MPRFS-based method for evaluating efficiency of gas-powder two-phase explosion suppressant in suppressing explosion of gas and coal dust

Abstract

The invention relates to an MPRFS-based method for evaluating the efficiency of a gas-powder two-phase explosion suppressant in suppressing gas and coal dust explosion, and belongs to the technical field of coal mine underground gas and coal dust explosion protection. The method comprises the following steps: constructing a mathematical model for inhibiting gas and coal dust explosion by the gas-powder two-phase explosion suppressant; determining 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 gas, coal dust and gas powder two-phase explosion suppressant distribution domain; creating a thermodynamic file and a reaction kinetics file of gas and coal dust composite explosion and explosion suppressant decomposition; developing a CFD (Computational Fluid Dynamics) numerical simulation solver and an OpenFOAM-Cantera coupling interface; solving a numerical model and correcting the model; and evaluating the explosion suppression efficiency of the gas-powder two-phase explosion suppressant. The method can effectively evaluate the inhibition effects of different gas-powder two-phase explosion suppressants in gas and coal dust explosion.

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 for suppressing gas and coal dust explosion efficiency evaluation method. Background Art

[0002] In the process of coal mining, the damage and property losses caused by gas and coal dust explosion accidents are huge. Therefore, research on gas and coal dust explosion suppression technology has always been the focus of coal mine disaster prevention and control in various countries. Gas / coal dust composite explosion is a complex reaction process of coupled gas phase combustion and solid phase pyrolysis. Compared with single-phase gas or coal dust explosion, the main control mechanism of gas / coal dust two-phase composite explosion has the characteristics of dynamic change and synergistic reaction, higher explosion sensitivity, explosion intensity and destructive ability, which seriously threatens the safety production of mines and the life and health of workers. In recent years, relevant teams at home and abroad have carried out extensive research on gas and coal dust composite explosion suppression technology. At present, traditional explosion suppression media used for gas and coal dust explosion prevention and control mainly include inert gas, inert powder, fine water mist, aerogel, porous medium materials, etc., and the research methods are mainly experimental testing and macroscopic characterization. These traditional single-phase explosion suppression media have limitations such as high cost, complex operation, and poor environmental adaptability in practical applications, and their explosion suppression effect is greatly affected by the particle size distribution and mass concentration of powder and liquid. In order to improve the suppression efficiency and environmental adaptability of explosion suppressants, researchers have explored the synergistic suppression effects of different media through powder compounding, acid-base modification, multiphase coupling and other methods. Among them, gas-powder two-phase explosion suppressants have attracted widespread attention due to their unique advantages in suppressing explosions. On the one hand, during the premixing process, heterogeneous explosion suppression media collide with the movement of airflow and produce energy exchange, which promotes the pre-decomposition reaction of inert powders, quickly snatches intermediate free radicals and blocks the chain reaction process of the explosion; on the other hand, inert gases and solid materials can effectively reduce oxygen concentration, slow down and prevent the spread of explosions through their cooling and barrier effects. These characteristics make gas-powder two-phase explosion suppressants show great application potential in the field of coal mine safety.

[0003] However, the current macroscopic experimental methods are difficult to accurately evaluate the suppression efficiency of gas-powder two-phase explosion suppressants on gas-coal dust composite explosions, and there are problems such as high cost, long cycle, 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 effects. Combining the two for the evaluation of the explosion suppression effect of gas-powder two-phase explosion suppressants can significantly improve the simulation accuracy and computing efficiency, and provide theoretical support and technical basis for the optimization 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 inhibiting 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 its 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 resistance 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 performance 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 calculation and experimental testing, and its 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 using 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, and 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 prior art 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, but 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 actual application environments, there are limitations such as model simplification and experimental condition restrictions, and it is impossible to comprehensively and objectively evaluate the impact of all potential factors on the thermal reaction mechanism and safety of hazardous chemicals; the evaluation method of the composite system 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, but it also has limitations such as huge demand for computing resources, low accuracy of simulation results 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 actual scenarios.

[0007] In summary, the existing explosion suppression efficiency evaluation methods are mostly based on experimental means, which have problems such as high cost, long cycle, complex conditions, and poor repeatability. The existing explosion suppression performance and evaluation methods are difficult to accurately and truly evaluate the suppression effect and influence law of the selected explosion suppressant. The existing simulation methods such as molecular dynamics and chemical reaction kinetics lack theoretical understanding of the detailed explosion suppression mechanism. In addition, numerical simulation technology has shown high demand and high dependence on computing resources, simulation accuracy and data accuracy. In recent years, with the continuous improvement of computer performance and the development of numerical simulation technology, the use of multiphase reaction flow simulation (MPRFS) method to study the explosion suppression effect of gas-powder two-phase explosion suppressants has become an efficient and economical way. The existing evaluation of explosion suppression effect only solves the explosion suppression effect of a single inhibitor on gas-coal dust composite explosion through a single CFD simulation or chemical kinetics calculation, and cannot accurately evaluate the temperature field, pressure field and reaction process of the gas-powder two-phase explosion suppressant in the real situation. Cantera and OpenFOAM are currently the most widely used chemical reaction and fluid mechanics coupling calculation software, with powerful computing power 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 of gas-powder two-phase explosion suppressant to suppress gas-coal dust explosion. On the basis of NS equation, construct a component transport model to solve the migration and change law of each gas component in the explosion suppression reaction process; construct a discrete phase model to track the force and movement of coal particles and powder inhibitor particles in the explosion suppression reaction process; construct a turbulence model to capture the flow and turbulence characteristics of the fluid in the container during the explosion suppression reaction; construct a reaction kinetic model to describe the kinetic process of gas-powder explosion suppressant suppressing gas-coal dust composite explosion gas phase / surface phase combustion chemical reaction; construct a radiation model to describe the effect of reaction heat radiation on heat transfer between solid particles in the explosion suppression reaction process;

[0012] S2: Determine the initial conditions, boundary conditions and input parameters of the mathematical model. On the basis of constructing 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, so as to accurately reflect the actual explosion environment;

[0013] S2: Determine the initial conditions, boundary conditions and input parameters of the mathematical model. On the basis of constructing 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, so as to accurately reflect the actual explosion environment;

[0014] S3: Establish a 3D physical model of the explosion container. According to the overall structural characteristics of the explosion reaction container, use Solidworks software 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, assemble them into a 3D physical model. After checking the constraints of each accessory, generate a 3D digital model of the explosion container.

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

[0016] S5: Create thermodynamic files and reaction kinetic files for gas-coal-dust composite explosion and explosion suppressant decomposition, use Cantera to carry out chemical reaction kinetic simulation of gas-solid powder suppressing gas-coal-dust explosion, and optimize the reaction mechanism files that characterize key elementary reactions at different reaction stages in the explosion suppression reaction process by analyzing the thermodynamic parameters and sensitivity characteristics of key elementary reactions;

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

[0018] S7: Numerical simulation solution and model correction of gas-powder two-phase explosion suppressant synergistically suppressing gas-coal dust explosion. Combined with mathematical model and grid model, the developed OpenFOAM-Cantera coupling simulation method is used to perform numerical simulation of gas-powder two-phase explosion suppressant suppressing gas-coal dust explosion. The changes of temperature, pressure and reaction during the explosion suppression reaction are output. Combined with the experimental results of typical working conditions, the mathematical model and input parameters established above are corrected.

[0019] S8: Evaluation of the effectiveness of gas-powder two-phase explosion suppressants 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 suppressants 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 and 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, and 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 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 kinetic model constructed 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. For coal particle combustion, the two-step competition model is used to simulate the precipitation of volatiles, the finite rate eddy dissipation model is used for volatile combustion, and the finite diffusion kinetic model is used for coke combustion;

[0024] Furthermore, in S1, the P1 radiation model is selected to describe the interactions between gas-gas, gas-solid, and gas-solid and wall 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 describes 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 5-20μm, 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 ;

[0027] Furthermore, in S3, according to the overall structural characteristics of the explosion reaction vessel, Solidworks software was used to construct the explosion reaction chamber, dispersion plate, electromagnetic control valve, high-pressure dust bin and other parts, and the parts parameters and positions were adjusted in the software and assembled into a three-dimensional physical model. After checking the constraints of each accessory, a three-dimensional digital model of the explosion vessel was generated;

[0028] Furthermore, in S4, in order to ensure that all interfaces in the mesh are effectively identified, the third-party meshing tool SnappyHexMesh is used for meshing, and after exporting the FLUENT solution mesh, fluentMeshToFoam is used to convert it into an OpenFOAM mesh;

[0029] Furthermore, in S4, three different numbers of grids 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 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 experimental results through laboratory tests. According to 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 files and reaction kinetic files of gas-coal-dust composite explosion and explosion suppressant decomposition used are constructed based on the gas / anthracite composite explosion reaction, and 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 decomposition process of the explosion suppressant;

[0032] Furthermore, in S6, the numerical solver developed for simulating the gas-powder two-phase explosion suppressant suppressing the gas-coal dust explosion reaction and the mathematical model of the explosion suppressant suppressing the gas-coal dust composite explosion reaction are 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 reaction, and OpenFOAM is used to process 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 is output through Paraview software, and the data of special points are drawn into line diagrams in a smoothing manner;

[0036] Furthermore, in S8, the evaluation of the suppression efficiency of the gas-powder two-phase explosion suppressant on gas and coal dust explosions 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 gas and coal dust explosion efficiency evaluation method proposed in the present invention is safer and more efficient for the evaluation process of the explosion suppression performance of the gas-powder two-phase explosion suppressant. In addition, the evaluation method does not require the construction of an expensive experimental platform, has a low investment cost, is simple and convenient to operate, and greatly simplifies the evaluation process of the explosion suppression performance of the gas-powder two-phase explosion suppressant.

[0039] (2) The MPRFS-based gas-powder two-phase explosion suppressant performance evaluation method for suppressing gas-coal dust explosions proposed in the present invention has high practical value. With regard 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 suppressing the gas-coal dust explosion process, the influence characteristics of the gas-powder two-phase explosion suppressant on the temperature, pressure and reaction of the gas-coal dust composite explosion 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 problems of uncontrollable explosion risks and high assessment costs in the current explosion suppression assessment 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, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can 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 in conjunction with the accompanying drawings, wherein:

[0043] Figure 1 It is a flow chart of the method for evaluating the effectiveness of the MPRFS-based gas-powder two-phase explosion suppressant in suppressing gas and coal dust explosions 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 A simulation calculation grid for a spherical explosion container in an embodiment of the present invention;

[0046] Figure 4 The results of the validation of the simulation calculation grid of the spherical explosion container in the embodiment of the present invention are as follows;

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

[0048] Figure 6 It is an 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 It is an 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] Fig. 9 The cloud diagram of the explosion pressure change of the gas-coal dust mixture at different times obtained by the simulation of the present invention;

[0052] Fig.10 The cloud diagram of the explosion temperature change of the gas-coal dust mixture at different times when the explosion suppressant is added obtained by simulation of the present invention;

[0053] Fig.11 The 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] Fig.12 The cloud diagram of the change of the particle size of the gas-coal dust mixture explosion at different times when the explosion suppressant is added obtained by simulation of the present invention;

[0055] Fig.13 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] Fig.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 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 only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

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

[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 the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position 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 Figure 1 to Figure 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 explosion with gas-powder two-phase explosion suppressant. Based on the NS equation, the component transport model, discrete phase model, turbulence model, radiation model and reaction kinetic model are integrated to form a set of mathematical equations.

[0062] Specifically, a component transport model considering Full Multicomponent Diffusion is selected to solve the migration and change rules of each gas component in the explosion suppression reaction process; in the discrete phase model, the pyrolysis and gasification of coal dust and powder explosion suppressant are considered, and 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 on coal particles and powder explosion suppressant particles are mainly particle inertia force, single particle drag, gravity and buoyancy, virtual mass force, pressure gradient force, Magnus lift, Saffman lift, etc.; the Scale-Adaptive Simulation (SAS) turbulence model is 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; a modified Areus formula is used to describe the thermal decomposition and reaction process of powder explosion suppressants in an explosive environment; a P1 radiation model is used to describe the interaction between gas-gas, gas-solid, and gas-solid and wall surfaces 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 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 powder inhibitor and coal dust;

[0066] Specifically, 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 describes 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;

[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: Figure 2 As shown in the figure, according to the overall structural characteristics of the 20L spherical explosion container, the explosion reaction chamber, dispersion plate, electromagnetic control valve, high-pressure dust bin and other parts are constructed using Solidworks software. After adjusting the parameters and positions of the parts in the software, they are assembled into a three-dimensional physical model. After checking the constraints of each accessory, a three-dimensional digital model of the explosion container is generated.

[0071] S4: Construct simulation calculation grid and distribution domain of gas, coal dust and gas-powder two-phase explosion suppressant. Based on the three-dimensional digital model, use 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 area, so as to construct the rigid gas-powder two-phase explosion suppressant calculation grid and fluid domain. Figure 3 1 is a schematic diagram of a computational mesh of an 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 numbers, which were defined as dense mesh (1206312), sparse mesh (986865) and super sparse mesh (696300), respectively. The mesh model was optimized by pre-processing software to ensure sufficient mesh density in the key area where the gas and coal dust explosion shock wave and the gas-solid two-phase inhibitor interact.

[0073] S5: Create thermodynamic files and reaction kinetic files for gas-coal-dust composite explosion and explosion suppressant decomposition, use Cantera to carry out chemical reaction kinetic simulation of gas-solid powder suppressing gas-coal-dust explosion, and optimize the reaction mechanism files that characterize key elementary reactions at different reaction stages in the explosion suppression reaction process by analyzing the thermodynamic parameters and sensitivity characteristics of key elementary reactions;

[0074] Specifically, the thermodynamic files and reaction kinetic files of the gas-coal dust composite explosion and explosion suppressant decomposition used 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 realize detailed modeling of the decomposition process of the explosion suppressant.

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

[0076] Specifically, the numerical solver developed is suitable for simulating the gas-powder two-phase explosion suppressant to suppress the gas-coal dust explosion reaction, and is called after modification based on the solvers ReactingParcelFoam and coalChemistryFoam, based on full consideration of the mathematical model of the explosion suppressant suppressing the gas-coal dust composite explosion reaction; 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 solution and model correction of gas-powder two-phase explosion suppressant synergistically suppressing gas-coal dust explosion. Combined with mathematical model and grid model, the developed OpenFOAM-Cantera coupling simulation method is used to perform numerical simulation of gas-powder two-phase explosion suppressant suppressing gas-coal dust explosion. The changes of temperature, pressure and reaction during the explosion suppression reaction are output. Combined with the experimental results of typical working conditions, the mathematical model and input parameters established above are corrected.

[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 cloud diagram of the change of temperature, pressure and reaction during the explosion suppression reaction was output by Paraview software, and the line diagram of the data of special points was drawn by smoothing method;

[0080] In 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 inhibits 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 in the present invention can well carry out accurate evaluation of the atmosphere explosion suppressant in 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 in the simulation data, and the spatiotemporal dynamic evolution characteristics of temperature, pressure, and free radical information before and after explosion suppression are analyzed. 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 Fig. 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. Fig.10 , Attachment Fig.11 , Attachment Fig.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. Fig.13 , Attachment Fig.14 The explosion pressure and temperature change characteristics of the gas-coal dust explosion mixture before and after the addition of gas-powder explosion suppressant were compared and analyzed. The explosion suppression performance of the gas-powder two-phase explosion suppressant can also be further evaluated through the quantitative data of explosion overpressure and explosion temperature. The suppression effect of the gas-powder two-phase explosion suppressant on gas-coal dust explosion is mainly reflected in the macroscopic characteristics. When the flame and pressure are greatly reduced, it shows that the gas-powder two-phase explosion suppressant has a good suppression effect on gas-coal dust explosion.

[0082] Secondly, by changing the working conditions with 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: Evaluation of the effectiveness of gas-powder two-phase explosion suppressant in synergistically suppressing gas-coal dust explosions. According to the output results of numerical simulation, evaluation indicators are created based on explosion temperature, explosion overpressure, etc., and a comprehensive explosion suppression evaluation index system is formulated. Table 1 shows the evaluation indicators and grades of the effectiveness of gas-powder two-phase explosion suppressant in suppressing gas-coal dust explosions described in an embodiment of the present invention; Table 2 shows the evaluation results of the effectiveness of gas-powder two-phase explosion suppressant in suppressing gas-coal dust explosions based on MPRFS described in an embodiment of the present invention.

[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 maximum explosion pressure decrease ratio, the maximum explosion pressure rise rate decrease ratio, the maximum explosion index decrease ratio, the maximum explosion temperature decrease ratio, and the maximum explosion temperature rise rate decrease ratio; p max 、p inhi,max They 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 rise 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 They are the maximum explosion pressure and the maximum explosion temperature with the addition of inhibitors; (dT / dt) max 、(dT / dt) inhi,max They are the maximum explosion pressure and the maximum explosion temperature rise rate with the addition of inhibitor.

[0092] In the above embodiments, the description's reference to "this embodiment" indicates 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 all refer to the same embodiment.

[0093] In the above-described embodiments, although the invention has been described in conjunction with specific embodiments of the invention, many substitutions, modifications, and variations of these embodiments will be apparent to those of ordinary skill in the art based on the foregoing description. For example, other storage structures (e.g., dynamic RAM (DRAM)) may use the embodiments discussed. Embodiments of the invention are intended to encompass all such substitutions, 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] The computer-readable storage medium in this embodiment can be understood by ordinary technicians in this field: all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to the computer program. The aforementioned computer program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes.

[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 to communicate, and the processor and the transceiver are used to run computer programs so that the electronic terminal executes each step 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 memory.

[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, discrete hardware components.

[0101] The present invention can be used in many general or special 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 electronic devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and the like.

[0102] The present invention may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. 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 through a communication network. In a distributed computing environment, program modules may be located in 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 solution of the present invention rather than to limit it. 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 solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. MPRFS-based gas-powder two-phase explosion suppressant performance evaluation method for suppressing gas and coal dust explosions, characterized by: The following steps are involved: S1: Construct a mathematical model for suppressing gas and coal dust explosion with gas-powder two-phase explosion suppressant. Based on the NS equation, the component transport model, discrete phase model, turbulence model, radiation model and reaction kinetic 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 powder inhibitor and coal dust; S3: Establish a three-dimensional physical model of the explosion container. According to the overall structural characteristics of the explosion reaction container, construct the explosion reaction cavity, dispersion sheet, electromagnetic control valve and high-pressure dust bin parts, assemble them into a three-dimensional physical model, and generate a three-dimensional digital model of the explosion container; S4: Construct simulation calculation grid and gas-coal dust and gas-powder two-phase explosion suppressant distribution domain, generate corresponding grid model based on three-dimensional digital model, verify the effectiveness of grid model, and name the boundary conditions of the region; S5: Create thermodynamic files and reaction kinetic files for gas-coal-dust composite explosion and explosion suppressant decomposition, use Cantera to carry out chemical reaction kinetic simulation of gas-solid powder suppressing gas-coal-dust explosion, and optimize the reaction mechanism files that characterize key elementary reactions at different reaction stages in the explosion suppression reaction process by analyzing the thermodynamic parameters and sensitivity characteristics of key elementary reactions; S6: Develop CFD numerical simulation solver and OpenFOAM-Cantera coupling interface file, develop CFD solver for calculating gas-solid powder suppression of gas and coal dust explosion, design coupling interface for data transmission between OpenFOAM and Cantera, and realize accurate solution of multi-phase and multi-reaction flow field; S7: Numerical simulation solution and model correction of gas-powder two-phase explosion suppressant synergistically suppressing gas-coal dust explosion. Combined with mathematical model and grid model, the developed OpenFOAM-Cantera coupling simulation method is used to perform numerical simulation of gas-powder two-phase explosion suppressant suppressing gas-coal dust explosion. The changes of temperature, pressure and reaction during the explosion suppression reaction are output. Combined with the experimental results of typical working conditions, the mathematical model and input parameters established above are corrected. S8: Evaluation of the effectiveness of gas-powder two-phase explosion suppressants 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 suppressants 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 and 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 selected 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 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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