MPRFS-based evaluation method for gas-powder two-phase explosion suppressant's effectiveness in suppressing gas and coal dust explosions

Abstract

The present invention relates to a method for evaluating the effectiveness of a gas-powder two-phase explosion suppressant in suppressing gas and coal dust explosions based on MPRFS, and belongs to the technical field of gas and coal dust explosion protection in coal mines. The method comprises: constructing a mathematical model for suppressing gas and coal dust explosions with a gas-powder two-phase explosion suppressant; determining the initial conditions, boundary conditions, and input parameters of the numerical model; establishing a three-dimensional physical model of the explosion container; constructing a simulation calculation grid and a distribution domain of gas and coal dust and the gas-powder two-phase explosion suppressant; creating thermodynamic files and reaction kinetic files for gas and coal dust composite explosions and explosion suppressant decomposition; developing a CFD numerical simulation solver and an OpenFOAM‑Cantera coupling interface; solving the numerical model and correcting the model; and evaluating the explosion suppression effectiveness of the gas-powder two-phase explosion suppressant. The present invention can effectively evaluate the suppression effects of different gas-powder two-phase explosion suppressants in gas and coal dust explosions.

Description

Technical Field

[0001] The invention belongs to the technical field of gas and coal dust explosion protection in coal mines, and relates to an MPRFS-based gas-powder two-phase explosion suppressant performance evaluation method for suppressing gas and coal dust explosions. Background Art

[0002] During coal mining, gas and coal dust explosions cause significant harm and property losses. Therefore, research on gas and coal dust explosion suppression technologies has been a key focus of coal mine disaster prevention and control worldwide. Gas / coal dust explosions are a complex reaction process involving coupled gas-phase combustion and solid-phase pyrolysis. Compared to single-phase gas or coal dust explosions, the primary control mechanism of a two-phase gas / coal dust explosion exhibits dynamic changes and synergistic reactions, resulting in higher explosion sensitivity, intensity, and destructive power, posing a serious threat to mine safety and the health and safety of workers. In recent years, research teams at home and abroad have conducted extensive research on gas and coal dust explosion suppression technologies. Currently, traditional explosion suppression media used for gas and coal dust explosion prevention and control primarily include inert gases, inert powders, fine water mist, aerogels, and porous media materials. Research methods primarily rely on experimental testing and macroscopic characterization. These traditional single-phase explosion suppression media have limitations in practical applications, including high cost, complex operation, and poor environmental adaptability. Furthermore, their suppression effectiveness is significantly affected by the particle size distribution and mass concentration of the powder and liquid. To improve the suppression efficiency and environmental adaptability of explosion suppressants, researchers are exploring the synergistic suppression effects of different media through methods such as powder compounding, acid-base modification, and multiphase coupling. Gas-powder two-phase explosion suppressants have garnered widespread attention due to their unique advantages in suppressing explosions. During the premixing process, heterogeneous explosion suppression media collide with the airflow, generating energy exchange. This promotes a pre-decomposition reaction within the inert powder, rapidly capturing intermediate free radicals and interrupting the chain reaction of the explosion. Furthermore, the inert gas and solid materials effectively reduce oxygen concentration, slowing and preventing the spread of explosions through their cooling and barrier effects. These properties give gas-powder two-phase explosion suppressants significant potential for application in coal mine safety.

[0003] However, current macro-experimental methods make it difficult to accurately evaluate the suppression effectiveness of gas-powder two-phase explosion suppressants on gas-coal dust combined explosions, due to high costs, long cycles, and complex conditions. With the development of numerical simulation technology, the use of multiphase reaction flow simulation to study the explosion suppression effect of gas-powder two-phase explosion suppressants has become an efficient and economical approach. Cantera and OpenFOAM are currently the most widely used chemical reaction and fluid mechanics coupling calculation software, with powerful computing power and accurate simulation results. Combining the two to evaluate the explosion suppression effect of gas-powder two-phase explosion suppressants can significantly improve simulation accuracy and computational efficiency, providing theoretical support and technical basis for the optimized design and engineering application of gas-powder two-phase explosion suppressants.

[0004] The advantage of conducting prediction and analysis research based on numerical simulation technology is that it can intuitively simulate the action behavior and energy transfer process of the reaction system, and then reveal the effects and inhibition mechanisms of different types of selected gas-powder two-phase explosion suppression media on the explosion reaction, making up for the limitations of traditional experimental evaluation methods with high cost, long cycle and low efficiency. The invention patent application with publication number CN112863610B provides a three-phase inhibitor compounding method for suppressing the thermal reaction process of gas explosion. This method determines the key free radicals and key elementary reactions of gas explosion through chemical reaction kinetics, and then optimizes the configuration of gas / solid / liquid three-phase inhibitors, and tests their effective inhibition characteristic parameters for the thermal reaction process of gas explosion through explosion suppression tests; the invention patent application with publication number CN113156045B provides a visual hydrogen explosion corrugated flame arrester fire performance test and detection protection device, which integrates multiple systems such as high-frequency response explosion suppression system, and comprehensively tests and analyzes the fire resistance and explosion suppression efficiency of hydrogen explosion flame arrester through program control; the invention patent application with publication number CN114295739A provides a method for studying the thermal reaction mechanism and safety of hazardous chemicals, using By combining molecular dynamics simulation with thermal-mass spectrometry experiments, the thermal reaction mechanism of hazardous chemicals is deeply analyzed through simulation calculations and experimental tests, and their thermal reaction safety is comprehensively evaluated; the invention patent application with publication number CN116312853A provides a surfactant compound system evaluation method based on molecular dynamics simulation. This method comprehensively analyzes the interfacial behavior and thermal reaction mechanism of the surfactant compound system by comprehensively applying a variety of molecular simulation software and force field parameters; the invention patent with publication number CN118248234A proposes a characteristic parameter prediction method based on the C1-C4 small molecule hydrocarbon substitution model library and combustion characteristic library. It uses numerical simulation and multi-attribute decision-making method to provide a scientific, systematic and efficient alternative modeling solution for the prediction of accident consequence characteristic parameters of flammable and explosive hazardous chemicals containing C, H and O.

[0005] In summary, it is found that the existing technology still has the following deficiencies:

[0006] The three-phase inhibitor compounding method provided by the invention patent with publication number CN112863610B failed to reveal in detail the synergistic mechanism of the gas / solid / liquid three-phase inhibitor, and failed to provide theoretical and experimental data support for the specific influence of the inhibitor on the chemical kinetic process of gas explosion; the test device provided by the invention patent application with publication number CN113156045B, although taking into account multiple influencing factors such as the structural parameters of the flame arrester during the explosion process, in actual applications, the parameters and environmental conditions that affect the explosion fire retardation and explosion suppression effects are more complex and diverse, and it is impossible to fully verify its stable fire retardation and explosion suppression effects under different explosion environments; the structural model and external thermal stimulation conditions established by the research method provided by the invention patent application with publication number CN114295739A cannot fully cover all actual Due to the complex situations in the actual application environment, there are limitations such as model simplification and experimental condition restrictions, which make it impossible to comprehensively and objectively evaluate the impact of all potential factors on the thermal reaction mechanism and safety of hazardous chemicals; the composite system evaluation method disclosed in the invention patent with publication number CN117530377A, although it can shorten the experimental cycle and deeply explore the microstructure and properties of the system, also has limitations such as huge computing resource requirements, low simulation result accuracy and the need for further experimental verification; the evaluation method disclosed in the invention patent with publication number CN118248234A, although it has significant advantages in predicting the consequences of hazardous chemical accidents, has a complex operation process, is highly dependent on input data and requires a large amount of computing resources, and does not have the effectiveness and reliability for application in a wide range of practical scenarios.

[0007] In summary, existing methods for evaluating the suppression effectiveness of explosion suppressants are mostly experimental, resulting in high costs, long cycles, complex conditions, and poor reproducibility. Existing explosion suppression performance and evaluation methods struggle to accurately and realistically assess the suppression effect and influence patterns of selected explosion suppressants. Existing simulation methods, such as molecular dynamics and chemical reaction kinetics, lack theoretical understanding of detailed explosion suppression mechanisms. Furthermore, numerical simulation techniques place high demands on and rely heavily on computing resources, simulation accuracy, and data precision. In recent years, with the continuous improvement of computer performance and the development of numerical simulation technology, the use of multiphase reacting flow simulation (MPRFS) to study the suppression effectiveness of gas-powder two-phase explosion suppressants has become an efficient and economical approach. Existing explosion suppression effectiveness assessments rely solely on single CFD simulations or chemical kinetics calculations to determine the suppression effect of a single inhibitor on a gas-coal dust explosion. These methods are unable to accurately assess the temperature, pressure, and reaction processes of a gas-powder two-phase explosion under real-world conditions. Cantera and OpenFOAM are currently the most widely used chemical reaction and fluid mechanics coupling calculation software, with powerful computing capabilities and accurate simulation effects. The OpenFOAM-Cantera coupling simulation based on multi-field reaction flow theory has significant advantages such as safety, efficiency, low cost, and no need for tedious experiments. Combining the two to evaluate the explosion suppression effect of gas-powder two-phase explosion suppressants can significantly improve simulation accuracy and computing efficiency. The MPRFS-based gas-powder two-phase explosion suppressant efficiency evaluation method proposed in this patent fills the gap in the evaluation of gas-powder two-phase explosion suppressants through numerical simulation methods, and provides reliable theoretical support and technical basis for mine safety prevention and control. Summary of the Invention

[0008] In view of this, the object of the present invention is to provide a method for evaluating the effectiveness of a gas-powder two-phase explosion suppressant in suppressing gas and coal dust explosions based on MPRFS.

[0009] In order to achieve the above object, the present invention provides the following technical solutions:

[0010] A method for evaluating the effectiveness of a gas-powder two-phase explosion suppressant in suppressing gas and coal dust explosions based on MPRFS comprises the following steps:

[0011] S1: Construct a mathematical model for suppressing gas and coal dust explosions with a gas-powder two-phase explosion suppressant. Based on the NS equation, a component transport model is constructed to solve the migration and change laws of each gas component during the explosion suppression reaction process; a discrete phase model is constructed to track the forces and movement of coal particles and powder inhibitor particles during the explosion suppression reaction; a turbulence model is constructed to capture the flow and turbulence characteristics of the fluid in the container during the explosion suppression reaction; a reaction kinetic model is constructed to describe the kinetic process of the gas-phase / surface-phase combustion chemical reaction of the gas-powder explosion suppressant suppressing a gas and coal dust composite explosion; a radiation model is constructed to describe the effect of reaction heat radiation on the heat transfer between solid particles during the explosion suppression reaction;

[0012] S2: Determine the initial conditions, boundary conditions and input parameters of the mathematical model. Based on the mathematical model, determine the initial conditions and boundary conditions required for simulation, such as initial temperature, initial pressure, powder spraying pressure, dust concentration and gas concentration, as well as the particle size distribution characteristics of powder inhibitor and coal dust, to accurately reflect the actual explosion environment;

[0013] S2: Determine the initial conditions, boundary conditions and input parameters of the mathematical model. Based on the mathematical model, determine the initial conditions and boundary conditions required for simulation, such as initial temperature, initial pressure, powder spraying pressure, dust concentration and gas concentration, as well as the particle size distribution characteristics of powder inhibitor and coal dust, to accurately reflect the actual explosion environment;

[0014] S3: Build a 3D physical model of the explosion vessel. Based on the overall structural characteristics of the explosion reaction vessel, use SolidWorks software to construct parts such as the explosion reaction chamber, dispersion plate, electromagnetic control valve, and high-pressure dust bin. Adjust the part parameters and positions in the software and assemble them into a 3D physical model. After checking the constraints of each component, generate a 3D digital model of the explosion vessel.

[0015] S4: Construct the simulation calculation grid and the distribution domain of gas, coal dust and gas-powder two-phase explosion suppressant. Based on the three-dimensional digital model, use meshing software to generate the corresponding grid model, verify the validity of the grid model, and name the boundary conditions of the region.

[0016] S5: Create thermodynamic and reaction kinetic files for gas-coal dust composite explosions and explosion suppressant decomposition. Use Cantera to simulate the chemical reaction kinetics of gas-solid powder suppression of gas-coal dust explosions. Analyze the thermodynamic parameters and sensitivity characteristics of key elementary reactions to optimize the reaction mechanism files that characterize key elementary reactions at different reaction stages during the explosion suppression reaction.

[0017] S6: Develop a CFD numerical simulation solver and OpenFOAM-Cantera coupling interface file, develop a CFD solver for calculating gas-solid powder suppression of gas and coal dust explosions, design a coupling interface for data transmission between OpenFOAM and Cantera, and achieve accurate solution of multi-phase and multi-reaction flow fields;

[0018] S7: Numerical simulation and model modification of the synergistic suppression of gas and coal dust explosions by gas-powder two-phase explosion suppressants. The developed OpenFOAM-Cantera coupled simulation method was used to perform numerical simulations of the suppression of gas and coal dust explosions by gas-powder two-phase explosion suppressants, combining mathematical models and grid models. The changes in temperature, pressure, and reaction during the explosion suppression reaction were output, and the mathematical model and input parameters established above were modified based on the experimental results of typical working conditions.

[0019] S8: Evaluation of the effectiveness of gas-powder two-phase explosion suppressant in synergistically suppressing gas and coal dust explosions. According to the output results of numerical simulation, an evaluation index system is created based on the explosion temperature decay rate, explosion overpressure decay rate, etc., and a comprehensive explosion suppression evaluation index system is formulated. Combined with the numerical simulation results, the suppression effectiveness of gas-powder two-phase explosion suppressant on gas and coal dust explosions is evaluated.

[0020] Furthermore, in S1, the component transport model considering Full Multicomponent Diffusion is selected to solve the migration change law of each gas component in the explosion suppression reaction process;

[0021] Furthermore, in S1, the pyrolysis and gasification of coal dust and powder explosion suppressant are considered in the discrete phase model. The Lagrangian method is used to track the motion trajectory of discrete phase particles, and the motion trajectory of individual particles is calculated by solving the momentum equation. The forces acting on coal particles and powder explosion suppressant particles mainly include particle inertia force, single particle drag force, gravity and buoyancy force, virtual mass force, pressure gradient force, Magnus lift force, Saffman lift force, etc.

[0022] Furthermore, in S1, the Scale-AdaptiveSimulation (SAS) turbulence model is used to capture the fluid flow and turbulence characteristics in the container during the explosion suppression reaction;

[0023] Furthermore, in S1, the reaction kinetics model constructed includes the homogeneous chemical reaction in the gas phase and the heterogeneous chemical reaction processes of the coke particles and the powdered explosion suppressant powder. The homogeneous reaction rate is determined by the minimum value of the chemical reaction rate and the turbulent mixing rate. For coal particle combustion, a two-step competition model is used to simulate the precipitation of volatiles, a finite rate eddy dissipation model is used for volatile combustion, and a finite diffusion kinetic model is used for coke combustion.

[0024] Furthermore, in S1, the P1 radiation model is selected to describe the gas-gas, gas-solid and gas-solid-wall interactions during the explosion suppression reaction;

[0025] Furthermore, in S2, the ignition delay is 60ms, the initial temperature is the ambient temperature (25°C), the initial pressures of the spherical tank and the dust bin are set to -0.06MPa and 2MPa respectively, the Peng-Robinson equation is used to describe the gas density state equation, and the Poisson distribution and Rosin-Rammler distribution functions are used to describe the particle size distribution characteristics of the powder inhibitor and coal dust;

[0026] Furthermore, in S2, the gas concentration is 9.5%; the inert gas is CO2 / N2, with concentrations of 2.5%, 5%, 7.5%, and 10% respectively; the powder explosion suppressant (modified kaolin) has a particle size range of 5-20 μm, a concentration of 10%-50%, and an increase of 10%; the coal dust particle size range is 30-75 μm, and the coal dust concentration is 300 g / m 3 ;

[0027] Furthermore, in S3, based on the overall structural characteristics of the explosion reaction vessel, Solidworks software was used to construct parts such as the explosion reaction chamber, dispersion plate, electromagnetic control valve, and high-pressure dust bin. After adjusting the part parameters and positions in the software, they were assembled into a three-dimensional physical model. After checking the constraints of each component, a three-dimensional digital model of the explosion vessel was generated.

[0028] Furthermore, in S4, to ensure that all interfaces in the mesh are effectively identified, a third-party meshing tool, SnappyHexMesh, is used for meshing. After the FLUENT solution mesh is exported, it is converted into an OpenFOAM mesh using fluentMeshToFoam.

[0029] Furthermore, in S4, three different grid numbers are obtained, which are defined as dense grid (1206312), sparse grid (986865) and super sparse grid (696300). The grid model is optimized by pre-processing software to ensure that the key area where the gas and coal dust explosion shock wave interacts with the gas-solid two-phase inhibitor has sufficient grid density. Figure 4 Validate the results for the grid;

[0030] Furthermore, in S4, the effectiveness of the model is determined by the pressure-time cloud diagram and pressure curve after the gas / coal dust / air mixture reaches equilibrium in the spherical container. The explosion suppression effect of the numerical simulation is compared with the actual gas and coal dust explosion test results through laboratory tests. Based on the experimental results, the parameters in the Cantera-OpenFOAM coupling model are fine-tuned to improve the consistency between the numerical simulation results and the actual explosion test results. Figure 5The results are used to verify the effectiveness of the numerical calculation model.

[0031] Furthermore, in S5, the thermodynamic and reaction kinetic files for the gas-coal-dust composite explosion and explosion suppressant decomposition were constructed based on the gas / anthracite composite explosion reaction. The decomposition reaction of the gas-dust two-phase inhibitor involved adopted the multi-component chemical reaction mechanism in the Cantera library to achieve detailed modeling of the explosion suppressant decomposition process.

[0032] Furthermore, in S6, the numerical solver developed for simulating the reaction of gas-powder two-phase explosion suppressant suppressing gas-coal dust explosion and the mathematical model of the reaction of gas-coal dust composite explosion suppressed by explosion suppressant were modified and called based on the solvers ReactingParcelFoam and coalChemistryFoam;

[0033] Further, in S6, the coupling interface between OpenFOAM and Cantera is designed through an open standard API to ensure data transmission efficiency and calculation accuracy between OpenFOAM and Cantera;

[0034] Furthermore, in S7, Cantera is used to calculate the detailed chemical reactions, and OpenFOAM is used to handle the CFD part. The flow field information such as temperature and pressure in OpenFOAM is transmitted to Cantera. Based on this information, Cantera calculates the chemical reaction process such as chemical reaction rate and species concentration change, and then feeds it back to OpenFOAM to update the material transport and energy conservation equations in the flow field.

[0035] Furthermore, in S7, the cloud diagram of the changes in temperature, pressure, and reaction during the explosion suppression reaction was output through Paraview software, and the data of special points were smoothed to draw line graphs;

[0036] Furthermore, in S8, the evaluation of the suppression efficiency of gas-powder two-phase explosion suppressant on gas and coal dust explosion is reflected in the macroscopic characteristics of the flame, which can be quantitatively evaluated by the temperature drop index and the explosion overpressure drop index.

[0037] The beneficial effects of the present invention are:

[0038] (1) Compared with experimental testing methods, the MPRFS-based gas-powder two-phase explosion suppressant performance evaluation method proposed in this invention is safer and more efficient for evaluating the explosion suppression performance of gas-powder two-phase explosion suppressants. Furthermore, this evaluation method does not require the construction of an expensive experimental platform, has low investment costs, and is simple and convenient to operate, greatly simplifying the evaluation process of the explosion suppression performance of gas-powder two-phase explosion suppressants.

[0039] (2) The MPRFS-based gas-powder two-phase explosion suppressant efficiency evaluation method proposed in the present invention has high practical value. With respect to the explosion suppressant testing method, by constructing a series of numerical calculation methods such as physical models, computational grids, and mathematical models, and using the OpenFOAM-Cantera coupling calculation method to simulate the gas-powder two-phase explosion suppressant's gas-coal dust explosion suppression process, the gas-powder two-phase explosion suppressant's influence characteristics on the gas-coal dust composite explosion temperature, pressure, and reaction can be obtained, and its explosion suppression performance can be evaluated. The method of the present invention can be used for the research and development of mine gas-coal dust explosion suppression technology, and provide a scientific basis for the optimization of related explosion-proof devices.

[0040] (3) The present invention is mainly used in the field of mine safety prevention and control, and can accurately, efficiently and economically evaluate the suppression efficiency of different types of gas-powder two-phase explosion suppressants. Through detailed material transfer and chemical reaction processing, a detailed simulation of the process of explosion suppressants suppressing gas and coal dust explosions is achieved, and the simulation results are highly reliable and have strong applicability. The present invention solves the technical difficulties of uncontrollable explosion risks and high evaluation costs in the current explosion suppression evaluation process of gas-powder two-phase explosion suppressants, and fills the gap in evaluating the explosion suppression performance of gas-powder two-phase explosion suppressants through numerical simulation.

[0041] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0043] Figure 1 This is a flow chart of a method for evaluating the effectiveness of a gas-powder two-phase explosion suppressant in suppressing gas and coal dust explosions based on MPRFS according to an embodiment of the present invention;

[0044] Figure 2 A three-dimensional physical model of a spherical explosion container in an embodiment of the present invention;

[0045] Figure 3 The simulation calculation grid of the spherical explosion container in the embodiment of the present invention;

[0046] Figure 4 This is the validation result of the simulation calculation grid for the spherical explosion container in the embodiment of the present invention;

[0047] Figure 5 The validity verification result of the numerical calculation model obtained by simulation of the present invention;

[0048] Figure 6 The isosurface diagram of the reaction interface of the explosive material of the gas-coal dust mixture at different times obtained by simulation of the present invention;

[0049] Figure 7 The isosurface diagram of the reaction interface of the explosive material of the gas-coal dust mixture at different times when the explosion suppressant is added obtained by simulation of the present invention;

[0050] Figure 8 The cloud diagram of the explosion temperature change of the gas-coal dust mixture at different times obtained by the simulation of the present invention;

[0051] Figure 9 This is a cloud diagram of the explosion pressure change of the gas-coal dust mixture at different times obtained by simulation of the present invention;

[0052] Figure 10 This is a cloud diagram of the explosion temperature change of the gas-coal dust mixture at different times when adding the explosion suppressant obtained by simulation of the present invention;

[0053] Figure 11 This is a cloud diagram of the explosion pressure change of the gas-coal dust mixture at different times when the explosion suppressant is added, obtained by simulation of the present invention;

[0054] Figure 12 This is a cloud diagram of the particle size change of the gas-coal dust mixture explosion at different times when adding explosion suppressant obtained by simulation of the present invention;

[0055] Figure 13 This is the explosion overpressure evolution curve of the gas-coal dust explosion mixture before and after adding the explosion suppressant obtained by simulation of the present invention;

[0056] Figure 14 This is the explosion temperature evolution curve of the gas-coal dust explosion mixture before and after adding the explosion suppressant obtained by simulation of the present invention. DETAILED DESCRIPTION

[0057] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0058] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0059] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0060] See also Figures 1 to 14 The embodiment of the present invention provides a method for evaluating the effectiveness of a gas-powder two-phase explosion suppressant in suppressing gas and coal dust explosions based on MPRFS, which specifically includes the following steps:

[0061] S1: Construct a mathematical model for suppressing gas and coal dust explosions using a gas-powder two-phase explosion suppressant. Based on the NS equations, the component transport model, discrete phase model, turbulence model, radiation model, and reaction kinetics model are integrated to form a set of mathematical equations.

[0062] Specifically, a component transport model considering Full Multicomponent Diffusion was selected to solve the migration and change laws of each gas component during the explosion suppression reaction process. In the discrete phase model, the pyrolysis and gasification of coal dust and powder explosion suppressant were considered, and the Lagrangian method was used to track the motion trajectory of discrete phase particles. The motion trajectory of individual particles was calculated by solving the momentum equation. The forces acting on coal particles and powder explosion suppressant particles mainly include particle inertia force, single particle drag force, gravity and buoyancy force, virtual mass force, pressure gradient force, Magnus lift force, Saffman lift force, etc. The Scale-Adaptive Simulation (SAS) turbulence model was used to capture the fluid flow and turbulence characteristics in the container during the explosion suppression reaction. The reaction kinetics model includes the homogeneous chemical reaction of the gas phase and the heterogeneous chemical reaction process of coke particles and powder explosion suppressant powder. The homogeneous reaction rate is determined by the minimum value of the chemical reaction rate and the turbulent mixing rate. For coal particle combustion, a two-step competition model is used to simulate the precipitation of volatiles, a finite rate eddy dissipation model is used for volatile combustion, and a finite diffusion kinetic model is used for coke combustion. The modified Areus formula is used to describe the thermal decomposition and reaction process of powder explosion suppressants in an explosive environment. The P1 radiation model is used to describe the gas-gas, gas-solid, and gas-solid-wall interactions during the explosion suppression reaction. The modified Areus formula is expressed as follows:

[0063]

[0064] Among them, r i is the decomposition rate of explosion suppressant; ρ s and ρ s0 are the real-time density and initial density of explosion suppressant respectively; A i and E i is the pre-exponential factor and activation energy of the explosion suppressant; R is the reaction constant, T s is the real-time temperature of the reaction system.

[0065] S2: Determine the initial conditions, boundary conditions and input parameters of the mathematical model, such as initial temperature, initial pressure, powder injection pressure, dust concentration and gas concentration, as well as the particle size range and distribution characteristics of the powder inhibitor and coal dust;

[0066] Specifically, the ignition delay was 60ms, the initial temperature was the ambient temperature (25°C), the initial pressures of the spherical tank and the dust bin were set to -0.06MPa and 2MPa, respectively. The Peng-Robinson equation was used to describe the gas density equation of state, and the Poisson distribution and Rosin-Rammler distribution functions were used to describe the particle size distribution characteristics of the powder inhibitor and coal dust.

[0067]

[0068] Where d is the average particle size and m is the propagation coefficient.

[0069] Specifically, the methane concentration is 9.5%; the inert gas is CO2 / N2, with concentrations of 2.5%, 5%, 7.5%, and 10% respectively; the powder explosion suppressant (modified kaolin) has a particle size range of 5-20μm, a concentration of 10%-50%, and an increase of 10%; the coal dust particle size range is 30-75μm, and the coal dust concentration is 300g / m 3 .

[0070] S3: If Figure 2 As shown in the figure, based on the overall structural characteristics of the 20L spherical explosion container, Solidworks software was used to construct the explosion reaction chamber, dispersion plate, electromagnetic control valve, high-pressure dust bin and other parts. After adjusting the parameters and positions of the parts in the software, they were assembled into a 3D physical model. After checking the constraints of each accessory, a 3D digital model of the explosion container was generated.

[0071] S4: Construct the simulation calculation grid and the distribution domain of gas, coal dust and gas-powder two-phase explosion suppressant. Based on the three-dimensional digital model, use the mesh division software to generate the corresponding grid model, verify the validity of the grid model, and name the boundary conditions of the region. To ensure that all interfaces in the grid are effectively identified, use the grid drawing tool SnappyHexMesh to draw the calculation grid of the powder spraying area, flow channel and reaction area. After exporting the FLUENT solution grid, use fluentMeshToFoam to convert it into an OpenFOAM grid, and name the boundary conditions of the region to construct the rigid gas-powder two-phase explosion suppressant calculation grid and fluid domain. Figure 3 1 is a schematic diagram of the calculation mesh of the explosion reaction vessel drawn using the SnappyHexMesh tool in an embodiment of the present invention.

[0072] Specifically, the mesh drawing tool SnappyHexMesh was used to obtain three different mesh sizes, which were defined as dense mesh (1206312), sparse mesh (986865), and super sparse mesh (696300). The mesh model was optimized using pre-processing software to ensure sufficient mesh density in the key area where the gas and coal dust explosion shock wave interacts with the gas-solid two-phase inhibitor.

[0073] S5: Create thermodynamic and reaction kinetic files for gas-coal dust composite explosions and explosion suppressant decomposition. Use Cantera to simulate the chemical reaction kinetics of gas-solid powder suppression of gas-coal dust explosions. Analyze the thermodynamic parameters and sensitivity characteristics of key elementary reactions to optimize the reaction mechanism files that characterize key elementary reactions at different reaction stages during the explosion suppression reaction.

[0074] Specifically, the thermodynamic files and reaction kinetic files used for gas-coal-dust composite explosion and explosion suppressant decomposition are constructed based on the gas / anthracite composite explosion reaction. The decomposition reaction of the gas-powder two-phase inhibitor involved adopts the multi-component chemical reaction mechanism in the Cantera library to achieve detailed modeling of the explosion suppressant decomposition process.

[0075] S6: Develop a CFD numerical simulation solver and OpenFOAM-Cantera coupling interface file, develop a CFD solver for calculating gas-solid powder suppression of gas and coal dust explosions, design a coupling interface for data transmission between OpenFOAM and Cantera, and achieve accurate solution of multi-phase and multi-reaction flow fields;

[0076] Specifically, the numerical solver developed is suitable for simulating the reaction of gas-powder two-phase explosion suppressant suppressing gas and coal dust explosions, and is called after being modified based on the solvers ReactingParcelFoam and coalChemistryFoam, taking full account of the mathematical model of the reaction of explosion suppressant suppressing gas and coal dust composite explosions; the coupling interface between OpenFOAM and Cantera is designed through an open standard API combined with Fortran language to ensure the data transmission efficiency and calculation accuracy between OpenFOAM and Cantera.

[0077] S7: Numerical simulation and model modification of the synergistic suppression of gas and coal dust explosions by gas-powder two-phase explosion suppressants. The developed OpenFOAM-Cantera coupled simulation method was used to perform numerical simulations of the suppression of gas and coal dust explosions by gas-powder two-phase explosion suppressants, combining mathematical models and grid models. The changes in temperature, pressure, and reaction during the explosion suppression reaction were output, and the mathematical model and input parameters established above were modified based on the experimental results of typical working conditions.

[0078] Specifically, OpenFOAM is used to process the CFD part, and the pressure-based transient solver is used to solve the explosion reaction process. The energy equation, momentum equation and mass equation are mainly solved. The SIMPLE pressure-velocity coupling algorithm is used to participate in the solution of the simulation process, and the second-order upwind format is used to spatially discretize the energy, momentum, process variables and average mixing fraction. Cantera is used to calculate the detailed chemical reaction, and the flow field information such as temperature and pressure in OpenFOAM is passed to Cantera. Based on this information, Cantera calculates the chemical reaction process such as chemical reaction rate and species concentration change, and then feeds it back to OpenFOAM to update the material transport and energy conservation equations in the flow field;

[0079] Specifically, the Paraview software was used to output the cloud diagram of the temperature, pressure and reaction changes during the explosion suppression reaction process, and the data of special points were smoothed to draw line graphs;

[0080] During the simulation process, the temporal and spatial evolution and distribution characteristics of the explosion temperature field, flow field and explosion pressure field are recorded, and the changing trends of temperature and pressure under different conditions are analyzed. Figure 6 and attached Figure 7 They are respectively a three-dimensional flame temperature rendering cloud map and a two-dimensional flame temperature slice cloud map obtained by simulation of the present invention; the two groups of working conditions in the figure correspond to the gas-coal dust explosion and the reaction cloud map of the gas-coal dust mixture when a gas-powder two-phase explosion suppressant is added. From the evaluation results of the reaction material interface, it can be seen that after adding the explosion suppressant, the material interface becomes rougher and the fractal characteristics become more obvious. In addition, the injection of the explosion suppressant increases the turbulent characteristics and suppresses the reaction process of the gas-coal dust explosion mixture. It can be seen that the MPRFS-based gas-powder two-phase explosion suppressant efficiency evaluation method proposed by the present invention for suppressing gas-coal dust explosions can well carry out accurate evaluation of the atmosphere explosion suppressant suppressing gas-coal dust composite explosions.

[0081] Data analysis tools are used to extract key features such as temperature evolution, explosion overpressure, and free radical distribution from the simulation data, and to analyze the spatiotemporal dynamic evolution characteristics of temperature, pressure, and free radical information before and after explosion suppression. The temperature and pressure evolution law of the gas-powder two-phase explosion suppressant in suppressing gas-coal dust composite explosions can be obtained, and the explosion suppression performance of the gas-powder two-phase explosion suppressant can be evaluated. Figure 8 , Attachment Figure 9 The cloud diagram of the explosion temperature field and pressure field of the gas-coal dust mixture changing with time is obtained through simulation analysis. Figure 10 , Attachment Figure 11 , Attachment Figure 12 The cloud diagram of the explosion temperature field, pressure field and particle size change over time of the gas-coal dust mixture when adding gas powder explosion suppressant is obtained through simulation analysis. Figure 13 , Attachment Figure 14 Comparative analysis of the explosion pressure and temperature characteristics of gas-coal-dust explosion mixtures before and after the addition of a gas-powder explosion suppressant allows for further evaluation of the suppression performance of the gas-powder two-phase explosion suppressant using quantitative data such as explosion overpressure and explosion temperature. The suppression effect of a gas-powder two-phase explosion suppressant on gas-coal-dust explosions is primarily reflected in its macroscopic characteristics. Significant reductions in flame and pressure indicate that the gas-powder two-phase explosion suppressant is effective in suppressing gas-coal-dust explosions.

[0082] Secondly, by changing the working conditions of other explosion suppressant ratios that need to be evaluated and repeating S1 to S7, and selecting appropriate reaction mechanisms and model input parameters, the influence of different ratios of gas-powder two-phase explosion suppressants on the suppression of various degrees of gas-coal dust composite explosions can be obtained.

[0083] S8: Evaluate the effectiveness of a gas-powder two-phase explosion suppressant in synergistically suppressing gas and coal dust explosions. Based on the numerical simulation output, evaluation indicators are created based on explosion temperature, explosion overpressure, and other factors, and a comprehensive explosion suppression evaluation index system is developed. Table 1 shows the evaluation indicators and grades for the effectiveness of a gas-powder two-phase explosion suppressant in suppressing gas and coal dust explosions, as described in an embodiment of the present invention. Table 2 shows the evaluation results of the effectiveness of a gas-powder two-phase explosion suppressant in suppressing gas and coal dust explosions, as described in an embodiment of the present invention, based on MPRFS.

[0084] Table 1

[0085]

[0086] Table 2

[0087]

[0088]

[0089] Combined with the numerical simulation results, the suppression efficiency of gas-powder two-phase explosion suppressant on gas and coal dust explosions was evaluated.

[0090]

[0091] Among them, Dp inhi,max 、D(dp / dt) inhi,max 、DK inhi,max DT inhi,max and D(dT / dt) inhi,max They are the decrease ratio of maximum explosion pressure, the decrease ratio of maximum explosion pressure rise rate, the decrease ratio of maximum explosion index, the decrease ratio of maximum explosion temperature, and the decrease ratio of maximum explosion temperature rise rate; p max 、p inhi,max are the maximum explosion pressure and the maximum explosion pressure with inhibitor added; (dp / dt) max 、(dp / dt) inhi,max are the maximum explosion pressure and the maximum explosion pressure rising rate with the addition of inhibitor; K max , K inhi,max are the maximum explosion pressure and the maximum explosion pressure index with inhibitor added; T max 、T inhi,max are the maximum explosion pressure and the maximum explosion temperature with the addition of inhibitors; (dT / dt) max 、(dT / dt) inhi,max are the maximum explosion pressure and the maximum explosion temperature rising rate with the addition of inhibitor, respectively.

[0092] In the above embodiments, references to "this embodiment" in the specification indicate that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least some embodiments, but not necessarily all embodiments. Multiple occurrences of "this embodiment" do not necessarily refer to the same embodiment.

[0093] In the above embodiments, although the invention has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations of these embodiments will be apparent to those skilled in the art based on the foregoing description. For example, other memory structures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed. The embodiments of the present invention are intended to encompass all such alternatives, modifications, and variations that fall within the broad scope of the appended claims.

[0094] This embodiment further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, any one of the methods in this embodiment is implemented.

[0095] This embodiment also provides an electronic terminal, including: a processor and a memory;

[0096] The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes any one of the methods in this embodiment.

[0097] Regarding the computer-readable storage medium in this embodiment, those skilled in the art will appreciate that all or part of the steps in the aforementioned method embodiments can be implemented using hardware associated with the computer program. The aforementioned computer program can be stored in a computer-readable storage medium. When executed, the program performs the steps in the aforementioned method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0098] The electronic terminal provided in this embodiment includes a processor, a memory, a transceiver and a communication interface. The memory and the communication interface are connected to the processor and the transceiver and complete communication with each other. The memory is used to store computer programs, the communication interface is used for communication, and the processor and the transceiver are used to run computer programs so that the electronic terminal executes the various steps of the above method.

[0099] In this embodiment, the memory may include a random access memory (RAM), and may also include a non-volatile memory (non-volatile memory), such as at least one disk storage.

[0100] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, and discrete hardware components.

[0101] The present invention can be used in a wide variety of general-purpose or special-purpose computing system environments or configurations, such as personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, and distributed computing environments that include any of the above.

[0102] The present invention may be described in the general context of computer-executable instructions, such as program modules, executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, and the like that perform specific tasks or implement specific abstract data types. The present invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media, including storage devices.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. An MPRFS-based method for evaluating the effectiveness of gas-powder two-phase explosion suppressants in suppressing gas and coal dust explosions is characterized by: The following steps are involved: S1: Construct a mathematical model for suppressing gas and coal dust explosions using a gas-powder two-phase explosion suppressant. Based on the NS equations, the component transport model, discrete phase model, turbulence model, radiation model, and reaction kinetics model are integrated to form a set of mathematical equations. S2: Determine the initial conditions, boundary conditions and input parameters of the mathematical model, including initial temperature, initial pressure, powder injection pressure, dust concentration and gas concentration, as well as the particle size range and distribution characteristics of the powder inhibitor and coal dust; S3: Establish a 3D physical model of the explosion container. According to the overall structural characteristics of the explosion reaction container, construct the explosion reaction cavity, dispersion plate, electromagnetic control valve and high-pressure dust bin parts, assemble them into a 3D physical model, and generate a 3D digital model of the explosion container. S4: Construct the simulation calculation grid and the distribution domain of gas, coal dust and gas-powder two-phase explosion suppressant. Based on the three-dimensional digital model, generate the corresponding grid model, verify the effectiveness of the grid model, and name the boundary conditions of the region. S5: Create thermodynamic and reaction kinetic files for gas-coal dust composite explosions and explosion suppressant decomposition. Use Cantera to simulate the chemical reaction kinetics of gas-solid powder suppression of gas-coal dust explosions. Analyze the thermodynamic parameters and sensitivity characteristics of key elementary reactions to optimize the reaction mechanism files that characterize key elementary reactions at different reaction stages during the explosion suppression reaction. S6: Develop a CFD numerical simulation solver and OpenFOAM-Cantera coupling interface file, develop a CFD solver for calculating gas-solid powder suppression of gas and coal dust explosions, design a coupling interface for data transmission between OpenFOAM and Cantera, and achieve accurate solution of multi-phase and multi-reaction flow fields; S7: Numerical simulation and model modification of the synergistic suppression of gas and coal dust explosions by gas-powder two-phase explosion suppressants. The developed OpenFOAM-Cantera coupled simulation method was used to perform numerical simulations of the suppression of gas and coal dust explosions by gas-powder two-phase explosion suppressants, combining mathematical models and grid models. The temperature, pressure, and reaction changes during the explosion suppression reaction were output, and the mathematical model and input parameters established above were modified based on the experimental results of typical working conditions. S8: Evaluation of the effectiveness of gas-powder two-phase explosion suppressant in synergistically suppressing gas and coal dust explosions. According to the output results of numerical simulation, evaluation indicators are created based on explosion temperature and explosion overpressure, and a comprehensive explosion suppression evaluation index system is formulated. Combined with the numerical simulation results, the suppression effectiveness of gas-powder two-phase explosion suppressant on gas and coal dust explosions is evaluated.

2. The MPRFS-based gas-powder two-phase explosion suppressant performance evaluation method for suppressing gas and coal dust explosions according to claim 1, characterized in that: In S1, a component transport model considering Full Multicomponent Diffusion is selected to solve the migration change law of each gas component in the explosion suppression reaction process.

3. The MPRFS-based gas-powder two-phase explosion suppressant performance evaluation method for suppressing gas and coal dust explosions according to claim 1, characterized in that: In S1, in the discrete phase model, the pyrolysis and gasification of coal dust and powder explosion suppressant are considered, the Lagrangian method is used to track the motion trajectory of discrete phase particles, and the motion trajectory of a single particle is calculated by solving the momentum equation.

4. The MPRFS-based gas-powder two-phase explosion suppressant performance evaluation method for suppressing gas and coal dust explosions according to claim 1, characterized in that: In S1, the Scale-AdaptiveSimulation turbulence model is used to capture the fluid flow and turbulence characteristics in the container during the explosion suppression reaction.

5. The MPRFS-based gas-powder two-phase explosion suppressant performance evaluation method for suppressing gas and coal dust explosions according to claim 1, characterized in that: In S1, the reaction kinetics model includes the homogeneous chemical reaction of the gas phase and the heterogeneous chemical reaction process of the coke particles and the powder explosion suppressant powder; the homogeneous reaction rate is determined by the minimum value of the chemical reaction rate and the turbulent mixing rate.

6. The MPRFS-based gas-powder two-phase explosion suppressant performance evaluation method for suppressing gas and coal dust explosions according to claim 1, characterized in that: In S1, the P1 radiation model is used to describe the gas-gas, gas-solid and gas-solid-wall interactions during the explosion suppression reaction.

7. The MPRFS-based gas-powder two-phase explosion suppressant performance evaluation method for suppressing gas and coal dust explosions according to claim 1, characterized in that: In S7, OpenFOAM is used to process the CFD part, and Cantera is used to calculate the detailed chemical reaction. The flow field information of temperature and pressure in OpenFOAM is transmitted to Cantera. Based on this information, Cantera calculates the chemical reaction rate and the chemical reaction process of the species concentration change, and then feeds it back to OpenFOAM to update the material transport and energy conservation equations in the flow field.

8. The MPRFS-based gas-powder two-phase explosion suppressant performance evaluation method for suppressing gas and coal dust explosions according to claim 1, characterized in that: In the above-mentioned S8, the evaluation of the suppression efficiency of the gas-powder two-phase explosion suppressant on gas and coal dust explosion is reflected in the macroscopic characteristics of the flame, and is quantitatively evaluated through the temperature drop index and the explosion overpressure drop index.

9. A computer-readable storage medium having a computer program stored thereon, wherein when the program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

10. An electronic terminal comprising: processor and memory; The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes the method according to any one of claims 1 to 8.

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