A measuring device and method for automatically controlling the temperature to measure the heat transfer characteristics of porous media

Abstract

The present invention belongs to the field of measuring the heat transfer characteristics of porous media, and relates to a measuring device and method for automatically controlling the temperature to measure the heat transfer characteristics of porous media, comprising the following steps: Step 1: The thermal conductivity measurement principle of porous media is based on the steady-state heat conduction method; Step 2: Determine whether convection is generated in the internal heat transfer process of porous media; Step 3: Design an experimental measurement device to realize the thermal conductivity measurement of porous media; Step 4: Calculate the effective thermal conductivity in the heat transfer process of porous media; Step 5: Calculate the proportion of heat conduction, heat convection, and heat radiation in the heat transfer process of porous media; The present invention can accurately measure the heat transfer proportion of porous media, has a wide measurable temperature range and is not affected by external unstable factors, and solves the problem of the joint action of three heat transfer modes in the heat transfer process of porous media.

Description

Technical Field

[0001] The invention relates to the technical field of measuring the heat transfer characteristics of porous media, and in particular to a measuring device and method for automatically controlling the temperature to measure the heat transfer characteristics of porous media. Background Art

[0002] The heat transfer process in porous media has been widely used in technical fields such as energy, environment and engineering thermodynamics. It is a typical heat transfer problem in practical engineering applications such as tunnels, underground heat storage in geotechnical engineering and heat transfer in building foundations. As a common medium in geotechnical engineering, the analysis of the heat transfer process of porous media is of great significance to the research and application of building thermodynamics.

[0003] In many applications, the heat transfer characteristics of porous media and the determination of their thermal conductivity are involved. However, heat transfer in porous media is not only related to the characteristics of the solid and gas (liquid) media themselves, but also to the pore structure and arrangement of the porous media. In addition to considering the heat conduction between the phases, the influence of thermal radiation heat transfer cannot be ignored. When there is fluid flow, the influence of convective heat transfer must also be considered. Therefore, the heat transfer of porous media is often the combined effect of heat conduction, heat convection and heat radiation, but the heat transfer proportion of the three heat transfer methods varies greatly in different heat transfer environments, which will lead to differences in the analysis of the heat transfer characteristics and mechanisms of porous media.

[0004] At present, the analysis of the heat transfer characteristics of porous media is mainly based on the establishment and calculation of models. In the test of the heat transfer characteristics of porous media, heat conduction and heat convection are mainly considered. However, due to the relatively complex structure of porous media, it is difficult to intuitively observe and analyze the heat transfer process in porous media during the test. The test process is mainly based on the thermal conductivity of heat conduction, and the analysis of the effects of convective heat transfer and thermal radiation heat transfer in the heat transfer process of porous media is insufficient, making it difficult to reveal the mechanism and law of the heat transfer process in porous media. Therefore, it is urgent to adopt a more accurate method to describe the heat transfer process of porous media in research and application. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a measuring device and method for measuring the heat transfer characteristics of porous media with automatic temperature control, which can not only measure the heat transfer process of porous media under different working conditions and ambient temperatures, but also measure the heat transfer proportions of the three heat transfer modes in the heat transfer process at different temperatures, which plays an important role in the study of the mechanism and law of the heat transfer process in porous media. In addition, the purpose of the present invention is to provide a measuring device and method for measuring the heat transfer characteristics of porous media with automatic temperature control, which can be unaffected by unstable factors such as external airflow and ambient temperature.

[0006] In order to achieve the above object, the present invention provides a measuring device and method for automatically controlling the temperature to measure the heat transfer characteristics of porous media, the method comprising the following steps:

[0007] S1. The thermal conductivity measurement principle of porous media is based on the steady-state heat conduction method;

[0008] S2, determine whether convection occurs during the heat transfer process inside the porous medium;

[0009] S3. Design a test measuring device to measure the thermal conductivity of porous media;

[0010] S4. Calculate the effective thermal conductivity of porous media during heat transfer;

[0011] S5. Calculate the proportion of heat transfer by conduction, convection and radiation in the heat transfer process of porous media.

[0012] Furthermore, in step S1, the thermal conductivity measurement principle of the porous medium is based on the steady-state heat conduction method:

[0013] ;

[0014] Where: is the effective thermal conductivity; T is temperature; t For time; is the solid phase volume heat capacity; is the specific heat capacity of air; is the air volume heat flux.

[0015] Furthermore, the flow direction of heat radiation heat transfer in the porous medium is the same as that of heat conduction. The problem of heat radiation heat transfer is simplified to a problem of heat conduction with a thermal conductivity that depends on temperature changes:

[0016] ;

[0017] Where: is the thermal conductivity of heat conduction, is the thermal radiation thermal conductivity.

[0018] Furthermore, step S2 specifically includes:

[0019] Step S201: Determine whether convection occurs in the heat transfer process inside the porous medium according to the top and bottom plate temperature settings. The determination parameter for natural convection inside the porous medium layer is the Rayleigh number. Ra , and its calculation formula is:

[0020] ;

[0021] Where: is the density of air; is the volume thermal expansion coefficient; g is the acceleration due to gravity; is the permeability of porous media; H is the actual sample filling height; is the temperature difference between the medium bottom plate and top plate; is the dynamic viscosity; is the thermal diffusion coefficient;

[0022] Step S202: There is a critical Rayleigh number ,when When , the porous medium is in a stable pure heat conduction state, and when When the length-to-height ratio is , the aspect ratio is , the critical Rayleigh number of a three-dimensional rectangular porous medium region with six closed sides, a lower boundary temperature higher than the upper boundary, and adiabatic sides The calculation formula is:

[0023] ;

[0024] ;

[0025] In the formula, l, m, n are the number of cells in the porous medium zone in the vertical height, horizontal length and horizontal width directions respectively.

[0026] Furthermore, step S3 designs a test measuring device to measure the thermal conductivity of the porous medium:

[0027] The measuring device includes a constant temperature circulator for setting the temperature, a hose connecting the constant temperature circulator and the temperature control fluid, a stainless steel plate and an aluminum plate for controlling the temperature of the top and bottom plates, a copper tube for circulating the temperature control fluid, a frame body, top, bottom and side insulation layers all made of polyurethane insulation boards, polyurethane foaming sealant, a top polyurethane cover plate, a copper tube inlet and outlet, a sensor opening, a temperature sensor, a heat flux sensor, a thermal radiation sensor, a wind speed sensor, a data acquisition system and a computing system.

[0028] Furthermore, the frame body is in the shape of a rectangular parallelepiped; the insulation layer uses a polyurethane insulation board to seal the frame body and uses a polyurethane foam sealant to seal the seams, and the thickness of the polyurethane insulation board is 10 cm; after the frame body is sealed, holes are opened on the polyurethane insulation board at the copper pipe inlet and outlet and the sensor connection, and the openings are sealed with a polyurethane foam sealant.

[0029] Furthermore, the temperature control top plate of the measuring device is composed of an upper clamping plate stainless steel plate, a lower clamping plate aluminum plate, and a copper tube for the circulation of the temperature control fluid; the temperature control bottom plate is composed of an upper clamping plate aluminum plate, a lower clamping plate stainless steel plate, and a copper tube for the circulation of the temperature control fluid; the copper tube for the circulation of the temperature control fluid is evenly laid on the stainless steel plate in a U-shaped connection with equal distances, and the inlet and outlet are arranged on the same horizontal plane and are passed through the polyurethane insulation board; the length and width of the stainless steel plate are 、The length and width of the aluminum plate are , the copper tube is a red copper coil with a diameter of 16mm.

[0030] Furthermore, the temperature sensors of the measuring device are arranged such that each temperature measuring plane includes 15 temperature sensors, the top and bottom temperature control plates each include a temperature measuring plane, and the temperature measuring plane at the center is evenly distributed according to the actual test loading height; the heat flux sensor is arranged at the center position of the bottom temperature control plate, and the other two are located at the boundaries of the bottom temperature control plate; the thermal radiation heat flux sensor is arranged at the center position of the actual frame; the wind speed sensor is arranged at the central horizontal plane, and 9 wind speed sensors are arranged on the plane, and the other two horizontal planes are arranged between the upper and lower temperature measuring planes.

[0031] Furthermore, step S4 specifically includes:

[0032] Effective thermal conductivity The calculation formula is:

[0033] ;

[0034] In the formula, Q is the bottom heat flux monitoring value after internal steady-state distribution; H is the actual sample filling height; It is the average value of the temperature measurement points on the surface of the top temperature control plate after internal steady-state distribution; It is the average value of the temperature measuring points on the surface of the bottom temperature control plate after internal steady-state distribution.

[0035] Furthermore, step S5 specifically includes:

[0036] Step S501, the influence of the structure of the solid-fluid combination of the two-phase porous geological material on the thermal conductivity of the geological material. The calculation formula of the thermal conductivity of the heat conduction term is:

[0037] ;

[0038] Where: is the thermal conductivity of the solid phase; is the thermal conductivity of the liquid phase; n is the porosity; φ is the empirical coefficient of the structural parameter, when The empirical coefficients of natural soil particles, gravel particles and sedimentary rock structure parameters are 0.81, 0.54 and 0.34 respectively. hour Empirical coefficients of structural parameters applicable to the three materials;

[0039] Step S502: Calculation formula of thermal conductivity of thermal radiation term in the porous medium heat transfer process without obvious natural convection effect:

[0040] ;

[0041] Step S503: Proportion of heat conduction and heat radiation during the porous medium heat transfer process without obvious natural convection effect:

[0042] ;

[0043] ;

[0044] Where: It is the proportion of a certain heat transfer in the porous medium heat transfer process to the total heat transfer;

[0045] Step S504: the proportion of heat conduction, heat convection and heat radiation in the porous medium heat transfer process under the condition of obvious natural convection effect:

[0046] ;

[0047] ;

[0048] .

[0049] The beneficial effects of the present invention are:

[0050] The measuring device and method can establish a stable temperature field without being affected by unstable factors such as external airflow and ambient temperature to achieve stability of heat flux and internal temperature. During the measurement process, different temperature conditions are designed in combination with the temperature in the application environment of the porous medium, and the Rayleigh number, a discriminant parameter for natural convection inside the porous medium layer, and the wind speed sensor are used to monitor whether convection effect occurs. The heat conduction term is calculated through the solid-fluid combination, thereby expressing the thermal radiation term. In addition, the heat transfer ratio of the three heat transfer modes is measured in the heat transfer process at different temperatures, which is helpful to study the mechanism and law of the heat transfer process in porous media. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a flow chart of the measuring device and method for automatically controlling the temperature to measure the heat transfer characteristics of porous media of the present invention;

[0052] Figure 2It is a schematic diagram of the structure of a measuring device for automatically controlling the temperature to measure the heat transfer characteristics of a porous medium according to the present invention;

[0053] Figure 3 It is a schematic diagram of the structure of the top and bottom temperature control plates of the measuring device for automatically controlling the temperature to measure the heat transfer characteristics of porous media according to the present invention;

[0054] Figure 4 This is a cross-sectional view of the sensor arrangement of the measuring device for automatically controlling the temperature to measure the heat transfer characteristics of porous media according to the present invention;

[0055] Figure 5 It is a top view of the bottom plate of the measuring device for automatically controlling temperature to measure the heat transfer characteristics of porous media according to the present invention.

[0056] In the figure, 1. constant temperature circulator; 2. hose; 3. frame body; 4. polyurethane insulation board; 5. stainless steel plate; 6. aluminum plate; 7. copper tube; 8. polyurethane foam filler; 9. polyurethane cover; 10. temperature sensor; 11. heat flux sensor; 12. thermal radiation sensor; 13. wind speed sensor; 14. copper tube inlet and outlet; 15. sensor opening; 16. data acquisition system; 17. computing system. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0058] like Figure 1 As shown, the measuring device and method for automatically controlling the temperature to measure the heat transfer characteristics of porous media of the present invention include the following steps:

[0059] S1. The thermal conductivity measurement principle of porous media is based on the steady-state heat conduction method;

[0060] S2, determine whether convection occurs during the heat transfer process inside the porous medium;

[0061] S3. Design a test measuring device to measure the thermal conductivity of porous media;

[0062] S4. Calculate the effective thermal conductivity of porous media during heat transfer;

[0063] S5. Calculate the proportion of heat transfer by conduction, convection and radiation in the heat transfer process of porous media.

[0064] like Figure 1As shown, the measuring device and method for measuring the heat transfer characteristics of porous media by automatic temperature control of the present invention: In step S1, the thermal conductivity measurement principle of the porous medium is based on the steady-state heat conduction method:

[0065] ;

[0066] Where: is the effective thermal conductivity; T is temperature; t For time; is the solid phase volume heat capacity; is the specific heat capacity of air; is the air volume heat flux.

[0067] like Figure 1 As shown, the measuring device and method for automatically controlling the temperature to measure the heat transfer characteristics of porous media of the present invention: In step S1, the flow direction of heat radiation heat exchange in the heat transfer process of the porous medium is the same as the flow direction of heat conduction, and the heat radiation heat transfer problem is simplified to the heat conduction problem of the thermal conductivity coefficient that depends on the temperature change:

[0068] ;

[0069] Where: is the thermal conductivity of heat conduction, is the thermal radiation thermal conductivity.

[0070] like Figure 1 As shown, the measuring device and method for measuring the heat transfer characteristics of porous media by automatic temperature control of the present invention specifically include: in step S2:

[0071] Step S201: Determine whether convection occurs in the heat transfer process inside the porous medium according to the top and bottom plate temperature settings. The determination parameter for natural convection inside the porous medium layer is the Rayleigh number. Ra , and its calculation formula is:

[0072] ;

[0073] Where: is the density of air; is the volume thermal expansion coefficient; g is the acceleration due to gravity; is the permeability of porous media; H is the actual sample filling height; is the temperature difference between the medium bottom plate and top plate; is the dynamic viscosity; is the thermal diffusion coefficient;

[0074] Step S202: There is a critical Rayleigh number ,when When , the porous medium is in a stable pure heat conduction state, and when When the length-to-height ratio is , the aspect ratio is , the critical Rayleigh number of a three-dimensional rectangular porous medium region with six closed sides, a lower boundary temperature higher than the upper boundary, and adiabatic sides The calculation formula is:

[0075] ;

[0076] ;

[0077] In the formula, l, m, n are the number of cells in the porous medium zone in the vertical height, horizontal length and horizontal width directions respectively.

[0078] like Figure 1 , Figure 2 As shown, the measuring device and method for measuring the heat transfer characteristics of porous media by automatic temperature control of the present invention: in step S3, a test measuring device is designed to measure the thermal conductivity of the porous media:

[0079] The measuring device includes a constant temperature circulator for setting the temperature, a hose connecting the constant temperature circulator and the temperature control fluid, a stainless steel plate and an aluminum plate for controlling the temperature of the top and bottom plates, a copper tube for circulating the temperature control fluid, a frame body, top, bottom and side insulation layers all made of polyurethane insulation boards, polyurethane foaming sealant, a top polyurethane cover plate, a copper tube inlet and outlet, a sensor opening, a temperature sensor, a heat flux sensor, a thermal radiation sensor, a wind speed sensor, a data acquisition system and a computing system.

[0080] like Figure 2 As shown, the measuring device and method for automatically controlling the temperature to measure the heat transfer characteristics of porous media of the present invention: the frame body is in a rectangular shape; the insulation layer uses a polyurethane insulation board to seal the frame body and uses a polyurethane foam sealant to seal the seams, and the thickness of the polyurethane insulation board is 10 cm; after the frame body is sealed, holes are opened on the polyurethane insulation board at the copper pipe inlet and outlet and the sensor connection, and the openings are sealed with a polyurethane foam sealant.

[0081] like Figure 2 , Figure 3 As shown, the measuring device and method for automatically controlling the temperature to measure the heat transfer characteristics of porous media of the present invention: the temperature control top plate of the measuring device is composed of an upper clamping plate stainless steel plate, a lower clamping plate aluminum plate, and a copper tube for the circulation of the temperature control fluid; the temperature control bottom plate is composed of an upper clamping plate aluminum plate, a lower clamping plate stainless steel plate, and a copper tube for the circulation of the temperature control fluid; the copper tube for the circulation of the temperature control fluid is evenly laid on the stainless steel plate in a U-shaped connection with equal distances, and the inlet and outlet are arranged on the same horizontal plane and are passed through the polyurethane insulation board; the length and width of the stainless steel plate are 、The length and width of the aluminum plate are , the copper tube is a red copper coil with a diameter of 16mm.

[0082] like Figure 4 , Figure 5 As shown, the measuring device and method for automatically controlling the temperature to determine the heat transfer characteristics of porous media of the present invention: the temperature sensors of the measuring device are arranged such that each temperature measuring plane includes 15 temperature sensors, the top and bottom temperature control plates each include a temperature measuring plane distribution, and the temperature measuring plane at the center is evenly distributed according to the actual test filling height; the heat flux sensor is arranged at the center position of the bottom temperature control plate, and the other two are respectively located at the boundaries of the bottom temperature control plate; the thermal radiation heat flux sensor is arranged at the center position of the actual frame; the wind speed sensor is arranged at the center horizontal plane, 9 wind speed sensors are arranged at the plane, and the other two horizontal planes are respectively arranged between the upper and lower temperature measuring planes.

[0083] like Figure 1 As shown, the measuring device and method for measuring the heat transfer characteristics of porous media by automatic temperature control of the present invention: step S4 specifically includes:

[0084] Effective thermal conductivity The calculation formula is:

[0085] ;

[0086] In the formula, Q is the bottom heat flux monitoring value after internal steady-state distribution; H is the actual sample filling height; It is the average value of the temperature measurement points on the surface of the top temperature control plate after internal steady-state distribution; It is the average value of the temperature measuring points on the surface of the bottom temperature control plate after internal steady-state distribution.

[0087] like Figure 1 As shown, the measuring device and method for measuring the heat transfer characteristics of porous media by automatic temperature control of the present invention: step S5 specifically includes:

[0088] Step S501, the influence of the structure of the solid-fluid combination of the two-phase porous geological material on the thermal conductivity of the geological material. The calculation formula of the thermal conductivity of the heat conduction term is:

[0089] ;

[0090] Where: is the thermal conductivity of the solid phase; is the thermal conductivity of the liquid phase; n is the porosity; φ is the empirical coefficient of the structural parameter, when The empirical coefficients of natural soil particles, gravel particles and sedimentary rock structure parameters are 0.81, 0.54 and 0.34 respectively. hour Empirical coefficients of structural parameters applicable to the three materials;

[0091] Step S502: Calculation formula of thermal conductivity of thermal radiation term in the porous medium heat transfer process without obvious natural convection effect:

[0092] ;

[0093] Step S503: Proportion of heat conduction and heat radiation during the porous medium heat transfer process without obvious natural convection effect:

[0094] ;

[0095] ;

[0096] Where: It is the proportion of a certain heat transfer in the porous medium heat transfer process to the total heat transfer;

[0097] Step S504: the proportion of heat conduction, heat convection and heat radiation in the porous medium heat transfer process under the condition of obvious natural convection effect:

[0098] ;

[0099] ;

[0100] .

[0101] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this application can be executed in parallel, sequentially or in different orders, as long as the expected results of the technical solution disclosed in this application can be achieved, and this document is not limited here.

[0102] The above specific implementations do not constitute a limitation on the protection scope of this application. The above specific implementations by those skilled in the art do not constitute a limitation on the protection scope of this application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application should be included in the protection scope of this application.

Claims

1. A method for automatically controlling the temperature to determine the heat transfer characteristics of porous media, characterized in that: The method comprises the following steps: S1. The thermal conductivity measurement principle of porous media is based on the steady-state heat conduction method; S2, determine whether convection occurs during the heat transfer process inside the porous medium; S3. Design a test measuring device to measure the thermal conductivity of porous media; S4. Calculate the effective thermal conductivity of porous media during heat transfer; S5. Calculate the proportion of heat conduction, heat convection and heat radiation in the heat transfer process of porous media; In step S1, the thermal conductivity measurement principle of porous media is based on the steady-state heat conduction method: ； Where: is the effective thermal conductivity; T is temperature; t For time; is the solid phase volume heat capacity; is the volumetric heat capacity of air; is the air volume heat flux; In addition, the flow direction of heat radiation heat transfer in the porous medium is the same as that of heat conduction. The problem of heat radiation heat transfer is simplified to a problem of heat conduction with a thermal conductivity that depends on temperature changes: ； Where: is the thermal conductivity of heat conduction, is the thermal radiation thermal conductivity; Step S2 specifically includes: Step S201: Determine whether convection occurs in the heat transfer process inside the porous medium according to the top and bottom plate temperature settings. The determination parameter for natural convection inside the porous medium layer is the Rayleigh number. Ra , and its calculation formula is: ； Where: is the density of air; is the volume thermal expansion coefficient; g is the acceleration due to gravity; is the permeability of porous media; H is the actual sample filling height; is the temperature difference between the medium bottom plate and top plate; is the dynamic viscosity; is the thermal diffusion coefficient; Step S202: There is a critical Rayleigh number ,when When , the porous medium is in a stable pure heat conduction state, and when When the length-to-height ratio is , the aspect ratio is , the critical Rayleigh number of a three-dimensional rectangular porous medium region with six closed sides, a lower boundary temperature higher than the upper boundary, and adiabatic sides The calculation formula is: ； ； In the formula, l, m, n are the number of cells in the porous medium area in the vertical height, horizontal length and horizontal width directions respectively; Step S5 specifically includes: Step S501, the influence of the structure of the solid-fluid combination of the two-phase porous geological material on the thermal conductivity of the geological material. The calculation formula of the thermal conductivity of the heat conduction term is: ； Where: is the thermal conductivity of the solid phase; is the thermal conductivity of the liquid phase; n is the porosity; φ is the empirical coefficient of the structural parameter, when The empirical coefficients of natural soil particles, gravel particles and sedimentary rock structure parameters are 0.81, 0.54 and 0.34 respectively. hour Empirical coefficients of structural parameters applicable to the three materials; Step S502: Calculation formula of thermal conductivity of thermal radiation term in the porous medium heat transfer process without obvious natural convection effect: ； Step S503: Proportion of heat conduction and heat radiation during the porous medium heat transfer process without obvious natural convection effect: ； ； Where: It is the proportion of a certain heat transfer in the porous medium heat transfer process to the total heat transfer; Step S504: the proportion of heat conduction, heat convection and heat radiation in the porous medium heat transfer process under the condition of obvious natural convection effect: ； ； 。 2. The method for measuring the heat transfer characteristics of porous media by automatic temperature control according to claim 1, characterized in that: Step S4 specifically includes: Effective thermal conductivity The calculation formula is: ； In the formula, Q is the bottom heat flux monitoring value after internal steady-state distribution; H is the actual sample filling height; It is the average value of the temperature measurement points on the surface of the top temperature control plate after internal steady-state distribution; It is the average value of the temperature measuring points on the surface of the bottom temperature control plate after internal steady-state distribution.

3. The method for measuring the heat transfer characteristics of porous media by automatic temperature control according to claim 2, characterized in that: Step S3: Design a test measurement device to measure the thermal conductivity of the porous medium: The measuring device includes a constant temperature circulator for setting the temperature, a hose connecting the constant temperature circulator and the temperature control fluid, a stainless steel plate and an aluminum plate for controlling the temperature of the top and bottom plates, a copper tube for circulating the temperature control fluid, a frame body, top, bottom and side insulation layers all made of polyurethane insulation boards, polyurethane foaming sealant, a top polyurethane cover plate, a copper tube inlet and outlet, a sensor opening, a temperature sensor, a heat flux sensor, a thermal radiation sensor, a wind speed sensor, a data acquisition system and a computing system.

4. A measuring device for automatically controlling the temperature to measure the heat transfer characteristics of porous media, characterized in that The measuring device is used to implement a method for automatically controlling the temperature to measure the heat transfer characteristics of a porous medium as described in claim 3: the frame body is in a rectangular shape; the insulation layer uses a polyurethane insulation board to seal the frame body and uses a polyurethane foam sealant to seal the seams, and the thickness of the polyurethane insulation board is 8~12cm; after the frame body is sealed, holes are opened on the polyurethane insulation board at the copper pipe inlet and outlet and the sensor connection, and the openings are sealed with a polyurethane foam sealant.

5. A measuring device for automatically controlling the temperature to measure the heat transfer characteristics of porous media, characterized in that The measuring device is used to implement a method for automatically controlling the temperature to measure the heat transfer characteristics of porous media as described in claim 3: the temperature control top plate of the measuring device is composed of an upper clamping plate stainless steel plate, a lower clamping plate aluminum plate, and a copper tube through which the temperature control fluid circulates; the temperature control bottom plate is composed of an upper clamping plate aluminum plate, a lower clamping plate stainless steel plate, and a copper tube through which the temperature control fluid circulates; the copper tube through which the temperature control fluid circulates is evenly laid on the stainless steel plate in a U-shaped connection with equal distances, and the inlet and outlet are both arranged on the same horizontal plane and passed through a polyurethane insulation board; the stainless steel plate and the aluminum plate are both set to be square.

6. A measuring device for automatically controlling the temperature to measure the heat transfer characteristics of porous media, characterized in that The measuring device is used to implement a method for automatically controlling the temperature to determine the heat transfer characteristics of porous media as described in claim 3: the temperature sensors of the measuring device are evenly arranged on each temperature measuring plane, the top and bottom temperature control plates each include a temperature measuring plane distribution, and the temperature measuring planes at the center are evenly distributed according to the actual test filling height; the heat flux sensor is arranged at the center position of the bottom temperature control plate, and the other two are located at the boundaries of the bottom temperature control plate; the thermal radiation heat flux sensor is arranged at the center position of the actual frame; the wind speed sensor is arranged at the center horizontal plane.

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