidably mounted on the moving guide rail 9 . The moving guide rail 9 is mounted on the test bench. The turntable 7 is mounted on the moving slider 9 - 1 .

[0038] The control modules of the movable guide rail 9 and the turntable 7 are both connected to the computing system 3 via control lines.

[0039] The control modules of the rotating guide rail 8 and the rocker arm 6 are both connected to the computing system 3 via control lines.

[0040] The scanning direction of the three-dimensional scanner 2 is facing the sample 10 to be inspected.

[0041] The three-dimensional scanner 2 is fixed on the side of the moving guide rail 9 of the experimental table, and its scanning direction is facing the sample above the turntable 7. The control system of the three-dimensional scanner 2 is connected to the computing system. The computing system 3 controls the rotation of the sample 10 to be tested above the turntable 7 and the image acquisition of the three-dimensional scanner 2 to obtain the three-dimensional morphology of the heterogeneous solid material to be tested. The CT detector 1 is fixed on the experimental table so that the moving guide rail 9 completely passes through the detection area of ​​the CT detector 1. Its control system is connected to the computing system 3. The computing system 3 controls the moving guide rail 9 so that the sample 10 to be tested can move back and forth in the detection area. At the same time, the computing system 3 controls the moving guide rail 9. The CT detector 1 issues a sampling instruction to obtain internal defects of the sample 10 to be tested. The rotating guide rail 8 is fixed on the test bench at the other end of the movable guide rail 9. The temperature detection device 5 is fixed on the rotating guide rail 8. The control systems of the rotating guide rail 8 and the temperature detection device 5 are simultaneously connected to the computing system 3, and the computing system 3 accurately controls the position of the temperature detection device 5. The rocker arm 6 is fixed on the test bench close to the movable guide rail 9. At the same time, the pulse light source system 4 is fixed on the rocker arm 6. The control systems of the rocker arm 6 and the pulse light source system 4 are simultaneously connected to the computing system 3, and the computing system accurately controls the position of the excitation heat source.

[0042] A sample 10 to be tested is placed on the turntable 7, and the slider 9-1 is used to move the sample 10 to the detection area of ​​the three-dimensional scanner 2. The three-dimensional scanner 2 performs scanning to determine whether the computing system 3 obtains a three-dimensional scanning signal. After obtaining the three-dimensional scanning signal, the slider 9-1 is moved to the detection area of ​​the CT detector 1. The CT detector 1 performs detection to determine whether the computing system 3 obtains the signal of the CT detector 1. After obtaining the signal of the CT detector 1, the computing system 3 calculates the optimal incident position of the light source of the pulse light source system 4 and the optimal detection position of the temperature detection device 5, and then controls the turntable 7, the rocker arm 6 and the rotating guide rail 8 to move to the corresponding positions respectively. The pulse light source system 4 emits energy, the temperature detection device 5 performs detection and transmits the temperature rise information to the computing system 3, and the computing system 3 performs data analysis to obtain the thermal conductivity coefficient.

[0043] The device combines the surface topography obtained by the three-dimensional scanner 2 with the internal defects obtained by the CT detector 1 to obtain the three-dimensional structure of the sample to be tested, and transmits the data to the computing system 3. The computing system 3 optimizes and calculates the optimal light source position and temperature measurement position through a genetic algorithm, which solves the problem of large measurement errors caused by the unclear temperature rise signal due to the randomness of line selection in the traditional heat source method. The optimal light source incident point and temperature measurement point of the device are optimized through the genetic algorithm, and a transient heat diffusion model is established to measure the temperature difference between the heat source excitation point and the temperature measurement under the boundary condition of constant heat flux density, and the thermal conductivity of the heterogeneous material is obtained by inversion.

[0044] A method for measuring thermal conductivity of an irregular block solid, comprising the following steps:

[0045] Step 1: Place the sample 10 to be tested on the turntable 7;

[0046] Step 2: Move the sample 10 to be tested to the detection area of ​​the three-dimensional scanner 2 by moving the slider 9-1, and scan it with the three-dimensional scanner 2;

[0047] Step 3: Determine whether the computing system 3 obtains a 3D scanning signal. If no 3D scanning signal is obtained, re-scanning is required using the 3D scanner 2.

[0048] Step 4: After obtaining the three-dimensional scanning signal, the movable slider 9 - 1 is moved to the detection area of ​​the CT detector 1 by the movable slider 9 - 1 , and detection is performed by the CT detector 1 ;

[0049] Step 5: Determine whether the computing system 3 obtains the signal from the CT detector 1. If the signal from the CT detector 1 is not obtained, the computing system 3 needs to re-detect the signal using the CT detector 1.

[0050] Step 6: After obtaining the signal from the CT detector 1, the computing system 3 calculates the optimal incident position of the pulse light source system 4 and the optimal detection position of the temperature detection device 5;

[0051] Step 7: Then control the turntable 7, rocker arm 6 and rotating guide rail 8 to move to corresponding positions respectively;

[0052] Step 8: The pulse light source system 4 emits energy, and the temperature detection device 5 detects and transmits the temperature rise information to the calculation system 3;

[0053] Step 9: The computing system 3 performs data analysis to obtain the thermal conductivity.

[0054] In step 6, the computing system 3 calculates the optimal incident position of the light source of the pulse light source system 4 and the optimal detection position of the temperature detection device 5 through genetic algorithm optimization.

[0055] Create a MATLAB function named code that accepts a two-element vector x as input. The main purpose of this function is to use the Java API of the COMSOL Multiphysics software to set the parameters of a physical model and run a simulation. It includes the following steps:

[0056] a: Get two integers m and n from the input vector x. These integers are used to extract specific node coordinates.

[0057] b: Import node data, extract the coordinate values ​​of nodes m and n, create a model using COMSOL's Java API, and set the model path and labels;

[0058] c: Set model parameters, such as position coordinates x_r, y_r, z_r and x_t, y_t, z_t, as well as laser width, power, radius and other parameters;

[0059] d: Generate mesh and solver settings;

[0060] e: Set material properties, such as thermal expansion coefficient, specific heat capacity, density, and thermal conductivity, set the heat source, and associate it with time and space distribution;

[0061] f: Run the mesh generation and solver, extract the maximum value, and calculate the best time.

[0062] In a measurement method for an irregular block solid thermal conductivity measurement device, in step 6, a computing system 3 calculates the optimal incident position of a pulse light source system 4 and the optimal detection position of a temperature detection device 5 through genetic algorithm optimization, wherein the genetic algorithm optimization calculation includes the following steps:

[0063] (1) Read the node coordinate data, import the node coordinate data, and store it in the variable nodes;

[0064] (2) Read node connection data, import node connection output, and store it in the variable elements;

[0065] (3) Design parameter limits. Calculate the length L of the data in the node, set the design parameter lb to [1,1], and the upper bound ub to [L,L]. The optimized parameters are searched within these limits.

[0066] (4) Set the options of the genetic algorithm;

[0067] (5) Call the objective function code, pass in two design parameters, output the optimization results, and display the best incident point position number and the best detection point position number.

[0068] The embodiments of the present invention disclosed above are intended only to illustrate the present invention. The embodiments do not describe all details in detail, nor do they limit the present invention to the specific embodiments described. Numerous modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention.

Claims

1. A device for measuring thermal conductivity of irregular block solids, characterized by: The invention comprises a CT detector (1), a three-dimensional scanner (2), a computing system (3), a pulse light source system (4), a temperature detection device (5), a rocker arm (6), a turntable (7), a rotating guide rail (8) and a horizontal moving mechanism, wherein the horizontal moving mechanism is arranged on a test bench, the turntable (7) is mounted on the horizontal moving mechanism, the three-dimensional scanner (2) is mounted on the side of the horizontal moving mechanism, the CT detector (1) is located above one end of the horizontal moving mechanism and is mounted on the test bench, the rotating guide rail (8) is mounted on the other end of the horizontal moving mechanism, the temperature detection device (5) is mounted on the rotating guide rail (8), the rocker arm (6) is mounted on the test bench and is arranged in contact with the side of the horizontal moving mechanism, the pulse light source system (4) is mounted on the rocker arm (6), the CT detector (1), the three-dimensional scanner (2), the pulse light source system (4), the temperature detection device (5), the rocker arm (6), the turntable (7), the rotating guide rail (8) and the horizontal moving mechanism are all connected to the computing system (3) via a control line, and a sample (10) to be detected is placed on the turntable (7).

2. The device for measuring thermal conductivity of irregular block solids according to claim 1, characterized in that: The horizontal movement mechanism comprises a moving guide rail (9) and a moving slider (9-1), wherein the moving slider (9-1) is slidably mounted on the moving guide rail (9), the moving guide rail (9) is mounted on a test bench, and the turntable (7) is mounted on the moving slider (9-1).

3. The device for measuring thermal conductivity of irregular block solids according to claim 2, characterized in that: The control modules of the movable guide rail (9) and the turntable (7) are both connected to the computing system (3) via control lines.

4. The device for measuring thermal conductivity of irregular block solids according to claim 1, characterized in that: The control modules of the rotating guide rail (8) and the rocker arm (6) are both connected to the computing system (3) via control lines.

5. The device for measuring thermal conductivity of irregular block solids according to claim 1, characterized in that: The three-dimensional scanner (2) scans in a direction facing the sample (10) to be inspected.

6. A method for measuring thermal conductivity of an irregular block solid according to any one of claims 1 to 5, characterized in that: It includes the following steps: Step 1: Place the sample to be tested (10) on the turntable (7); Step 2: Move the sample to be tested (10) to the detection area of ​​the three-dimensional scanner (2) by moving the slider (9-1), and scan it with the three-dimensional scanner (2); Step 3: Determine whether the computing system (3) obtains a three-dimensional scanning signal; Step 4: After obtaining the three-dimensional scanning signal, the movable slider (9-1) is moved to the detection area of ​​the CT detector (1) by the movable slider (9-1), and detection is performed by the CT detector (1); Step 5: Determine whether the computing system (3) obtains the signal of the CT detector (1); Step 6: After obtaining the signal from the CT detector (1), the computing system (3) calculates the optimal incident position of the light source of the pulse light source system (4) and the optimal detection position of the temperature detection device (5); Step 7: Then control the turntable (7), rocker arm (6) and rotating guide rail (8) to move to corresponding positions respectively; Step 8: The pulse light source system (4) emits energy, and the temperature detection device (5) detects and transmits the temperature rise information to the calculation system (3); Step 9: The calculation system (3) performs data analysis to obtain the thermal conductivity.

7. The method for measuring thermal conductivity of an irregular block solid according to claim 6, characterized in that: If no three-dimensional scanning signal is obtained in step 3, scanning must be performed again using the three-dimensional scanner (2).

8. The method for measuring thermal conductivity of an irregular block solid according to claim 6, characterized in that: In step 5, if the signal of the CT detector (1) is not obtained, the signal needs to be detected again by the CT detector (1).

9. The device for measuring thermal conductivity of irregular block solids according to claim 6, characterized in that: In step 6, the calculation system (3) calculates the optimal incident position of the light source of the pulse light source system (4) and the optimal detection position of the temperature detection device (5) through genetic algorithm optimization.

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