Gas diffusion simulation device and test method and applications

Abstract

This invention discloses a gas diffusion simulation device, testing method, and application. The gas diffusion simulation device includes a wind field system, a gas release system, and a concentration monitoring system. The wind field system provides a stable wind speed to the concentration monitoring system. The gas release system provides a stable flow rate of gas to the concentration monitoring system. The output terminals of the wind field system and the gas release system are located on the same side of the concentration monitoring system. The concentration monitoring system includes a test frame, an anemometer, and a gas concentration acquisition module. The concentration monitoring system is used to acquire gas concentration. The simulation device of this invention can be used to accurately acquire data on the diffusion concentration in the downstream space after a natural gas leak. It also provides a testing method based on the above-mentioned gas diffusion simulation device and its application in calculating Gaussian diffusion model coefficients.

Description

Technical Field

[0001] This invention relates to the field of natural gas leakage and diffusion technology, specifically to gas diffusion simulation devices, testing methods, and applications. Background Technology

[0002] Natural gas, due to its environmental friendliness, high heat production, and ease of transportation and storage, has occupied an irreplaceable position in social development and people's lives. However, along with its widespread use, natural gas leaks have also occurred frequently. Once a leak occurs, natural gas rapidly disperses into the air, and insufficient timeliness in handling it can seriously threaten the lives and property of the general public. Therefore, research on the diffusion characteristics of natural gas leaks has become one of the key areas for ensuring the safe production of natural gas. At the same time, preventative measures to avoid such incidents and timely prediction and emergency response after an accident are also crucial. Currently, diffusion models are widely used to quickly predict the spread and impact range of leak events. These models are primarily based on basic information about the leak source and surrounding environment, using models to estimate and simulate the diffusion concentration, migration path, and boundary range of leaked natural gas after an accident, and to quantitatively analyze the impact of the accident.

[0003] Currently, there are two main methods for studying the diffusion of natural gas leaks: experimental testing and numerical simulation.

[0004] Experimental testing can closely simulate the conditions at a leak site. However, existing gas diffusion experimental devices are mainly suitable for heavier gases with a density greater than air, such as CO2, which diffuse and migrate to the ground and deposit. Therefore, simply placing gas concentration probes on the ground can monitor changes in gas concentration at different locations. But because natural gas is less dense than air, once it leaks and escapes into the air, it diffuses and migrates upwards. Existing techniques for placing gas concentration probes on the ground are insufficient to capture natural gas clouds diffusing upwards in the air, and even more difficult to obtain the distribution of natural gas concentration at different locations in the downstream space. This makes it impossible to provide detailed and reliable experimental data for natural gas leak diffusion research and numerical simulation.

[0005] Numerical simulations, such as Gaussian diffusion models, are widely used to predict the diffusion range and concentration distribution of leaks. However, because the lift height and diffusion coefficient in the model are mainly calculated based on empirical formulas, their general applicability is poor, resulting in a large deviation between the calculated results and the measured values. The average accuracy of the error in existing technologies typically reaches 57.7%. Summary of the Invention

[0006] The purpose of this invention is to provide a gas diffusion simulation device that can be used to accurately obtain the diffusion concentration in the downstream space after a natural gas leak, and can provide detailed and reliable experimental data for natural gas leak diffusion research and its numerical simulation, thereby improving the calculation accuracy.

[0007] Furthermore, the present invention also provides a test method based on the above-mentioned gas diffusion simulation device and its application in calculating Gaussian diffusion model coefficients.

[0008] This invention is achieved through the following technical solution:

[0009] The gas diffusion simulation device includes a wind field system, a gas release system, and a concentration monitoring system;

[0010] The wind field system is used to provide a wind field with stable wind speed to the concentration monitoring system; the gas venting system is used to provide gas with stable flow rate to the concentration monitoring system; the output end of the wind field system and the output end of the gas venting system are located on the same side of the concentration monitoring system.

[0011] The concentration monitoring system includes a test frame, an anemometer, and a gas concentration acquisition module.

[0012] The test frame has an internal diffusion space for gas diffusion. The anemometer is located at the air inlet of the test frame to collect wind speed in real time. The gas concentration acquisition module is located in the diffusion space within the test frame via a sliding mechanism. The gas concentration acquisition module is used to collect gas concentration in real time. The sliding mechanism enables the gas concentration acquisition module to move in the diffusion space along the X, Y, and Z directions.

[0013] The wind field system and gas venting system described in this invention are used to provide wind field and gas to the concentration monitoring system to simulate gas leakage. The concentration monitoring system can adjust the gas concentration acquisition module to different coordinates through a sliding mechanism. Therefore, the concentration monitoring system can acquire gas concentration data at different coordinates. This data can provide detailed and reliable experimental data for natural gas leakage diffusion research and its numerical simulation, thereby improving calculation accuracy.

[0014] Furthermore, the gas concentration acquisition module in the concentration monitoring system of the present invention is placed in the diffusion space within the test frame, and its position within the diffusion space can be adjusted by a sliding mechanism. Therefore, it can be used to acquire the concentration of gases with a density less than air that diffuse upwards (such as natural gas). In other words, the simulation device of the present invention can be used to accurately obtain data on the diffusion concentration in the downstream space after a natural gas leak.

[0015] Furthermore, the sliding mechanism includes connecting rod one, connecting rod two, and connecting rod three;

[0016] The connecting rod is slidably mounted on the test frame, and the connecting rod can move up and down in the Z direction;

[0017] The second connecting rod is slidably mounted on the first connecting rod, and the second connecting rod can move left and right in the X direction;

[0018] The connecting rod three is slidably mounted on the connecting rod two, and the connecting rod three can move back and forth in the Y direction;

[0019] The gas concentration acquisition module is installed on connecting rod three.

[0020] The number and specific sliding method of the connecting rod 1, connecting rod 2 and connecting rod 3 of the present invention can be set according to the actual situation, as long as the gas concentration acquisition module can be moved in the X, Y and Z directions by sliding the connecting rod 1, connecting rod 2 and connecting rod 3.

[0021] Furthermore, the sliding mechanism includes two symmetrically arranged connecting rods 1, with both ends of the connecting rods 1 slidably mounted on the test frame; two connecting rods 2 are symmetrically arranged between the two connecting rods 1, with both ends of the connecting rods 2 slidably mounted on the two connecting rods 1 respectively; and two connecting rods 3 are symmetrically arranged between the two connecting rods 2, with both ends of the connecting rods 3 slidably mounted on the two connecting rods 2 respectively.

[0022] Furthermore, the sliding settings can be achieved through a combination of a slide rail and a slider, or by using a reciprocating linear motor.

[0023] Furthermore, distance scales are provided on the test frame, connecting rod one, connecting rod two, and connecting rod three.

[0024] Furthermore, at least two sets of sliding mechanisms are provided.

[0025] Preferably, the sliding mechanism is provided in two sets, with connecting rod one, connecting rod two, and connecting rod three arranged in parallel in each set, and at least two gas concentration acquisition modules are provided on each connecting rod three.

[0026] Furthermore, the gas concentration acquisition module includes a natural gas concentration monitoring probe and a natural gas concentration sensor.

[0027] Furthermore, the wind farm system includes a speed controller, a fan, and an airflow stabilization mechanism;

[0028] The speed controller is connected to the fan, the air outlet of the fan is connected to the air inlet of the airflow stabilizing mechanism, and the air outlet of the airflow stabilizing mechanism is located close to the test frame.

[0029] The airflow stabilization mechanism is used to stabilize the vortex flow blown out by the fan into a laminar airflow field similar to the atmosphere.

[0030] Furthermore, the airflow stabilization mechanism includes a honeycomb flow stabilizing tube or a corrugated tube.

[0031] Furthermore, the gas venting system includes a gas storage cylinder and a flow meter;

[0032] The gas storage cylinder supplies gas to the diffusion space within the test frame via a pipeline, and the flow meter is installed on the pipeline.

[0033] Furthermore, a pressure reducing valve and a regulating valve are installed upstream of the flow meter on the pipeline used to supply gas.

[0034] Furthermore, the concentration monitoring system also includes a data storage unit electrically connected to the anemometer and the gas concentration acquisition module.

[0035] The method for testing the lift height in a Gaussian diffusion model using the aforementioned gas diffusion simulation apparatus includes the following steps:

[0036] S1: Prepare for a gas diffusion simulation experiment: Use the flow meter outlet of the gas venting system as the origin of the coordinate system, i.e., the height H of the leakage source. s =0, the sliding mechanism makes the initial coordinates of the gas concentration acquisition module (x,0,z);

[0037] S2: Gas diffusion simulation experiment with stable wind speed and stable gas leakage rate: Move the gas concentration acquisition module up and down in the Z direction. When the monitored gas concentration value reaches its maximum, record the coordinates (x, y) of the gas concentration acquisition module at this moment. h1 ,0,z h1 ), obtain the distance x from the leak source h1 The lifting height z at that time h1 ;

[0038] S3: Move the gas concentration acquisition module sequentially in the X direction to x h2 ,...,x hn Repeat step S2 to obtain the rise height z at different leak source distances. h2 ,...,z hn ;

[0039] S4: Based on the different leak source distances and their corresponding rise heights, and combined with the rise height fitting function, the relationship between the rise height and the leak source distance is obtained;

[0040] S5: The rise height can be calculated based on the relationship between the rise height and the distance to the leak source, combined with the distance to the gas leak source.

[0041] Preferably, in step S4, the lifting height fitting function is:

[0042] ΔH=m-ns x (1)

[0043] In the formula: ΔH is the lifting height; x is the distance from the leakage source in the X direction; m, n, and s are all fitting parameters.

[0044] The method for testing the diffusion coefficient in a Gaussian diffusion model using the aforementioned gas diffusion simulation apparatus includes the following steps:

[0045] S1': Preparing for a gas diffusion simulation experiment: using the flow meter outlet of the gas venting system as the origin of the coordinate system, i.e., the height H of the leakage source. s =0;

[0046] S2': A gas diffusion simulation experiment was conducted with a stable wind speed and a stable gas leakage rate. The position of the gas concentration acquisition module was moved by a sliding mechanism to monitor the gas concentration data at distances from the leakage source (x1,0,z1), (x1,y2,z1), (x2,0,z2), and (x2,y4,z2), which were denoted as C1, C2, C3, and C4, respectively.

[0047] S3': The diffusion coefficient includes lateral and vertical diffusion coefficients, which are expressed by the lateral diffusion coefficient fitting formula and the vertical diffusion coefficient fitting formula, respectively. Substituting the lateral diffusion coefficient fitting formula and the vertical diffusion coefficient fitting formula into the Gaussian diffusion model, the concentration calculation formulas of C1, C2, C3 and C4 are obtained.

[0048] S4': The lateral diffusion coefficient fitting parameter in the lateral diffusion coefficient fitting formula is calculated according to the concentration ratio formula, wherein the concentration ratio formula is the ratio of two concentrations under the same horizontal position and the same height conditions;

[0049] S5': Substitute the lateral diffusion coefficient fitting parameters into the lateral diffusion coefficient fitting formula, and calculate the lateral diffusion coefficient based on the lateral diffusion coefficient fitting formula after substituting the lateral diffusion coefficient fitting parameters, combined with the distance of the gas leakage source.

[0050] S6': Substitute the lateral diffusion coefficient fitting formula after substituting the lateral diffusion coefficient fitting parameters into the concentration calculation formulas of C1 and C2, and solve to obtain the vertical diffusion coefficient fitting parameters of the vertical diffusion coefficient fitting formula.

[0051] S7': Substitute the vertical diffusion coefficient fitting parameters into the vertical diffusion coefficient fitting formula. Based on the vertical diffusion coefficient fitting formula after substituting the vertical diffusion coefficient fitting parameters, and combined with the distance of the gas leakage source, the vertical diffusion coefficient can be calculated.

[0052] Preferably, in step S3', the lateral diffusion coefficient fitting formula and the vertical diffusion coefficient fitting formula are respectively:

[0053] σ y =ax b (2)

[0054] σ z =cxd (3)

[0055] Where: σ y σ is the lateral diffusion coefficient; a and b are the fitting parameters for the lateral diffusion coefficient; x is the distance from the leakage source in the X direction; σ z is the vertical diffusion coefficient; c and d are the fitting parameters for the vertical diffusion coefficient.

[0056] Preferably, in step S3', the concentrations of C1 and C2 are calculated using the following formulas:

[0057]

[0058]

[0059] In the formula: Q is the natural gas leakage flow rate; ΔH represents the average wind speed; ΔH represents the lift height.

[0060] Preferably, in step S4', the concentration ratio formula is:

[0061]

[0062]

[0063] The values ​​of parameters a and b are obtained as follows:

[0064]

[0065]

[0066] The above-mentioned gas diffusion simulation device is used in obtaining data for calculating the coefficients of the Gaussian diffusion model.

[0067] The above-mentioned gas diffusion simulation device is used to obtain the gas concentration of gases with a density less than air at different coordinates.

[0068] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0069] 1. The simulation device described in this invention can be used to accurately obtain diffusion concentration data in the downstream space after a natural gas leak, and can provide detailed and reliable experimental data for natural gas leak diffusion research and its numerical simulation, so as to improve the calculation accuracy.

[0070] 2. This invention obtains Gaussian diffusion model coefficients based on concentration data measured in natural gas diffusion experiments. Compared with coefficients calculated using existing empirical formulas, the natural gas diffusion concentration calculated based on the Gaussian diffusion model coefficients of this invention is more accurate, with an average deviation of 30.7% and an average accuracy of 69.3%. This effectively improves the accuracy of calculating natural gas leakage diffusion concentrations using the Gaussian model. Attached Figure Description

[0071] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0072] Figure 1 This is a schematic diagram of the structure of the bulk diffusion simulation device of the present invention;

[0073] Figure 2 This is a schematic diagram of the test framework of the present invention.

[0074] The attached diagram shows the markings and corresponding component names:

[0075] 1-Gas cylinder, 2-Pressure reducing valve, 3-Regulating valve, 4-Flow meter, 5-Speed ​​controller, 6-Fan, 7-Airflow stabilizing mechanism, 8-Anemometer, 9-Test frame, 901-Connecting rod one, 902-Connecting rod two, 903-Connecting rod three, 10-Gas concentration acquisition module, 11-Serial port server, 12-Computer. Detailed Implementation

[0076] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0077] Example 1:

[0078] like Figures 1-2 As shown, the gas diffusion simulation device includes a wind field system, a gas release system, and a concentration monitoring system;

[0079] The wind field system is used to provide a wind field with stable wind speed to the concentration monitoring system; the gas venting system is used to provide gas with stable flow rate to the concentration monitoring system; the output end of the wind field system and the output end of the gas venting system are located on the same side of the concentration monitoring system.

[0080] The concentration monitoring system includes a test frame 9, an anemometer 8, a gas concentration acquisition module 10, a serial server 11, and a computer 12.

[0081] The internal structure of the test frame 9 is a diffusion space for gas diffusion. The anemometer 8 is installed at the air inlet of the test frame 9 to collect wind speed in real time. The gas concentration acquisition module 10 is installed in the diffusion space within the test frame 9 via a sliding mechanism. The gas concentration acquisition module 10 is used to collect gas concentration in real time. The sliding mechanism enables the gas concentration acquisition module 10 to slide in the diffusion space along the X, Y, and Z directions. The serial port server 11 and the computer 12 are used to collect and record the gas concentration monitored by the gas concentration acquisition module 10 and the wind speed monitored by the anemometer 8.

[0082] In one specific embodiment, the wind field system includes a speed controller 5, a fan 6, and an airflow stabilization mechanism 7. The speed controller 5 is connected to the fan 6, and the air outlet of the fan 6 is connected to the air inlet of the airflow stabilization mechanism 7. The air outlet of the airflow stabilization mechanism 7 is arranged adjacent to the concentration monitoring system. Optionally, the speed controller 5 is a variable frequency drive. In this embodiment, by connecting the speed controller 5 to the fan 6, the wind speed can be controlled by adjusting the fan blade speed. The airflow stabilization mechanism 7 can stabilize the vortex flow blown by the fan 6 into a laminar flow wind field similar to that of the atmosphere. It should be noted that the airflow stabilization mechanism 7 can use a honeycomb flow stabilization tube for flow stabilization, or other existing wind field stabilization methods, such as corrugated pipes, can be used.

[0083] In one specific embodiment, the gas venting system includes a gas storage cylinder 1, which supplies gas to the concentration monitoring system via a pressure-resistant hose. The pressure-resistant hose is sequentially connected from the gas inlet to the gas outlet to a pressure reducing valve 2, a regulating valve 3, and a flow meter 4. In this embodiment, by setting up a two-stage pressure regulation system using the pressure reducing valve 2 and the regulating valve 3, the gas output flow rate can be more accurately adjusted to the target test flow rate. Optionally, in the above embodiment, a flow meter with a regulating valve can also be directly used to form a two-stage pressure regulation structure.

[0084] In one specific embodiment, the test frame 9 includes a square frame constructed from eight square tubes, which forms a gas diffusion space. At least two sets of slidable supports are provided within the square frame. Each slidable support consists of two parallel connecting rods 901, two parallel connecting rods 902, and at least two connecting rods 903. The left and right ends of the two connecting rods 901 are respectively connected to the left and right square tubes on the front and rear sides of the square frame, and the connecting rods 901 can move along the... The square tube slides up and down (i.e., moves in the Z direction). The front and rear ends of the second connecting rod 902 are respectively connected to the two first connecting rods 901, and the second connecting rod 902 can slide left and right along the first connecting rod 901 (i.e., moves in the X direction). The left and right ends of the third connecting rod 903 are respectively connected to the two second connecting rods 902, and the third connecting rod 903 can slide back and forth along the second connecting rod 902 (i.e., moves in the Y direction). The gas concentration acquisition module 10 is mounted on the third connecting rod 903.

[0085] Optionally, such as Figure 2 As shown, the sliding bracket (sliding mechanism) is provided in two groups. Each group has two connecting rods 901, 902, and 903, and the two connecting rods 903 are arranged in parallel. Each connecting rod 903 is provided with two gas concentration acquisition modules 10.

[0086] In one specific embodiment, connecting rod 901, connecting rod 902, and connecting rod 903 all slide via a slide rail and a slider. It should be noted that sliding via a slide rail and slider is existing technology, and the specific structure will not be described in detail here. Furthermore, besides this structure, other existing structures such as linear reciprocating motors can also achieve this function. The specific sliding structure is not limited in this invention; any structure capable of sliding / translation is applicable to this invention.

[0087] In one specific embodiment, the square tube, connecting rod 1 901, connecting rod 2 902, and connecting rod 3 903 are all provided with distance scales to facilitate recording the coordinates of the gas concentration acquisition module 10 within the diffusion space formed by the square frame.

[0088] In one specific embodiment, the gas diffusion simulation device is used to simulate the diffusion of natural gas. In this embodiment, the gas in the gas storage cylinder is natural gas, and the gas concentration acquisition module 10 is a natural gas concentration monitoring probe. Optionally, the natural gas concentration monitoring probe is a laser-type methane sensor, and the laser-type methane sensor has wireless transmission capabilities. The natural gas concentration monitoring probe used in this embodiment has advantages such as high testing accuracy, short response time, and the ability to instantaneously synchronize natural gas concentration data within the diffusion space, thereby reducing the influence of physical factors such as data cables on the diffusion field. It should be noted that the laser-type methane sensor in the above embodiment is prior art, and in addition to the natural gas concentration monitoring probe used in the above embodiment, other types of natural gas concentration sensors such as infrared or catalytic combustion sensors can be selected according to requirements in practical applications, and the probe type should be selected based on parameters such as monitoring accuracy and response time.

[0089] In one specific embodiment, the serial port server 11 is connected to the laser methane sensor, the anemometer 8 and the serial port server 11 are connected to the computer 12 via a data cable, and the computer 12 is equipped with corresponding data acquisition software to record and store the changes in wind speed and natural gas concentration over time.

[0090] Application of the above-mentioned gas diffusion simulation device in calculating Gaussian diffusion model coefficients:

[0091] Preferably, the Gaussian diffusion model is:

[0092]

[0093] In the formula: C(x,y,z,H) is the average concentration of the leaked and diffused gas at any point in the coordinate system; Q is the gas leakage flow rate; σ is the average wind speed; y σ is the lateral diffusion coefficient; z denoted as , where y is the vertical diffusion coefficient; y is the distance from the leakage source in the Y direction; z is the distance from the leakage source in the Z direction; and H is the height of the effective source, H = H0. s +ΔH,H s Where ΔH is the height of the leakage source, and ΔH is the rise height;

[0094] The Gaussian diffusion model coefficients include the lateral diffusion coefficient, the vertical diffusion coefficient, and the lift height.

[0095] In one specific embodiment, the lifting height is calculated through the following steps:

[0096] S1: Prepare for a gas diffusion simulation experiment, using the flow meter outlet of the gas venting system as the origin of the coordinate system, i.e., the height H of the leakage source. s=0, the initial coordinates of the gas concentration monitoring probe 10 on the moving connecting rod 3903 are set to (x,0,z);

[0097] S2: Conduct a gas diffusion simulation experiment with a stable wind speed and a stable gas leakage rate. Move the gas concentration monitoring probe 10 up and down using the connecting rod 901. When the monitored gas concentration value reaches its maximum, record the coordinates (x, y) of the gas concentration monitoring probe at this point. h1 ,0,z h1 ), obtain the distance x from the leak source h1 The lifting height z at that time h1 ;

[0098] S3: Move the gas concentration monitoring probe horizontally to x in sequence. h2 ,...,x hn Repeat step S2 to obtain the rise height z at different leak source distances. h2 ,...,z hn ;

[0099] S4: Based on the distances to different leakage sources and their corresponding rise heights, a rise height fitting function is used to obtain the relationship between the rise height and the distance to the leakage source; the rise height fitting function is:

[0100] ΔH=m-ns x (2)

[0101] In the formula: m, n, and s are all fitting parameters; x is the distance from the leakage source in the X direction.

[0102] S5: The lifting height can be calculated based on the relationship between the lifting height and the distance to the leakage source, combined with the distance to the gas leakage source.

[0103] In one specific embodiment, the lateral diffusion coefficient and the vertical diffusion coefficient are calculated through the following steps:

[0104] S1': Prepare for a gas diffusion simulation experiment, using the flow meter outlet of the gas venting system as the origin of the coordinate system, i.e., the height H of the leakage source. s =0;

[0105] S2': A gas diffusion simulation experiment was conducted with a stable wind speed and a stable gas leakage rate. The probe position was moved by connecting rod 1 (901), connecting rod 2 (902), and connecting rod 3 (903) to monitor the gas concentration data at distances from the leakage source (x1,0,z1), (x1,y2,z1), (x2,0,z2), and (x2,y4,z2), which were recorded as C1, C2, C3, and C4, respectively.

[0106] S3': The lateral diffusion coefficient and the vertical diffusion coefficient are expressed by the lateral diffusion coefficient fitting formula shown in formula (3) and the vertical diffusion coefficient fitting formula shown in formula (4), respectively. The lateral diffusion coefficient fitting formula and the vertical diffusion coefficient fitting formula are substituted into the Gaussian diffusion model to obtain the concentration calculation formulas of C1, C2, C3 and C4.

[0107] σ y =ax b (3)

[0108] σ z =cx d (4)

[0109] In the formula: a and b are the fitting parameters for the lateral diffusion coefficient; x is the distance from the leakage source in the X direction; c and d are the fitting parameters for the vertical diffusion coefficient.

[0110] The formulas for calculating the concentrations of C1 and C2 are as follows:

[0111]

[0112]

[0113] S4': The lateral diffusion coefficient fitting parameter in the lateral diffusion coefficient fitting formula is calculated according to the concentration ratio formula. The concentration ratio formula is the ratio of two concentrations under the same horizontal position and the same height conditions. The concentration ratio formula is specifically as follows:

[0114]

[0115]

[0116] The specific fitting parameters for the lateral diffusion coefficient are:

[0117]

[0118]

[0119] S5': Substitute the lateral diffusion coefficient fitting parameters into the lateral diffusion coefficient fitting formula, and calculate the lateral diffusion coefficient based on the lateral diffusion coefficient fitting formula after substituting the lateral diffusion coefficient fitting parameters, combined with the distance of the gas leakage source.

[0120] S6': Substitute the lateral diffusion coefficient fitting formula after substituting the lateral diffusion coefficient fitting parameters into the concentration calculation formulas of C1 and C2, and solve to obtain the vertical diffusion coefficient fitting parameters of the vertical diffusion coefficient fitting formula.

[0121] S7': Substitute the vertical diffusion coefficient fitting parameters into the vertical diffusion coefficient fitting formula, and calculate the vertical diffusion coefficient based on the vertical diffusion coefficient fitting formula after substituting the vertical diffusion coefficient fitting parameters, combined with the distance to the gas leakage source.

[0122] In a specific embodiment, taking a wind speed of 0.5 m / s and a leakage rate of 0.0023 g / s as an example, the gas diffusion simulation device described in this invention is used to experimentally test the diffusion concentration of natural gas, and the coefficients of the Gaussian diffusion model are calculated accordingly. In this embodiment, the rise height results obtained in step S3 at different leakage source distances are shown in Table 1:

[0123] Table 1. Lifting height at different leak source distances

[0124]

[0125]

[0126] Based on the experimental results in Table 1, and combined with the lifting height fitting function shown in formula (2), a lifting height fitting formula with a goodness of fit greater than 0.99 is obtained:

[0127] ΔH=0.04782-0.04661×0.25139 x (11)

[0128] The elevation height at any x can be obtained according to equation (11).

[0129] Based on the obtained elevation height, the experiment continued, measuring the natural gas concentration data at distances from the leakage source (x1,0,z1), (x1,y2,z1), (x2,0,z2), and (x2,y4,z2) in the downstream space of diffusion. These data were denoted as C1, C2, C3, and C4, respectively. The results are shown in Table 2.

[0130] Table 2 Natural gas concentration at different leak source distances

[0131] Serial Number x, m y, m z,m <![CDATA[C,g / m 3 ]]> 1 0.2 0 0.21 0.4060 2 0.2 0.05 0.21 0.0018 3 0.507 0 0.205 0.1113 4 0.507 0.05 0.205 0.0347

[0132] Based on the experimental results in Table 2, substituting them into equations (9) and (10) yields the lateral diffusion coefficient fitting parameters a = 0.06 and b = 0.852. Using these fitting parameters and equation (3), the lateral diffusion coefficient can then be obtained.

[0133] σ y =0.060x 0.852 (12)

[0134] Based on the experimental results in Table 2 and the results of the lateral diffusion coefficient, substituting them into equations (5) and (6) yields the vertical diffusion coefficient fitting parameters c = 0.051 and d = 0.637. Based on these vertical diffusion coefficient fitting parameters, combined with equation (4), the vertical diffusion coefficient can be obtained:

[0135] σ z =0.051x 0.637 (13)

[0136] In summary, the Gaussian diffusion equation for natural gas under the conditions of wind speed of 0.5 m / s and leakage rate of 0.0023 g / s can be obtained as follows:

[0137]

[0138] The lifting height ΔH is:

[0139] ΔH=0.04782-0.04661×0.25139 x (15)

[0140] Under the same wind speed and leakage rate conditions, the Gaussian diffusion equation for natural gas obtained using existing technology is used as a comparative example of this invention. It should be noted that in this comparative example, GB / T 3840-91 "Technical Methods for Formulating Local Air Pollutant Emission Standards" is referenced, primarily applicable to air pollutants such as flue gas and particulate matter. Since the lift height calculation formula in the standard is based on the heat release rate and is designed for high-temperature flue gas, while the leakage temperature of natural gas is essentially the same as the atmospheric temperature, the lift height calculation formula in the standard is not applicable to natural gas. Therefore, the lift height in this comparative example is calculated using the lift height calculation formula proposed in this invention.

[0141] The experimental wind speed was 0.5 m / s, and there was no direct sunlight. The atmospheric stability was found to be F from the table. Therefore, the corresponding lateral and longitudinal diffusion coefficients are:

[0142] σ y =0.055x 0.929 (16)

[0143] σ z =0.062x 0.784 (17)

[0144] Under conditions of wind speed of 0.5 m / s and leakage rate of 0.0023 g / s, the existing Gaussian diffusion equation for natural gas is as follows:

[0145]

[0146] Taking the natural diffusion at four different leakage source distances in Table 2 as examples, the natural gas diffusion concentration was calculated using the natural gas Gaussian diffusion equation obtained in this invention and the Gaussian diffusion equation obtained by existing technology, respectively. The results are shown in Table 3:

[0147] Table 3 Comparison of Natural Gas Diffusion Concentration

[0148]

[0149] As can be seen from Table 3, the calculation results of this invention are closer to the measured values ​​of natural gas diffusion concentration, and the accuracy is significantly improved compared to existing technologies. It is worth noting that although this invention calculates the diffusion coefficient based on the tested natural gas diffusion concentration, the final calculation results will inevitably contain deviations due to data rounding and inherent errors in the rise height during the calculation process.

[0150] In summary, the simulation device of this invention utilizes a small number of movable natural gas concentration probes to capture natural gas clouds, thus avoiding the influence of physical factors such as a large number of probes and data cables on the diffusion field of natural gas, which could affect the experimental results. Furthermore, the concentration distribution at different locations downstream of the natural gas leak diffusion can be obtained based on the natural gas concentration probes. Based on specific diffusion experimental data under specific wind speed and leakage rate conditions, and combined with coefficient fitting formulas, the calculation formula for the Gaussian diffusion model coefficients under specific conditions is derived, thereby obtaining a more accurate Gaussian model for natural gas diffusion under specific conditions, with an average accuracy of 69.3%, representing a significant improvement compared to existing technologies.

[0151] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0152] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the disclosed technical content. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

Claims

1. A method for testing the lift height in the Gaussian diffusion equation based on a gas diffusion simulation device, characterized in that, The gas diffusion simulation device includes a wind field system, a gas release system, and a concentration monitoring system; The wind field system is used to provide a wind field with stable wind speed to the concentration monitoring system; the gas venting system is used to provide gas with stable flow rate to the concentration monitoring system; the output end of the wind field system and the output end of the gas venting system are located on the same side of the concentration monitoring system. The concentration monitoring system includes a test frame (9), an anemometer (8), and a gas concentration acquisition module (10). The internal structure of the test frame (9) is a diffusion space for gas diffusion. The anemometer (8) is set at the air inlet of the test frame (9) for real-time wind speed acquisition. The gas concentration acquisition module (10) is set in the diffusion space of the test frame (9) through a sliding mechanism. The gas concentration acquisition module (10) is used to acquire gas concentration in real time. The sliding mechanism enables the gas concentration acquisition module (10) to move in the diffusion space along the X, Y, and Z directions. Includes the following steps: S1: Prepare for a gas diffusion simulation experiment: Use the flow meter outlet of the gas venting system as the origin of the coordinate system, i.e., the height of the leakage source. H s =0, the sliding mechanism makes the initial coordinates of the gas concentration acquisition module (10) ( x ,0, z ); S2: Gas diffusion simulation experiment with stable wind speed and stable gas leakage: The gas concentration acquisition module (10) is moved up and down in the Z direction. When the monitored gas concentration value reaches the maximum, the coordinates of the gas concentration acquisition module (10) at this time are recorded. x h1 ,0, z h1 ), to obtain the distance to the leak source x h1 Lifting height at time z h1 ; S3: Move the gas concentration acquisition module (10) sequentially in the X direction to x h2 ,..., x hn Repeat step S2 to obtain the rise height at different leak source distances. z h2 ,..., z hn ; S4: Based on the different leak source distances and their corresponding rise heights, and combined with the rise height fitting function, the relationship between the rise height and the leak source distance is obtained; S5: The rise height can be calculated based on the relationship between the rise height and the distance to the leak source, combined with the distance to the gas leak source.

2. The method for testing the lift height in the Gaussian diffusion equation based on a gas diffusion simulation device according to claim 1, characterized in that, The sliding mechanism includes connecting rod one (901), connecting rod two (902) and connecting rod three (903); The first connecting rod (901) is slidably disposed on the test frame (9), and the first connecting rod (901) can move up and down in the Z direction; The second connecting rod (902) is slidably disposed on the first connecting rod (901), and the second connecting rod (902) can move left and right in the X direction; The third connecting rod (903) is slidably disposed on the second connecting rod (902), and the third connecting rod (903) can move back and forth in the Y direction; The gas concentration acquisition module (10) is installed on the connecting rod three (903).

3. The method for testing the lift height in the Gaussian diffusion equation based on a gas diffusion simulation device according to claim 2, characterized in that, The sliding mechanism includes two symmetrically arranged connecting rods 1 (901), with both ends of the connecting rods 1 (901) slidably disposed on the test frame (9); two connecting rods 2 (902) are symmetrically arranged between the two connecting rods 1 (901), with both ends of the connecting rods 2 (902) slidably disposed on the two connecting rods 1 (901); two connecting rods 3 (903) are symmetrically arranged between the two connecting rods 2 (902), with both ends of the connecting rods 3 (903) slidably disposed on the two connecting rods 2 (902).

4. The method for testing the lift height in the Gaussian diffusion equation based on a gas diffusion simulation device according to claim 2, characterized in that, The sliding settings can be achieved through a combination of a slide rail and a slider, or by using a reciprocating linear motor.

5. The method for testing the lift height in the Gaussian diffusion equation based on a gas diffusion simulation device according to claim 2, characterized in that, Distance scales are provided on the test frame (9), connecting rod one (901), connecting rod two (902) and connecting rod three (903).

6. The method for testing the lift height in the Gaussian diffusion equation based on a gas diffusion simulation device according to claim 1, characterized in that, The sliding mechanism is provided in at least two sets.

7. The method for testing the lift height in the Gaussian diffusion equation based on a gas diffusion simulation device according to any one of claims 1-6, characterized in that, The gas concentration acquisition module (10) includes a natural gas concentration monitoring probe and a natural gas concentration sensor.

8. The method for testing the lift height in the Gaussian diffusion equation based on a gas diffusion simulation device according to any one of claims 1-6, characterized in that, The wind farm system includes a speed controller (5), a fan (6), and an airflow stabilization mechanism (7). The speed regulator (5) is connected to the fan (6), the air outlet of the fan (6) is connected to the air inlet of the airflow stabilizing mechanism (7), and the air outlet of the airflow stabilizing mechanism (7) is located close to the test frame (9). The airflow stabilization mechanism (7) is used to stabilize the vortex flow blown out by the fan (6) into a laminar airflow field similar to the atmosphere.

9. The method for testing the lift height in the Gaussian diffusion equation based on a gas diffusion simulation device according to claim 8, characterized in that, The airflow stabilization mechanism (7) includes a honeycomb flow stabilization tube or a corrugated tube.

10. The method for testing the lift height in the Gaussian diffusion equation based on a gas diffusion simulation device according to any one of claims 1-6, characterized in that, The gas venting system includes a gas storage cylinder (1) and a flow meter (4); The gas storage cylinder (1) supplies gas to the diffusion space within the test frame (9) through a pipeline, and the flow meter (4) is installed on the pipeline.

11. The method for testing the lift height in the Gaussian diffusion equation based on a gas diffusion simulation device according to claim 10, characterized in that, A pressure reducing valve (2) and a regulating valve (3) are installed at the front end of the flow meter (4) on the pipeline used to supply gas.

12. The method for testing the lift height in the Gaussian diffusion equation based on a gas diffusion simulation device according to any one of claims 1-6, characterized in that, The concentration monitoring system also includes a data storage unit electrically connected to the anemometer (8) and the gas concentration acquisition module (10).

13. A method for testing the diffusion coefficient in a Gaussian diffusion model using the gas diffusion simulation apparatus according to claim 1, characterized in that, Includes the following steps: S1': Preparing for a gas diffusion simulation experiment: using the flow meter outlet of the gas venting system as the origin of the coordinate system, i.e., the height of the leakage source. H s =0; S2': A gas diffusion simulation experiment was conducted with a stable wind speed and a stable gas leakage rate. The position of the gas concentration acquisition module (10) was moved by a sliding mechanism to monitor the distance from the leakage source. x 1 ,0, z 1 ), ( x 1 , y 2 , z 1 ), ( x 2 ,0, z 2 )as well as( x 2 , y 4 , z 2 The gas concentration data at point () are denoted as follows: C 1 , C 2 , C 3 , C 4 ; S3': The diffusion coefficient includes lateral and vertical diffusion coefficients, expressed by lateral diffusion coefficient fitting formulas and vertical diffusion coefficient fitting formulas, respectively. Substituting these formulas into the Gaussian diffusion model yields the desired result. C 1 , C 2 , C 3 , C 4 The formula for calculating concentration; S4': The lateral diffusion coefficient fitting parameter in the lateral diffusion coefficient fitting formula is calculated according to the concentration ratio formula, wherein the concentration ratio formula is the ratio of two concentrations under the same horizontal position and the same height conditions; S5': Substitute the lateral diffusion coefficient fitting parameters into the lateral diffusion coefficient fitting formula, and calculate the lateral diffusion coefficient based on the lateral diffusion coefficient fitting formula after substituting the lateral diffusion coefficient fitting parameters, combined with the distance of the gas leakage source. S6': Substitute the lateral diffusion coefficient fitting formula after substituting the lateral diffusion coefficient fitting parameters into... C 1 and C 2 In the concentration calculation formula, the vertical diffusion coefficient fitting parameters of the vertical diffusion coefficient fitting formula are obtained by solving; S7': Substitute the vertical diffusion coefficient fitting parameters into the vertical diffusion coefficient fitting formula. Based on the vertical diffusion coefficient fitting formula after substituting the vertical diffusion coefficient fitting parameters, and combined with the distance of the gas leakage source, the vertical diffusion coefficient can be calculated.

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