In-situ measurement device and method for viscosity coefficient of pyrolysis gas

Abstract

The present invention discloses an in-situ measurement device and method for the viscosity coefficient of pyrolysis gas, comprising an experimental cabin connected to a vacuum pump and an inert gas storage tank, wherein a heat flow measurement component, an air pressure sensor and a pressure sensor are arranged in the experimental cabin, and a material to be measured is placed on the pressure sensor; the measurement device also comprises a heat source system for heating the heat flow measurement component or the material to be measured and a temperature measurement component for detecting the surface temperature of the material to be measured; the present invention has the beneficial effects of recording the steady-state heat flow value of the heat source system by the heat flow measurement component, thereby obtaining the heat flow value of the material to be measured, and recording the pressure in the experimental cabin by the air pressure sensor at the same time, and obtaining the mass flow rate of the pyrolysis gas overflow by the pressure sensor in real time, thereby calculating the dynamic change of the gas viscosity coefficient of the surface of the material to be measured with the temperature by the pyrolysis inversion algorithm.

Description

Technical Field

[0001] The present invention relates to the field of thermal protection of aerospace materials, and in particular to an in-situ measurement device and method for the viscosity coefficient of pyrolysis gas. Background Art

[0002] In cutting-edge fields like aerospace, resin-based composites, thanks to their exceptional strength-to-weight ratio, specific modulus, and excellent moldability, have become a core material for thermal protection structures. When these aircraft travel through the atmosphere at hypersonic speeds, the intense friction between their surfaces and the air causes the ambient temperature of the resin-based composite to rise dramatically. This triggers the pyrolysis gases to flow within the composite and in the surrounding boundary layer. Their viscosity has a profound impact on the performance of the entire thermal protection system. On the one hand, it determines the percolation characteristics of the pyrolysis gases within the composite's pore structure, thereby affecting the internal heat conduction paths and heat dissipation efficiency. On the other hand, the viscosity of the pyrolysis gases is directly related to their cooling effect on the aircraft surface and their interaction with the external high-temperature, high-speed airflow, crucial for maintaining the aircraft's structural integrity and stability in extreme thermal environments. Without the ability to accurately determine the viscosity of the pyrolysis gases, thermal protection system design must rely on empirical formulas and approximate estimates, resulting in significant deviations from actual requirements. This can lead to increased aircraft weight and reduced performance due to overly conservative designs, or even inadequate protection leading to flight accidents. Therefore, developing an accurate and reliable device and method for measuring the viscosity coefficient of pyrolysis gas of resin-based composite materials under high-temperature conditions is crucial to promoting the development of aerospace technology and ensuring aircraft safety.

[0003] Currently, measurement technology for the high-temperature viscosity coefficient of pyrolysis gases has significant shortcomings. Traditional testing methods struggle to simulate the extreme flight conditions experienced by hypersonic vehicles, resulting in significant deviations from actual test results. Existing testing equipment and technology also face bottlenecks in accuracy, stability, and applicability, failing to meet the high-precision pyrolysis gas parameters required for thermal protection design. This results in a lack of reliable data support for thermal protection system design, significantly increasing the risks and costs of aircraft development.

[0004] The patent with application number "202210809476.4" discloses "a gas viscosity coefficient measuring device and its measuring method", and the patent with application number "202210180418.X" discloses "a liquid viscosity coefficient measuring device". Although the above patents involve the measurement of fluid viscosity coefficient, there are the following problems during use: First, the influence of temperature on the viscosity coefficient of pyrolysis gas is not considered; second, the influence of external air pressure on the viscosity coefficient of pyrolysis gas is not considered; third, no real-time measurement method for the change of pyrolysis gas viscosity coefficient with temperature during the pyrolysis of resin-based composite materials is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide an in-situ measurement device and method for the viscosity coefficient of pyrolysis gas, which not only takes into account the influence of temperature and air pressure on the viscosity coefficient, but also can measure the change of its viscosity coefficient in real time when the external temperature changes.

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

[0007] An in-situ measurement device for the viscosity coefficient of pyrolysis gas includes an experimental chamber connected to a vacuum pump and an inert gas storage tank, a heat flow measurement component, an air pressure sensor, and a pressure sensor provided in the experimental chamber, and a material to be measured is placed on the pressure sensor;

[0008] The measuring device also includes a heat source system for heating the heat flow measuring component or the material to be measured and a temperature measuring component for detecting the surface temperature of the material to be measured.

[0009] Preferably, the measuring device further comprises:

[0010] An external source starting high pressure device connected to the heat source system;

[0011] A data acquisition system connected to the heat flow measurement component, air pressure sensor, pressure sensor, and temperature measurement component;

[0012] A cooling system that cools the back of the heat flow measurement component and the bottom of the pressure sensor.

[0013] Preferably, the experimental chamber is provided with a first placement platform for placing the heat flow measurement component and a second placement platform for placing the pressure sensor, and a sample table for accommodating the material to be tested is placed on the pressure sensor; the side wall of the experimental chamber is also provided with a placement chamber for accommodating the air pressure sensor.

[0014] Preferably, a sealing ring and a secondary sealing device are provided at the door of the experimental cabin, an observation window is provided at the front end of the experimental cabin, and a first window for the heat source system to pass through, a second window and a third window for the temperature measurement component to pass through are provided on the top of the experimental cabin;

[0015] The first window is located directly above the heat flow measurement component, and the second window is located directly above the material to be measured.

[0016] Preferably, the secondary sealing device includes a threaded hole opened on the surface of the experimental cabin, a bolt is screwed into the threaded hole, and a gasket that can apply pressure to the cabin door is sleeved on the bolt.

[0017] Preferably, the heat source system includes a bracket, a movable device placer is provided on the bracket, a laser is installed on the device placer, a positioning hole is opened on the bracket, and a positioning key cooperating with the positioning hole is provided on the device placer.

[0018] Preferably, the present application also discloses an in-situ measurement method for the viscosity coefficient of pyrolysis gas, comprising the following steps:

[0019] S1. Install the heat flow measurement assembly, air pressure sensor, pressure sensor and the material to be tested in the experimental chamber;

[0020] S2. Start the vacuum pump to evacuate the experimental chamber;

[0021] S3. Inject inert gas into the experimental chamber through the inert gas storage tank;

[0022] S4. heating the heat flow measurement component using a heat source system and recording a steady-state heat flow value;

[0023] S5. Use a heat source system to heat the material to be tested;

[0024] S6. When performing step S5, the temperature measuring component is simultaneously operated to measure the surface temperature of the material to be tested, the mass flow rate of the pyrolysis gas overflow is measured by the pressure sensor, and the cabin pressure is measured by the air pressure sensor;

[0025] S7. Data processing based on pyrolysis inversion algorithm.

[0026] Preferably, the data processing in step S7 includes the following steps:

[0027] The gas constant R, carbonized layer permeability K, specimen top surface area S, and the measured pyrolysis gas overflow mass flow rate are Substitute the surface temperature T and air pressure P into the following formula:

[0028]

[0029] The viscosity coefficient μ and the pyrolysis gas pressure gradient at the internal surface of the specimen can be obtained The measured heat flow, surface temperature, air pressure and other parameters are substituted into the control equation, boundary conditions and initial conditions, and another pressure gradient is obtained by numerical solution. The relationship between the viscosity coefficient μ and the viscosity coefficient μ can be used to calculate the viscosity coefficient of the pyrolysis gas under certain ambient pressure conditions as it changes with temperature;

[0030] The governing equations are as follows:

[0031]

[0032] The boundary conditions are as follows:

[0033] p=p w x=x w

[0034]

[0035] The initial conditions are as follows:

[0036]

[0037] The meanings of the parameters in the formula are as follows:

[0038] K——Permeability (m 2 ); μ——viscosity coefficient (Pa·s); q——heat flux of hot wall (W / m 2 ); ——thermal blocking coefficient (-); ξ——porosity (-); u——pyrolysis gas velocity (m / s); S——specimen area (m 2 ); A——pre-exponential factor; E——activation energy (J); n——reaction order (-); t——time (s); ρ——density (kg / m 3 ); h——enthalpy value (J / kg); x——material thickness direction coordinate (m); k——thermal conductivity (W / (m·K)); T——temperature (K); ——specimen mass flow rate (kg / s); ΔH——pyrolysis heat (J / kg); R——gas constant (J / (kg·K)); subscript g——gas; subscript p——interface between original material layer and pyrolysis layer; subscript c——interface between pyrolysis layer and carbonization layer; subscript w——material surface; subscript 1——original material layer; subscript 2——pyrolysis layer; subscript 3——carbonization layer.

[0039] The beneficial effects of the present invention are:

[0040] 1. The heat flow measurement component can record the steady-state heat flow value of the heat source system, and then derive the heat flow value of the material to be tested. At the same time, the pressure in the experimental chamber is recorded by the air pressure sensor. The pressure sensor can obtain the mass flow rate of the pyrolysis gas overflow in real time, and then calculate the dynamic change of the gas viscosity coefficient on the surface of the material to be tested with temperature through the pyrolysis inversion algorithm.

[0041] 2. The heat source system can be moved and accurately positioned above the experimental chamber to heat the heat flow measurement components and the material to be tested respectively, ensuring that the heat source provided is stable and reliable, thereby improving the accuracy of the test results.

[0042] 3. The secondary sealing device is used to reliably seal the door of the experimental chamber to prevent heat leakage. It is also equipped with a cooling system to quickly cool the equipment after the measurement is completed, making it convenient for the next test.

[0043] 4. The present invention also discloses an in-situ measurement method for the viscosity coefficient of pyrolysis gas, and calculates the viscosity coefficient based on the test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the overall structure of the measuring device;

[0045] Figure 2 Schematic diagram of the working process of the measuring device;

[0046] Figure 3 This is a schematic diagram of the structure of the experimental cabin in the measurement device;

[0047] Figure 4 It is a structural diagram of the heat source system in the measuring device;

[0048] Figure 5 Schematic diagram of the structure of the secondary sealing device.

[0049] The accompanying drawings are for illustrative purposes only and are not to be construed as limitations on this patent. To better illustrate this embodiment, some components of the accompanying drawings may be omitted, enlarged, or reduced in size, and do not represent the actual dimensions of the product. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted from the accompanying drawings. DETAILED DESCRIPTION

[0050] The present invention will be further described below with reference to the accompanying drawings.

[0051] The following are some explanations of terms in this application:

[0052] Pyrolysis gases: When hypersonic vehicles fly at high speeds in the atmosphere, intense friction with the air generates extremely high aerodynamic heat, posing a serious threat to the vehicle's structural safety. Resin-based composites, due to their excellent performance, have become a key material for thermal protection in hypersonic vehicles. Under the influence of aerodynamic heat, resin-based composites decompose to produce pyrolysis gases. The composition of the gases produced by the pyrolysis of different resin-based composites varies, with common components including methane (CH4), ethylene (C2H4), propylene (C3H6), carbon monoxide (CO), carbon dioxide (CO2), and water (H2O).

[0053] Viscosity coefficient: A physical quantity that measures the viscosity of a fluid. For pyrolysis gases produced by the pyrolysis of resin-based composite materials, the viscosity coefficient describes the property of internal friction generated when adjacent fluid layers within the gas flow in relative motion. The viscosity coefficient of pyrolysis gases is affected by many factors. On the one hand, it is closely related to the composition of the gas. Different pyrolysis products have different molecular structures and properties, resulting in different viscosity coefficients. On the other hand, temperature has a significant impact on the viscosity coefficient. Generally speaking, as the temperature of the pyrolysis gas increases, the molecular thermal motion intensifies, and the viscosity coefficient usually increases. At the same time, pressure also has an impact on it. Under certain conditions, changes in pressure can alter the distance and interaction between gas molecules, thereby affecting viscosity. In the thermal protection system of hypersonic aircraft, it determines the flow characteristics of the pyrolysis gas in the carbonized layer, thereby affecting the heat transfer process and thermal protection effectiveness.

[0054] In-situ measurement of pyrolysis gas viscosity coefficient: The invented measuring device directly measures the pyrolysis gas generated by the thermal decomposition of resin-based composite materials, and obtains the relationship between the viscosity coefficient and temperature and air pressure in real time, which can truly reflect the composition and properties of the pyrolysis gas.

[0055] Importance of pyrolysis gas viscosity coefficient: Accurate measurement of pyrolysis gas viscosity coefficient can make aerodynamic heat and aerodynamic force calculations more precise, providing accurate thermal and mechanical load data for thermal protection system design; combined with the viscosity coefficient, the thermal response and ablation rate of materials under the action of pyrolysis gas can be analyzed, providing a basis for selecting and improving thermal protection materials; based on the viscosity coefficient, the system structure and material layout can be optimized to improve the reliability and effectiveness of the thermal protection system.

[0056] Example 1

[0057] like Figure 1 — Figure 3 As shown, the in-situ measurement device for the viscosity coefficient of pyrolysis gas includes an experimental chamber 3. Two inlet and outlet valves 302 are provided on the side wall of the experimental chamber 3, which are connected to the vacuum pump 1 and the inert gas storage tank 2 respectively. A heat flow measurement component 17, an air pressure sensor 16 and a pressure sensor 13 are provided in the experimental chamber 3. The material to be tested 15 is placed on the pressure sensor 13;

[0058] The measuring device further includes a heat source system 6 for heating the heat flow measuring component 17 or the material to be measured 15 and a temperature measuring component 4 for detecting the surface temperature of the material to be measured 15 .

[0059] In this embodiment, the heat flow measurement component 17 is a Gordon type heat flow meter, the inert gas storage tank 2 is an argon tank, the temperature measurement component 4 is an infrared temperature measurement device located outside the experimental chamber 3, and the heat source system 6 is a laser heat source system. The ultimate vacuum degree of the vacuum pump is 5×10 -4Pa, argon purity ≥99.999%, and the inflation pressure range is adjustable from 0.1 to 5 MPa.

[0060] Since the starting voltage of the strong laser that provides the heat source is high voltage, an external source starting high voltage device 5 is required as the starting voltage to activate the laser. In order to collect data from the heat flow measurement component 17, the air pressure sensor 16, the pressure sensor 13, and the temperature measurement component 4 in real time, a data acquisition system connected to the above devices is also provided. The data acquisition system includes a collector and an industrial computer 7, a data acquisition wire 8, and the data acquisition wire 8 is a shielded cable. The data acquisition system is connected to the following sensors through the data acquisition wire 8: the temperature signal T of the temperature measurement component 4 s , the pressure difference signal ΔP of the pressure sensor 13, the cabin pressure signal P of the air pressure sensor 16 g As well as the heat flow signal Q0 of the heat flow measurement component 17, the industrial computer runs the data acquisition program to achieve multi-parameter synchronous acquisition and real-time display.

[0061] To promptly cool the back of heat flux measurement assembly 17 and the bottom of pressure sensor 13, a cooling system 9 is provided. This system uses circulating water cooling and comprises a water pump, an outlet pipe 10, and an inlet pipe 11. The cooling circuit of heat flux measurement assembly 17 is in close contact with the back of heat flux measurement assembly 17 via a copper heat sink, while the cooling circuit of pressure sensor 13 is integrated into its bottom.

[0062] The experimental chamber 3 is equipped with a first placement platform 306 for the heat flux measurement assembly 17 and a second placement platform 305 for the pressure sensor 13. A sample platform 14, which holds the test material 15, is placed on the pressure sensor 13. The sample platform 14 is made of high-temperature-resistant alumina ceramic and contains a low-thermal-conductivity, high-temperature ceramic plate. The test material 15 is placed on the ceramic plate to prevent three-dimensional heating and ensure one-dimensional heat transfer to the test piece. The sample platform 14 is sized to completely embed the test material, leaving no gaps around it. This ensures that during heating, pyrolysis gases diffuse only vertically above the material. The pressure sensor 13 is located at the bottom of the sample platform 14 and can measure the mass flow rate of the pyrolysis gas outflow in real time. The mass of the test piece decreases due to the pyrolysis gas outflow, and the weight of the test piece is determined by the pressure sensor. The weight loss is the weight of the pyrolysis gas. An air pressure sensor 16 is also installed on the sidewall of the experimental chamber 3. This capacitive thin-film sensor is directly welded to the chamber's sidewall to eliminate piping delays. A placement cabin 307 may also be provided outside the air pressure sensor 16 to provide a certain degree of protection therefor.

[0063] like Figure 5As shown, the hatch of the experimental chamber 3 is equipped with a sealing ring 304 and a secondary sealing device 12. A high-temperature-resistant rubber sealing ring 304 is embedded in the edge of the hatch. When the hatch is closed, the sealing ring 304 fits tightly against the hatch, preventing the air inside the cabin from flowing between the cabin and the outside air. The secondary sealing device 12 includes a threaded hole 1203 on the surface of the experimental chamber 3. A bolt 1201 is screwed into the threaded hole 1203. A metal gasket 1202 is mounted on the bolt 1201 to apply pressure to the hatch. When the hatch is closed, the bolt 1201 is rotated to apply pressure, which tightly presses the metal gasket 1202 against the hatch, ensuring a more secure seal with the cabin. The metal gasket 1202 is resistant to deformation and aging at high temperatures and can withstand high temperatures and pressures, making it suitable for harsh environments such as high-temperature and high-vacuum environments. The combination of the sealing ring 304 and the secondary sealing device 12 can improve the sealing effect.

[0064] An observation window 303 is provided at the front end of the experimental chamber 3, which is convenient for real-time observation of the experimental conditions in the chamber; a first window 308, a second window 309 and a third window 310 for the temperature measuring component 4 to pass through are provided on the top of the experimental chamber 3; the temperature measuring component 4 is located outside the third window 310. When the laser heat source heats the material to be tested, the temperature measuring component 4 can measure the surface temperature of the material to be tested through the third window 310. During installation, it is necessary to ensure that the infrared beam of the temperature measuring component 4 is directly aimed at the center of the material to be tested to ensure the accuracy of the temperature measurement.

[0065] The first window 308, the second window 309 and the third window 310 are all sapphire windows. Since sapphire is resistant to high temperatures and has high light transmittance, its melting point is as high as 2050°C. It can withstand the high temperature environment generated by the laser in the experiment and has excellent light transmittance in the infrared and visible light bands, which facilitates the penetration of temperature measurement components and heat source laser beams while ensuring sealing.

[0066] First window 308 is located directly above heat flux measurement assembly 17. The diameter of the copper sensor of heat flux measurement assembly 17 strictly matches the aperture of first window 308. This ensures that the laser beam completely covers the surface of heat flux measurement assembly 17 when passing through first window 308. This prevents energy loss or edge effects caused by aperture mismatch during heat flux measurement, ensuring data accuracy. Second window 309 is located directly above material to be measured 15.

[0067] like Figure 4As shown, the heat source system 6 includes a bracket 601, a movable device placer 605 is provided on the bracket 601, a laser is installed on the device placer 605, two positioning holes 602 are provided on the bracket 601, and a positioning key 604 cooperating with the positioning hole 602 is provided on the device placer 605; the device placer 605 is also provided with a button 603 that can control the extension or retraction of the positioning key 604, and the button 603 is connected to a spring. When there is no external force, the positioning key 604 is extended under the elastic force of the spring; when the button 603 is pressed by an external force, the positioning key 604 is retracted into the device placer 605. When positioning key 604 is retracted, device placement device 605 can drive the laser to move back and forth on bracket 601. If button 603 is released during this movement, positioning key 604 is constantly driven outward. When positioning key 604 moves to align with positioning hole 602, it automatically enters positioning hole 602. At this point, device placement device 605 cannot move, effectively positioning the laser. When positioning key 604 enters both positioning holes 602, the laser is aligned with first window 308 and second window 309, respectively, to heat heat flow measurement assembly 17 or material under test 15. To move device placement device 605 again, press button 603 to retract positioning key 604.

[0068] This embodiment also discloses an in-situ measurement method for the viscosity coefficient of pyrolysis gas, comprising the following steps:

[0069] S1. Place the heat flow measurement assembly 17 on the first placement platform 306, install the air pressure sensor 16 into the placement chamber 307, place the pressure sensor 13 on the second placement platform 305, and then place the sample table 14 and the material to be tested 15 on top.

[0070] S2. Close the door, tighten the bolts 1201, and then start the vacuum pump 1 to evacuate the experimental chamber 3 to ensure that no oxidation reaction occurs during the pyrolysis of the material and burns the specimen;

[0071] S3. Inject inert argon gas into the experimental chamber 3 through the inert gas storage tank 2 to prevent oxidation reaction during material pyrolysis or air interference with gas viscosity measurement;

[0072] S4, moving the heat source system 6 to above the first window 308, heating the heat flux measurement component 17 with the power density required by the experiment, and recording the steady-state heat flux value;

[0073] S5, moving the heat source system 6 to above the second window 309, and using the heat source system 6 to heat the material to be tested 15;

[0074] S6. When performing step S5, the temperature measuring component 4 is synchronously started to measure the surface temperature of the material to be tested 15, the mass flow rate of the pyrolysis gas overflow is measured by the pressure sensor 13, and the cabin pressure is measured by the air pressure sensor 16;

[0075] S7. Data processing based on pyrolysis inversion algorithm.

[0076] The data processing of step S7 includes the following steps:

[0077] The gas constant R, carbonized layer permeability K, specimen top surface area S, and the measured pyrolysis gas overflow mass flow rate are Substitute the surface temperature T and air pressure P into the following formula:

[0078]

[0079] The viscosity coefficient μ and the pyrolysis gas pressure gradient at the internal surface of the specimen can be obtained The relationship between the viscosity coefficient μ and the pyrolysis gas pressure gradient at the internal surface of the specimen The measured heat flux, surface temperature, air pressure and other parameters are substituted into the control equation, boundary conditions and initial conditions, and the combined numerical solution is used to obtain another pressure gradient. The relationship between the two equations can be used to calculate the viscosity coefficient of the pyrolysis gas as it changes with temperature under certain ambient pressure conditions. It is worth noting that when the ambient pressure changes, the viscosity coefficient will also change accordingly.

[0080] The governing equations are as follows:

[0081]

[0082]

[0083] The boundary conditions are as follows:

[0084] p=p w x=x w

[0085]

[0086] The initial conditions are as follows:

[0087]

[0088] The meanings of the parameters in the formula are as follows:

[0089] K——Permeability (m 2 ); μ——viscosity coefficient (Pa·s); q——heat flux of hot wall (W / m 2 ); ——thermal blocking coefficient (-); ξ——porosity (-); u——pyrolysis gas velocity (m / s); S——specimen area (m 2); A——pre-exponential factor; E——activation energy (J); n——reaction order (-); t——time (s); ρ——density (kg / m 3 ); h——enthalpy value (J / kg); x——material thickness direction coordinate (m); k——thermal conductivity (W / (m·K)); T——temperature (K); ——specimen mass flow rate (kg / s); ΔH——pyrolysis heat (J / kg); R——gas constant (J / (kg·K)); subscript g——gas; subscript p——interface between original material layer and pyrolysis layer; subscript c——interface between pyrolysis layer and carbonization layer; subscript w——material surface; subscript 1——original material layer; subscript 2——pyrolysis layer; subscript 3——carbonization layer.

[0090] The above embodiments do not impose any formal restrictions on the shape, material, structure, etc. of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of protection of the technical solution of the present invention.

[0091] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the protection content of the present invention.

[0092] If words such as "first" and "second" are used in this document to limit components, those skilled in the art should know that the use of "first" and "second" is only for the convenience of describing the present invention and simplifying the description. Unless otherwise stated, the above words have no special meaning.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An in-situ measuring device for the viscosity coefficient of pyrolysis gas, comprising an experimental chamber (3), characterized in that: The experimental chamber (3) is connected to a vacuum pump (1) and an inert gas storage tank (2); a heat flow measurement component (17), an air pressure sensor (16), and a pressure sensor (13) are provided in the experimental chamber (3); a material to be tested (15) is placed on the pressure sensor (13); The measuring device further comprises a heat source system (6) for heating a heat flow measuring component (17) or a material to be measured (15) and a temperature measuring component (4) for detecting the surface temperature of the material to be measured (15).

2. The in-situ measurement device for the viscosity coefficient of pyrolysis gas according to claim 1, characterized in that: Also includes: An external source starts a high pressure device (5) connected to a heat source system (6); A data acquisition system connected to the heat flow measurement component (17), the air pressure sensor (16), the pressure sensor (13), and the temperature measurement component (4); A cooling system (9) is provided for cooling the back of the heat flow measurement component (17) and the bottom of the pressure sensor (13).

3. The in-situ measurement device for the viscosity coefficient of pyrolysis gas according to claim 1, characterized in that: The experimental chamber (3) is provided with a first placement platform (306) for placing a heat flow measurement component (17) and a second placement platform (305) for placing a pressure sensor (13); a sample table (14) for accommodating a material to be tested (15) is placed on the pressure sensor (13); and a placement chamber (307) for accommodating an air pressure sensor (16) is also provided on the side wall of the experimental chamber (3).

4. The in-situ measurement device for the viscosity coefficient of pyrolysis gas according to claim 1, characterized in that: The door of the experimental cabin (3) is provided with a sealing ring (304) and a secondary sealing device (12); the front end of the experimental cabin (3) is provided with an observation window (303); the top of the experimental cabin (3) is provided with a first window (308) for the heat source system (6) to pass through, a second window (309) and a third window (310) for the temperature measurement component (4) to pass through; The first window (308) is located directly above the heat flow measurement component (17), and the second window (309) is located directly above the material to be measured (15).

5. The in-situ measurement device for the viscosity coefficient of pyrolysis gas according to claim 4, characterized in that: The secondary sealing device (12) includes a threaded hole (1203) opened on the surface of the experimental cabin (3), a bolt (1201) is screwed into the threaded hole (1203), and a gasket (1202) that can apply pressure to the cabin door is sleeved on the bolt (1201).

6. The in-situ measurement device for the viscosity coefficient of pyrolysis gas according to claim 1, characterized in that: The heat source system (6) comprises a bracket (601), a movable device placement device (605) is provided on the bracket (601), a laser is installed on the device placement device (605), a positioning hole (602) is provided on the bracket (601), and a positioning key (604) that cooperates with the positioning hole (602) is provided on the device placement device (605).

7. An in-situ measurement method for the viscosity coefficient of pyrolysis gas, based on the in-situ measurement device for the viscosity coefficient of pyrolysis gas according to claim 1, characterized in that: The following steps are involved: S1, installing the heat flow measurement assembly (17), the air pressure sensor (16), the pressure sensor (13) and the material to be tested (15) in the experimental chamber (3); S2, start the vacuum pump (1) to evacuate the experimental chamber (3); S3, injecting inert gas into the experimental chamber (3) through the inert gas storage tank (2); S4, using the heat source system (6) to heat the heat flow measurement component (17), and recording the steady-state heat flow value; S5, heating the material to be tested (15) using the heat source system (6); S6. When performing step S5, the temperature measuring component (4) is operated synchronously to measure the surface temperature of the material to be tested (15), the mass flow rate of the pyrolysis gas overflow is measured by the pressure sensor (13), and the cabin pressure is measured by the air pressure sensor (16); S7. Data processing based on pyrolysis inversion algorithm.

8. The in-situ measurement method of pyrolysis gas viscosity coefficient according to claim 7, characterized in that: The data processing in step S7 includes the following steps: The gas constant R, carbonized layer permeability K, specimen top surface area S, and the measured pyrolysis gas overflow mass flow rate are Substitute the surface temperature T and air pressure P into the following formula: The viscosity coefficient μ and the pyrolysis gas pressure gradient at the internal surface of the specimen can be obtained The measured heat flow, surface temperature, air pressure and other parameters are substituted into the control equation, boundary conditions and initial conditions, and another pressure gradient is obtained by numerical solution. The relationship between the viscosity coefficient μ and the viscosity coefficient μ can be used to calculate the viscosity coefficient of the pyrolysis gas under certain ambient pressure conditions as it changes with temperature; The governing equations are as follows: The boundary conditions are as follows: p=p w x=x w The initial conditions are as follows: The meanings of the parameters in the formula are as follows: K——Permeability (m 2 ); μ——viscosity coefficient (Pa·s); q——heat flux of hot wall (W / m 2 ); ——thermal blocking coefficient (-); ξ——porosity (-); u——pyrolysis gas flow rate (m / s); S——test piece area (m 2 ); A——pre-exponential factor; E——activation energy (J); n——reaction order (-); t——time (s); ρ——density (kg / m 3 ); h——enthalpy (J / kg); x——material thickness direction coordinate (m); k——thermal conductivity (W / (m·K)); T——temperature (K); ——mass flow rate of specimen (kg / s); ΔH——thermal heat (J / kg); R——Gas constant (J / (kg·K)) Subscript g—gas; Subscript p—the interface between the original material layer and the pyrolysis layer; subscript c—the interface between the pyrolysis layer and the carbonized layer; Subscript w——material surface; Subscript 1—original material layer; Subscript 2—pyrolysis layer; Subscript 3—carbonized layer.

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