Calculation Method and System for Overpressure of Blast Wave in Natural Gas Pipeline

Abstract

The present invention provides a method and system for calculating the overpressure of blast shock waves in natural gas pipelines, belonging to the technical field of natural gas safety. The method for calculating the overpressure of blast shock waves in natural gas pipelines according to the embodiments of the present invention optimizes the calculation method of the overpressure of blast shock waves in natural gas pipelines. For the coupling of numerical simulation and physical models and multiple parameter corrections, through refined CFD modeling and comparative analysis, the overpressure spatio-temporal evolution data that conforms to the actual situation is finally obtained, and then more accurate coupled overpressure data is obtained. It has strong practicability and can be widely applied to the safety assessment and protection design of natural gas pipelines to improve the protection efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas safety, and particularly to a method and system for calculating the overpressure of explosion shock waves in natural gas pipelines. Background Art

[0002] As a key infrastructure for energy transportation, the safe operation of natural gas pipelines is crucial for industrial production and people's livelihood. However, due to material aging, construction defects, corrosion, or external impacts such as mechanical excavation and earthquakes, pipelines may rupture or leak. When high-pressure natural gas is instantaneously released, two main types of explosions may occur. One is a physical explosion (PE), and the other is a vapor cloud explosion (VCE).

[0003] A physical explosion generates shock waves due to the rapid expansion of high-pressure gas in the pipeline, and its energy mainly depends on the initial pressure, volume, and release rate of the gas. A vapor cloud explosion occurs when the leaked natural gas mixes with air to form a combustible cloud, and after encountering an ignition source, it undergoes intense combustion (deflagration or detonation), and the released chemical energy is converted into shock wave overpressure. Overpressure is the core damage parameter of explosion shock waves, usually measured in kilopascals (kPa), and its hazards include direct damage, secondary disasters, and environmental risks.

[0004] Existing overpressure calculation techniques mainly rely on empirical models and numerical simulations, but there are still significant defects. For example, the overpressures of physical explosions and vapor cloud explosions are simply superimposed. Although the conservative superposition method improves safety, it overestimates the overpressure value, resulting in redundant protection designs and increased engineering costs. Summary of the Invention

[0005] The present invention provides a method and system for calculating the overpressure of explosion shock waves in natural gas pipelines to solve the defect of inaccurate overpressure calculation in the prior art and achieve the effect of improving the accuracy of overpressure calculation data.

[0006] The present invention provides a method for calculating the overpressure of explosion shock waves in natural gas pipelines, including:

[0007] Based on the pipeline leakage data, determine the initial physical explosion overpressure data, and based on the initial physical explosion overpressure data, determine the initial vapor cloud explosion overpressure data;

[0008] Based on the peak overpressures of the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data at different positions, determine that the absolute value of the difference in peak overpressures between the physical explosion and the vapor cloud explosion at the same position is greater than a first threshold;

[0009] Based on the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data, the physical explosion and vapor cloud explosion processes are dynamically coupled through a computational fluid dynamics (CFD) model to generate initial overpressure spatio-temporal evolution data;

[0010] Based on the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data, determine the parameters to be corrected for the dynamic coupling of the physical explosion and vapor cloud explosion processes in the CFD model;

[0011] Correct the parameters to be corrected for the dynamic coupling of the physical explosion and vapor cloud explosion processes in the CFD model, and analyze the overpressure spatio-temporal evolution data output by the corrected CFD model with the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data until the overpressure data in the final target overpressure spatio-temporal evolution data output by the CFD model matches the overpressure data obtained from the experimental simulation.

[0012] According to a method for calculating the overpressure of the explosion shock wave of a natural gas pipeline provided by the present invention, the determining of the parameters to be corrected for the dynamic coupling of the physical explosion and vapor cloud explosion processes in the CFD model based on the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data includes:

[0013] Based on typical points in the spatial grid, extract the overpressure spatio-temporal data based on the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data respectively; the typical points are the points that spread away from the explosion center point centered on the explosion center point;

[0014] Determine the deviation values between the peak overpressures in the overpressure spatio-temporal data of the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data at different typical point positions;

[0015] Determine the deviation characteristics corresponding to the deviation values of the typical points with deviation values greater than the second threshold, and the deviation characteristics include at least one of spatial characteristics, time characteristics, coupling characteristics, and obstacle characteristics;

[0016] Determine the parameters to be corrected based on the deviation characteristics.

[0017] According to a method for calculating the overpressure of the explosion shock wave of a natural gas pipeline provided by the present invention, when the deviation characteristics include spatial characteristics, the determining of the parameters to be corrected based on the deviation characteristics includes:

[0018] Determine that the spatial characteristic is that the deviation is concentrated in the area near the explosion center;

[0019] Determine that the parameter to be corrected is the initial explosion energy parameter.

[0020] According to a method for calculating the overpressure of an explosion shock wave in a natural gas pipeline provided by the present invention, the deviation characteristics include spatial characteristics, and determining the parameter to be corrected based on the deviation characteristics includes:

[0021] Determine that the spatial characteristic is that the deviation is concentrated in the area far from the explosion center;

[0022] Determine that the parameter to be corrected is the gas diffusion coefficient or the shock wave propagation parameter.

[0023] According to a method for calculating the overpressure of an explosion shock wave in a natural gas pipeline provided by the present invention, the deviation characteristics include temporal characteristics, and determining the parameter to be corrected based on the deviation characteristics includes:

[0024] Determine that the temporal characteristic is that the deviation is concentrated on the evolution rate of the overpressure with time;

[0025] Determine that the parameter to be corrected is the explosion reaction rate constant or the turbulent mixing time.

[0026] According to a method for calculating the overpressure of an explosion shock wave in a natural gas pipeline provided by the present invention, the deviation characteristics include coupling characteristics, and determining the parameter to be corrected based on the deviation characteristics includes:

[0027] Determine that the coupling characteristic is that the difference between the peak overpressures of the physical explosion and the vapor cloud explosion is greater than a third threshold;

[0028] Determine that the parameter to be corrected is the delay time for the physical explosion to trigger the vapor cloud explosion.

[0029] According to a method for calculating the overpressure of an explosion shock wave in a natural gas pipeline provided by the present invention, the deviation characteristics include obstacle characteristics, and determining the parameter to be corrected based on the deviation characteristics includes:

[0030] Determine that the obstacle characteristic is that the overpressure deviation in the obstacle area is greater than a fourth threshold;

[0031] Determine that the parameter to be corrected is the obstacle turbulence parameter.

[0032] The present invention also provides a device for calculating the overpressure of an explosion shock wave in a natural gas pipeline, including:

[0033] A first processing module, configured to determine initial physical explosion overpressure data based on pipeline leakage data, and determine initial vapor cloud explosion overpressure data based on the initial physical explosion overpressure data;

[0034] A second processing module, configured to determine that the absolute value of the difference in peak overpressure between a physical explosion and a vapor cloud explosion at the same location is greater than a first threshold based on the peak overpressures of the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data at different locations;

[0035] A third processing module, configured to generate initial overpressure spatio-temporal evolution data by dynamically coupling the physical explosion and vapor cloud explosion processes through a computational fluid dynamics (CFD) model based on the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data;

[0036] A fourth processing module, configured to determine parameters to be corrected for the dynamic coupling of the physical explosion and vapor cloud explosion processes in the CFD model based on the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data;

[0037] A fifth processing module, configured to correct the parameters to be corrected for the dynamic coupling of the physical explosion and vapor cloud explosion processes in the CFD model, and analyze the overpressure spatio-temporal evolution data output by the corrected CFD model with the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data until the overpressure data in the finally obtained target overpressure spatio-temporal evolution data matches the overpressure data obtained from the experimental simulation.

[0038] The present invention further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the natural gas pipeline explosion shock wave overpressure calculation method as described in any one of the above is implemented.

[0039] The present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the natural gas pipeline explosion shock wave overpressure calculation method as described in any one of the above is implemented.

[0040] The present invention further provides a computer program product, including a computer program. When the computer program is executed by a processor, the natural gas pipeline explosion shock wave overpressure calculation method as described in any one of the above is implemented.

[0041] The natural gas pipeline explosion shock wave overpressure calculation method and system provided by the present invention optimize the calculation method of the natural gas pipeline explosion shock wave overpressure. For the coupling of numerical simulation and physical models and multiple parameter corrections, through refined CFD modeling and comparative analysis, finally, overpressure spatio-temporal evolution data that conforms to the actual situation is obtained, and then more accurate coupled overpressure data is obtained. It has strong practicability and can be widely applied to the safety assessment and protection design of natural gas pipelines to improve the protection efficiency. Description of the Drawings

[0042] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0043] Figure 1 It is one of the schematic flowcharts of the method for calculating the overpressure of the blast wave of a natural gas pipeline provided by the present invention;

[0044] Figure 2 It is the second of the schematic flowcharts of the method for calculating the overpressure of the blast wave of a natural gas pipeline provided by the present invention;

[0045] Figure 3 It is the schematic structural diagram of the system for calculating the overpressure of the blast wave of a natural gas pipeline provided by the present invention;

[0046] Figure 4 It is the schematic structural diagram of the electronic device provided by the present invention. Specific Embodiments

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present invention fall within the scope of protection of the present invention.

[0048] The following will be combined with Figures 1-4 Describe the method and system for calculating the overpressure of the blast wave of a natural gas pipeline of the present invention.

[0049] As Figure 1 shown, a method for calculating the overpressure of the blast wave of a natural gas pipeline according to an embodiment of the present invention mainly includes step 110, step 120, step 130, step 140, and step 150.

[0050] Step 110: Based on the pipeline leakage data, determine the initial physical explosion overpressure data, and based on the initial physical explosion overpressure data, determine the initial vapor cloud explosion overpressure data.

[0051] The basic parameters of pipeline leakage, such as leakage rate, leakage location, pipeline internal pressure, temperature, gas type, etc., can be obtained through monitoring devices or sensors.

[0052] Physical explosion (PE) is triggered by the release of high-pressure gas and involves the expansion process of the gas. The initial physical explosion overpressure can be calculated through the following steps.

[0053] First, determine the initial pressure and volume of the gas. Based on the leakage point and the pressure inside the pipeline, estimate the pressure and volume during gas leakage. On this basis, apply the principles of thermodynamics to calculate the expansion process of high-pressure gas. Commonly used gas expansion models include the ideal gas state equation or the isentropic expansion formula. Based on the gas expansion velocity and release rate, calculate the overpressure of the generated shock wave. Alternatively, an improved TNT equivalent method or empirical formula can also be used to calculate the initial overpressure distribution generated by physical explosion.

[0054] The calculation of the initial vapor cloud explosion overpressure data can be carried out according to the following process. When natural gas leaks and mixes with air, a vapor cloud may form, and a vapor cloud explosion (VCE) occurs after encountering an ignition source. The calculation of its overpressure data needs to consider gas concentration distribution, cloud diffusion, gas combustion rate, etc. The gas concentration distribution can use diffusion equations (such as Fick's law) to simulate the diffusion process of the gas and calculate the gas concentration at different positions. The energy of the cloud explosion can be estimated based on the concentration and volume of the combustible cloud to calculate the combustion energy inside the cloud. The final overpressure value is calculated based on the shock wave pressure converted from the thermal energy of combustion to determine the overpressure of the vapor cloud explosion.

[0055] Step 120: Based on the initial physical explosion overpressure data and the peak overpressure at different positions of the initial vapor cloud explosion overpressure data, determine that the absolute value of the difference in peak overpressure between the physical explosion and the vapor cloud explosion at the same position is greater than the first threshold.

[0056] Extract the peak overpressure at each calculation point from the physically exploded and vapor cloud exploded overpressure data obtained from the preliminary calculation. These peaks can be extracted using numerical simulations or experimental data.

[0057] On this basis, compare the peak overpressures of the physical explosion and the vapor cloud explosion. If at a certain position, the absolute value of the difference in peak overpressure between the two is greater than the set first threshold, it indicates that this position requires further correction. For example, the threshold can be set according to the pipeline type, gas type, and leakage scale.

[0058] Step 130: Based on the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data, dynamically couple the physical explosion and vapor cloud explosion processes through a computational fluid dynamics (CFD) model to generate initial overpressure spatio-temporal evolution data.

[0059] Use CFD software such as ANSYS Fluent, OpenFOAM, etc. to build a coupled model of physical explosion and vapor cloud explosion. The model can include the following parts.

[0060] Gas dynamics: Simulate the injection, expansion, and turbulent processes of the gas.

[0061] Flammable cloud dispersion: Based on factors such as wind speed, gas diffusion coefficient, and obstacles, simulate the dispersion process of the flammable cloud.

[0062] Reaction kinetics: Consider the reaction rate and combustion process after the gas is mixed with air.

[0063] Explosion wave propagation: Simulate the propagation process of the explosion wave and calculate the overpressure at each position.

[0064] Dynamic coupling: In the same CFD model, couple the processes of physical explosion and vapor cloud explosion. Specifically, the gas injection process affects the cloud dispersion, and the cloud dispersion affects the explosion wave propagation. The two are interdependent.

[0065] Spatiotemporal evolution data generation: Through CFD simulation, calculate the spatiotemporal evolution data of the overpressure at different time steps to obtain the distribution and change trend of the initial overpressure.

[0066] The physical explosion stage can use the compressible Euler equations to simulate the high-pressure gas injection process. The vapor cloud explosion stage can simulate the combustion of the flammable cloud based on a combustion model (such as EDC) and a detailed chemical reaction mechanism.

[0067] The flow field data (velocity, concentration, temperature) at the end of the physical explosion can be used as the initial conditions for the vapor cloud explosion, and by solving the Navier-Stokes equations, generate the spatiotemporal evolution data of the overpressure.

[0068] The initial spatiotemporal evolution data of the overpressure includes the overpressure distribution and time series of the coupled physical explosion and vapor cloud explosion.

[0069] A fine grid can be established in the computational domain, especially using a higher grid resolution in the explosion center and the vapor cloud distribution area to ensure that the pressure wave and combustion process can be accurately captured.

[0070] Furthermore, set reasonable boundary conditions for the computational domain, such as no-slip conditions, open boundary conditions, or periodic boundary conditions. Couple the initial pressure and temperature fields of the physical explosion with the initial fuel concentration field and ignition conditions of the vapor cloud explosion to construct a complete initial field.

[0071] The coupling of the physical explosion and the vapor cloud explosion is the key to this simulation, and the mutual influence of the two needs to be considered simultaneously. The coupling process includes the coupling of explosion wave propagation and combustion reaction, multiphase fluid interaction, time step coupling, etc.

[0072] Coupled Simulation of Blast Wave Propagation and Combustion Reaction How the shock wave generated by a physical explosion propagates in space and triggers a vapor cloud explosion. The combustion reaction of the vapor cloud explosion further enhances the shock wave, resulting in the superposition effect of the pressure wave. If the vapor cloud contains droplets or solid particles, it is also necessary to simulate the momentum, energy, and mass exchange between the multiphase fluids. Since the explosion process is extremely violent, the time step needs to be small enough to capture the rapid propagation of the pressure wave. The adaptive time step technique can be used to dynamically adjust the time step when the intensity of the pressure wave changes drastically.

[0073] After completing the CFD calculation, the overpressure spatio-temporal evolution data can be extracted from the simulation results. At typical point positions within the computational domain, record the change in pressure over time to generate a pressure-time curve. Extract the pressure data at all grid nodes to construct a complete overpressure spatio-temporal distribution. Record the pressure peak at each grid node and its corresponding time to analyze the propagation process of the overpressure wave.

[0074] The final simulation result is the complete initial overpressure spatio-temporal evolution data, which includes at least the spatial distribution, temporal distribution, and kinetic characteristics.

[0075] The spatial distribution is the change in pressure with space (3D distribution map). The temporal distribution is the change in pressure over time (time series data). The kinetic characteristics include the shock wave velocity, the propagation velocity of the combustion front of the vapor cloud, etc. These data can be used for further analysis of the explosion impact area and evaluation of computational characteristics such as the accuracy of parameters.

[0076] Step 140, based on the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data, determine the parameters to be corrected for the dynamic coupling of the physical explosion and vapor cloud explosion processes in the CFD model.

[0077] Compare the spatio-temporal evolution data obtained from the initial calculation with the peak overpressure data of the physical explosion and vapor cloud explosion to identify which parameters need to be corrected. For example, parameters related to gas leakage rate, diffusion coefficient, combustion model, and turbulence effect.

[0078] If the estimated leakage rate is too high or too low, it will affect the calculation of the initial overpressure. The accuracy of the gas diffusion process directly affects the formation of the combustible cloud and the calculation of the overpressure. Parameters such as reaction rate, ignition condition, and temperature may need to be adjusted to better fit the actual overpressure data.

[0079] In addition, the role of the turbulence effect caused by obstacles in overpressure formation needs to be further adjusted through the turbulence model.

[0080] For the parameters that need to be corrected, adjust the corresponding settings in the CFD model, such as correcting the leakage rate, diffusion model, turbulence model, etc.

[0081] Step 150: Modify the parameters to be corrected for the dynamic coupling of the physical explosion and vapor cloud explosion processes in the CFD model, and analyze the overpressure spatio-temporal evolution data output by the modified CFD model with the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data until the overpressure data in the final target overpressure spatio-temporal evolution data output by the CFD model matches the overpressure data obtained from the experimental simulation.

[0082] According to the parameters to be corrected determined in the previous step, correct the CFD model and re-run it. This process is an iterative process, which specifically includes the following steps.

[0083] First, the model parameters can be adjusted according to the preliminary results and the CFD simulation can be re-run. Compare the corrected overpressure data with the overpressure data obtained from the experimental simulation to evaluate the matching degree of the peak overpressure. If the gap is still large, continue to correct the parameters and re-conduct the numerical simulation until the corrected overpressure data matches the overpressure data obtained from the experimental simulation.

[0084] Matching can mean that the difference between the key features such as the peak overpressure in the output data of the corrected CFD model and the peak overpressure obtained from the experimental simulation is reduced to an acceptable range.

[0085] According to the method for calculating the overpressure of the blast wave of a natural gas pipeline provided by the embodiment of the present invention, by optimizing the method for calculating the overpressure of the blast wave of a natural gas pipeline, for the coupling of numerical simulation and physical model and multiple parameter corrections, through refined CFD modeling and comparative analysis, the overpressure spatio-temporal evolution data that conforms to the actual situation is finally obtained, and then more accurate coupled overpressure data is obtained, which has strong practicability and can be widely applied to the safety assessment and protection design of natural gas pipelines to improve the protection efficiency.

[0086] In some embodiments, as Figure 2 shown, determining the parameters to be corrected for the dynamic coupling of the physical explosion and vapor cloud explosion processes in the CFD model based on the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data includes Step 210, Step 220, Step 230, and Step 240.

[0087] Step 210: Based on the typical points in the spatial grid, extract the overpressure spatio-temporal data based on the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data respectively.

[0088] Step 220: Determine the deviation values between the peak overpressures in the overpressure spatio-temporal data of the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data at different typical point positions.

[0089] Step 230, determine the deviation characteristics corresponding to the deviation values of the typical points whose deviation values are greater than the second threshold.

[0090] Step 240, determine the parameter to be corrected based on the deviation characteristics.

[0091] The typical points are the points that spread away from the explosion center point centered on the explosion center point. The deviation characteristics include at least one of spatial characteristics, temporal characteristics, coupling characteristics, and obstacle characteristics.

[0092] In a CFD (Computational Fluid Dynamics) model, the simulation region is divided into multiple small units or grids, and each grid corresponds to a spatial position. These grids are used for numerical calculations to simulate physical phenomena such as gas flow and temperature change.

[0093] Typical points refer to some representative positions selected within the simulation region, and these positions can reflect important characteristics during the explosion process, such as the explosion center, adjacent high overpressure regions, near obstacles, etc.

[0094] In a CFD simulation, first, the simulation region needs to be divided into multiple grid cells. These grids can be divided by the finite element method or other numerical methods.

[0095] Through simulation calculations, a series of overpressure data will be generated for each grid point (especially the selected typical points), and these data contain the overpressure values of each point at different times.

[0096] It is necessary to extract the overpressure data of these typical points from the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data. By extracting the overpressure spatio-temporal data, it can help analyze different stages of the explosion event and its impact on the surrounding environment.

[0097] Peak overpressure refers to the maximum value in the overpressure data during the explosion process, which usually represents the most intense impact of the explosion.

[0098] The deviation value refers to the deviation value between the peak overpressures in the overpressure spatio-temporal data of the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data at different typical point positions.

[0099] Compare the peak overpressures at different typical point positions. By comparing the peak overpressures extracted from the initial overpressure spatio-temporal evolution data, physical explosion data, and vapor cloud explosion data, the differences between them can be found.

[0100] Calculate the overpressure difference at each typical point location to obtain the deviation value for each point. Compare the deviations between the peaks of different types of overpressure data (physical explosion overpressure, vapor cloud explosion overpressure, overpressure spatio-temporal evolution data).

[0101] Since the overpressure peaks in the directly calculated initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data have strong reference value, by calculating the deviation values between the initial overpressure spatio-temporal evolution data and them, the differences between different simulation data and actual data can be quantified, and further provide a basis for subsequent correction of the CFD model, identifying which regions or parameters need to be adjusted to improve the simulation accuracy.

[0102] The second threshold refers to a preset deviation threshold. If the deviation value of a certain typical point exceeds this threshold, it indicates that there is a large deviation in the overpressure data of this point.

[0103] Deviation characteristics refer to the characteristics related to the deviation value, such as spatial characteristics (influence in position), temporal characteristics (trend of deviation changing with time), coupling characteristics (mutual influence between physical explosion and vapor cloud explosion), and obstacle characteristics (whether obstacles affect the overpressure distribution).

[0104] Extract the points whose deviation values exceed the second threshold through the calculated deviation values. The deviation values of these points are relatively large, which may represent significant differences between the CFD simulation results and the actual situation. Conduct a detailed analysis of these typical points to identify their deviation characteristics.

[0105] Spatial characteristics indicate whether the deviation is concentrated in certain specific spatial regions, such as near the explosion center or specific obstacle positions.

[0106] Temporal characteristics indicate whether the deviation gradually increases or decreases with time, especially the difference in the occurrence time of the overpressure peak in the simulation and the actual situation.

[0107] Coupling characteristics indicate the coupling situation of the physical explosion and vapor cloud explosion processes, whether the interaction between the two affects the overpressure distribution.

[0108] Obstacle characteristics indicate whether the obstacle changes the propagation path of the explosion shock wave, resulting in uneven overpressure distribution.

[0109] In this embodiment, by analyzing the deviation characteristics, we can understand more deeply why the deviations of certain points are large, and further provide important clues for correcting the CFD model. This process can ensure that the CFD model more accurately reflects the actual situation, especially by considering the influences of space, time, coupling, and obstacles.

[0110] In some embodiments, the deviation feature includes a spatial feature, and determining the parameter to be corrected based on the deviation feature includes: determining that the spatial feature is that the deviation is concentrated in a region near the explosion center; determining that the parameter to be corrected is the initial explosion energy parameter.

[0111] If the simulation results show that the deviation of the pressure value is large near the explosion center, it means that the simulation of the release of explosion energy, wave propagation, or other physical phenomena at this position is inaccurate.

[0112] The parameter to be corrected refers to the parameter that needs to be adjusted in the model. In this case, the parameter to be corrected is the initial explosion energy parameter. The initial explosion energy parameter determines the energy intensity of the explosion or the release rate of the explosion source, which has an important impact on the simulation results.

[0113] The initial explosion energy parameter refers to the parameter used in the CFD model to simulate the energy release in the initial stage of the explosion. This parameter affects the intensity of the pressure wave and shock wave generated by the explosion, as well as the spatio-temporal evolution of the pressure field. The larger the energy parameter, the greater the pressure generated by the explosion, and vice versa.

[0114] In some implementation manners, the deviation feature includes a spatial feature, and determining the parameter to be corrected based on the deviation feature includes: determining that the spatial feature is that the deviation is concentrated in a region far from the explosion center; determining that the parameter to be corrected is the gas diffusion coefficient or the shock wave propagation parameter.

[0115] If the simulation results show that there are large deviations in places far from the explosion center, it indicates that the simulation of the model in the region far from the explosion source is inaccurate.

[0116] The gas diffusion coefficient is a parameter that describes the diffusion speed of gas in the air. The larger the gas diffusion coefficient, the faster the gas propagates; conversely, the slower the gas diffuses.

[0117] In an explosion event, the speed of gas diffusion affects the diffusion of the vapor cloud and the mixing degree of the explosion gas with the surrounding air, and thus affects the overpressure distribution after the explosion.

[0118] If the deviation appears in the region far from the explosion center, it may be because the simulation of gas diffusion is inaccurate, resulting in a pressure field generated by the gas cloud during long-distance diffusion that does not match the actual situation.

[0119] The shock wave propagation parameter is related to the propagation speed, intensity, and diffusion of the shock wave generated by the explosion. The shock wave propagation parameter affects the intensity, speed, and propagation path of the shock wave in the air.

[0120] When simulating the explosion process, the propagation speed and intensity of the shock wave will determine the distribution of the overpressure wave. If the deviation appears in the area far from the explosion center, it may be because the simulation of the propagation speed or path of the shock wave is inaccurate, resulting in the mismatch between the overpressure in the far - distance area and the actual situation.

[0121] In other words, if the deviation is large in the far - distance area, it may be because the gas diffusion is insufficient, resulting in the mismatch between the gas distribution after the explosion and the actual situation. By adjusting the gas diffusion coefficient, the model can better simulate the gas diffusion process in space, especially in the place far from the explosion source. If there is a large deviation in the area far from the explosion center, it may be due to the inaccurate setting of some parameters during the propagation of the shock wave. Adjusting the propagation speed, propagation intensity or other propagation characteristics of the shock wave can more accurately simulate the propagation of the explosion wave and reduce the deviation in the area far from the explosion center.

[0122] Simply put, if the deviation appears in the area far from the explosion source, it indicates that the model has deficiencies in simulating gas diffusion and shock - wave propagation. Therefore, the parameters to be corrected required to correct these deviations are the parameters related to gas diffusion and shock - wave propagation, such as the gas diffusion coefficient and shock - wave propagation parameters. By adjusting these parameters, the CFD model can more accurately simulate the pressure field far from the explosion center, thereby improving the accuracy of the simulation.

[0123] In some embodiments, the deviation feature includes a time feature, and determining the parameter to be corrected based on the deviation feature includes: determining that the time feature is that the deviation is concentrated on the evolution rate of the overpressure over time; determining that the parameter to be corrected is the explosion reaction rate constant or the turbulent mixing time.

[0124] The time feature refers to the change of the overpressure over time, especially the change rate of the overpressure. For example, if the overpressure changes too fast or too slow, it will affect the real - time simulation results of the explosion. Based on the deviation of the time feature, it can be determined that the model parameters to be adjusted are the explosion reaction rate constant or the turbulent mixing time.

[0125] The explosion reaction rate constant determines the speed of the reaction during the explosion process. If the rate of change of the overpressure over time does not meet the expectation, it may be because the reaction rate constant is set inappropriately and needs to be corrected. The turbulent mixing time describes the mixing speed of gas and substances in the explosion and affects the rate of gas diffusion. If there is a deviation in the rate of change of the overpressure over time, it may be because the setting of the mixing time is inaccurate and needs to be adjusted.

[0126] It can be understood that by analyzing the time - evolution rate of the overpressure, it can be judged whether it is necessary to adjust the explosion reaction rate constant or the turbulent mixing time to more accurately simulate the change of the overpressure over time.

[0127] In some embodiments, the deviation feature includes a coupling feature, and determining the parameter to be corrected based on the deviation feature includes: determining that the coupling feature is that the difference between the peak overpressures of a physical explosion and a vapor cloud explosion is greater than a third threshold; determining that the parameter to be corrected is the delay time for the physical explosion to trigger the vapor cloud explosion.

[0128] The coupling feature refers to the interaction characteristics between a physical explosion and a vapor cloud explosion. In actual situations, a physical explosion may trigger a vapor cloud explosion, and there is a certain time delay between the two.

[0129] In simulation or actual measurement, the peak overpressures of a physical explosion and a vapor cloud explosion should be within a certain range. If the difference between the two exceeds a preset third threshold, it indicates that there is a deviation in the coupling characteristics.

[0130] When it is found that there is a deviation in the coupling characteristics, it is necessary to adjust the model parameters to more accurately simulate the interaction between the two. In this case, the parameter to be corrected is the delay time for the physical explosion to trigger the vapor cloud explosion. By adjusting this parameter, the coupling process between the two can be simulated more precisely.

[0131] In some embodiments, the deviation feature includes an obstacle feature, and determining the parameter to be corrected based on the deviation feature includes: determining that the obstacle feature is that the overpressure deviation in the obstacle area is greater than a fourth threshold; determining that the parameter to be corrected is the obstacle turbulence parameter.

[0132] In a computational fluid dynamics (CFD) model of a natural gas pipeline explosion, the presence of obstacles will significantly affect the propagation of the explosion shock wave and the overpressure distribution. When there is a large deviation between the overpressure predicted by the model in the obstacle area and the actual observed value, it may be necessary to correct the turbulence parameters in the model.

[0133] Specifically, if the overpressure deviation in the obstacle area exceeds a preset fourth threshold, then consideration should be given to adjusting the turbulence parameters related to the obstacle to improve the accuracy of the model. These turbulence parameters can include the local turbulence intensity and turbulence dissipation rate caused by the obstacle. By adjusting these parameters, the influence of the obstacle on the explosion shock wave can be better simulated, thereby improving the prediction ability of the CFD model for actual situations.

[0134] The natural gas pipeline explosion shock wave overpressure calculation system provided by the present invention will be described below. The natural gas pipeline explosion shock wave overpressure calculation system described below can be mutually referred to in correspondence with the natural gas pipeline explosion shock wave overpressure calculation method described above.

[0135] As Figure 3As shown in the figure, the natural gas pipeline explosion shock wave overpressure calculation system according to the embodiment of the present invention mainly includes a first processing module 310, a second processing module 320, a third processing module 330, a fourth processing module 340, and a fifth processing module 350.

[0136] The first processing module 310 is configured to determine initial physical explosion overpressure data based on pipeline leakage data, and determine initial vapor cloud explosion overpressure data based on the initial physical explosion overpressure data;

[0137] The second processing module 320 is configured to determine that the absolute value of the difference between the peak overpressures of the physical explosion and the vapor cloud explosion at the same position is greater than a first threshold based on the peak overpressures of the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data at different positions;

[0138] The third processing module 330 is configured to dynamically couple the physical explosion and the vapor cloud explosion processes through a computational fluid dynamics (CFD) model based on the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data, and generate initial overpressure spatio-temporal evolution data;

[0139] The fourth processing module 340 is configured to determine the parameters to be corrected for the dynamic coupling of the physical explosion and the vapor cloud explosion processes in the CFD model based on the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data;

[0140] The fifth processing module 350 is configured to correct the parameters to be corrected for the dynamic coupling of the physical explosion and the vapor cloud explosion processes in the CFD model, and analyze the overpressure spatio-temporal evolution data output by the corrected CFD model with the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data until the peak overpressure of the overpressure data in the final target overpressure spatio-temporal evolution data output by the CFD model matches the peak overpressure of the overpressure data obtained from the experimental simulation.

[0141] According to the natural gas pipeline explosion shock wave overpressure calculation system provided by the embodiment of the present invention, by optimizing the calculation method of the natural gas pipeline explosion shock wave overpressure, for the coupling of numerical simulation and physical model and multiple parameter corrections, through refined CFD modeling and comparative analysis, the overpressure spatio-temporal evolution data that conforms to the actual situation is finally obtained, and then more accurate coupled overpressure data is obtained, which has strong practicability and can be widely applied to the safety assessment and protection design of natural gas pipelines to improve the protection efficiency.

[0142] Figure 4 An example of the physical structure diagram of an electronic device is shown in Figure 4As shown, the electronic device may include: a processor 410, a communications interface 420, a memory 430, and a communication bus 440. Among them, the processor 410, the communication interface 420, and the memory 430 communicate with each other through the communication bus 440. The processor 410 may call the logical instructions in the memory 430 to execute the calculation method for the overpressure of the blast wave of a natural gas pipeline explosion. The method includes: determining initial physical explosion overpressure data based on pipeline leakage data, and determining initial vapor cloud explosion overpressure data based on the initial physical explosion overpressure data; determining that the absolute value of the difference in peak overpressure between the physical explosion and the vapor cloud explosion at the same location is greater than a first threshold based on the initial physical explosion overpressure data and the peak overpressure of the initial vapor cloud explosion overpressure data at different locations; dynamically coupling the physical explosion and the vapor cloud explosion processes through a computational fluid dynamics (CFD) model based on the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data to generate initial overpressure spatio-temporal evolution data; determining the parameters to be corrected for the dynamic coupling of the physical explosion and the vapor cloud explosion processes in the CFD model based on the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data; correcting the parameters to be corrected for the dynamic coupling of the physical explosion and the vapor cloud explosion processes in the CFD model, and analyzing the overpressure spatio-temporal evolution data output by the corrected CFD model with the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data until the overpressure data in the final target overpressure spatio-temporal evolution data output by the CFD model matches the overpressure data obtained from the experimental simulation.

[0143] In addition, when the logical instructions in the above-mentioned memory 430 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs that can store program codes.

[0144] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the natural gas pipeline explosion shock wave overpressure calculation method provided by each of the above methods. The method includes: determining initial physical explosion overpressure data based on pipeline leakage data, and determining initial vapor cloud explosion overpressure data based on the initial physical explosion overpressure data; determining that the absolute value of the difference in peak overpressure between physical explosion and vapor cloud explosion at the same position is greater than a first threshold based on the initial physical explosion overpressure data and the peak overpressure of the initial vapor cloud explosion overpressure data at different positions; generating initial overpressure spatio-temporal evolution data by dynamically coupling the physical explosion and vapor cloud explosion processes through a computational fluid dynamics (CFD) model based on the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data; determining the parameters to be corrected for the dynamic coupling of the physical explosion and vapor cloud explosion processes in the CFD model based on the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data; correcting the parameters to be corrected for the dynamic coupling of the physical explosion and vapor cloud explosion processes in the CFD model, and analyzing the overpressure spatio-temporal evolution data output by the corrected CFD model with the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data until the overpressure data in the final target overpressure spatio-temporal evolution data output by the CFD model matches the overpressure data obtained from the experimental simulation.

[0145] In another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the natural gas pipeline explosion shock wave overpressure calculation method provided by the above-mentioned various methods. The method includes: based on pipeline leakage data, determining initial physical explosion overpressure data, and determining initial vapor cloud explosion overpressure data based on the initial physical explosion overpressure data; based on the peak overpressures of the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data at different positions, determining that the absolute value of the difference in peak overpressure between the physical explosion and the vapor cloud explosion at the same position is greater than a first threshold; based on the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data, dynamically coupling the physical explosion and the vapor cloud explosion processes through a computational fluid dynamics (CFD) model to generate initial overpressure spatio-temporal evolution data; based on the initial overpressure spatio-temporal evolution data, the initial physical explosion overpressure data, and the initial vapor cloud explosion overpressure data, determining the parameters to be corrected for the dynamic coupling of the physical explosion and the vapor cloud explosion processes in the CFD model; correcting the parameters to be corrected for the dynamic coupling of the physical explosion and the vapor cloud explosion processes in the CFD model, and analyzing the overpressure spatio-temporal evolution data output by the corrected CFD model with the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data until the overpressure data in the final target overpressure spatio-temporal evolution data output by the CFD model matches the overpressure data obtained from the experimental simulation.

[0146] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0147] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0148] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating overpressure of explosion shock wave in a natural gas pipeline, characterized in that: include: Determining initial physical explosion overpressure data based on the pipeline leakage data, and determining initial vapor cloud explosion overpressure data based on the initial physical explosion overpressure data; Based on the peak overpressures of the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data at different locations, it is determined that the absolute value of the difference between the peak overpressures of the physical explosion and the vapor cloud explosion at a certain location is greater than a first threshold, and then it is determined that the location needs to be corrected; Based on the initial physical explosion overpressure data and the initial steam cloud explosion overpressure data, the physical explosion and steam cloud explosion processes are dynamically coupled by a computational fluid dynamics (CFD) model to generate initial overpressure spatiotemporal evolution data; the coupling process of the physical explosion and the steam cloud explosion includes the coupling of explosion wave propagation and combustion reaction, multiphase fluid interaction, and time step coupling; the initial overpressure spatiotemporal evolution data includes the overpressure distribution and time series of the coupled physical explosion and steam cloud explosion; Determine the parameters to be corrected for the dynamic coupling of the physical explosion and the steam cloud explosion process in the CFD model based on the initial overpressure spatiotemporal evolution data, the initial physical explosion overpressure data, and the initial steam cloud explosion overpressure data; Correcting the parameters to be corrected for the dynamic coupling of the physical explosion and the vapor cloud explosion process in the CFD model, and analyzing the overpressure spatiotemporal evolution data output by the corrected CFD model with the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data, until the overpressure data in the final target overpressure spatiotemporal evolution data output by the CFD model matches the overpressure data obtained by the test simulation; The determining of the parameters to be corrected for the dynamic coupling of the physical explosion and the steam cloud explosion process in the CFD model based on the initial overpressure spatiotemporal evolution data, the initial physical explosion overpressure data, and the initial steam cloud explosion overpressure data includes: Based on the typical points in the spatial grid, overpressure spatiotemporal data based on the initial overpressure spatiotemporal evolution data, the initial physical explosion overpressure data, and the initial steam cloud explosion overpressure data are respectively extracted; the typical points are points that spread away from the explosion center point with the explosion center point as the center; Determine the deviation values ​​at different typical point positions between the peak overpressures in the overpressure spatiotemporal data of the initial overpressure spatiotemporal evolution data, the initial physical explosion overpressure data, and the initial steam cloud explosion overpressure data; Determine a deviation feature corresponding to a deviation value of a typical point whose deviation value is greater than a second threshold, where the deviation feature includes at least one of a spatial feature, a temporal feature, a coupling feature, and an obstacle feature; The parameter to be corrected is determined based on the deviation feature.

2. The method for calculating overpressure of natural gas pipeline explosion shock wave according to claim 1, characterized in that: The deviation feature includes a spatial feature, and determining the parameter to be corrected based on the deviation feature includes: Determining the spatial feature as a region where the deviations are concentrated near the explosion center; The parameter to be corrected is determined to be an initial explosion energy parameter.

3. The method for calculating overpressure of explosion shock wave in natural gas pipeline according to claim 1, characterized in that: The deviation feature includes a spatial feature, and determining the parameter to be corrected based on the deviation feature includes: Determining the spatial feature as a deviation concentrated in an area far from the explosion center; The parameter to be corrected is determined to be a gas diffusion coefficient or a shock wave propagation parameter.

4. The method for calculating overpressure of natural gas pipeline explosion shock wave according to claim 1, characterized in that: The deviation feature includes a time feature, and determining the parameter to be corrected based on the deviation feature includes: Determining the temporal characteristic as a deviation focused on the rate of evolution of the overpressure with time; The parameter to be corrected is determined to be an explosion reaction rate constant or a turbulent mixing time.

5. The method for calculating overpressure of explosion shock wave in natural gas pipeline according to claim 1, characterized in that: The deviation feature includes a coupling feature, and determining the parameter to be corrected based on the deviation feature includes: Determining that the coupling characteristic is that a difference between peak overpressures of the physical explosion and the vapor cloud explosion is greater than a third threshold; The parameter to be corrected is determined to be the delay time of the physical explosion triggering the steam cloud explosion.

6. The method for calculating overpressure of explosion shock wave in natural gas pipeline according to claim 1, characterized in that: The deviation features include obstacle features, The determining the parameter to be corrected based on the deviation feature includes: Determining that the obstacle characteristic is that the overpressure deviation of the obstacle area is greater than a fourth threshold; The parameter to be corrected is determined to be an obstacle turbulence parameter.

7. A natural gas pipeline explosion shock wave overpressure calculation system, characterized in that: The system adopts the natural gas pipeline explosion shock wave overpressure calculation method according to any one of claims 1 to 6 to calculate overpressure data, and the system comprises: A first processing module, for determining initial physical explosion overpressure data based on pipeline leakage data, and determining initial vapor cloud explosion overpressure data based on the initial physical explosion overpressure data; A second processing module is used to determine, based on the initial physical explosion overpressure data and the peak overpressures of the initial vapor cloud explosion overpressure data at different locations, that a difference in the peak overpressures between the physical explosion and the vapor cloud explosion at a certain location is greater than a first threshold value, and then determine that the location needs to be corrected; A third processing module is used to generate initial overpressure spatiotemporal evolution data based on the initial physical explosion overpressure data and the initial steam cloud explosion overpressure data by dynamically coupling the physical explosion and the steam cloud explosion process through a computational fluid dynamics (CFD) model; the coupling process of the physical explosion and the steam cloud explosion includes the coupling of explosion wave propagation and combustion reaction, multiphase fluid interaction, and time step coupling; the initial overpressure spatiotemporal evolution data includes the overpressure distribution and time series of the coupled physical explosion and the steam cloud explosion; a fourth processing module, for determining parameters to be corrected for dynamic coupling of physical explosion and steam cloud explosion process in a CFD model based on the initial overpressure spatiotemporal evolution data, the initial physical explosion overpressure data, and the initial steam cloud explosion overpressure data; The fifth processing module is used to correct the parameters to be corrected for the dynamic coupling of the physical explosion and the steam cloud explosion process in the CFD model, and analyze the overpressure spatiotemporal evolution data output by the corrected CFD model with the initial physical explosion overpressure data and the initial steam cloud explosion overpressure data, until the overpressure data in the final target overpressure spatiotemporal evolution data output by the CFD model matches the overpressure data obtained by the experimental simulation.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and capable of running on the processor, characterized in that: When the processor executes the program, the method for calculating overpressure of explosion shock waves in a natural gas pipeline as described in any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for calculating overpressure of explosion shock waves in a natural gas pipeline as claimed in any one of claims 1 to 6 is implemented.

Images