Indoor natural gas explosion hazard assessment method for double-row arrangement of congestion objects

Abstract

The present application relates to an indoor natural gas explosion disaster assessment method applicable to double-row arrangement of congested objects, and belongs to the technical field of natural gas explosion disaster assessment. The method of the present application includes: investigating the explosion accident site, obtaining technical parameter data of the object to be assessed; when judging that the accident is an indoor explosion accident with double-row arrangement of congested objects according to the indoor layout information contained in the technical parameter data, calling a pre-constructed indoor natural gas explosion peak overpressure assessment model, importing the model required data in the technical parameter data into the assessment model for calculation, obtaining the peak overpressure assessment result and outputting it. The present application helps to quickly and effectively implement the assessment of indoor natural gas explosion disasters with double-row arrangement of congested objects.

Description

Technical Field

[0001] The present application belongs to the technical field of natural gas explosion disaster assessment, and specifically relates to an indoor natural gas explosion disaster assessment method suitable for double-row arrangement of congested objects. Background Art

[0002] As a green, clean, and high-quality energy source, natural gas is widely used in civilian cooking and heating. However, due to aging pipelines and improper use of gas facilities, gas explosion accidents occur frequently, causing serious casualties and economic losses. Generally speaking, natural gas explosions in civil buildings usually occur in kitchens, and the explosion process is particularly affected by explosion vents such as kitchen doors and windows, as well as large-scale obstacles such as internal furniture and electrical equipment. Therefore, it is necessary to accurately grasp the influence of explosion vents and obstacles on natural gas explosions in the kitchen, establish a natural gas explosion disaster assessment method suitable for typical kitchen scenarios, and provide technical support for on-site rescue of such accidents and rapid and accurate disaster assessment.

[0003] Peak overpressure is the core indicator for assessing the intensity of overpressure disasters caused by natural gas explosions. A large amount of literature shows that the overpressure of indoor natural gas explosions decreases with the increase of the explosion area and increases with the increase of the opening pressure of the explosion surface; there are obvious differences in the overpressure of indoor natural gas explosions under different concentrations, and the maximum explosion overpressure is obtained at the equivalent ratio concentration. The coupling of different explosion parameter conditions during natural gas explosions not only increases the complexity of explosion disasters, but also brings challenges to on-site rescue and post-disaster rapid assessment of natural gas explosion disasters.

[0004] In the relevant technologies, the assessment of indoor natural gas explosion hazards is mainly completed using the TNT equivalent method. Existing gas explosion hazard assessment methods such as the TNT equivalent method and the TNO multi-energy method are based on the condensed phase explosion theory, which largely ignores the impact of factors such as the explosion venting window structure and large-scale indoor obstacles on the disaster results, does not start from the evolution dynamics of gas explosion hazards, and does not examine the influencing factors of the explosion process comprehensively and thoroughly, which greatly limits the accurate assessment of explosion hazards.

[0005] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0006] In order to overcome the problems existing in the related art at least to a certain extent, the present application provides an indoor natural gas explosion hazard assessment method suitable for double-row arrangement of congested objects. This method can effectively realize the rapid assessment of natural gas explosion overpressure hazards in typical indoor scenarios with double-row arrangement of congested objects.

[0007] To achieve the above objectives, this application adopts the following technical solutions:

[0008] The present application provides an indoor natural gas explosion disaster assessment method applicable to double-row arrangement of congested objects, and the indoor natural gas explosion disaster assessment method comprises the following steps:

[0009] Investigate the explosion accident site and obtain technical parameter data of the object to be evaluated;

[0010] When it is determined that the accident is an indoor explosion accident with double-row arrangement of congested objects based on the indoor layout information contained in the technical parameter data, a pre-built indoor natural gas explosion peak overpressure assessment model is called, and the data required by the model in the technical parameters is imported into the assessment model for calculation to obtain and output a peak overpressure assessment result;

[0011] The indoor natural gas explosion peak overpressure assessment model is expressed as:

[0012]

[0013] In the model expression, P max Indicates the peak overpressure of indoor natural gas explosion. Indicates the concentration of combustible gas, P a It indicates the opening pressure of the explosion relief surface, and A indicates the explosion relief area.

[0014] Optionally, the process of pre-building the indoor natural gas explosion peak overpressure assessment model includes:

[0015] The numerical analysis method is used to obtain the three explosion influencing parameters of combustible gas concentration, explosion venting surface opening pressure and explosion venting area, and the experimental data on the influence of the peak overpressure of indoor natural gas explosion in double-row congestion arrangement;

[0016] The experimental data are subjected to nonlinear fitting to establish the indoor natural gas explosion peak overpressure assessment model.

[0017] Optionally, the process of using a numerical analysis method to obtain three explosion influencing parameters, namely, the concentration of combustible gas, the opening pressure of the explosion relief surface, and the explosion relief area, to obtain experimental data on the impact of the peak overpressure of indoor natural gas explosions in a double-row arrangement of congested objects includes:

[0018] Create several groups of numerical calculation physical models including three explosion influencing parameters: combustible gas concentration, explosion venting surface opening pressure and explosion venting area;

[0019] Based on the structure of the numerical calculation physical model, the influence of three explosion influencing parameters, namely, the concentration of combustible gas, the opening pressure of the explosion venting surface and the explosion venting area, on the peak overpressure of indoor natural gas explosion is obtained, and the corresponding experimental data are obtained;

[0020] Among them, in several groups of numerical calculation physical models, the numerical ranges of explosion influence parameters are:

[0021] The concentration of combustible gas is 6% to 14%, and the explosion venting area is 0.36m 2 ~1.96m 2 The opening pressure of the explosion relief surface is 0kPa~50kPa.

[0022] Optionally, the structure of the physical model based on numerical calculation is used to obtain the influence of three explosion influencing parameters, namely, the concentration of combustible gas, the opening pressure of the explosion relief surface, and the explosion relief area, on the peak overpressure of indoor natural gas explosion, and obtain corresponding experimental data, specifically:

[0023] The fluid dynamics simulation software is used to perform simulation calculations based on the structure of the numerical calculation physical model to obtain the experimental data.

[0024] Optionally, the fluid dynamics simulation software includes AutoReaGas simulation tool software.

[0025] This application adopts the above technical solution, which has at least the following beneficial effects:

[0026] The technical solution of the present application pre-constructs a targeted indoor natural gas explosion peak overpressure assessment model for a typical indoor scenario with double-row arrangement of congested objects. When an explosion accident occurs in a typical scenario, the relevant technical parameter data obtained from the accident site investigation can be directly used to perform calculations and evaluations based on the model, thereby quickly and effectively realizing the assessment of the natural gas explosion overpressure disaster in the accident.

[0027] 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 by the structures particularly pointed out in the following description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the technical solution of the present application or the prior art, and constitute a part of the specification. Among them, the accompanying drawings expressing the embodiments of the present application are used together with the embodiments of the present application to explain the technical solution of the present application, but do not constitute a limitation on the technical solution of the present application.

[0029] Figure 1 This is a schematic diagram of the kitchen structure for a Type II kitchen layout;

[0030] Figure 2A flow chart of an indoor natural gas explosion hazard assessment method applicable to double-row arrangement of congested objects provided by one embodiment of the present application;

[0031] Figure 3 This is a structural diagram of a numerical calculation physical model in an embodiment of the present application;

[0032] Figure 4 Schematic diagram of a curve showing a change in the peak overpressure of a natural gas explosion with the opening pressure of the explosion relief surface in one embodiment of the present application ( in some cases);

[0033] Figure 5 Schematic diagram of a curve showing a change in the peak overpressure of a natural gas explosion with the opening pressure of the explosion relief surface in one embodiment of the present application ( in some cases);

[0034] Figure 6 Schematic diagram of correlation analysis of a natural gas explosion peak overpressure assessment model in one embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other implementation methods obtained by ordinary technicians in the field without creative work belong to the scope of protection of the present application.

[0036] As mentioned in the background technology, natural gas explosion accidents in civil buildings usually occur in the kitchen, and the explosion process is particularly affected by explosion vents such as kitchen doors and windows, as well as large-scale obstacles such as internal furniture and electrical equipment. Therefore, it is necessary to accurately understand the influence of explosion vents and obstacles on natural gas explosions in the kitchen, establish a natural gas explosion disaster assessment method suitable for typical kitchen scenarios, and provide technical support for on-site rescue of such accidents and rapid and accurate disaster assessment.

[0037] Based on the current status of civil buildings, the most typical kitchen scene is a double-row kitchen. In 14J913-2 "National Building Standard Design Atlas - Residential Kitchen", a typical kitchen reference room with a double-row (Type II) layout is given (see attached). Figure 1 The type II kitchen layout is a typical representative of the double-row layout of indoor congestion objects. The present invention selects this typical type II kitchen layout as the research object.

[0038] The embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. Figure 2 The figure is a flow chart of a method for evaluating indoor natural gas explosion hazards in double-row arrangement of congested objects provided by an embodiment of the present application, the method comprising:

[0039] Step S110, investigating the explosion accident site to obtain technical parameter data of the object to be evaluated;

[0040] It is easy to understand that the investigation here is generally conducted by personnel related to the accident investigation, and the technical parameter data obtained must at least include the layout information data of the room where the accident occurred, as well as the relevant parameter data required for subsequent model calculations, such as natural gas volume concentration data, explosion venting surface (window) size (width × height), explosion venting surface (window glass) opening pressure (when the explosion venting surface is in the open state or belongs to unconstrained explosion venting, Pa = 0), etc.

[0041] Then, step S120 is performed. When it is determined that the accident is an indoor explosion accident with double-row arrangement of congested objects (e.g., the room where the accident occurred is a kitchen with a type II structure) based on the indoor layout information contained in the technical parameter data, a pre-built indoor natural gas explosion peak overpressure assessment model is called, and the data required by the model in the technical parameter data is imported into the assessment model for calculation, and the peak overpressure assessment result is obtained and output;

[0042] Among them, the indoor natural gas explosion peak overpressure assessment model is expressed as:

[0043]

[0044] In expression (1), P max Indicates the peak overpressure of indoor natural gas explosion (in kPa), Indicates the concentration of combustible gas (volume fraction), P a It represents the opening pressure of the explosion relief surface (unit: kPa). When the explosion relief surface is in the open state or belongs to unconstrained explosion relief, Pa = 0. A represents the explosion relief area (unit: m 2 ).

[0045] It should be noted here that if the accident is not an indoor explosion accident with double-row congestion, the model shown in the above expression (1) of this application cannot be applied, and other methods can be used for disaster assessment (which does not fall within the scope of the technical solution of this application and will not be introduced here).

[0046] The technical solution of the present application, through the typical indoor scene of double-row arrangement of congested objects, pre-constructs a targeted indoor natural gas explosion peak overpressure assessment model, and then when an explosion accident occurs in a typical scene, the relevant technical parameter data obtained by investigating the accident site can be directly used to perform calculations and evaluations based on the model, so as to quickly and effectively evaluate the natural gas explosion overpressure disaster in the accident, that is, to achieve post-disaster evaluation. And it is easy to understand that the model shown in the above expression (1) of the present application can also be used to predict the indoor natural gas restrained explosion overpressure in double-row arrangement of congested objects before the disaster.

[0047] To facilitate understanding of the technical solution of the present application, the construction process of the indoor natural gas explosion peak overpressure assessment model in the present application is introduced below.

[0048] In summary, this application utilizes numerical simulation and mathematical statistics analysis methods to construct an indoor natural gas explosion peak overpressure assessment model.

[0049] Specifically, the process of the indoor natural gas explosion peak overpressure assessment model pre-constructed in this application includes:

[0050] Step 1, using numerical analysis method to obtain three explosion influencing parameters, namely, the concentration of combustible gas, the opening pressure of the explosion relief surface, and the explosion relief area, and experimental data on the influence of the peak overpressure of indoor natural gas explosion in double-row arrangement of congested objects;

[0051] Furthermore, in this step, it is first necessary to create several sets of numerical calculation physical models including three explosion influencing parameters: the concentration of combustible gas, the opening pressure of the explosion venting surface, and the explosion venting area;

[0052] Then, based on the structure of the numerical calculation physical model, the influence of three explosion influencing parameters, namely, the concentration of combustible gas, the opening pressure of the explosion venting surface, and the explosion venting area, on the peak overpressure of indoor natural gas explosion was obtained, and the corresponding experimental data were obtained;

[0053] Among them, in several groups of numerical calculation physical models, the numerical ranges of explosion influence parameters are:

[0054] The concentration of combustible gas is 6% to 14%, and the explosion venting area is 0.36m 2 ~1.96m 2 The opening pressure of the explosion relief surface is 0kPa~50kPa.

[0055] For example, based on Figure 1 The room type features of the typical type II kitchen shown in the figure, the structural schematic diagram of the numerical calculation physical model established in this application is as follows Figure 3 As shown;

[0056] The model size is 3.4m (length) × 2.1m (width) × 2.4m (height). The objects in the room are set according to the general real size, mainly including counters, wall cabinets, refrigerators, range hoods and other objects. The handles, decorative patterns and other small structures that may exist on the surface of some objects are ignored. The walls, roofs, floors and congested surfaces around the model are set as rigid walls, and the kitchen volume congestion rate is about 33.72%. Referring to the window size and glass static opening pressure of ordinary residences, the window located in the center of the wall in the type II kitchen layout is regarded as a square explosion vent with a fixed opening function, and the opening time is 0s. In order to accurately capture the impact of the explosion outside the explosion vent on the indoor combustion and explosion process, the calculation domain is extended outward along the direction of the explosion vent by 5 times the length of the room, and the external calculation domain is set as a free outflow boundary. The overall size of the calculation domain is 20.4m (length) × 2.1m (width) × 2.4m (height), and the calculation domain is discretized using a cubic structure grid with a size of 0.1m. This method has been verified in relevant literature. The initial pressure and initial temperature of the environment in the calculation domain are set to 1.01325×102 kPa and 300 K, respectively. An ignition source with a radius of 0.015 m is set at a distance of 0.05 m from the geometric center of the rear wall of the room.

[0057] Then, based on the above numerical calculation physical model structure, the influence of three explosion influencing parameters, namely, combustible gas concentration, explosion venting surface opening pressure and explosion venting area, on the peak overpressure of indoor natural gas explosion was obtained, and the corresponding experimental data were obtained; in this process, the numerical calculation range of each explosion influencing parameter was: combustible gas concentration: 6%~14%, explosion venting area: 0.36m 2 ~1.96m 2 The opening pressure of the explosion relief surface is 0kPa~50kPa. The specific parameter values ​​are shown in Table 1 below.

[0058] Table 1 Numerical calculation experimental parameter values

[0059]

[0060] In the embodiment, a total of 150 sets of numerical calculation physical models were created, and a total of 150 sets of data were obtained by numerical calculation. The data results were all taken from the center measurement point of the model. Specifically, the model parameters and numerical simulation results are shown in Table 2.

[0061] Table 2 Parameters of the natural gas explosion numerical calculation experimental model and experimental data

[0062]

[0063]

[0064]

[0065]

[0066]

[0067] It should be noted that, in this embodiment, the above data are obtained by simulation calculation based on the structure of the numerical calculation physical model using fluid dynamics simulation software; specifically, the fluid dynamics simulation software used in this application is the AutoReaGas simulation tool software (the implementation principle of which is to solve the transient flow field of constrained explosion relief in a confined space, and the relevant technical introduction can be found in the existing public technical information).

[0068] After step 1, step 2 can be carried out. In step 2, nonlinear fitting is performed on the experimental data to establish an indoor natural gas explosion peak overpressure assessment model.

[0069] Here we continue with the previous example. In the fitting process, based on the data shown in Table 2, we can obtain the variation curve of the peak overpressure of natural gas explosion with the opening pressure of the explosion relief surface (part of the curve is shown in Figure 2). Figure 4 , Figure 5 As shown in Figure 1, it can be seen that the overall shape of the curve is quite different when the combustible gas concentration is 9.5%. Therefore, the present application uses 9.5% as the boundary to perform nonlinear fitting based on experimental data, and finally obtains the indoor natural gas explosion peak overpressure assessment model as shown in the above expression (1).

[0070] Then, the data obtained from the evaluation model and 150 numerical calculation results were subjected to linear regression analysis to verify the credibility of the evaluation model. The linear regression analysis showed that the variance of the peak overpressure calculated by the numerical method for indoor natural gas explosion and the peak overpressure predicted by the formula was R2 = 0.92241 (the correlation analysis of the indoor natural gas explosion peak overpressure evaluation model is shown in Figure 2). Figure 6 This fully demonstrates that the evaluation model has significant credibility.

[0071] The following is a specific example to illustrate the evaluation method of this application:

[0072] Assume that a natural gas leak and explosion occurred in Room 302, Unit 2, Building 5, in a certain community on November 11, 2018. The building was completed and put into use in 2014. The structure type is steel-concrete structure, with 16 floors above ground and a total of 2 units. A gas leak and explosion occurred in Room 302, Unit 2, at around 7 o'clock in the morning. The accident injured two people, shattered the windows of more than ten floors of the building, and the flying glass and other items flew more than 100 meters away. The appearance of other residential buildings in the community was not damaged, but the residents' homes were damaged to varying degrees, and the marble countertops in some residents' kitchens were broken.

[0073] The on-site accident investigation found that the natural gas explosion accident originated from the kitchen of the room. The size of the kitchen where the explosion occurred (length × width × height) is 3m × 2.1m × 2.4m, the wall size where the room window is located is 2.1m × 2.4m, the window size (width × height) is 1.0m × 1.2m, and the static opening pressure of the window glass is 25kPa. There are large-scale obstacles such as cabinets, wall cabinets, and refrigerators in the kitchen, which are arranged on both sides of the length of the kitchen. The volume concentration of natural gas on site is 10%. The method of this application is used to evaluate the peak overpressure of the on-site natural gas explosion accident. The specific steps are as follows:

[0074] Based on the background information and investigation, the layout type of the obstruction in the room of the assessment object was determined. The size of the kitchen where the explosion occurred (length × width × height) was 3m × 2.1m × 2.4m, and the large-scale obstacles in the kitchen were arranged along both sides of the length of the kitchen, which met the requirements of the type II layout kitchen specified in 14J913-2 "National Building Standard Design Atlas - Residential Kitchen", that is, the indoor obstructions were arranged in double rows.

[0075] Based on background information and investigation, we can understand the key technical parameters of the evaluation object, natural gas volume concentration, Explosion venting surface (window) size (width × height) A = 1.2m 2 , the opening pressure of the explosion-proof surface (window glass) Pa = 25kPa.

[0076] Determine the range of natural gas volume concentration and comprehensively calculate the peak overpressure Pmax of indoor natural gas explosion.

[0077] Due to the volume concentration of natural gas Calculate using the lower formula in expression (1).

[0078] The parameters A=1.2m 2 , Pa=25kPa are simultaneously substituted into the formula for calculation to obtain the peak overpressure Pmax of the natural gas explosion in the kitchen.

[0079]

[0080] From this, we can see that the assessment result is that the intensity of this explosion is 34.38kPa.

[0081] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any person familiar with the technology within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for assessing indoor natural gas explosion hazards suitable for double-row arrangement of congested objects, characterized in that: The steps include: Investigate the explosion accident site and obtain technical parameter data of the object to be evaluated; When it is determined that the accident is an indoor explosion accident with double-row arrangement of congested objects based on the indoor layout information contained in the technical parameter data, a pre-built indoor natural gas explosion peak overpressure assessment model is called, and the data required by the model in the technical parameter data is imported into the assessment model for calculation, and a peak overpressure assessment result is obtained and output; The indoor natural gas explosion peak overpressure assessment model is expressed as: In the model expression, P max Indicates the peak overpressure of indoor natural gas explosion. Indicates the concentration of combustible gas, P a It indicates the opening pressure of the explosion relief surface, and A indicates the explosion relief area.

2. The method according to claim 1, characterized in that The process of the pre-built indoor natural gas explosion peak overpressure assessment model includes: The numerical analysis method is used to obtain the three explosion influencing parameters of combustible gas concentration, explosion venting surface opening pressure and explosion venting area, and the experimental data on the influence of the peak overpressure of indoor natural gas explosion in double-row congestion arrangement; The experimental data are subjected to nonlinear fitting to establish the indoor natural gas explosion peak overpressure assessment model.

3. The method according to claim 2, characterized in that The process of using the numerical analysis method to obtain three explosion influencing parameters, namely, the concentration of combustible gas, the opening pressure of the explosion relief surface, and the explosion relief area, and experimental data on the influence of the peak overpressure of indoor natural gas explosion in a double-row arrangement of congested objects includes: Create several groups of numerical calculation physical models including three explosion influencing parameters: combustible gas concentration, explosion venting surface opening pressure and explosion venting area; Based on the structure of the numerical calculation physical model, the influence of three explosion influencing parameters, namely, the concentration of combustible gas, the opening pressure of the explosion venting surface and the explosion venting area, on the peak overpressure of indoor natural gas explosion is obtained, and the corresponding experimental data are obtained; Among them, in several groups of numerical calculation physical models, the numerical ranges of explosion influence parameters are: The concentration of combustible gas is 6% to 14%, and the explosion venting area is 0.36m 2 ~1.96m 2 The opening pressure of the explosion relief surface is 0kPa~50kPa.

4. The method according to claim 3, characterized in that The structure of the physical model based on numerical calculation is used to obtain the influence of three explosion influencing parameters, namely, the concentration of combustible gas, the opening pressure of the explosion relief surface, and the explosion relief area, on the peak overpressure of indoor natural gas explosion, and obtain corresponding experimental data, specifically: The fluid dynamics simulation software is used to perform simulation calculations based on the structure of the numerical calculation physical model to obtain the experimental data.

5. The method according to claim 4, characterized in that The fluid dynamics simulation software includes AutoReaGas simulation tool software.

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