A CFD-based method for detecting ventilation rate of cultural relics display cabinets

Abstract

The present invention relates to the field of cultural relics collection, and specifically discloses a method for detecting ventilation rate of cultural relics display cabinet based on CFD, comprising the following steps: S1, drawing a three-dimensional model of the cultural relics display cabinet; S2, recording the experimental detection results of the temperature and humidity outside the cabinet and the experimental detection results of the carbon dioxide concentration in the cabinet changing with time from the starting time; S3, obtaining the numerical detection results of the carbon dioxide concentration in the cabinet changing with time; S4, obtaining the three-dimensional CFD model of the display cabinet calibrated with carbon dioxide; S5, selecting a tracer gas with a molecular mass close to that of air, and obtaining the numerical detection results of the tracer gas concentration in the cabinet changing with time; S6, obtaining the ventilation rate of the display cabinet by function regression. The present invention uses a gas with a molecular mass closer to that of air as a tracer gas under the premise of accuracy, convenience, low cost, and harmlessness to people and the environment, and realizes the detection of the ventilation rate of the museum cultural relics display cabinet by means of numerical experiments in a virtual space, so as to obtain a more accurate ventilation rate of the display cabinet.

Description

Technical Field

[0001] The present invention relates to the field of cultural relics collection, and in particular to a method for detecting ventilation rate of cultural relics display cabinets based on CFD. Background Art

[0002] The sealing performance of a showcase is an important indicator for evaluating the quality of a showcase. A showcase with good sealing performance can isolate pollutants in the outside air to a certain extent, thereby effectively reducing the impact of pollutants in the outside environment on the environment inside the showcase. At the same time, it has a buffering effect on the humidity changes in the outside environment. Therefore, the sealing performance of the showcase is also the main basis for formulating humidity control measures inside the showcase. The sealing performance of the showcase is usually expressed by the showcase ventilation rate, that is, the ratio of the volume of air entering the showcase from outside to the volume of the showcase in one day without external power and pressure difference.

[0003] At present, the tracer gas detection method is mainly used to determine the ventilation rate of the showcase. Commonly used tracer gases include carbon dioxide, nitrous oxide, nitric oxide, carbon monoxide, ethylene, etc. The specific method is as follows: First, a certain amount of high-concentration tracer gas is introduced into the showcase. As the air outside the showcase continuously penetrates into the showcase through the gaps in the showcase, the high-concentration tracer gas in the showcase also penetrates out of the showcase through the gaps in the showcase. As the gas inside and outside the showcase is exchanged, the high-concentration tracer gas in the showcase is continuously diluted. Since there is no pressure difference between the inside and outside of the showcase, the amount of gas entering the showcase and the amount of gas leaking out of the showcase at the same time are the same, and the tracer gas concentration in the air outside the showcase is a constant value, that is, the ventilation rate of the showcase can be calculated by the following formula:

[0004] C-C1=(C0-C1)·exp(-R0·t);

[0005]

[0006] Where C is the tracer gas concentration in the showcase, C1 is the initial tracer gas concentration in the showcase, C0 is the tracer gas concentration in the air, t is the time, R0 is the showcase ventilation rate, q is the air intake of the showcase per unit time, and V is the showcase volume.

[0007] However, this experimental method can be further improved: first, when carbon dioxide is used as a tracer gas, the molecular mass of carbon dioxide is larger than that of air. In actual experiments, carbon dioxide is easy to settle at the bottom of the display cabinet and cannot be fully mixed with the air in the cabinet, thus affecting the test results; second, when carbon monoxide, nitric oxide, etc. are used as tracer gases for experimental detection, they are very toxic to the human body, and have high requirements for detection personnel and equipment, and are not suitable for use in places such as museums; third, when ethylene is used as a tracer gas for experimental detection, the operation is complicated and the detection cost is high, which is difficult to promote in museums. Therefore, an accurate, safe and low-cost display cabinet ventilation rate detection method is needed.

[0008] In recent years, with the development of computer technology and fluid mechanics, more and more practical engineering problems can be solved by applying numerical simulation technology. CFD, or computational fluid dynamics, is an emerging interdisciplinary subject that integrates fluid mechanics and computer science. It starts from the computational method and uses the fast computing power of computers to obtain approximate solutions to fluid control equations. The basic characteristics of computational fluid dynamics are numerical simulation and computer experiments. Starting from basic physical theorems, it has largely replaced the expensive fluid dynamics experimental equipment and has a huge impact on scientific research and engineering technology. CFD software usually refers to commercial CFD programs with a good human-computer interaction interface. The current mainstream CFD software includes CFX, Fluent, Phoenics, Star-CD, Comsol, Star-ccm+, Flow-3D, etc. Summary of the invention

[0009] In view of this, the purpose of the present invention is to provide a CFD-based method for detecting the ventilation rate of a cultural relic display case, and to conduct numerical experiments in a virtual space based on CFD tools to measure the ventilation rate. This method uses a gas with a molecular mass closer to that of air as a tracer gas, and detects the ventilation rate of a museum cultural relic display case by means of numerical experiments in a virtual space, while being accurate, convenient, low-cost, and harmless to humans and the environment, so as to obtain a more accurate ventilation rate of the museum cultural relic display case.

[0010] To achieve the above object, the present invention provides a method for detecting ventilation rate of a cultural relic display cabinet based on CFD, comprising the following steps:

[0011] S1. Obtaining entity parameters of a cultural relic display cabinet and drawing a three-dimensional model of the cultural relic display cabinet in CFD software;

[0012] S2, filling the cultural relic display cabinet in S1 with high concentration of carbon dioxide gas, selecting the moment when the carbon dioxide in the cabinet is evenly mixed with the air in the cabinet and the concentration of carbon dioxide in the cabinet decreases and becomes basically stable as the starting moment of the experiment, at which time the concentration of carbon dioxide in the cabinet is the initial concentration, and recording the experimental test results of the temperature and humidity outside the cabinet and the experimental test results of the change of the concentration of carbon dioxide in the cabinet over time from the starting moment;

[0013] S3, compile the experimental test results of temperature and humidity outside the cabinet obtained in S2 using programming software, and import them into the three-dimensional model of the showcase in S1 as temperature and humidity boundary conditions for calculation; import the initial concentration value of carbon dioxide inside the cabinet obtained in S2 into the three-dimensional model of the showcase in S1 as initial conditions for calculation, and obtain the numerical test results of the change of carbon dioxide concentration inside the cabinet over time;

[0014] S4, comparing the experimental test results of the carbon dioxide concentration changing with time in the cabinet obtained in S2 with the numerical test results of the carbon dioxide changing with time obtained in S3, calibrating the model accordingly, and outputting the three-dimensional CFD model of the showcase after carbon dioxide calibration;

[0015] S5, select a tracer gas with a molecular mass close to that of air, set the initial concentration of the tracer gas in the showcase in the three-dimensional CFD model of the showcase calibrated with carbon dioxide outputted in S4, perform calculations while keeping other model conditions unchanged, and output the numerical detection results of the concentration of the tracer gas in the showcase over time;

[0016] S6. Plot the numerical detection results of the tracer gas concentration in the cabinet with a molecular mass close to that of air outputted in S5 as a function of time, and obtain the ventilation rate of the cabinet through function regression.

[0017] Preferably, in step S1, the physical parameters of the cultural relic display cabinet include the material and size of the display cabinet and the width of the gap connecting the display cabinet with the outside world.

[0018] Preferably, in step S2, the carbon dioxide concentration data in the showcase is obtained by a wireless carbon dioxide concentration detection recorder disposed inside the showcase.

[0019] Preferably, in step S2, the temperature and humidity data outside the showcase are obtained by using temperature and humidity wireless sensors arranged outside the showcase and outside the showcase base near the gap of the showcase;

[0020] Preferably, in step S2, when the carbon dioxide concentration in the display cabinet decreases by no more than 1000 ppm per hour, it is determined that the carbon dioxide concentration in the cabinet has decreased to a substantially stable state.

[0021] Preferably, in step S2, the initial concentration of carbon dioxide in the cabinet needs to be higher than 2000 ppm, otherwise high-concentration carbon dioxide gas needs to be refilled into the cabinet.

[0022] Preferably, in step S4, when calibrating, the gap width of the cultural relics display cabinet is an adjustable parameter of the model, the sum of square errors between the numerical detection results and the experimental detection results is used as the objective function, and the gap width value when the objective function reaches the minimum value of the interval is obtained as the calibrated model parameter.

[0023] Preferably, in step S5, the tracer gas is carbon monoxide, nitric oxide or ethylene.

[0024] Compared with the existing tracer gas detection method, the present invention has the following beneficial technical effects:

[0025] The CFD-based ventilation rate detection method for cultural relics display cabinets provided by the present invention is more accurate than the carbon dioxide tracer gas experimental detection method; it is harmless to operators and the environment compared with the carbon monoxide, nitric oxide and other tracer gas experimental detection methods; it is more convenient to operate and has lower cost compared with the ethylene tracer gas experimental detection method. Therefore, the present method is an accurate, safe and low-cost detection method for measuring the ventilation rate of cultural relics display cabinets.

[0026] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a flow chart of a method for detecting ventilation rate of a cultural relic display cabinet based on CFD in Embodiment 1 of the present invention;

[0028] Figure 2 A schematic diagram of a three-dimensional model of a cultural relic display cabinet established in Example 1 of the present invention;

[0029] Figure 3 This is a schematic diagram showing the change of the carbon dioxide concentration in the display cabinet over time in the first embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram showing the change of carbon monoxide concentration in the display cabinet over time in the first embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram showing the change of the concentration of nitric oxide in the display cabinet over time in the second embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the result of the change of ethylene concentration in the display cabinet over time in Example 3 of the present invention. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0034] Embodiment 1

[0035] This embodiment provides a method for detecting the ventilation rate of a display cabinet, which is based on a CFD (computational fluid dynamics) tool and a carbon dioxide tracer gas experimental detection method. Therefore, it is a CFD-based method for detecting the ventilation rate of a cultural relic display cabinet, which mainly includes 6 steps, as described in S1 to S6 below.

[0036] S1. Obtain entity parameters of a cultural relic display cabinet, and draw a three-dimensional model of the cultural relic display cabinet in CFD software (for example, Fluent software).

[0037] The cultural relic display case may include a base for placing cultural relics and an isolation cover arranged outside the cultural relics. The isolation cover is a rectangular transparent glass frame structure with an opening at the bottom. There is a gap between the metal part and the wood part of the base, and the gap is the part connecting the display case with the outside world. The three-dimensional model is provided with an interface corresponding to the gap. The physical parameters of the cultural relic display case may include the material and size of the display case and the width of the gap connecting the display case with the outside world.

[0038] This embodiment uses a cultural relic display cabinet with a desktop display cabinet structure, whose length, width and height are 1.2m, 0.6m and 0.355m respectively. The bottom is surrounded by metal frames and the middle of the bottom is a wooden board. There is a gap of about 2.00mm between the metal frame and the wooden board, which connects the inside of the cabinet with the external environment. Therefore, the gap is the part connecting the cultural relic display cabinet with the outside world. Except for the bottom surface, the other five surfaces of the cultural relic display cabinet are made of transparent organic glass, and the thickness of the transparent organic glass is 0.012m. According to the above dimensions and materials, a three-dimensional model of the cultural relic display cabinet is established, as shown in FIG. Figure 2 shown.

[0039] S2. Fill the cultural relic display cabinet (physical display cabinet) in S1 with high concentration of carbon dioxide gas, select the moment when the carbon dioxide and air in the cabinet are evenly mixed and the concentration of carbon dioxide in the cabinet decreases and stabilizes, as the starting time of the experiment. At this time, the concentration of carbon dioxide in the cabinet is the initial concentration, and record the experimental test results of the temperature and humidity outside the cabinet and the experimental test results of the change of carbon dioxide concentration in the cabinet over time from the starting time.

[0040] Before filling with carbon dioxide gas, it is necessary to install temperature and humidity wireless sensors on the outside of the showcase and outside the showcase base near the gap of the showcase, and place a carbon dioxide concentration wireless detection recorder inside the showcase; both the temperature and humidity wireless sensors and the carbon dioxide concentration wireless detection recorder can be connected to the host computer, and both can be recorded by the online continuous detection recorder, so as to obtain the carbon dioxide concentration data inside the cabinet through the carbon dioxide concentration wireless detection recorder, and obtain the temperature and humidity data outside the cabinet through the temperature and humidity wireless sensors installed on the outside of the showcase and outside the showcase base near the gap of the showcase.

[0041] High-concentration carbon dioxide gas is uniformly filled into the physical cultural relic display cabinet. When the value recorded by the carbon dioxide concentration wireless detection recorder drops from a high value to 6000ppm (parts per million), the air inlet is closed; when the carbon dioxide concentration in the cabinet drops to a basically stable state (when the carbon dioxide concentration in the display cabinet drops by no more than 1000ppm per hour, it can be determined that the carbon dioxide concentration in the cabinet has dropped to a basically stable state), as the starting time of the experiment, the carbon dioxide concentration in the display cabinet is continuously detected, and the carbon dioxide concentration in the cabinet at this time is recorded as the initial concentration (it should be noted that the initial concentration of carbon dioxide in the cabinet must be higher than 2000ppm, otherwise high-concentration carbon dioxide gas must be refilled into the cabinet; in this embodiment, 2219ppm is recorded as the initial concentration), the instrument detects and saves a set of data every 15 minutes; from the start of the experiment, the temperature and humidity of the environment outside the cabinet are detected and saved every 15 minutes.

[0042] S3. The experimental test results of the temperature and humidity outside the cabinet obtained in S2 are compiled using programming software and imported into the three-dimensional model in S1 as boundary conditions for calculation; the initial concentration value of carbon dioxide inside the cabinet obtained in S2 is imported into the three-dimensional model in S1 as initial conditions for calculation, and the numerical test results of the change of carbon dioxide concentration inside the cabinet over time are obtained.

[0043] The UDF (User Define Function) is used to compile the test results of the temperature and humidity experiment outside the cabinet, and then imported into the CFD software as the boundary conditions of the model for calculation; the species transport model is introduced, and the gas in the fluid zone inside the display cabinet is set to a mixed gas, which is carbon dioxide (CO2), water vapor (H2O), and dry air (air). The mass fraction of carbon dioxide in the cabinet in the initial state is set to 0.003367 (the initial concentration of carbon dioxide in the cabinet), the mass fraction of water vapor is set to 0.012, and the mass fraction of carbon dioxide in the air outside the cabinet is set to 0.001138 as the boundary conditions at the gap for calculation; the model outputs and saves a set of numerical test results of carbon dioxide concentration in the cabinet every 15 minutes.

[0044] S4. Compare the experimental test results of the carbon dioxide concentration changing with time in the cabinet obtained in S2 with the numerical test results of the carbon dioxide changing with time obtained in S3, calibrate the model accordingly, and output the three-dimensional CFD model of the showcase after carbon dioxide calibration.

[0045] The experimental test results and numerical test results of the carbon dioxide concentration in the cabinet over time are plotted, and the results are as follows: Figure 3As shown (the black dots in the figure represent the experimental test results of the carbon dioxide concentration in the cabinet changing with time; curve a represents the numerical test results of the carbon dioxide concentration in the cabinet changing with time of the calibrated model; curve b represents the numerical test results of the carbon dioxide concentration in the cabinet changing with time of the initial model).

[0046] In order to make the experimental test results better consistent with the numerical test results, during calibration, the gap width of the cultural relics display cabinet is used as the adjustable parameter of the model, and the sum of squares of the errors between the numerical test results and the experimental test results is used as the objective function. The gap width value when the objective function reaches the minimum value of the interval is obtained as the calibrated model parameter.

[0047] The basis for the gap width of the cultural relics display cabinet as an adjustable parameter is as follows: According to the formula When the volume of the showcase remains unchanged, the ventilation rate of the showcase is determined by the air intake volume (q) of the showcase per unit time, and the air intake volume of the showcase per unit time is determined by the gap width of the showcase; the gap width of the showcase is obtained by experimental measurement, the experimental measurement error is within 1mm, and the gap width at each position may be slightly different, so in this method, the gap width can be used as an adjustable parameter of the model.

[0048] In this embodiment, the initial gap width is 2.00 mm, and after calibration, when the experimental test results and the numerical test results are best matched, the gap width is 2.01 mm.

[0049] S5. Select carbon monoxide as the tracer gas, set the initial concentration of the tracer gas in the cabinet in the three-dimensional CFD model of the showcase calibrated with carbon dioxide output by S4, perform calculations while keeping other conditions of the model unchanged, and output the numerical detection results of the tracer gas concentration in the cabinet changing with time.

[0050] Specifically, in the above-mentioned model calibrated by the carbon dioxide experiment, the mixed gas components in the component transport model are reset, and the mixed gas is set to carbon monoxide (CO), water vapor (H2O), and dry air (air); the mass fraction of carbon monoxide in the cabinet in the initial state is set to 0.00003 (the initial concentration of carbon monoxide in the cabinet); the mass fraction of carbon monoxide in the air outside the cabinet is set to 0 as the boundary condition at the gap for calculation; the model outputs and saves a set of numerical detection results of the carbon monoxide concentration in the cabinet every 15 minutes.

[0051] S6. Plot the numerical detection result of the tracer gas concentration in the cabinet outputted in S5 as a function of time, and obtain the ventilation rate of the cabinet through function regression.

[0052] Specifically, the results of the change of carbon monoxide concentration in the above cabinet over time are plotted (such as Figure 4As shown), the exponential decay equation is used for fitting. 2 When ≥0.99, the air change rate of the showcase measured using carbon monoxide as the tracer gas is obtained.

[0053] In this embodiment, the ventilation rate of the showcase measured by using carbon monoxide as the tracer gas is 4.79.

[0054] Embodiment 2

[0055] The present embodiment provides a CFD-based ventilation rate detection method for a cultural relic display cabinet, the main steps and principles of which are substantially the same as those of the method shown in the first embodiment, and the similarities will not be described again.

[0056] Compared with the first embodiment, this embodiment uses nitric oxide as the tracer gas, so there are some differences between step S5 and step S6 and the first embodiment.

[0057] When the tracer gas source is nitric oxide (NO), in the model calibrated by the carbon dioxide experiment, the mixed gas components in the component transport model are reset, and the mixed gas is set to nitric oxide (NO), water vapor (H2O), and dry air (air). The mass fraction of nitric oxide in the cabinet in the initial state is set to 0.00003 (the initial concentration of nitric oxide in the cabinet); the mass fraction of nitric oxide in the air outside the cabinet is set to 0 as the boundary condition at the gap for calculation. The model outputs and saves a set of numerical detection results of nitric oxide concentration in the cabinet every 15 minutes.

[0058] Plot the results of the change of nitric oxide concentration in the above cabinet over time (such as Figure 5 As shown), the exponential decay equation is used for fitting. 2 When ≥0.99, the ventilation rate of the display cabinet measured using nitric oxide as the tracer gas is obtained.

[0059] In this embodiment, the ventilation rate of the showcase measured by using nitric oxide as the tracer gas is 4.84.

[0060] Embodiment 3

[0061] The present embodiment provides a CFD-based ventilation rate detection method for a cultural relic display cabinet, the main steps and principles of which are substantially the same as those of the methods shown in the first and second embodiments, and the similarities will not be described again.

[0062] Compared with the first and second embodiments, this embodiment uses ethylene as the tracer gas, so there are some differences between step S5 and step S6 and the first and second embodiments.

[0063] When the tracer gas source is ethylene (C2H4), in the model calibrated by the carbon dioxide experiment, the mixed gas components in the component transport model are reset to ethylene (C2H4), water vapor (H2O), and dry air (air). The mass fraction of ethylene in the cabinet in the initial state is set to 0.00003 (the initial concentration of ethylene in the cabinet); the mass fraction of ethylene in the air outside the cabinet is set to 0 as the boundary condition at the gap for calculation. The model outputs and saves a set of numerical detection results of the ethylene concentration in the cabinet every 15 minutes.

[0064] Plot the results of the above cabinet ethylene concentration changes over time (such as Figure 6 As shown), the exponential decay equation is used for fitting. 2 When ≥0.99, the ventilation rate of the display cabinet measured using ethylene as the tracer gas is obtained.

[0065] In this embodiment, the ventilation rate of the display cabinet measured by using nitric oxide as the tracer gas is 4.80.

[0066] The test results of the above embodiments 1 to 3 are shown in Table 1 below:

[0067] Table 1 Comparison between numerical experimental results and experimental measurement results for calculating ventilation rate of cultural relics display cabinets

[0068] <![CDATA[Display cabinet air change rate / d -1 > <![CDATA[R 2 ]]> Carbon dioxide test results 3.44 0.99205 Numerical detection results of carbon dioxide for the initial model 3.19 0.99489 The numerical detection results of carbon dioxide of the calibrated model 3.50 0.99492 Carbon monoxide numerical test results 4.79 0.99411 Nitric oxide value test results 4.84 0.99378 Ethylene numerical test results 4.80 0.99447

[0069] As shown in Table 1, the experimental test results when using carbon dioxide as the tracer gas are close to the numerical test results of the calibrated model, indicating that the model has a higher accuracy after calibration; while when carbon monoxide / nitric oxide / ethylene are used as the tracer gas, there is a certain difference between the numerical test results of the model and the numerical test results when carbon dioxide is used as the tracer gas, indicating that it is necessary to use a gas with a molecular mass close to that of air as the tracer gas to detect the ventilation rate of the showcase. Using the above-mentioned gas source with a molecular mass closer to that of air as the tracer gas can better and more accurately reflect the actual ventilation rate of the showcase during use.

[0070] When using carbon monoxide / nitric oxide / ethylene as tracer gases, the numerical detection results of the three are close, which can be explained by their similar molecular masses.

[0071] Finally, it should be noted that this article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only to help understand the core idea of ​​the present invention. Without departing from the principles of the present invention, the present invention may also be improved and modified, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A CFD-based method for detecting ventilation rate of cultural relics display cabinets, characterized in that: The following steps are involved: S1. Obtaining entity parameters of a cultural relic display cabinet and drawing a three-dimensional model of the cultural relic display cabinet in CFD software; S2, filling the cultural relic display cabinet in S1 with high concentration of carbon dioxide gas, selecting the time when the carbon dioxide in the cabinet is evenly mixed with the air in the cabinet and the carbon dioxide concentration in the cabinet decreases and stabilizes as the starting time of the experiment, at which time the carbon dioxide concentration in the cabinet is the initial concentration, and recording the experimental test results of the temperature and humidity outside the cabinet and the experimental test results of the change of carbon dioxide concentration in the cabinet over time from the starting time; S3, compile the experimental test results of temperature and humidity outside the cabinet obtained in S2 using programming software, and import them into the three-dimensional model of the showcase in S1 as temperature and humidity boundary conditions for calculation; import the initial concentration value of carbon dioxide inside the cabinet obtained in S2 into the three-dimensional model of the showcase in S1 as initial conditions for calculation, and obtain the numerical test results of the change of carbon dioxide concentration inside the cabinet over time; S4, comparing the experimental test results of the carbon dioxide concentration changing with time in the cabinet obtained in S2 with the numerical test results of the carbon dioxide changing with time obtained in S3, calibrating the model accordingly, and outputting the three-dimensional CFD model of the showcase after carbon dioxide calibration; S5, select a tracer gas with a molecular mass close to that of air, set the initial concentration of the tracer gas in the showcase in the three-dimensional CFD model of the showcase calibrated with carbon dioxide outputted in S4, perform calculations while keeping other model conditions unchanged, and output the numerical detection results of the concentration of the tracer gas in the showcase over time; S6. Plot the numerical detection results of the tracer gas concentration in the cabinet with a molecular mass close to that of air outputted in S5 as a function of time, and obtain the ventilation rate of the cabinet through function regression.

2. The CFD-based ventilation rate detection method for cultural relics display cabinets according to claim 1, characterized in that: In step S1 , the physical parameters of the cultural relic display cabinet include the material and size of the display cabinet and the width of the gap connecting the display cabinet with the outside world.

3. The CFD-based ventilation rate detection method for cultural relics display cabinets according to claim 1 is characterized in that: In step S2, the carbon dioxide concentration experimental detection data in the cabinet is obtained by a carbon dioxide concentration wireless detection recorder installed inside the cabinet.

4. The CFD-based ventilation rate detection method for cultural relics display cabinets according to claim 3 is characterized in that: In step S2, the temperature and humidity data outside the showcase are obtained through temperature and humidity wireless sensors arranged outside the showcase and outside the showcase base near the gap of the showcase.

5. The CFD-based ventilation rate detection method for cultural relics display cabinets according to claim 1 is characterized in that: In step S2, when the carbon dioxide concentration in the display cabinet decreases by no more than 1000 ppm per hour, it is determined that the carbon dioxide concentration in the cabinet has decreased to a substantially stable state.

6. The CFD-based ventilation rate detection method for cultural relics display cabinets according to claim 5 is characterized in that: In step S2, the initial concentration of carbon dioxide in the cabinet must be higher than 2000 ppm, otherwise high-concentration carbon dioxide gas must be refilled into the cabinet.

7. The CFD-based ventilation rate detection method for cultural relics display cabinets according to claim 1 is characterized by: In step S4, during calibration, the gap width of the cultural relics display cabinet is used as an adjustable parameter of the model, and the sum of squares of the errors between the numerical detection results and the experimental detection results is used as the objective function. The gap width value when the objective function reaches the minimum value of the interval is obtained as the calibrated model parameter.

8. A CFD-based ventilation rate detection method for cultural relics display cabinets according to any one of claims 1 to 7, characterized in that: In step S5, the tracer gas is carbon monoxide.

9. A CFD-based ventilation rate detection method for a cultural relic display cabinet according to any one of claims 1 to 7, characterized in that: In step S5, the tracer gas is nitric oxide.

10. A CFD-based ventilation rate detection method for a cultural relic display cabinet according to any one of claims 1 to 7, characterized in that: In step S5, the tracer gas is ethylene.

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