Prediction method for simulating steam cloud explosion consequence

Abstract

The invention relates to a prediction method for simulating a steam cloud explosion consequence. The prediction method comprises the following steps: acquiring an ignition source position and leakage source information of natural gas pipeline leakage; the mass of combustible gas in the steam cloud is calculated through leakage source information, and the combustible boundary of the steam cloud is determined through the isoconcentration lines of the upper limit and the lower limit of explosion, namely the explosion hazard range of the steam cloud is generated; determining a death area, a property loss area and a collapsed building area by taking the position of the ignition source as an original point; calculating the population density in the steam cloud explosion hazard range; and inputting the parameters into a pre-trained emergency accident consequence model to obtain a prediction result of the number of dead people of the simulated steam cloud explosion shock waves. Compared with the prior art, the method has the remarkable advantages that the potential steam cloud explosion accident consequence and the probability of occurrence thereof are evaluated by establishing an emergency accident consequence model and performing comprehensive prediction through a simulation algorithm; and decision support is provided for subsequent development of an effective prevention mechanism and perfect emergency measures.

Description

Technical Field

[0001] This invention relates to the field of emergency accident consequence modeling technology, and in particular to a method for predicting the consequences of a vapor cloud explosion. Background Technology

[0002] A vapor cloud explosion, or VCE for short, is a chemical explosion of an explosive mixture formed when a flammable material leaks and mixes with air. Four conditions generally need to be met for a vapor cloud explosion to occur:

[0003] 1. Combustible materials must be released under suitable pressure or temperature conditions, and leaks will form either an explosive gas mixture or a gaseous suspension of liquid particles;

[0004] 2. An ignition source is present, and ignition should only occur after the vapor cloud has diffused to a sufficient extent;

[0005] 3. The concentration of the explosive gas mixture reaches the explosive range;

[0006] 4. There must be a condition within the flammable zone of the vapor cloud that causes the flame to accelerate.

[0007] Vapor cloud explosions are extremely dangerous and serious safety accidents. They not only pose a significant threat to people's lives, property, and environmental safety, but also severely impact daily life and production. The consequences of a vapor cloud explosion are unpredictable and unbearable; therefore, research on simulated risk assessments and consequence predictions for vapor cloud explosions is essential.

[0008] Reference 1: Chinese invention patent CN202110977163.5 discloses a gas cloud explosion assessment method and system with multiple potential gas explosion sources coupled together. It uses the Baker-Strehlow model for analysis. The model has relatively strict assumptions, such as requiring the data to follow a normal distribution, which is difficult to meet in actual explosion accident application scenarios. Summary of the Invention

[0009] The purpose of this invention is to provide a method for predicting the consequences of simulating vapor cloud explosions. Addressing the current difficulties in remediation after vapor cloud explosions and the challenge in controlling the extent of public harm, this invention employs accident consequence simulation to provide early warning of potential accidents.

[0010] The technical solution to achieve the purpose of this invention is as follows:

[0011] A method for predicting the consequences of a vapor cloud explosion, comprising the following steps:

[0012] Step 1: Obtain the location of the ignition source and information on the source of the natural gas pipeline leak;

[0013] Step 2: Calculate the mass of combustible gas in the vapor cloud using the leak source information, and determine the combustible boundary of the vapor cloud by using the isoconcentration lines of the upper and lower explosive limits, thus generating the hazard range of the vapor cloud explosion;

[0014] Step 3: Using the location of the ignition source as the origin, determine the death area with the radius of death, the property loss area with the radius of property loss, and the area of ​​collapsed buildings.

[0015] Step 4: Calculate the population density within the hazard zone of the vapor cloud explosion;

[0016] Step 5: Input the population density, death zone, property damage zone, and collapsed building area within the hazard range of the vapor cloud explosion into the pre-trained emergency accident consequence model to obtain the predicted number of deaths caused by the simulated vapor cloud explosion shock wave.

[0017] Furthermore, the leak source information includes the diameter of the leak hole, the pressure of the medium inside the natural gas pipeline, the gas temperature, and the leak time.

[0018] Furthermore, the pre-trained emergency accident consequence model analyzes all input parameters and calculates the number of deaths caused by the simulated vapor cloud explosion shock wave by multiplying the total population within the hazard range of the vapor cloud explosion by the probability of death.

[0019] Furthermore, the TNT equivalent method was used to analyze and obtain the death radius and property damage radius of the vapor cloud explosion.

[0020] Furthermore, the mass of combustible gas in the vapor cloud is calculated using information about the leak source, including:

[0021]

[0022] In the formula: W TNT W represents the TNT equivalent of a combustible gas. f Q represents the total mass of combustible gas in the vapor cloud, α represents the equivalence coefficient of the combustible cloud, and Q represents the mass of the total combustible gas in the vapor cloud. f Q represents the heat of combustion of a combustible gas. TNT This indicates the explosive heat of TNT.

[0023] Furthermore, the population density within the hazard zone of the vapor cloud explosion is calculated, including:

[0024]

[0025] In the formula, ρ kl r represents the actual population density within the hazard zone of a vapor cloud explosion. ijP(i) represents the distance between the i-th building and the j-th building, and P(i) represents the weight of the i-th building.

[0026] Compared with existing technologies, the significant advantages of this invention are: by establishing an emergency accident consequence model and simulation algorithm to comprehensively predict the consequences of potential vapor cloud explosion accidents and their probability of occurrence; providing decision support for the subsequent development of effective prevention mechanisms and improved emergency measures, so as to minimize the occurrence of vapor cloud explosion accidents and reduce their impact on humans. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating the method for predicting the consequences of a simulated vapor cloud explosion according to the present invention. Detailed Implementation

[0028] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0029] The main consequences of a vapor cloud explosion include shock wave overpressure, debris, and thermal radiation, among which shock wave overpressure has the widest impact and poses the greatest risk to human health. Therefore, the technical solution of this invention is mainly used to predict the impact range of shock wave overpressure in order to simulate and analyze the consequences of a vapor cloud explosion.

[0030] like Figure 1 As shown, a method for predicting the consequences of a vapor cloud explosion is proposed, which includes the following steps:

[0031] Step 1: Obtain the location of the ignition source and the leak source information of the natural gas pipeline leak; the leak source information includes the diameter of the leak hole, the pressure of the medium inside the natural gas pipeline, the gas temperature, and the leak time.

[0032] Step 2: Calculate the mass of combustible gas in the vapor cloud using the leak source information, and determine the combustible boundary of the vapor cloud by using the isoconcentration lines of the upper and lower explosion limits, thus generating the hazard range of the vapor cloud explosion.

[0033] Step 3: Based on the TNT equivalent method, the death radius and property damage radius of the vapor cloud explosion are obtained; taking the ignition source location as the origin, the death area is determined by the death radius, the property damage area is determined by the property damage radius, and the area of ​​collapsed buildings is determined by the property damage radius.

[0034] Step 4: Calculate the population density within the hazard range of the vapor cloud explosion.

[0035] Step 5: Input the population density, death zone, property damage zone, and collapsed building area within the hazard range of the vapor cloud explosion into the pre-trained emergency accident consequence model to obtain the predicted number of deaths caused by the simulated vapor cloud explosion shock wave.

[0036] Specifically, referring to the conditions for vapor cloud explosion accidents, it can be seen that when combustible gas leaks under certain conditions, a combustible vapor cloud is formed in a confined space. Under the action of an ignition source, a violent thermochemical reaction occurs, forming a shock wave, which leads to a vapor cloud explosion accident.

[0037] The maximum heat release and pressure generated in an explosive mixture occurs when the concentration ratio of the combustible material to the oxidizer in the mixture is such that a complete chemical reaction occurs. The actual stoichiometric concentration is slightly higher than the calculated stoichiometric concentration because explosive mixtures typically contain impurities.

[0038] The upper explosive limit (ULP) refers to the highest concentration of a flammable mixture at which it can explode. Above the ULP, insufficient air prevents the flame from spreading, resulting in neither explosion nor ignition. The lower explosive limit (LEL) refers to the lowest concentration of a flammable mixture at which it can explode. Due to insufficient concentration of flammable material, the cooling effect of excess air prevents the flame from spreading; therefore, below the LLE, it neither explodes nor ignites.

[0039] The explosion hazard of combustible gases or vapors can be expressed by the explosion hazard level, which is the ratio of the explosion concentration limit range to the lower explosion limit concentration. It can be seen from the explosion hazard level that the wider the explosion concentration limit range of a gas or vapor, the lower explosion limit concentration, and the higher the upper explosion limit concentration, the greater its explosion hazard.

[0040] Specifically, in step 2, the mass of combustible gas in the vapor cloud is calculated using the leak source information:

[0041]

[0042] In the formula: W TNT W represents the TNT equivalent of a combustible gas. f Q represents the total mass of combustible gas in the vapor cloud, α represents the equivalence coefficient of the combustible cloud (generally taken as 0.01-0.1, with a statistical average of 0.04), and Q f Q represents the heat of combustion of a combustible gas. TNT This indicates the heat of explosion of TNT, typically taken as 4.52 MJ / kg.

[0043] The TNT equivalent algorithm transforms the destructive effect of a material explosion into the destructive effect of a TNT explosion. It multiplies the data of the combustible gas by the heat of combustion per unit mass of the gas to obtain the total heat of combustion of the vapor cloud explosion. The actual heat of combustion is obtained according to a preset equivalent coefficient. The ratio of the actual heat of combustion to the heat of combustion of TNT is calculated to obtain the TNT equivalent.

[0044] Specifically, in step 3, the formulas for calculating the fatal radius and property damage radius of a vapor cloud explosion based on the TNT equivalent method are as follows:

[0045] R1=Z(W TNT ) 0.3

[0046]

[0047] In the formula: R1 represents the death radius, Z represents the proportional distance caused by overpressure, and R2 represents the property damage radius. Specifically, in step 4, the population density within the hazard range of the vapor cloud explosion is calculated, including:

[0048] ρ0=ρ ′ 0 / (1-β)

[0049]

[0050] In the formula, ρ0 represents the initial population density within the hazard range of a vapor cloud explosion, ρ ′ 0 represents the statistical population density within the hazard range of a vapor cloud explosion, β represents the green space and water coverage within the hazard range of a vapor cloud explosion, and ρ represents the population density within the hazard range of a vapor cloud explosion. kl r represents the actual population density within the hazard zone of a vapor cloud explosion. ij P(i) represents the distance between the i-th building and the j-th building, and P(i) represents the weight of the i-th building.

[0051] Specifically, in step 5, the pre-trained emergency accident consequence model analyzes all input parameters and calculates the number of deaths caused by the simulated vapor cloud explosion shock wave by multiplying the total population within the hazard range of the vapor cloud explosion by the probability of death.

[0052] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, the above description focuses on specific embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in a different order than that shown in the embodiments and still achieve the desired results. Additionally, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing are also possible or may be advantageous.

[0053] The various embodiments in this application are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device, equipment, and storage medium embodiments are basically similar to the method embodiments, so the descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0054] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0055] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for predicting the consequences of a simulated vapor cloud explosion, characterized in that: The prediction method includes the following steps: Step 1: Obtain the location of the ignition source and information on the source of the natural gas pipeline leak; Step 2: Calculate the mass of combustible gas in the vapor cloud using the leak source information, and determine the combustible boundary of the vapor cloud by using the isoconcentration lines of the upper and lower explosive limits, thus generating the hazard range of the vapor cloud explosion. Step 3: Using the location of the ignition source as the origin, determine the death area with the radius of death, the property loss area with the radius of property loss, and the area of ​​the collapsed buildings. Step 4: Calculate the population density within the hazard zone of the vapor cloud explosion; Step 5: Input the population density, death zone, property damage zone, and collapsed building area within the hazard range of the vapor cloud explosion into the pre-trained emergency accident consequence model to obtain the predicted number of deaths caused by the simulated vapor cloud explosion shock wave.

2. The method for predicting the consequences of a simulated vapor cloud explosion according to claim 1, characterized in that: The leak source information includes the diameter of the leak hole, the pressure of the medium inside the natural gas pipeline, the gas temperature, and the leak time.

3. The method for predicting the consequences of a simulated vapor cloud explosion according to claim 2, characterized in that: The pre-trained emergency accident consequence model analyzes all input parameters and calculates the number of deaths caused by the simulated vapor cloud explosion shock wave by multiplying the total population within the hazard range of the vapor cloud explosion by the probability of death.

4. The method for predicting the consequences of a simulated vapor cloud explosion according to claim 3, characterized in that: The death radius and property damage radius of a vapor cloud explosion were obtained by using the TNT equivalent method.

5. The method for predicting the consequences of a simulated vapor cloud explosion according to claim 4, characterized in that: The calculation of the mass of combustible gas in the vapor cloud using leak source information includes: In the formula: W TNT W represents the TNT equivalent of a combustible gas. f Q represents the total mass of combustible gas in the vapor cloud, α represents the equivalence coefficient of the combustible cloud, and Q f Q represents the heat of combustion of a combustible gas. TNT This indicates the explosive heat of TNT.

6. The method for predicting the consequences of a simulated vapor cloud explosion according to claim 5, characterized in that: The calculation of population density within the hazard range of a vapor cloud explosion includes: In the formula, ρ kl r represents the actual population density within the hazard zone of a vapor cloud explosion. ij P(i) represents the distance between the i-th building and the j-th building, and P(i) represents the weight of the i-th building.

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