Explosive shock wave overpressure calculation method and system for natural gas pipeline

Abstract

The invention provides a natural gas pipeline explosion shock wave overpressure calculation method and a natural gas pipeline explosion shock wave overpressure calculation system, and belongs to the technical field of natural gas safety. For numerical simulation, coupling of a physical model and multiple times of parameter correction, through refined CFD modeling and comparative analysis, overpressure spatio-temporal evolution data conforming to the actual situation are finally obtained, more accurate coupling overpressure data are further obtained, the practicability is high, and the method can be widely applied to safety evaluation and protection design of natural gas pipelines and has good application prospects. The protection efficiency is improved.

Description

Technical Field

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

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

[0003] Physical explosions are caused by the rapid expansion of high-pressure gas in pipelines, which generates shock waves. The energy of the shock waves mainly depends on the initial pressure, volume and release rate of the gas. Vapor cloud explosions are caused by the mixing of leaked natural gas and air to form a flammable cloud. After encountering an ignition source, it burns violently (deflagration or detonation), and the released chemical energy is converted into shock wave overpressure. Overpressure is the core destructive parameter of the explosion shock wave, usually measured in kilopascals (kPa). Its hazards include direct damage, secondary disasters and environmental risks.

[0004] Existing overpressure calculation technology mainly relies on empirical models and numerical simulations, but it still has significant defects. For example, the overpressure of physical explosions and steam cloud explosions will be simply superimposed. Although the conservative superposition method improves safety, it will overestimate the overpressure value, resulting in redundant protection design and increased engineering costs. Summary of the invention

[0005] The present invention provides a method and system for calculating overpressure of explosion shock wave in a natural gas pipeline, which are used 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 overpressure of explosion shock wave in a natural gas pipeline, comprising: 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, determining that an absolute value of a difference in peak overpressures between a physical explosion and a vapor cloud explosion at the same location 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 vapor cloud explosion processes through a computational fluid dynamics (CFD) model to generate initial overpressure spatiotemporal evolution data; 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; The parameters to be corrected for the dynamic coupling of the physical explosion and the steam cloud explosion process in the CFD model are corrected, and the overpressure spatiotemporal evolution data output by the corrected CFD model are analyzed 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 from the experimental simulation.

[0007] According to a method for calculating overpressure of a natural gas pipeline explosion shock wave provided by the present invention, the parameters to be corrected for the dynamic coupling of the physical explosion and the steam cloud explosion process in the CFD model are determined based on the initial overpressure spatiotemporal evolution data, the initial physical explosion overpressure data, and the initial steam cloud explosion overpressure data, including: 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.

[0008] According to a method for calculating overpressure of a natural gas pipeline explosion shock wave provided by the present invention, 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.

[0009] According to a method for calculating overpressure of a natural gas pipeline explosion shock wave provided by the present invention, 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.

[0010] According to a method for calculating overpressure of a natural gas pipeline explosion shock wave provided by the present invention, 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.

[0011] According to a method for calculating overpressure of a natural gas pipeline explosion shock wave provided by the present invention, 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.

[0012] According to a method for calculating overpressure of a natural gas pipeline explosion shock wave provided by the present invention, the deviation feature includes an obstacle feature, and 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.

[0013] The present invention also provides a natural gas pipeline explosion shock wave overpressure calculation device, comprising: 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 that the absolute value of the difference between the peak overpressures of the physical explosion and the vapor cloud explosion at the same location is greater than a first threshold value based on the initial physical explosion overpressure data and the peak overpressures of the initial vapor cloud explosion overpressure data at different locations; A third processing module is used to generate initial overpressure spatiotemporal evolution data by dynamically coupling the physical explosion and the steam cloud explosion process through a computational fluid dynamics (CFD) model based on the initial physical explosion overpressure data and the initial steam cloud explosion overpressure data; 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.

[0014] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, any of the above-mentioned methods for calculating overpressure of explosion shock waves in a natural gas pipeline is implemented.

[0015] 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, the method for calculating overpressure of explosion shock wave in a natural gas pipeline as described in any one of the above is implemented.

[0016] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements any of the above-mentioned methods for calculating overpressure of explosion shock waves in a natural gas pipeline.

[0017] The method and system for calculating overpressure of explosion shock wave of natural gas pipeline provided by the present invention optimize the calculation method of overpressure of explosion shock wave of natural gas pipeline, aiming at the coupling of numerical simulation and physical model and multiple parameter corrections, and finally obtain the overpressure spatiotemporal evolution data in line with the actual situation through refined CFD modeling and comparative analysis, and then obtain more accurate coupled overpressure data, which has strong practicality and can be widely used in natural gas pipeline safety assessment and protection design to improve protection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is one of the flow diagrams of the method for calculating overpressure of explosion shock wave in a natural gas pipeline provided by the present invention; Figure 2 This is the second flow chart of the method for calculating overpressure of explosion shock wave in a natural gas pipeline provided by the present invention; Figure 3 It is a structural schematic diagram of a natural gas pipeline explosion shock wave overpressure calculation system provided by the present invention; Figure 4 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Combine the following Figure 1-Figure 4 The invention describes a method and system for calculating overpressure of explosion shock wave in a natural gas pipeline.

[0022] like Figure 1 As shown, a method for calculating overpressure of explosion shock wave in 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.

[0023] Step 110, determining initial physical explosion overpressure data based on the pipeline leakage data, and determining initial steam cloud explosion overpressure data based on the initial physical explosion overpressure data.

[0024] The basic parameters of pipeline leakage, such as leakage rate, leakage location, pressure in the pipeline, temperature, gas type, etc., can be obtained through monitoring equipment or sensors.

[0025] Physical explosion (PE) is initiated by the release of high pressure gas, which involves the expansion process of gas. The initial physical explosion overpressure can be calculated by the following steps.

[0026] First, determine the initial pressure and volume of the gas. Based on the leak point and the pressure in the pipeline, estimate the pressure and volume of the gas when it leaks. 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 speed and release rate, calculate the generated shock wave overpressure. Alternatively, you can use the improved TNT equivalent method or empirical formula to calculate the initial overpressure distribution generated by the physical explosion.

[0027] The calculation of initial vapor cloud explosion overpressure data can be performed according to the following process. When natural gas leaks and mixes with air, a vapor cloud may be formed, and a vapor cloud explosion (VCE) may occur 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 gas and calculate the gas concentration at different locations. The cloud explosion energy can estimate the combustion energy in the cloud based on the concentration and volume of the combustible cloud. The final overpressure value calculation determines the overpressure of the vapor cloud explosion based on the shock wave pressure converted from the heat energy of the combustion.

[0028] Step 120, based on the peak overpressures of the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data at different locations, determine whether 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.

[0029] From the preliminary calculated physical explosion and vapor cloud explosion overpressure data, extract the peak overpressure at each calculation point. These peaks can be extracted using numerical simulations or experimental data.

[0030] On this basis, the peak overpressures of the physical explosion and the vapor cloud explosion are compared. If the absolute value of the difference between the peak overpressures of the two at a certain location is greater than the set first threshold, it indicates that the location needs further correction. For example, the threshold can be set according to the pipeline type, gas type and leakage scale.

[0031] Step 130, based on the initial physical explosion overpressure data and the initial steam cloud explosion overpressure data, dynamically couple the physical explosion and steam cloud explosion processes through a computational fluid dynamics (CFD) model to generate initial overpressure spatiotemporal evolution data.

[0032] 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.

[0033] Gas dynamics: Simulate the ejection, expansion and turbulence of gases.

[0034] Combustible cloud diffusion: Simulates the diffusion process of flammable clouds based on factors such as wind speed, gas diffusion coefficient and obstacles.

[0035] Reaction kinetics: Considers the reaction rate and combustion process after the gas is mixed with air.

[0036] Blast wave propagation: simulate the propagation of blast waves and calculate the overpressure at each location.

[0037] Dynamic coupling: In the same CFD model, the physical explosion and vapor cloud explosion processes are coupled. Specifically, the gas injection process affects the cloud diffusion, and the cloud diffusion affects the propagation of the explosion wave. The two are interdependent.

[0038] Generation of spatiotemporal evolution data: Through CFD simulation, the spatiotemporal evolution data of overpressure are calculated at different time steps to obtain the distribution and change trend of the initial overpressure.

[0039] The physical explosion stage can use the compressible Euler equation to simulate the high-pressure gas injection process. The vapor cloud explosion stage can simulate the flammable cloud combustion based on the combustion model (such as EDC) and detailed chemical reaction mechanism.

[0040] The flow field data (velocity, concentration, temperature) at the end of the physical explosion can be used as the initial conditions of the vapor cloud explosion, and the overpressure spatiotemporal evolution data can be generated by solving the Navier-Stokes equations.

[0041] The temporal and spatial evolution data of initial overpressure include the overpressure distribution and time series of coupled physical explosion and steam cloud explosion.

[0042] A fine grid can be established in the computational domain, especially using a higher grid resolution in the explosion center and steam cloud distribution area to ensure that the pressure wave and combustion process can be accurately captured.

[0043] Furthermore, reasonable boundary conditions are set for the computational domain, such as no-slip conditions, open boundary conditions, or periodic boundary conditions. The initial pressure and temperature fields of the physical explosion are coupled with the initial fuel concentration field and ignition conditions of the vapor cloud explosion to construct a complete initial field.

[0044] The coupling of physical explosion and vapor cloud explosion is the key to the simulation, and the mutual influence of the two needs to be considered at the same time. The coupling process includes the coupling of explosion wave propagation and combustion reaction, multiphase fluid interaction, time step coupling, etc.

[0045] The coupling of explosion wave propagation and combustion reaction simulates how the shock wave generated by the physical explosion propagates in space and triggers the 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, the momentum, energy and mass exchange between the multiphase fluids must also be simulated. 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 technology can be used to dynamically adjust the time step when the pressure wave intensity changes dramatically.

[0046] After completing the CFD calculation, the overpressure spatiotemporal evolution data can be extracted from the simulation results. At typical points in the computational domain, the pressure changes over time are recorded to generate a pressure-time curve. The pressure data on all grid nodes are extracted to construct a complete overpressure spatiotemporal distribution. The peak pressure of each grid node and its corresponding time are recorded to analyze the propagation process of the overpressure wave.

[0047] The final simulation result is the complete spatiotemporal evolution data of the initial overpressure, which includes at least the spatial distribution, temporal distribution and dynamic characteristics.

[0048] Spatial distribution is the change of pressure over space (3D distribution graph). Temporal distribution is the change of pressure over time (time series data). Dynamic characteristics include shock wave velocity, vapor cloud combustion front propagation velocity, etc. These data can be used to further analyze the explosion impact area and evaluate the accuracy of calculation characteristics such as parameters.

[0049] Step 140, based on the initial overpressure spatiotemporal evolution data, the initial physical explosion overpressure data and the initial steam cloud explosion overpressure data, determine the parameters to be corrected for the dynamic coupling of the physical explosion and steam cloud explosion processes in the CFD model.

[0050] The temporal and spatial evolution data obtained from the initial calculation are compared with the peak overpressure data of physical explosions and vapor cloud explosions to identify which parameters need to be corrected, such as gas leakage rate, diffusion coefficient, combustion model, and parameters involved in turbulence effects.

[0051] If the leak rate is overestimated or underestimated, it will affect the calculation of the initial overpressure. The accuracy of the gas diffusion process directly affects the formation of the flammable cloud and the calculation of the overpressure. Parameters such as reaction rate, ignition conditions and temperature may need to be adjusted to better fit the actual overpressure data.

[0052] In addition, the role of obstacle-induced turbulence effects in overpressure formation needs to be further adjusted through turbulence models.

[0053] For 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.

[0054] Step 150, 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 of 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 from the experimental simulation.

[0055] According to the parameters to be corrected determined in the previous step, the CFD model is corrected and rerun. This process is an iterative process, which specifically includes the following processes.

[0056] You can adjust the model parameters based on the preliminary results and rerun the CFD simulation. Compare the revised overpressure data with the overpressure data obtained from the test simulation to evaluate the matching degree of the peak overpressure. If the gap is still large, continue to revise the parameters and rerun the numerical simulation until the revised overpressure data matches the overpressure data obtained from the test simulation.

[0057] Matching can mean that the difference between the key features in the output data of the modified CFD model, such as the peak overpressure, and the peak overpressure obtained by the experimental simulation is reduced to an acceptable range.

[0058] The method for calculating overpressure of explosion shock waves in natural gas pipelines provided in an embodiment of the present invention optimizes the method for calculating overpressure of explosion shock waves in natural gas pipelines, targets the coupling of numerical simulation and physical models and multiple parameter corrections, and finally obtains overpressure spatiotemporal evolution data that conforms to actual conditions through refined CFD modeling and comparative analysis, thereby obtaining more accurate coupled overpressure data. The method has strong practicability and can be widely used in natural gas pipeline safety assessment and protection design to improve protection efficiency.

[0059] In some embodiments, Figure 2 As shown, based on the initial overpressure spatiotemporal evolution data, the initial physical explosion overpressure data and the initial steam cloud explosion overpressure data, the parameters to be corrected for the dynamic coupling of the physical explosion and steam cloud explosion processes in the CFD model are determined, including step 210, step 220, step 230 and step 240.

[0060] Step 210, based on typical points in the spatial grid, respectively extract 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.

[0061] Step 220, determining deviation values ​​at different typical point positions between 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.

[0062] Step 230 , determining the deviation feature corresponding to the deviation value of the typical point whose deviation value is greater than the second threshold.

[0063] Step 240: Determine the parameter to be corrected based on the deviation feature.

[0064] The typical points are points that spread away from the explosion center point. The deviation feature includes at least one of a spatial feature, a temporal feature, a coupling feature, and an obstacle feature.

[0065] In a CFD (Computational Fluid Dynamics) model, the simulation area is divided into multiple small cells or grids, each corresponding to a spatial location. These grids are used in numerical calculations to simulate physical phenomena such as gas flow and temperature changes.

[0066] Typical points refer to some representative locations selected within the simulation area. These locations can reflect important characteristics of the explosion process, such as the explosion center, adjacent high overpressure areas, and near obstacles.

[0067] In CFD simulation, the simulation area must first be divided into multiple grid cells. These grids can be divided by finite element method or other numerical methods.

[0068] Through simulation calculation, each grid point (especially the selected typical point) will generate a series of overpressure data, which contain the overpressure values ​​of each point at different times.

[0069] It is necessary to extract the overpressure data of these typical points from the initial overpressure spatiotemporal evolution data, the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data. By extracting the overpressure spatiotemporal data, it can help analyze the different stages of the explosion event and its impact on the surrounding environment.

[0070] Peak overpressure refers to the maximum value in the overpressure data during the explosion, which usually represents the strongest impact of the explosion.

[0071] The deviation value refers to the deviation value at different typical points 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.

[0072] The peak overpressures at different typical point locations are compared to find the differences between them by comparing the peak overpressures extracted from the initial overpressure spatiotemporal evolution data, physical explosion data and vapor cloud explosion data.

[0073] Calculate the overpressure difference at each typical point and get the deviation value of each point. Compare the deviations between the peaks of different types of overpressure data (physical explosion overpressure, vapor cloud explosion overpressure, overpressure spatiotemporal evolution data).

[0074] Since the overpressure peak values ​​in the initial physical explosion overpressure data obtained by direct calculation and the initial steam cloud explosion overpressure data have strong reference value, the differences between different simulation data and actual data can be quantified by calculating the initial overpressure spatiotemporal evolution data and the deviation values ​​between them, thereby providing a basis for the subsequent correction of the CFD model and identifying which areas or parameters need to be adjusted to improve the simulation accuracy.

[0075] The second threshold refers to a preset deviation threshold. If the deviation value of a typical point exceeds this threshold, it means that there is a large deviation in the overpressure data of the point.

[0076] Deviation characteristics refer to characteristics related to the deviation value, such as spatial characteristics (influence on location), temporal characteristics (trend of deviation over time), coupling characteristics (interaction between physical explosion and vapor cloud explosion), and obstacle characteristics (whether obstacles affect overpressure distribution).

[0077] The calculated deviation values ​​are used to extract points that exceed the second threshold. These points have large deviation values ​​and may represent significant differences between the CFD simulation results and the actual situation. These typical points are analyzed in detail to identify their deviation characteristics.

[0078] Spatial features indicate whether the deviations are concentrated in certain specific spatial regions, such as near the center of the explosion or at specific obstacle locations.

[0079] The temporal characteristics indicate whether the deviation increases or decreases gradually over time, especially the difference between the time of the overpressure peak in the simulation and the actual situation.

[0080] The coupling characteristics indicate the coupling between the physical explosion and the vapor cloud explosion process, and whether the interaction between the two affects the distribution of overpressure.

[0081] The obstacle characteristics indicate whether the obstacle changes the propagation path of the explosion shock wave, resulting in uneven overpressure distribution.

[0082] In this embodiment, by analyzing the deviation characteristics, we can have a deeper understanding of why the deviations at certain points are large, thereby providing important clues for correcting the CFD model. This process can ensure that the CFD model reflects the actual situation more accurately, especially by considering the effects of space, time, coupling and obstacles.

[0083] In some embodiments, 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 deviation is concentrated near the explosion center; and determining the parameter to be corrected as an initial explosion energy parameter.

[0084] If the simulation results show that the deviation of the pressure value is larger near the explosion center, it means that the release of explosion energy, wave propagation or other physical phenomena are not accurately simulated at this location.

[0085] 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.

[0086] The initial explosion energy parameter refers to the parameter used in the CFD model to simulate the initial energy release of the explosion. This parameter affects the intensity of the pressure wave and shock wave generated by the explosion, as well as the temporal and spatial evolution of the pressure field. The larger the energy parameter, the greater the pressure generated by the explosion, and vice versa.

[0087] In some implementations, 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 deviation is concentrated away from the explosion center; and determining the parameter to be corrected as a gas diffusion coefficient or a shock wave propagation parameter.

[0088] If the simulation results show that there are large deviations at locations far from the explosion center, it means that the model is not accurate in simulating areas far from the explosion source.

[0089] The gas diffusion coefficient is a parameter that describes the diffusion rate of gas in the air. The larger the gas diffusion coefficient, the faster the gas spreads; conversely, the gas diffuses slower.

[0090] In an explosion event, the rate of gas diffusion will affect the diffusion of the vapor cloud and the degree of mixing of the explosion gas with the surrounding air, which in turn affects the overpressure distribution after the explosion.

[0091] If the deviation occurs in areas far from the explosion center, it may be because the simulation of gas diffusion is inaccurate, resulting in the pressure field generated by the gas cloud when it spreads over long distances not matching the actual situation.

[0092] Shock wave propagation parameters are related to the propagation speed, intensity and diffusion of the shock wave generated by the explosion. Shock wave propagation parameters affect the intensity and speed of the shock wave and the path it propagates in the air.

[0093] When simulating an explosion, the propagation speed and intensity of the shock wave determine the distribution of the overpressure wave. If deviations occur in areas far from the center of the explosion, it may be because the propagation speed or path of the shock wave is not simulated accurately, resulting in overpressure in distant areas that do not match the actual situation.

[0094] In other words, if the deviation is large in the distant area, it may be because the gas diffusion is not sufficient, resulting in the gas distribution after the explosion not matching the actual situation. By adjusting the gas diffusion coefficient, the model can better simulate the diffusion process of gas in space, especially far away from the explosion source. If there is a large deviation in the area far from the explosion center, it may be due to inaccurate settings of some parameters in the shock wave propagation process. 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.

[0095] In simple terms, if deviations occur in areas far from the explosion source, it means that the model is insufficient in simulating gas diffusion and shock wave propagation. Therefore, the parameters to be corrected required to correct these deviations are those related to gas diffusion and shock wave propagation, such as 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.

[0096] In some embodiments, the deviation characteristic includes a time characteristic, and determining the parameter to be corrected based on the deviation characteristic includes: determining the time characteristic as a deviation concentrated on the evolution rate of overpressure with time; determining the parameter to be corrected as an explosion reaction rate constant or a turbulent mixing time.

[0097] The time characteristic refers to the change of overpressure over time, especially the rate of change of overpressure. For example, if the overpressure changes too fast or too slowly, it will affect the actual simulation results of the explosion. Based on the deviation of the time characteristic, the model parameters that need to be adjusted can be determined as the explosion reaction rate constant or the turbulent mixing time.

[0098] The explosion reaction rate constant determines the speed of the reaction during the explosion. If the rate at which the overpressure changes with time is not as expected, it may be because the reaction rate constant is not set appropriately and needs to be corrected. The turbulent mixing time describes how quickly the gas and material mix in the explosion and affects the rate at which the gas diffuses. If the rate at which the overpressure changes with time is deviated, it may be because the mixing time is not set accurately and needs to be adjusted.

[0099] It can be understood that by analyzing the time evolution rate of overpressure, it can be determined whether the explosion reaction rate constant or turbulent mixing time needs to be adjusted in order to more accurately simulate the change of overpressure with time.

[0100] 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 overpressure of the physical explosion and the vapor cloud explosion is greater than a third threshold; and determining that the parameter to be corrected is the delay time for the physical explosion to trigger the vapor cloud explosion.

[0101] The coupling characteristics refer to the interaction characteristics between physical explosion and vapor cloud explosion. In actual situations, physical explosion may trigger vapor cloud explosion, and there is a certain time delay between the two.

[0102] In simulations or actual measurements, the peak overpressures of physical explosions and vapor cloud explosions should be within a certain range. If the difference between the two exceeds the preset third threshold, it indicates that there is a deviation in the coupling characteristics.

[0103] When deviations in the coupling characteristics are found, the model parameters need to be adjusted 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 of the two can be simulated more accurately.

[0104] 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; and determining that the parameter to be corrected is an obstacle turbulence parameter.

[0105] In the computational fluid dynamics (CFD) model of natural gas pipeline explosions, the presence of obstacles can significantly affect the propagation of explosion shock waves and the distribution of overpressure. When the overpressure predicted by the model in the obstacle area deviates significantly from the actual observed value, the turbulence parameters in the model may need to be corrected.

[0106] Specifically, if the overpressure deviation in the obstacle area exceeds the preset fourth threshold, the turbulence parameters related to the obstacle should be adjusted to improve the accuracy of the model. These turbulence parameters may include the local turbulence intensity and turbulence dissipation rate caused by the obstacle. By adjusting these parameters, the impact of obstacles on the explosion shock wave can be better simulated, thereby improving the CFD model's ability to predict actual conditions.

[0107] The natural gas pipeline explosion shock wave overpressure calculation system provided by the present invention is described below. The natural gas pipeline explosion shock wave overpressure calculation system described below and the natural gas pipeline explosion shock wave overpressure calculation method described above can be referenced to each other.

[0108] like Figure 3 As shown, 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 .

[0109] The first processing module 310 is used to determine initial physical explosion overpressure data based on the pipeline leakage data, and determine initial steam cloud explosion overpressure data based on the initial physical explosion overpressure data; The second processing module 320 is used 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 location is greater than a first threshold value based on the peak overpressures of the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data at different locations; The third processing module 330 is used to generate initial overpressure spatiotemporal evolution data by dynamically coupling the physical explosion and the steam cloud explosion process through a computational fluid dynamics (CFD) model based on the initial physical explosion overpressure data and the initial steam cloud explosion overpressure data; The fourth processing module 340 is used to 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; The fifth processing module 350 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 peak overpressure of the overpressure data obtained by the experimental simulation.

[0110] The natural gas pipeline explosion shock wave overpressure calculation system provided by the embodiment of the present invention optimizes the calculation method of the natural gas pipeline explosion shock wave overpressure, targets the coupling of numerical simulation and physical models and multiple parameter corrections, and finally obtains the overpressure spatiotemporal evolution data that conforms to the actual situation through refined CFD modeling and comparative analysis, and then obtains more accurate coupled overpressure data. The system has strong practicality and can be widely used in natural gas pipeline safety assessment and protection design to improve protection efficiency.

[0111] Figure 4 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 4As shown, the electronic device may include: a processor 410, a communication interface 420, a memory 430 and a communication bus 440, wherein 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 logic instructions in the memory 430 to execute the natural gas pipeline explosion shock wave overpressure calculation method, the method comprising: determining the initial physical explosion overpressure data based on the pipeline leakage data, and determining the initial steam 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 steam cloud explosion at the same location is greater than a first threshold value based on the initial physical explosion overpressure data and the initial steam cloud explosion overpressure data at different locations; generating 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; Based on the initial overpressure spatiotemporal evolution data, the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data, the parameters to be corrected for the dynamic coupling of the physical explosion and the vapor cloud explosion process in the CFD model are determined; the parameters to be corrected for the dynamic coupling of the physical explosion and the vapor cloud explosion process in the CFD model are corrected, and the overpressure spatiotemporal evolution data output by the corrected CFD model are analyzed 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 from the experimental simulation.

[0112] In addition, the logic instructions in the above-mentioned memory 430 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0113] 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 the above methods, the method comprising: 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 peak overpressure of the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data at different locations; 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 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 spatiotemporal evolution data; determine 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 spatiotemporal evolution data, the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data; 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 spatiotemporal evolution data of 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 from the experimental simulation.

[0114] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the processor executes the method for calculating the overpressure of the explosion shock wave of the natural gas pipeline provided by the above-mentioned methods, the method comprising: determining the initial physical explosion overpressure data based on the pipeline leakage data, and determining the 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 value based on the peak overpressure of the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data at different locations; and 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 value 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 spatiotemporal evolution data; based on the initial overpressure spatiotemporal evolution data, the initial physical explosion overpressure data and the initial vapor cloud explosion overpressure data, the parameters to be corrected for the dynamic coupling of the physical explosion and vapor cloud explosion processes in the CFD model are determined; the parameters to be corrected for the dynamic coupling of the physical explosion and vapor cloud explosion processes in the CFD model are corrected, and the overpressure spatiotemporal evolution data output by the corrected CFD model are analyzed 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 from the experimental simulation.

[0115] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0116] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for 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.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the 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, determining that an absolute value of a difference in peak overpressures between a physical explosion and a vapor cloud explosion at the same location 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 vapor cloud explosion processes through a computational fluid dynamics (CFD) model to generate initial overpressure spatiotemporal evolution data; 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; The parameters to be corrected for the dynamic coupling of the physical explosion and the steam cloud explosion process in the CFD model are corrected, and the overpressure spatiotemporal evolution data output by the corrected CFD model are analyzed 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 from the experimental simulation.

2. The method for calculating overpressure of natural gas pipeline explosion shock wave according to claim 1, characterized in that: 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.

3. The method for calculating overpressure of explosion shock wave in natural gas pipeline according to claim 2, 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.

4. The method for calculating overpressure of natural gas pipeline explosion shock wave according to claim 2, 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.

5. The method for calculating overpressure of explosion shock wave in natural gas pipeline according to claim 2, 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.

6. The method for calculating overpressure of explosion shock wave in natural gas pipeline according to claim 2, 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.

7. The method for calculating overpressure of explosion shock wave in natural gas pipeline according to claim 2, 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.

8. A natural gas pipeline explosion shock wave overpressure calculation system, characterized in that: include: 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 that the absolute value of the difference between the peak overpressures of the physical explosion and the vapor cloud explosion at the same location is greater than a first threshold value based on the initial physical explosion overpressure data and the peak overpressures of the initial vapor cloud explosion overpressure data at different locations; A third processing module is used to generate initial overpressure spatiotemporal evolution data by dynamically coupling the physical explosion and the steam cloud explosion process through a computational fluid dynamics (CFD) model based on the initial physical explosion overpressure data and the initial steam cloud explosion overpressure data; 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.

9. 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 7 is implemented.

10. 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 7 is implemented.

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