Methane, hydrogen and hydrogen-doped methane under-expansion jet fire flame evaluation processing method

Abstract

The invention relates to a methane, hydrogen and hydrogen-doped methane under-expansion jet fire flame evaluation processing method and application. The method comprises the following steps: acquiring the proportion of each gas component in a mixed gas, the absolute pressure of the mixed gas and the temperature of the mixed gas; determining the molar mass, the gas adiabatic index and the air-fuel ratio of the mixed gas according to the proportion of each gas component; the constant-pressure adiabatic combustion temperature of the mixed gas is determined according to the proportion of all the gas components and the first law of thermodynamics; the gas speed at the leakage opening is determined; determining the gas density at the leakage port; the flame Froude number of the under-expansion jet flame is determined according to the air-fuel ratio of the mixed gas, the constant-pressure adiabatic combustion temperature, the gas density at the leakage opening and the gas speed at the leakage opening; and determining the flame length of the under-expansion jet flame according to the flame Froude number of the under-expansion jet flame and the proportion of each gas component in the mixed gas. In this way, the flame length of the under-expansion jet flow flame can be accurately and consistently determined.

Description

Technical Field

[0001] This application relates to the field of safety maintenance technology for gas pipelines and storage equipment, and in particular to a method, apparatus, equipment and medium for assessing and treating underexpanded jet fires of methane, hydrogen and hydrogen-doped methane. Background Technology

[0002] To reduce carbon dioxide emissions, transporting hydrogen directly through pipelines or blending it into existing natural gas pipelines is a key direction for addressing bottlenecks in the hydrogen energy industry supply chain.

[0003] During the transportation of natural gas, pure hydrogen, and hydrogen-blended natural gas pipelines, damage may occur due to manufacturing defects, self-corrosion, or third-party sabotage, leading to leakage of the transported flammable and explosive gases. If the leaked gas is ignited, it will cause jet fire. Accurately calculating the length of the jet fire flame is of great guiding significance for determining the safe distance for pipeline thermal radiation protection and conducting quantitative risk analysis of pipeline fires during operation.

[0004] Currently, the design pressure of large-scale gas transmission pipelines is often above 4 MPa. If a leak occurs, the high-pressure gas inside the pipeline will be ejected, resulting in an underexpansion jet condition for both hydrogen and hydrogen-blended natural gas. The calculation of flame length under this condition is currently mainly achieved using semi-empirical formulas. There are three main types of formulas that have gained industry acceptance: First, flame length calculation formulas based on the Froude number. These formulas have different fitting coefficients for different types of gases, and even for the same gas, different researchers have given varying fitting coefficients. This means that the accuracy of the calculation results largely depends on the choice of formula, leading to relatively poor consistency in the results. Second, flame length calculation formulas based on the flame Froude number. The most widely accepted formula in this category was proposed by Delichatsios in 1993. However, this formula is only applicable to single-type gases and has poor applicability to mixed gases. Studer's research indicates that the calculated value of this formula is too small when used to calculate hydrogen-blended methane. Third, flame length calculation formulas based on injection pressure. These formulas have only been applied and verified for hydrogen and are not applicable to other gases.

[0005] Therefore, determining the flame length of an underexpansion jet fire caused by hydrogen-doped methane mixtures, and ensuring the accuracy and consistency of the results, is of great guiding significance for determining the safe distance for pipeline thermal radiation protection and conducting quantitative risk analysis of pipeline fires during operation. Summary of the Invention

[0006] Therefore, it is necessary to provide a method and application for evaluating and treating methane, hydrogen, and underexpanded jet fires of hydrogen-doped methane with relatively good accuracy and consistency, applicable to different doping ratios of hydrogen-doped methane.

[0007] In a first aspect, this application provides a method for evaluating and treating underexpanded jet fires involving methane, hydrogen, and hydrogen-doped methane, characterized by comprising the following steps:

[0008] Obtain the proportions of each gas component in the gas mixture, as well as the absolute pressure and temperature of the gas mixture;

[0009] The molar mass, adiabatic index, and air-fuel ratio of the gas mixture are determined based on the proportions of each gas component.

[0010] The isobaric adiabatic combustion temperature of the gas mixture is determined based on the proportions of each gas component and in conjunction with the first law of thermodynamics.

[0011] The gas velocity at the leak point is determined based on the molar mass and temperature of the mixed gas.

[0012] The gas density at the leak point is determined based on the absolute pressure of the mixed gas, the gas adiabatic index of the mixed gas, and the proportion of each gas component.

[0013] The flame Froude number of the underexpansion jet flame is determined based on the air-fuel ratio of the mixture, the constant pressure adiabatic combustion temperature, the gas density at the leak point, and the gas velocity at the leak point.

[0014] The flame length of the underexpanded jet flame is determined based on the flame Froude number of the underexpanded jet flame and the proportions of each gas component in the mixed gas.

[0015] In one embodiment, the mixed gas comprises methane and hydrogen;

[0016] In one embodiment, after determining the flame length of the underexpanded jet flame, the method further includes: determining a thermal radiation protection safety distance based on the flame length of the underexpanded jet flame.

[0017] In one embodiment, after determining the flame length of the underexpanded jet flame, the method further includes: performing a quantitative risk analysis of pipeline fires during operation based on the flame length of the underexpanded jet flame.

[0018] In one embodiment, the molar mass of the mixed gas is determined using the following formula when determining the molar mass of the mixed gas based on the proportions of each gas component:

[0019]

[0020] in, These are the molar masses of the mixed gas, methane, and hydrogen, respectively, in kg / mol. This represents the volume fraction of hydrogen in the gas mixture.

[0021] And / or, in determining the gas adiabatic index of the mixed gas based on the proportions of each gas component, the gas adiabatic index of the mixed gas is determined using the following formula:

[0022]

[0023] in, These are the adiabatic indices for the mixed gas, methane, and hydrogen, respectively.

[0024] And / or, in determining the air-fuel ratio of the mixture based on the proportions of each gas component, the following calculation formula is used:

[0025]

[0026] Where S is the stoichiometric air-fuel ratio of the mixture; M air M is the molar mass of air. fuel Let x and y be the molar mass of the gas mixture, and C be the molar mass of the gas mixture. x H y Median value, C x H y It is obtained by doping methane and hydrogen in equal proportions.

[0027] In one embodiment, the isobaric adiabatic combustion temperature of the mixed gas is determined based on the proportions of each gas component and the first law of thermodynamics, using CHEMKIN software to perform heat balance calculations based on the proportions of each gas component in the mixed gas and the combustion process.

[0028] In one embodiment, the gas velocity at the leak outlet is determined using the following formula in the process of determining the gas velocity at the leak outlet based on the molar mass and temperature of the mixed gas:

[0029]

[0030] Among them, v e R is the gas velocity at the leak point, in m / s; R is the gas constant, 8.314 J / (mol·K); T0 is the temperature of the mixed gas, in K.

[0031] And / or, in determining the gas density at the leak outlet based on the absolute pressure of the mixed gas, the gas adiabatic index of the mixed gas, and the proportion of each gas component, the gas density at the leak outlet is determined using the following formula:

[0032]

[0033] ρ e The gas density at the leak point is expressed in kg / m³. 3 P0 is the absolute pressure of the mixed gas, in Pa.

[0034] In one embodiment, the flame Froude number of the underexpanded jet flame is determined based on the air-fuel ratio of the mixed gas, the isobaric adiabatic combustion temperature, the gas density at the leak point, and the gas velocity at the leak point, using the following formula:

[0035]

[0036] Among them, Fr f For the flame Froude number; T f The isobaric adiabatic combustion temperature of a gas mixture, expressed in Kelvin (K); T ∞ The ambient atmospheric temperature is expressed in Kelvin (K); ρ ∞ Atmospheric density, in kg / m³ 3 ;d e The diameter of the leak is in meters (m).

[0037] In one embodiment, the flame length of the underexpanded jet flame is determined based on the flame Froude number of the underexpanded jet flame and the proportions of the gas components in the mixed gas, using the following formula:

[0038]

[0039] Among them, L f This refers to the flame length of the underexpansion jet flame, measured in meters (m).

[0040] Secondly, this application provides a flame assessment and treatment apparatus for methane, hydrogen, and hydrogen-doped methane underexpansion jet fires, the apparatus comprising:

[0041] The acquisition module is used to acquire the proportion of each gas component in the gas mixture, as well as the absolute pressure and temperature of the gas mixture.

[0042] The physical property parameter determination module is used to determine the molar mass, gas adiabatic index, and air-fuel ratio of the mixed gas based on the proportion of each gas component; the physical property parameter determination module is also used to determine the isobaric adiabatic combustion temperature of the mixed gas based on the proportion of each gas component and in conjunction with the first law of thermodynamics.

[0043] The gas velocity determination module is used to determine the gas velocity at the leak point based on the molar mass and temperature of the mixed gas.

[0044] The gas density determination module is used to determine the gas density at the leak point based on the absolute pressure of the mixed gas, the gas adiabatic index of the mixed gas, and the proportion of each gas component.

[0045] The Froude number determination module is used to determine the flame Froude number of the underexpansion jet flame based on the air-fuel ratio of the mixture, the constant pressure adiabatic combustion temperature, the gas density at the leak point, and the gas velocity at the leak point.

[0046] The flame length determination module is used to determine the flame length of the underexpanded jet flame based on the flame Froude number of the underexpanded jet flame and the proportion of each gas component in the mixed gas.

[0047] Thirdly, this application provides a computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the method as described in any of the above embodiments.

[0048] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method as described in any of the above embodiments.

[0049] The aforementioned method for evaluating and processing under-expanded jet fires of methane, hydrogen, and hydrogen-doped methane can accurately and consistently determine the flame length of under-expanded jet fires. It is applicable to the evaluation of under-expanded jet fires in gas pipelines and storage facilities with different doping ratios of hydrogen-doped methane. Furthermore, compared to conventional flame length calculation formulas based on Froude numbers, this invention has a definite formula, ensuring the accuracy of the calculation results. This invention can calculate mixtures of methane and hydrogen. Moreover, this invention is applicable not only to hydrogen but also to methane and mixtures of methane and hydrogen. Attached Figure Description

[0050] Figure 1 This is a schematic flowchart of a method for evaluating and treating underexpanded jet fires of methane, hydrogen, and hydrogen-doped methane, according to one embodiment.

[0051] Figure 2 This is a schematic diagram of the flame length of an underexpansion jet fire in a gas pipeline according to one embodiment.

[0052] Figure 3 This is a schematic diagram of the module structure of a methane, hydrogen and hydrogen-doped methane underexpansion jet fire flame assessment and treatment device according to an embodiment.

[0053] Figure 4 This is a schematic diagram of the structure of a computer device in one embodiment. Detailed Implementation

[0054] To facilitate understanding of this application and to make the aforementioned objectives, features, and advantages of this application more apparent, a detailed description of specific embodiments of this application is provided below in conjunction with the accompanying drawings. Numerous specific details are set forth in the following description to provide a thorough understanding of this application, and preferred embodiments are shown in the accompanying drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application. This application can be implemented in many other ways than those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0055] Firstly, this application provides a method for evaluating and treating underexpanded jet fires involving methane, hydrogen, and hydrogen-doped methane. Please refer to [link to relevant documentation]. Figure 1 It includes the following steps:

[0056] S110: Obtain the proportions of each gas component in the mixed gas, as well as the absolute pressure and temperature of the mixed gas;

[0057] In this application, the mixed gas refers to a gas pipeline, a storage tank in a transport vehicle, or another gas storage container. For example, the gas pipeline is a natural gas pipeline mixed with hydrogen. Of course, the pipelines applicable to the methane, hydrogen, and hydrogen-mixed methane underexpansion jet fire flame assessment and treatment method of this application are also suitable for pipelines containing hydrogen, methane, and mixtures of methane and hydrogen, or for transport vehicle storage tanks or other gas storage containers.

[0058] For the jet fire mentioned in this application, please refer to [link / reference needed]. Figure 2 This refers to a flame formed when gas is injected horizontally into the atmosphere. The jet fire in this application is a sub-expansion jet fire from a gas pipeline. Sub-expansion, as mentioned in this invention, refers to a condition where the static pressure of the jet itself is higher than the back pressure of the surrounding environment when the gas flows out of the outlet. The flame length mentioned in this invention refers to the distance from the gas injection outlet along the injection centerline to the flame tip, i.e., the horizontal length of the flame. Figure 2 As shown. Furthermore, the underexpansion jet fire of this application refers to the case where the ratio of atmospheric pressure to the absolute pressure of the mixed gas is lower than the critical pressure ratio, where the critical pressure ratio CPR satisfies the following formula:

[0059]

[0060] If P∞ / P0, the CPR is in an under-expanded jet, where P0 is the absolute pressure of the mixed gas (the absolute pressure inside the pipe or container), and P ∞ is the atmospheric pressure. k fuel is the adiabatic index of the mixed gas.

[0061] In this step S110, the proportion of each gas component in the mixed gas, the absolute pressure of the mixed gas, and the temperature of the mixed gas can be obtained according to the gas transmission pipeline or other gas storage containers, so as to be used for subsequent determination of the flame length. Among them, the proportion of each gas component refers to the composition and volume ratio of each gas component in the gas transmission pipeline or other gas storage containers. The absolute pressure of the mixed gas refers to the absolute pressure in the gas transmission pipeline or other gas storage containers. The temperature of the mixed gas refers to the temperature of the gas in the gas transmission pipeline or other gas storage containers.

[0062] In one embodiment, the mixed gas includes methane and hydrogen; for example, the proportion of each gas component includes the volume fraction of hydrogen. Thus, the volume fraction of methane can be obtained through the volume fraction of hydrogen. For example, the mixed gas is a hydrogen-doped natural gas gas, for example, the mixed gas is hydrogen-doped methane.

[0063] S120: Determine the molar mass, gas adiabatic index, and air-fuel ratio of the mixed gas according to the proportion of each gas component;

[0064] Based on the determined proportion of each gas component in this application, the molar mass, gas adiabatic index, and air-fuel ratio of the mixed gas are determined.

[0065] In one embodiment, in determining the molar mass of the mixed gas according to the proportion of each gas component, the following calculation formula is used to determine the molar mass of the mixed gas:

[0066]

[0067] Among them, are the molar masses of the mixed gas, methane, and hydrogen respectively, with the unit of kg / mol; is the volume fraction of hydrogen in the mixed gas; thus, it is convenient to determine the molar mass of the mixed gas.

[0068] In one embodiment, in determining the gas adiabatic index of the mixed gas according to the proportion of each gas component, the following calculation formula is used to determine the gas adiabatic index of the mixed gas:

[0069]

[0070] Among them, These are the adiabatic indices of the mixed gas, methane, and hydrogen, respectively; thus, the gas adiabatic index of the mixed gas in the gas pipeline or other gas storage container can be determined more accurately.

[0071] In one embodiment, the air-fuel ratio of the mixture is determined using the following formula based on the proportions of each gas component:

[0072]

[0073] Where S is the stoichiometric air-fuel ratio of the mixture; M air M is the molar mass of air. fuel Let x and y be the molar mass of the gas mixture, and C be the molar mass of the gas mixture. x H y Median value, C x H y It is obtained by ensuring that the doping ratio of methane and hydrogen is equal. In this way, the air-fuel ratio of the gas mixture can be determined more accurately.

[0074] Of course, it should be noted that C x H y The general formula for a mixed gas obtained by doping methane and hydrogen in equal proportions can be prepared based on the volume fractions of hydrogen and methane. For example, the volume fraction of hydrogen is... The volume fraction of methane is then... The molar ratio of hydrogen to methane is Then, based on the molecular formulas of hydrogen (H2) and methane (CH4), and their molar ratio, the equivalent general formula C2 of the mixed gas can be determined. x H y The values ​​of x and y in the equation.

[0075] In this embodiment, x and y can be determined based on the following formula:

[0076]

[0077] Where N is the number of subscripts x of element C or the number of subscripts y of element H. In the formula: n i Y represents the number of C atoms or H atoms in the i-th component; i Let be the volume fraction of the i-th component.

[0078] In this application, the air-fuel ratio is determined based on the reaction equation of the following general formula for a gas mixture:

[0079] C x H y +(x+y / 4)(O2+3.76N2)→xCO2+(y / 2)H2O+3.76(x+y / 4)N2

[0080] The formula for calculating the air-fuel ratio, derived from the above reaction process, is as follows:

[0081]

[0082] Therefore, the air-fuel ratio can be determined relatively accurately based on the above calculation formula.

[0083] S130: Determine the isobaric adiabatic combustion temperature of the gas mixture based on the proportions of each gas component and in conjunction with the first law of thermodynamics;

[0084] It should be noted that the adiabatic combustion temperature is a relatively universally accepted definition. For a single gas, it can be obtained by looking up a table or similar method, but for a mixed gas, it can be determined by software calculation.

[0085] In one embodiment, the isobaric adiabatic combustion temperature of the mixed gas is determined based on the proportions of each gas component and the first law of thermodynamics, using CHEMKIN software to perform heat balance calculations based on the proportions of each gas component in the mixed gas and the combustion process.

[0086] It should be further explained that the combustion flame temperature is an important parameter in the combustion process. Given a reaction mixture and initial temperature, if the composition of the combustion products is known, the product temperature can be calculated using the first law of thermodynamics. When the air-fuel ratio and fuel temperature are constant, the temperature achievable in an adiabatic combustion process is called the adiabatic combustion (flame) temperature (T). f For both constant-volume combustion and constant-pressure combustion, the adiabatic combustion temperatures are referred to as the constant-pressure adiabatic combustion temperature and the constant-volume adiabatic combustion temperature, respectively. In this application, since combustion takes place in the atmospheric environment, the adiabatic combustion temperature determined in this application is the constant-pressure adiabatic combustion temperature.

[0087] For isobaric combustion, the first law of thermodynamics can be expressed as:

[0088] The absolute enthalpy of the combustion products equals the absolute enthalpy of the reactants in their initial state, i.e., H2 prod (T2)=H reac (T1)

[0089] In the formula, T1 and T2 are the temperatures of the reactant (reac) and product (prod), respectively. H represents enthalpy.

[0090] in,

[0091] h i (T) is the sum of visible enthalpy and chemical enthalpy. When the reactant composition and temperature are constant, H can be calculated. reac and H prodThen, based on the composition of the combustion products, the temperature T2 of the combustion products can be calculated. Generally, the composition of the products refers to the composition at chemical equilibrium, which is related to the product temperature. Therefore, solving the energy equation is an iterative process. Specifically, based on the determined product enthalpy, the following formula can be used to determine...

[0092]

[0093] in, Standard enthalpy of formation; Specific heat capacity can be found in the physical property parameter table. f This is the adiabatic combustion temperature.

[0094] In this application, the reaction equation is based on the general formula for mixed gases:

[0095] C x H y +(x+y / 4)(O2+3.76N2)→xCO2+(y / 2)H2O+3.76(x+y / 4)N2

[0096] From the above, we can determine the molar number N of carbon dioxide, water, and nitrogen in the product. i Then consult the enthalpy of carbon dioxide, water, and nitrogen, through...

[0097]

[0098] This allows us to determine the product enthalpies of carbon dioxide, water, and nitrogen. In the above formula... The standard enthalpy of formation (298K) corresponds to carbon dioxide, water, and nitrogen. Then, based on the determined standard product production, the enthalpy is substituted into the following formula:

[0099]

[0100] The constant pressure adiabatic combustion temperature can then be determined.

[0101] S140: Determine the gas velocity at the leak point based on the molar mass and temperature of the mixed gas;

[0102] In this application, the gas velocity at the leak point is determined based on the molar mass and temperature of the mixed gas. The gas velocity at the leak point of a pipeline or other gas storage container is the velocity of the leaking gas.

[0103] In one embodiment, the gas velocity at the leak outlet is determined using the following formula in the process of determining the gas velocity at the leak outlet based on the molar mass and temperature of the mixed gas:

[0104]

[0105] Among them, v e Let R be the gas velocity at the leak point in m / s; R be the gas constant in 8.314 J / (mol·K); and T0 be the temperature of the mixed gas in K. In this way, the gas velocity at the leak point can be determined relatively well.

[0106] S150: Determine the gas density at the leak point based on the absolute pressure of the mixed gas, the gas adiabatic index of the mixed gas, and the proportion of each gas component.

[0107] In one embodiment, the gas density at the leak outlet is determined using the following formula in the process of determining the gas density based on the absolute pressure of the mixed gas, the gas adiabatic index of the mixed gas, and the proportion of each gas component:

[0108]

[0109] ρ e The gas density at the leak point is expressed in kg / m³. 3 P0 is the absolute pressure of the mixed gas, in Pa. This allows for a better determination of the gas density at the leak point.

[0110] S160: Determine the flame Froude number of the underexpansion jet flame based on the air-fuel ratio of the mixture, the constant pressure adiabatic combustion temperature, the gas density at the leak point, and the gas velocity at the leak point.

[0111] In one embodiment, the flame Froude number of the underexpanded jet flame is determined based on the air-fuel ratio of the mixed gas, the isobaric adiabatic combustion temperature, the gas density at the leak point, and the gas velocity at the leak point, using the following formula:

[0112]

[0113] Among them, Fr f For the flame Froude number; T f The isobaric adiabatic combustion temperature of a gas mixture, expressed in Kelvin (K); T ∞ The ambient atmospheric temperature is expressed in Kelvin (K); ρ ∞ Atmospheric density, in kg / m³ 3 ;d e The diameter of the leak is in meters (m). This allows for a better determination of the flame Froude number of the underexpansion jet flame.

[0114] S170: Determine the flame length of the underexpanded jet flame based on the flame Froude number of the underexpanded jet flame and the proportion of each gas component in the mixed gas.

[0115] In one embodiment, the flame length of the underexpanded jet flame is determined based on the flame Froude number of the underexpanded jet flame and the proportions of the gas components in the mixed gas, using the following formula:

[0116]

[0117] Among them, L f This refers to the flame length of the underexpansion jet flame, measured in meters (m).

[0118] The aforementioned method for evaluating and processing under-expanded jet fires of methane, hydrogen, and hydrogen-doped methane can accurately and consistently determine the flame length of under-expanded jet fires. It is applicable to the evaluation of under-expanded jet fires in gas pipelines and storage facilities with different doping ratios of hydrogen-doped methane. Furthermore, compared to conventional flame length calculation formulas based on Froude numbers, this invention has a definite formula, ensuring the accuracy of the calculation results. This invention can calculate mixtures of methane and hydrogen. Moreover, this invention is applicable not only to hydrogen but also to methane and mixtures of methane and hydrogen.

[0119] This invention defines a method for calculating the flame Froude number in high-pressure gas underexpansion jet applications. It proposes a new formula for calculating flame length and a method for calculating the flame length of underexpansion jet fires, enabling quantitative calculation of the flame length of underexpansion jet fires using methane, hydrogen, and mixtures of methane and hydrogen in arbitrary proportions.

[0120] In one embodiment, after determining the flame length of the underexpanded jet flame, the method further includes: determining a thermal radiation protection safety distance based on the flame length of the underexpanded jet flame.

[0121] In one embodiment, after determining the flame length of the underexpanded jet flame, the method further includes: performing a quantitative risk analysis of pipeline fires during operation based on the flame length of the underexpanded jet flame.

[0122] Secondly, this application provides a flame assessment and treatment apparatus for underexpansion jet fires involving methane, hydrogen, and hydrogen-doped methane. Please refer to [link to relevant documentation]. Figure 3 The device includes:

[0123] The acquisition module is used to acquire the proportion of each gas component in the gas mixture, as well as the absolute pressure and temperature of the gas mixture.

[0124] The physical property parameter determination module is used to determine the molar mass, gas adiabatic index, and air-fuel ratio of the mixed gas based on the proportion of each gas component; the physical property parameter determination module is also used to determine the isobaric adiabatic combustion temperature of the mixed gas based on the proportion of each gas component and in conjunction with the first law of thermodynamics.

[0125] The gas velocity determination module is used to determine the gas velocity at the leak point based on the molar mass and temperature of the mixed gas.

[0126] The gas density determination module is used to determine the gas density at the leak point based on the absolute pressure of the mixed gas, the gas adiabatic index of the mixed gas, and the proportion of each gas component.

[0127] The Froude number determination module is used to determine the flame Froude number of the underexpansion jet flame based on the air-fuel ratio of the mixture, the constant pressure adiabatic combustion temperature, the gas density at the leak point, and the gas velocity at the leak point.

[0128] The flame length determination module is used to determine the flame length of the underexpanded jet flame based on the flame Froude number of the underexpanded jet flame and the proportion of each gas component in the mixed gas.

[0129] In one embodiment, the device further includes a safety distance determination module for determining a thermal radiation protection safety distance based on the flame length of the underexpansion jet flame.

[0130] In one embodiment, the apparatus further includes a risk analysis module for performing quantitative risk analysis of pipeline fires during operation based on the flame length of the underexpanded jet flame.

[0131] In one embodiment, the physical property parameter determination module uses the following formula to determine the molar mass of the mixed gas:

[0132]

[0133] in, These are the molar masses of the mixed gas, methane, and hydrogen, respectively, in kg / mol. This represents the volume fraction of hydrogen in the gas mixture.

[0134] In one embodiment, the gas adiabatic index of the mixed gas is determined in the physical property parameter determination module using the following formula:

[0135]

[0136] in, These are the adiabatic indices for the mixed gas, methane, and hydrogen, respectively.

[0137] In one embodiment, the air-fuel ratio is determined in the physical property parameter determination module using the following formula:

[0138]

[0139] Where S is the stoichiometric air-fuel ratio of the mixture; M air M is the molar mass of air. fuel Let x and y be the molar mass of the gas mixture, and C be the molar mass of the gas mixture. x H y Median value, C x H y It is obtained by doping methane and hydrogen in equal proportions.

[0140] In one embodiment, the physical property parameter determination module determines the constant pressure adiabatic combustion temperature based on the thermal balance calculation of the proportion of each gas component in the mixed gas and the combustion process using CHEMKIN software.

[0141] In one embodiment, the gas velocity determination module uses the following formula to determine the gas velocity at the leak:

[0142]

[0143] Among them, v e R is the gas velocity at the leak point, in m / s; R is the gas constant, 8.314 J / (mol·K); T0 is the temperature of the mixed gas, in K.

[0144] In one embodiment, the gas density determination module uses the following formula to determine the gas density at the leak:

[0145]

[0146] ρ e The gas density at the leak point is expressed in kg / m³. 3 P0 is the absolute pressure of the mixed gas, in Pa.

[0147] The Froude number determination module uses the following formula to determine the flame Froude number of the underexpanded jet flame:

[0148]

[0149] Among them, Fr f For the flame Froude number; T f The isobaric adiabatic combustion temperature of a gas mixture, expressed in Kelvin (K); T ∞ The ambient atmospheric temperature is expressed in Kelvin (K); ρ ∞ Atmospheric density, in kg / m³ 3 ;d e The diameter of the leak is in meters (m).

[0150] The flame length determination module uses the following formula to determine the flame length of the underexpanded jet flame:

[0151]

[0152] Among them, L f This refers to the flame length of the underexpansion jet flame, measured in meters (m).

[0153] Thirdly, this application provides a computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the method as described in any of the above embodiments.

[0154] In one embodiment, a computer device is provided, which may be a terminal, i.e., a device to be upgraded, and its internal structure diagram may be as follows. Figure 4 As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The network interface is used to communicate with a server via a network connection. When executed by the processor, the computer program implements a method for evaluating and processing flames of methane, hydrogen, and hydrogen-doped methane underexpansion jet fires. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0155] Those skilled in the art will understand that Figure 4 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0156] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method as described in any of the above embodiments.

[0157] Those skilled in the art will understand that all or part of the processes in the methods of 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, and when executed, it 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 memory bus dynamic RAM (RDRAM), etc.

[0158] The technical features of the embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. It should be noted that the terms "in one embodiment," "for example," and "again," etc., in this application are intended to illustrate the application and not to limit it. The embodiments described above only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be pointed out that for those skilled in the art, several modifications and improvements can be made 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 evaluating and treating underexpanded jet fires involving methane, hydrogen, and hydrogen-doped methane, characterized in that, Includes the following steps: Obtain the proportions of each gas component in the gas mixture, as well as the absolute pressure and temperature of the gas mixture; The molar mass, adiabatic index, and air-fuel ratio of the gas mixture are determined based on the proportions of each gas component. The isobaric adiabatic combustion temperature of the gas mixture is determined based on the proportions of each gas component and in conjunction with the first law of thermodynamics. The gas velocity at the leak point is determined based on the molar mass and temperature of the mixed gas. The gas density at the leak point is determined based on the absolute pressure of the mixed gas, the gas adiabatic index of the mixed gas, and the proportion of each gas component. The flame Froude number of the underexpansion jet flame is determined based on the air-fuel ratio of the mixture, the constant pressure adiabatic combustion temperature, the gas density at the leak point, and the gas velocity at the leak point. The flame length of the underexpanded jet flame is determined based on the flame Froude number of the underexpanded jet flame and the proportions of each gas component in the mixed gas.

2. The method according to claim 1, characterized in that, The mixed gas includes methane and hydrogen; And / or, after determining the flame length of the underexpanded jet flame, the method further includes: determining a thermal radiation protection safety distance based on the flame length of the underexpanded jet flame; And / or, after determining the flame length of the underexpanded jet flame, the method further includes: performing a quantitative risk analysis of pipeline fires during operation based on the flame length of the underexpanded jet flame.

3. The method according to claim 2, characterized in that, In determining the molar mass of the mixed gas based on the proportions of its components, the following formula is used: in, These are the molar masses of the mixed gas, methane, and hydrogen, respectively, in kg / mol. This represents the volume fraction of hydrogen in the gas mixture. And / or, in determining the gas adiabatic index of the mixed gas based on the proportions of each gas component, the gas adiabatic index of the mixed gas is determined using the following formula: Where, k fuel , These are the adiabatic indices for the mixed gas, methane, and hydrogen, respectively. And / or, in determining the air-fuel ratio of the mixture based on the proportions of each gas component, the following calculation formula is used: Where S is the stoichiometric air-fuel ratio of the mixture; M air M is the molar mass of air. fuel Let x and y be the molar mass of the gas mixture, and C be the molar mass of the gas mixture. x H y Median value, C x H y It is obtained by doping methane and hydrogen in equal proportions.

4. The method according to claim 3, characterized in that, The isobaric adiabatic combustion temperature of the gas mixture, determined by the proportions of each gas component and in accordance with the first law of thermodynamics, is obtained by performing heat balance calculations based on the proportions of each gas component in the gas mixture and the combustion process using CHEMKIN software.

5. The method according to claim 3, characterized in that, In determining the gas velocity at the leak point based on the molar mass and temperature of the mixed gas, the following formula is used to determine the gas velocity at the leak point: Among them, v e R is the gas velocity at the leak point, in m / s; R is the gas constant, 8.314 J / (mol·K); T0 is the temperature of the mixed gas, in K. And / or, in determining the gas density at the leak outlet based on the absolute pressure of the mixed gas, the gas adiabatic index of the mixed gas, and the proportion of each gas component, the gas density at the leak outlet is determined using the following formula: ρ e The gas density at the leak point is expressed in kg / m³. 3 P0 is the absolute pressure of the mixed gas, in Pa.

6. The method according to claim 5, characterized in that, In determining the flame Froude number of the underexpanded jet flame based on the air-fuel ratio of the mixed gas, the isobaric adiabatic combustion temperature, the gas density at the leak point, and the gas velocity at the leak point, the flame Froude number of the underexpanded jet flame is determined using the following formula: Among them, Fr f For the flame Froude number; T f The isobaric adiabatic combustion temperature of a gas mixture, expressed in Kelvin (K); T ∞ The ambient atmospheric temperature is expressed in Kelvin (K); ρ ∞ Atmospheric density, in kg / m³ 3 ;d e The diameter of the leak is in meters (m).

7. The method according to claim 6, characterized in that, In determining the flame length of the underexpanded jet flame based on the flame Froude number and the proportions of each gas component in the mixed gas, the flame length of the underexpanded jet flame is determined using the following formula: Among them, L f This refers to the flame length of the underexpansion jet flame, measured in meters (m).

8. A device for evaluating and treating underexpanded jet fires involving methane, hydrogen, and hydrogen-doped methane, characterized in that, The device includes: The acquisition module is used to acquire the proportion of each gas component in the gas mixture, as well as the absolute pressure and temperature of the gas mixture. The physical property parameter determination module is used to determine the molar mass, gas adiabatic index, and air-fuel ratio of the mixed gas based on the proportion of each gas component; the physical property parameter determination module is also used to determine the isobaric adiabatic combustion temperature of the mixed gas based on the proportion of each gas component and in conjunction with the first law of thermodynamics. The gas velocity determination module is used to determine the gas velocity at the leak point based on the molar mass and temperature of the mixed gas. The gas density determination module is used to determine the gas density at the leak point based on the absolute pressure of the mixed gas, the gas adiabatic index of the mixed gas, and the proportion of each gas component. The Froude number determination module is used to determine the flame Froude number of the underexpansion jet flame based on the air-fuel ratio of the mixture, the constant pressure adiabatic combustion temperature, the gas density at the leak point, and the gas velocity at the leak point. The flame length determination module is used to determine the flame length of the underexpanded jet flame based on the flame Froude number of the underexpanded jet flame and the proportion of each gas component in the mixed gas.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the method according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1-7.

Images