A gas cloud explosion assessment method and system for coupling multiple potential gas explosion sources

Abstract

The present disclosure provides a gas cloud explosion assessment and system coupled with multiple potential gas explosion sources, comprising: obtaining a gas cloud concentration according to a gas leakage time and a gas leakage height; obtaining a gas cloud mass according to the gas cloud concentration and an integral method, and respectively obtaining explosion overpressures of multiple gas explosion sources according to the gas cloud mass and a BST method; obtaining explosion overpressure distribution of multiple gas explosion sources superimposed according to the obtained overpressures of the multiple gas explosion sources and a nonlinear superposition law of shock waves of multiple explosion sources; the present disclosure mainly solves the problem of analyzing explosion shock wave overpressures of multiple potential gas explosion sources formed in a process in which dangerous gases diffuse to form a vapor cloud, and multiple congested areas are formed within a gas cloud diffusion range.

Description

Technical Field

[0001] The present invention relates to the technical field of gas cloud explosion assessment, and in particular to a method and system for assessing gas cloud explosion coupled with multiple potential gas explosion sources. Background Art

[0002] Gas explosion source: refers to a blocked, enclosed space or area that may produce flammable gas within the explosion limit. When the flammable gas encounters a delayed ignition source, it will produce gas deflagration or detonation. Gas explosion source is also called gas explosion blockage area.

[0003] At present, the analysis of gas cloud explosion formed by combustible gas is mostly reflected in the analysis of single gas explosion source. The main methods currently used for the analysis of explosion effect of single gas explosion source are TNT (trinitrotoluene explosive) equivalent method, TNO (Netherlands Institute for Scientific Research) multi-energy method, experimental research and numerical simulation method.

[0004] The TNT equivalent method has analyzed all explosion sources as equivalent to TNT explosives, without considering the degree of gas confinement or obstruction, which is quite different from gas cloud explosion and has great limitations in solving vapor cloud explosion. The TNO multi-energy method is mainly used to analyze partially confined or obstructed gas cloud explosions, and considers the degree of gas obstruction or partial confinement in the explosion area. However, this method requires manual estimation when determining the combustion energy of the gas explosion source, which has strong human subjectivity, resulting in low accuracy of the calculation results when calculating the far-field explosion shock wave. Experimental research requires a lot of time for preparation. From the design of the experimental plan to the construction and implementation of the experimental device, it often takes a long time to prepare for an experiment that can be completed in a few hours. Moreover, due to the limited experimental scale, the simple experimental data does not have good universality. Numerical simulation methods, especially CFD (computational fluid dynamics) technology, provide great convenience for studying explosion wave related issues. However, the computational fluid dynamics method requires a lot of time to calculate the control equations of each unit in each time step. This time consumption is closely related to the setting conditions such as the number of units, grid size, and time step size, and these conditions also have an important impact on the calculation accuracy. In order to obtain higher accuracy, more computing time is often required. Even for relatively simple working conditions, the calculation process may last for several hours or even days. Therefore, although the CFD method has good analysis accuracy, it cannot solve the problem of fast calculation required in engineering applications.

[0005] The inventors of the present disclosure have found that, according to actual engineering conditions, within the scope of the vapor cloud formed by the leakage, there are often multiple congested areas (the basic condition for constituting an explosion source). When multiple congested areas are detonated, the superposition effect of the explosion shock wave will be formed, which will cause complex impacts on the surrounding areas. However, the current analysis of the explosion vapor cloud usually only considers the situation of one explosion source, which will lead to conservative calculations and easily lead to underestimation of risks. The calculation results caused by single explosion source analysis and simple cumulative analysis are inaccurate. Summary of the invention

[0006] In order to solve the above problems, the present disclosure proposes a gas cloud explosion assessment method and system coupled with multiple potential gas explosion sources. The present disclosure mainly solves the problem of explosion shock wave overpressure analysis caused by the formation of multiple congested areas within the diffusion range of the gas cloud during the process of dangerous gas diffusion to form a vapor cloud, thereby forming multiple potential gas explosion sources.

[0007] In a first aspect, the present disclosure provides a method for assessing a gas cloud explosion coupled with multiple potential gas explosion sources, comprising:

[0008] According to the gas leakage time and gas leakage height, the gas cloud concentration is obtained;

[0009] According to the gas cloud concentration and the integral method, the gas cloud mass is obtained.

[0010] According to the gas cloud mass and the BST method, the explosion overpressures of multiple gas explosion sources are obtained respectively;

[0011] According to the obtained overpressures of multiple gas explosion sources and the nonlinear superposition law of shock waves from multiple explosion sources, the explosion overpressure distribution of the superposition of multiple gas explosion sources is obtained.

[0012] Furthermore, when the gas cloud concentration is obtained according to the gas leakage time and the gas leakage height, the Gaussian smoke puff model is used to obtain the gas cloud concentration distribution at any time during the instantaneous leakage, and the Gaussian smoke plume model is used to obtain the gas cloud concentration distribution when the continuous leakage source is in a stable state.

[0013] Furthermore, the mass of the gas cloud is obtained according to the gas cloud concentration within the lower explosion limit and the upper explosion limit and the integration method.

[0014] Furthermore, the contents of obtaining the explosion overpressure of a single gas explosion source include:

[0015] According to the mass of the gas cloud, the explosion energy is obtained, and according to the explosion energy, the dimensionless distance is obtained;

[0016] According to the dimensionless distance and the dimensionless overpressure-distance curve, the explosion overpressure of a single gas explosion source is obtained.

[0017] Furthermore, according to the gas cloud mass, the explosion energy content includes:

[0018] According to the mass of the vapor cloud, assuming that the concentration of the leaked gas and air mixture is the stoichiometric concentration, the volume of the vapor cloud is obtained;

[0019] The explosion source radius is obtained according to the volume of the gas cloud;

[0020] The explosion source energy is obtained according to the explosion source radius and the combustion heat of hydrocarbons at stoichiometric concentration.

[0021] Furthermore, the dimensionless distance is determined by the relationship between the distance from the center of the gas explosion source, the explosion energy and the ambient atmospheric pressure.

[0022] Furthermore, the nonlinear superposition law of shock waves from multiple explosion sources is: according to the increments of density, shock wave velocity and pressure at the target point caused by a single explosion source at a certain moment, based on the principles of conservation of mass, momentum and energy, the density, shock wave velocity and pressure of the gas at the target point are obtained respectively; wherein the shock wave velocity is a vector.

[0023] In a second aspect, the present disclosure further provides a gas cloud explosion assessment system coupled with multiple potential gas explosion sources, including a gas cloud concentration acquisition module, a gas cloud mass acquisition module, an explosion overpressure acquisition module, and an explosion assessment module;

[0024] The gas cloud concentration acquisition module is configured to: obtain the gas cloud concentration according to the gas leakage time and the gas leakage height;

[0025] The gas cloud mass acquisition module is configured to: obtain the gas cloud mass according to the gas cloud concentration and the integral method,

[0026] The explosion overpressure acquisition module is configured to: obtain explosion overpressures of multiple gas explosion sources respectively according to the gas cloud mass and the Baker-Strehlow-Tang method;

[0027] The explosion assessment module is configured to obtain the explosion overpressure distribution of multiple gas explosion sources superimposed on each other according to the obtained overpressure of multiple gas explosion sources and the nonlinear superposition law of shock waves of multiple explosion sources.

[0028] In a third aspect, the present disclosure further provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps in the method for assessing gas cloud explosions coupled with multiple potential gas explosion sources described in the first aspect are implemented.

[0029] In a fourth aspect, the present disclosure further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the gas cloud explosion assessment coupled with multiple potential gas explosion sources described in the first aspect.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present disclosure makes systematic improvements in the distribution of actual explosion gas clouds, the participation of gas clouds in explosions, and the analysis of the superposition effect of multiple gas explosion sources, so that it can better reflect the actual situation of gas cloud explosions, while improving the calculation accuracy as much as possible, achieving the purpose of improving the analysis and calculation efficiency, and improving the engineering universality of the method;

[0032] 2. In the process of determining the mass of gas cloud, the present invention abandons the traditional view that all leaked gases constitute explosive gas clouds, and only considers the gas clouds within the upper and lower explosion limits, and uses the integral method to obtain the mass of the gas cloud that will actually participate in the explosion, thereby avoiding overestimation of the explosion effect;

[0033] 3. The present disclosure uses the BST (Baker-Strehlow-Tang) method to calculate the overpressure of the vapor cloud explosion generated by a single gas explosion source, eliminating the shortcomings of the previous methods;

[0034] 4. The present disclosure combines the propagation and superposition laws of multi-source explosion shock waves and uses the LAMB criterion for superposition analysis, abandoning the drawbacks of traditional simple accumulation and ignoring the coupling laws of explosion waves;

[0035] This method can fully improve the calculation accuracy while further improving the analysis and calculation efficiency, which is more in line with the actual needs of balancing accuracy and calculation efficiency in engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings in the specification that constitute a part of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments of this embodiment and their descriptions are used to explain this embodiment and do not constitute improper limitations on this embodiment.

[0037] Figure 1 This is the technical roadmap of Example 1 of the present disclosure;

[0038] Figure 2 is the dimensionless overpressure-distance curve of Example 1 of the present disclosure;

[0039] Figure 3 This is a schematic diagram of the blocking degree of Example 1 of the present disclosure. DETAILED DESCRIPTION

[0040] The present disclosure is further described below in conjunction with the accompanying drawings and embodiments.

[0041] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0042] As described in the background technology, single explosion source analysis and simple cumulative analysis will cause inaccurate calculation results. Based on the analysis of explosion shock wave overpressure formed by a single explosion source and the basic law of energy superposition of explosion shock wave overpressure formed by multiple explosion sources, the technical method of the present disclosure is proposed, and the specific implementation methods are as follows:

[0043] Embodiment 1:

[0044] like Figure 1 As shown, the present disclosure provides a method for evaluating a gas cloud explosion coupled with multiple potential gas explosion sources; the method mainly comprises the following steps:

[0045] Calculate the diffusion of combustible gas and obtain the spatial distribution of gas cloud concentration in the area;

[0046] The integral method (the upper and lower limits of the integral are the combustion limits) calculates the mass (or volume) of the flammable vapor cloud and the explosion energy involved in the explosion in each potential gas explosion source (i.e., congested space);

[0047] The BST method calculates the vapor cloud explosion overpressure generated by a single gas explosion source;

[0048] The superposition effect of multiple potential gas explosion sources at the same target location is analyzed to obtain the explosion overpressure distribution under the conditions of multiple potential explosion sources.

[0049] Gas cloud diffusion analysis:

[0050] The assessment of flammable vapor cloud explosions first requires an analysis of the concentration distribution of flammable gas clouds. A relevant diffusion model is needed to predict the changes in the concentration of hazardous substances released into the environment over time and space. Factors that affect the diffusion of substances include: (1) release conditions, including substance type, phase state, and physical properties; source model (exit velocity, leakage mass rate, release amount, etc.); location of the leakage source; (2) meteorological conditions, including wind direction, wind speed, atmospheric stability, etc.; (3) terrain conditions, mainly ground roughness. The diffusion model uses the Gaussian model. According to the release type, the Gaussian model is mainly divided into two types: the puff model that simulates the instantaneous release of gas and the plume model that simulates the continuous release of gas.

[0051] The Gaussian plume model is applicable to continuous leakage sources, and its results can describe the distribution of neutral gas cloud concentration when the leakage is in a stable state. The specific calculation formula is as follows:

[0052]

[0053] Where C(x,y,z,H) is the concentration at a given location x,y,z, in kg / m 3 ; q is the leakage rate, in kg / s; u is the wind speed, in m / s; σ y ,σ z is the diffusion coefficient in the crosswind direction and vertical wind direction, which is a function of the downwind distance x, in meters; H is the effective leakage height, in meters; x is the downwind distance, in meters; y is the crosswind distance, in meters; z is the vertical wind distance, that is, the height, in meters.

[0054] The Gaussian puff model is suitable for describing instantaneous leakage. The model can calculate the gas cloud concentration distribution at any time t. The calculation formula is as follows:

[0055]

[0056] Where C(x,y,z,H,t) is the concentration at a given position x,y,z at time t, in kg / m 3 ; Q is the leakage mass, in kg; σ x ,σ y ,σ z is the diffusion coefficient in the downwind, crosswind and vertical wind directions, in m; H is the release height, in m; x is the downwind distance, in m; y is the crosswind distance, in m; z is the vertical wind distance, i.e. the height, in m; t is the time, in s.

[0057] Determine the mass and explosion energy of combustible gas by integration method:

[0058] Due to the influence of meteorological conditions, the gas cloud formed by combustible gas has an irregular shape and its internal concentration is uneven. Therefore, it is necessary to use the integral method to analyze the mass of the gas cloud in the continuous space to improve the accuracy of the gas cloud mass calculation results. Here, the mass of the gas cloud within the lower explosion limit (LEL) and the upper explosion limit (UEL) is analyzed, and the integral formula is as follows:

[0059]

[0060] Where: dV = dx × dy × dz.

[0061] Then, based on the vapor cloud mass and assuming that the concentration of the fuel and air mixture is stoichiometric, the vapor cloud volume can be obtained:

[0062]

[0063] Where V c is the volume of the vapor cloud in m 3 ; W fis the mass of fuel in the vapor cloud, in kg; ρ is the density of the substance (gas) at ambient temperature, in kg / m 3 ; C s It is the stoichiometric concentration of the fuel and air mixture in %.

[0064] The explosion source radius is related to the volume of the vapor cloud. The total energy of the gas explosion source can be obtained by calculating the explosion source radius. The explosion source radius is calculated as follows:

[0065]

[0066] In the formula, r 0 is the explosion source radius, in meters.

[0067] The total energy of the explosion source is calculated as follows

[0068]

[0069] In the formula, E 0 is the total energy of the explosion source, in MJ; E c is the heat of combustion of hydrocarbons at stoichiometric concentration, 3.5 MJ / m 3 .

[0070] Calculate the vapor cloud explosion overpressure generated by each potential gas explosion source:

[0071] Determine the relevant conditions for explosion, including flame propagation mode, obstruction degree and fuel activity; the selection basis is shown in Table 1, Figure 3 (degree of obstruction) and Table 2.

[0072] Table 1 Flame propagation mode:

[0073]

[0074]

[0075] Table 2 Fuel activity:

[0076] Fuel activity Laminar flame speed LFS substance high <![CDATA[LFS>75cm s -1 ]]> Acetylene, ethylene oxide, hydrogen, 1-3 propylene oxide, ethylene middle <![CDATA[45cm s -1 ≤LFS≤75cm s -1 ]]> Acetone, 1-3 butadiene, propane Low <![CDATA[LFS<45cm s -1 ]]> Methane, Carbon Monoxide

[0077] The flame speed is determined based on the degree of confinement, fuel activity and choke level, and the Mach number is used to characterize the flame. The Mach number is determined from Table 3.

[0078] Table 3 Determination of flame speed Mach number:

[0079]

[0080] Compute the dimensionless distance:

[0081]

[0082] In the formula, is the dimensionless distance; R is the distance from the target position to the center of the gas explosion source, in meters; E is the explosion energy, in J; P a is the ambient atmospheric pressure, in Pa.

[0083] Select the corresponding curve according to the Mach number. Figure 2 Get the dimensionless explosion overpressure

[0084] Analysis of explosion effects superposition of multiple potential gas explosion sources:

[0085] Combined with the results of the explosion shock wave overpressure of a single explosion source calculated in (3), the nonlinear superposition law of shock waves from multiple explosion sources, the LAMB superposition law, is introduced. This law is based on the approximate principles of conservation of mass, momentum and energy. The calculation law is as follows:

[0086]

[0087]

[0088]

[0089] in, and P represent the density, shock wave velocity and pressure at the target point at a certain moment, respectively, ρ 0 and P 0 represent the initial density and pressure at the target point, Δρ i , and ΔP i They respectively represent the increments of density, shock wave velocity and pressure at the target point caused by the i-th explosion source at that moment, and the shock wave velocity is a vector.

[0090] Embodiment 2:

[0091] This embodiment provides a gas cloud explosion assessment system coupled with multiple potential gas explosion sources, including a gas cloud concentration acquisition module, a gas cloud mass acquisition module, an explosion overpressure acquisition module and an explosion assessment module;

[0092] The gas cloud concentration acquisition module is configured to: obtain the gas cloud concentration according to the gas leakage time and the gas leakage height;

[0093] The gas cloud mass acquisition module is configured to: obtain the gas cloud mass according to the gas cloud concentration and the integral method,

[0094] The explosion overpressure acquisition module is configured to: obtain explosion overpressures of multiple gas explosion sources respectively according to the gas cloud mass and the BST method;

[0095] The explosion assessment module is configured to obtain the explosion overpressure distribution of multiple gas explosion sources superimposed on each other according to the obtained overpressure of multiple gas explosion sources and the nonlinear superposition law of shock waves of multiple explosion sources.

[0096] Embodiment 3:

[0097] This embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps in the method for assessing gas cloud explosions coupled with multiple potential gas explosion sources described in Example 1 are implemented.

[0098] Embodiment 4:

[0099] This embodiment provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the steps in the method for assessing gas cloud explosions coupled with multiple potential gas explosion sources described in Embodiment 1 are implemented.

[0100] The above description is only a preferred embodiment of the present embodiment and is not intended to limit the present embodiment. For those skilled in the art, the present embodiment may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present embodiment shall be included in the protection scope of the present embodiment.

Claims

1. A method for assessing gas cloud explosions coupled with multiple potential gas explosion sources, characterized in that: include: According to the gas leakage time and gas leakage height, the gas cloud concentration is obtained; According to the gas cloud concentration and the integral method, the gas cloud mass is obtained. According to the gas cloud mass and the Baker-Strehlow-Tang method, the explosion overpressures of multiple gas explosion sources are obtained respectively; According to the obtained overpressure of multiple gas explosion sources and the nonlinear superposition law of shock waves of multiple explosion sources, the explosion overpressure distribution of multiple gas explosion sources superimposed is obtained; The nonlinear superposition law of shock waves from multiple explosion sources is as follows: according to the increments of density, shock wave velocity and pressure at a target point caused by a single explosion source at a certain moment, based on the principles of conservation of mass, momentum and energy, the density, shock wave velocity and pressure of the gas at the target point are obtained respectively; the shock wave velocity is a vector.

2. A method for assessing gas cloud explosions coupled with multiple potential gas explosion sources as claimed in claim 1, characterized in that: When the gas cloud concentration is obtained according to the gas leakage time and the gas leakage height, the Gaussian smoke puff model is used to obtain the gas cloud concentration distribution at any time during the instantaneous leakage, and the Gaussian smoke plume model is used to obtain the gas cloud concentration distribution when the continuous leakage source is in a stable state.

3. A method for assessing gas cloud explosions coupled with multiple potential gas explosion sources as claimed in claim 1, characterized in that: The mass of the gas cloud is obtained based on the gas cloud concentration within the lower explosion limit and the upper explosion limit and the integration method.

4. A method for assessing gas cloud explosions coupled with multiple potential gas explosion sources as claimed in claim 1, characterized in that: The contents of obtaining the explosion overpressure of a single gas explosion source include: According to the mass of the gas cloud, the explosion energy is obtained, and according to the explosion energy, the dimensionless distance is obtained; According to the dimensionless distance and the dimensionless overpressure-distance curve, the explosion overpressure of a single gas explosion source is obtained.

5. A method for assessing gas cloud explosions coupled with multiple potential gas explosion sources as claimed in claim 4, characterized in that: According to the mass of the gas cloud, the explosion energy content includes: According to the mass of the vapor cloud, assuming that the concentration of the leaked gas and air mixture is the stoichiometric concentration, the volume of the vapor cloud is obtained; The explosion source radius is obtained according to the volume of the gas cloud; The explosion source energy is obtained according to the explosion source radius and the combustion heat of hydrocarbons at stoichiometric concentration.

6. A method for assessing gas cloud explosions coupled with multiple potential gas explosion sources as claimed in claim 1, characterized in that: The dimensionless distance is determined by the relationship between the distance of the target location from the center of the gas explosion source, the explosion energy and the ambient atmospheric pressure.

7. A gas cloud explosion assessment system coupled with multiple potential gas explosion sources, characterized in that: It includes a gas cloud concentration acquisition module, a gas cloud mass acquisition module, an explosion overpressure acquisition module and an explosion assessment module; The gas cloud concentration acquisition module is configured to: obtain the gas cloud concentration according to the gas leakage time and the gas leakage height; The gas cloud mass acquisition module is configured to: obtain the gas cloud mass according to the gas cloud concentration and the integral method, The explosion overpressure acquisition module is configured to: obtain explosion overpressures of multiple gas explosion sources respectively according to the gas cloud mass and the BST method; The explosion assessment module is configured to: obtain the explosion overpressure distribution of the superposition of multiple gas explosion sources according to the obtained overpressure of multiple gas explosion sources and the nonlinear superposition law of shock waves of multiple explosion sources; The nonlinear superposition law of shock waves from multiple explosion sources is as follows: according to the increments of density, shock wave velocity and pressure at a target point caused by a single explosion source at a certain moment, based on the principles of conservation of mass, momentum and energy, the density, shock wave velocity and pressure of the gas at the target point are obtained respectively; the shock wave velocity is a vector.

8. An electronic device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps in the gas cloud explosion assessment method coupled with multiple potential gas explosion sources as described in any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, the steps in the gas cloud explosion assessment method coupled with multiple potential gas explosion sources as described in any one of claims 1 to 6 are implemented.

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